30 day supply: 60 capsules
Provides nutrition support for those with diabetes mellitus or those highly at risk for this condition.
Supports visual and whole body health.
Based on the latest scientific research, DiaVis delivers nutrients that:
help combat oxidative stress
can be marginally deficient and that play a role in supporting normal metabolism
may be affected by the use of diabetes-related medications
support retinal vessel health
promote a healthy equilibrium of fluids in the eye
Made from premium ingredients and manufactured according to the highest quality standards.
It is highly recommended that DiaVis be taken in conjunction with ScienceBased Health’s OmegaAdvance®, a pharmaceutical grade fish oil supplement that provides a concentrated source of the omega-3 fats EPA and DHA, along with lutein and olive leaf extract.
Suggested Use: take a total of two capsules daily with meals.
Note: people with diabetes using prescription medications should consult their primary care doctor, as routine monitoring of certain medications is suggested. Pregnant or lactating women or individuals with medical conditions should consult a physician before using.
Quercetin (110 mg)
Quercetin, a dietary flavonoid, has been shown experimentally to inhibit
tyrosine kinase, an enzyme which mediates vascular endothelial growth
factor (VEGF). VEGF induces vascular permeability. Quercetin has also
demonstrated protection of retinal pigment epithelial and cortical cells
during oxidative stress in vitro. Several large-scale epidemiologic
studies report clear associations between dietary quercetin and lower
risk of mortality from CHD and stroke. Recent work suggests that quercetin
accumulates in atherosclerotic lesions where it down-regulates expression
of scavenger receptors for oxidized LDL in macrophages. In a clinical
trial, diabetics fed a diet high in quercetin exhibited significantly
less DNA damage in lymphocytes compared to a diet low in quercetin.
DiaVis provides quercetin at the level investigated in that clinical
Pine Bark Polyphenols
(125 mg) - Including 20 mg Pycnogenol®
Pine bark is a concentrated source of polyphenols, which are found in
grapes and other dietary sources. Polyphenols exhibit strong antioxidant
action and act as natural anti-inflammatories, possibly by inhibiting
pro-inflammatory gene expression. They selectively bind to collagen
and elastin, strengthening blood vessel walls and improving capillary
resistance capillaries. Finally, they aid in the production of the endothelial
vasodilator nitric oxide.
Pine bark extract (Pycnogenol®) has been tested
in about 1200 people with retinopathy and diabetic retinopathy in open
and controlled trials, with reported results generally supporting a
beneficial delay of progression. Preliminary studies report that supplemental
Pycnogenol® pine bark extract improves microcirculation and symptoms
in patients with diabetes, neuropathy, and edema. In a double-blind
study in type 2 diabetics on ACE inhibitors, researchers report that
3 months of supplementation lowered the use of this medication by 50%
Alpha Lipoic Acid (300
lipoic acid is a fat and water soluble antioxidant that plays a
crucial role in the energy-producing mitochondria of cells. It regenerates
other antioxidants including glutathione, a key antioxidant enzyme in
eye tissue. In animal models of diabetic retinopathy, alpha
lipoic acid has shown a protective effect against microvascular
lipoic acid is also concentrated in nerve cells, and numerous well-controlled
clinical trials report that this antioxidant reduces symptoms of diabetic
sensorimotor polyneuropathy. DiaVis delivers high potency alpha
to 500 IU), Vitamins A (500 IU), C (250 mg) and E (60 IU)
People with diabetes often have increased oxidative stress - a factor
in the development of many diabetic complications. Both types 1 and
2, as well as those with retinopathy, can have lower blood antioxidant
levels. DiaVis includes antioxidant beta-carotene
because it has been reported to be significantly lower in diabetic patients
than controls. Some pre-formed vitamin
A is also provided, as the bioavailability of dietary beta-carotene
has been found to be lower and more variable than previously believed,
particularly in women. Vitamin
C is highly concentrated in the eye's aqueous humor and in nerve
cells, and higher blood levels are reportedly linked with a lower risk
of developing diabetes in people followed long term. In one study, long
term use of C,
and / or a multinutrient supplement was associated with a reduced risk
of retinopathy. The level of vitamin
C contained in DiaVis is within the range estimated to saturate
The fat soluble antioxidant, vitamin
E, is provided to ensure adequacy of the full antioxidant team.
Evidence suggests that antioxidants with different activities and redox
potentials work in a synergistic network to help combat oxidative stress.
Overall, research indicates that levels of vitamin
E in line with amounts obtainable from foods are sufficient to provide
protective antioxidant effects; hence DiaVis offers a prudent level
of natural source alpha and gamma vitamin
Vitamin D (800 IU)
D status is more common in type 2 than type 1, and hypovitaminosis
D is highly prevalent in type 2 adults. Both vitamin
D & calcium insufficiency may negatively influence blood glucose
levels. One large prospective study found that levels of vitamin
D greater than 800 IU are significantly better than 400 IU in reducing
type 2 diabetes risk. Vitamin
D exerts anti-inflammatory action by decreasing production of pro-inflammatory
interleukins. In addition, preliminary evidence has shown that vitamin
D intake reduces C-reactive protein (CRP), a marker of systemic
inflammation. In type 2 diabetes, higher circulating levels of vitamin
D are also reported to be strongly and independently associated
with increased thickening of the carotid artery wall, a measure for
assessing atherosclerotic cardiovascular disease. Experts calculate
that 1,000 IU vitamin
D daily is required to bring half the population into the range
of serum D
associated with multiple health endpoints, while risk assessments conclude
that this is a safe supplemental level. DiaVis supplies 800 IU daily,
to accommodate any additional vitamin
D an individual may be ingesting from a calcium or other multi supplement.
B-Vitamins: Thiamine (B1,
18 mg), riboflavin (B2, 3.4 mg), niacinamide (B3, 20 mg ), pyridoxine
(B6 10 mg), folic acid (200 mcg), cobalmin (B12, 50 mcg), & biotin
Recent research reports that type 1 & 2 diabetics excrete more B1,
& have low plasma levels of this vitamin. B1
plays a role in glucose metabolism, and inadequate levels increase risk
of kidney, nerve and eye complications in animal models of diabetes.
have been linked to decreased cataract risk. Low plasma B6
has been observed in those with types 1 and 2 diabetes, and B6
status declines with age. Older people in general are at high risk of
low blood levels of B12,
a vitamin critical to proper nerve function. Folic
acid , B6
also help maintain healthy homocysteine levels. Elevated homocysteine
levels have been associated with the prevalence and the severity of
kidney failure in diabetes patients. Vitreous homocysteine levels have
also been shown to be elevated in patients with proliferative diabetic
retinopathy compared to nondiabetic patients with nonproliferative ocular
diseases. DiaVis furnishes a full array of B
vitamins to ensure adequacy and maintain a balance between them.
Minerals: Magnesium (200
mg), Chromium (200 mcg), Zinc (7.5 mg)
It is well established that diabetics with poor glucose control are
often low in magnesium, a mineral involved in maintaining normal endothelial
function and insulin sensitivity. In an analysis of the NHANES survey,
magnesium supplementation was associated with lower levels of the inflammatory
biomarker CRP. Population health studies consistently link adequate
intakes of this mineral with a reduced chance of developing hypertension,
diabetes and the metabolic syndrome. A meta-analysis reports that for
every 100 mg increase in magnesium intake, the observed risk of developing
type 2 declined by 15%. DiaVis delivers concentrated and bioavailable
forms of magnesium at a well tolerated level.
plays a vital role in the production, storage and secretion of insulin.
It is also a co-factor for the antioxidant enzyme superoxide dismutase
present in eye tissues. Increased insulin secretion is associated with
a greater urinary zinc
loss in type 1 & 2 diabetics, thus DiaVis includes a modest level
to offset any increased urinary excretion of this mineral.
The role of chromium in the body is to facilitate
the action of insulin. Some trials examining whether chromium can decrease
fasting blood glucose, insulin levels, and HbA1c in diabetics report
benefit; others do not. Evidence indicates that this trace mineral is
of benefit primarily to those low in chromium and with impaired glucose.
DiaVis provides a maintenance dose of chromium in the most-studied form,
FloraGLO Lutein (2 mg) Zeaxanthin (120 mcg)
compose the macular pigment of the retina, where they filter blue (visible)
light that can induce photo-oxidative stress. A number of population
health studies link higher intakes of these carotenoids with a reduced
risk of cataract and macular degeneration. Findings from one study suggest
that higher levels of plasma lutein
may be protective against early atherosclerosis. In an animal model
of diabetes, lutein
decreased oxidative stress in acute retinal ischemia. The amount of
contained in DiaVis doubles the average US dietary intake of this carotenoid.
Pycnogenol® is a registered trademark of Horphag
Research Ltd. Use of this product is protected by one ore more of U.S.
patents #5,720,956 / #6,372,266 and other international patents. FloraGLO®
is a registered trademark of Kemin Foods, LC. U.S. Patent No. 4,822,816.
Other patents pending.
Trio of Nutrients May Help Combat Type 2 Diabetes
Take Positive Steps to Counter Type 2
When it comes to preventing type 2 diabetes – or controlling blood sugar in those who already have it – the factors with the biggest punch by far are pretty straight forward: lose weight if you need to, exercise regularly, and eat a healthy Mediterranean or low glycemic index diet.
In addition, researchers continue to explore the contribution of individual nutrients in combating type 2. This issue of Staying Healthy highlights recent findings related to omega-3 fats, magnesium and cinnamon.
New Understanding of Omega-3 Benefits
The American Diabetes Association (ADA) already recommends that people with diabetes eat 2-3 servings of fish weekly. That’s because studies have shown that consuming more omega-3s can help stave off coronary heart disease in diabetics, who have a greater risk of developing cardiovascular conditions than non-diabetics.
New research also points to a potential role for the omega-3 fatty acids EPA and DHA in helping to activate anti-diabetic genes (1). The study, carried out in animals, found that these omega-3 fatty acids activate genes that help regulate fat cells and maintain blood sugar balance. The factor activated by the omega-3s (transcription factor PPARy) is one that’s targeted by a number of anti-diabetic drugs. If the findings hold true in humans, it may mean additional benefits for those meeting ADA guidelines for omega-3 intake.
Study Underscores Importance of Magnesium
Low blood levels of magnesium occur in about 25-30% of people with type 2, and are more common in those with poorly controlled diabetes. Many studies have also reported that a better intake of this mineral can lower the risk of developing type 2. Results from a long term study appear to confirm that association (2).
Led by investigators at the University of North Carolina at Chapel Hill, the study recruited nearly 4,500 young adults 18-30 years of age who were free of diabetes and assessed their intake of dietary magnesium.
Three hundred and thirty cases of diabetes developed over the next 20 years of follow-up.
People with the highest magnesium intake were 47% less likely to acquire type 2 compared to those eating the least. Those getting the most averaged about 200 mg of magnesium for every 1,000 calories consumed compared with the lowest intake group who got about 100 mg of the mineral per 1,000 calories.
High magnesium consumers also had lower blood levels of inflammatory markers, and less insulin resistance (the inability of some cells to respond to insulin). One of magnesium’s jobs is to help insulin move glucose out of the blood stream and into cells.
As mentioned in the March Staying Healthy, a recently published survey found that less than ½ of US adults consume recommended magnesium levels. Dietary sources include beans, whole grains, broccoli, squash, and green leafy veggies, seeds, and nuts (especially almonds). Dairy, meats, chocolate, and coffee also provide magnesium, as does "hard" water.
Cinnamon Useful for Some Diabetics
From the UK comes a study suggesting that cinnamon may be useful in patients with poorly controlled type 2 diabetes (3). Fifty eight type-2 patients with high HbA1c (a key measure of glucose control) were given 2 grams of cinnamon or placebo daily for 3 months. Compared to placebo-takers, those supplemented with cinnamon experienced a significant reduction in HbA1c as well as a decrease in blood pressure (both systolic and diastolic values).
According to the researchers, this spice could be a useful addition to conventional drugs for diabetics who have trouble controlling their blood sugar levels.
Emerging Vitamin D Research: Immunity, Muscle Function
Emerging Areas of Vitamin D Research
As many as a billion people worldwide, including more than 30% of Americans, have low levels of vitamin D (1). Those figures are fairly stunning since insufficient blood levels of vitamin D may well contribute to a spectrum of health conditions such as osteoporosis, certain cancers, cardiovascular disease and diabetes. [See Staying Healthy newsletters March, 2010 and November, 2007].
The Institute of Medicine (IOM) has been conducting a review of the available vitamin D science, and is due to deliver its findings later this year. Many experts expect the IOM to recommend daily intakes much above the current levels of 400 IU.
In the meantime, researchers are delving deeper into the potential benefits of getting enough vitamin D, as well as how this vitamin works throughout the body. Two areas receiving attention are the role of vitamin D in the immune system and its possible contribution to maintaining strong, healthy muscles.
Promise Against Seasonal Flu
That vitamin D is involved in regulating the immune system is not a new idea. But researchers from the University of Copenhagen believe they have figured out how: it’s crucial for activating key immune defense cells. The Danish scientists report that vitamin D is necessary to trigger the action of T-cells (2) – the immune system’s killer cells. Too little vitamin D means these cells remain inactive and unable to mobilize against foreign invaders.
Researchers recently tested the effects of vitamin D in a placebo-controlled trial among 300+ school children in Japan (3). They found that supplemental doses of vitamin D reduced the incidence of seasonal flu (influenza A) by over 40% compared to the placebo group over the course of 4 months. The benefits were even more noticeable in children who had low levels of vitamin D at the start of the study.
Canada’s Public Health Agency also confirmed last year that it is partnering with universities and hospitals to find out whether there’s a correlation between severe seasonal flu and low vitamin D levels and/or a person’s genetic make-up. The bottom line is to continue getting seasonal flu shots and practice preventive hygiene. But it’s also a good idea to get adequate vitamin D for a healthy immune response.
Strong Muscles and Vitamin D Linked
A study by researchers from McGill University and University of Southern California is one of the first to show a clear link between vitamin D levels and the accumulation of fat in muscle tissue (4) – a factor in muscle strength and overall health. They found that the lower the levels of vitamin D the more unwanted fat was present in subjects' muscles.
A remarkable 59% of the study subjects had too little vitamin D in their blood, and nearly 25% of the group had serious deficiencies (less than 20 ng/ml). These results are surprising, because the subjects – all healthy young women living in California – could be expected to benefit from ample exposure to sunshine, the trigger that causes the body to produce vitamin D.
The authors of the study are not yet sure what’s causing vitamin D insufficiency in these women. Better levels of vitamin D might be helping to keep fat from infiltrating muscles. Or also it’s possible that in overweight people more vitamin D is retained in fat tissues leaving a shortage in blood.
Studies in the elderly, though, have led scientists to believe that vitamin D is essential for muscle strength. Older, bedridden patients, for example, have been shown to gain strength when given vitamin D. And a recent study reports that fatty degeneration of thigh muscles in elderly adults is associated with low levels of the vitamin in blood and poor balance and gait (5).
In the News:
Magnesium, Flavonoids and Vitamin D
Magnesium May Improve Lung Function
Observational studies have reported beneficial effects of magnesium on the occurrence and management of asthma. To test whether this mineral could bolster lung function in asthmatics, researchers at Bastyr University in Washington recruited 55 people with mild to moderate asthma who received either 340 mg of magnesium or a placebo pill daily for 6 ½ months (1).
The supplemented group showed a greater improvement in lung function compared to those receiving placebo pills. In order to determine the ability of the airways to stay open, both groups were given a drug that causes the airways to constrict and narrow, as they do during an asthma attack. The magnesium group needed 20% more of the drug to constrict the airways to the same degree as seen in the placebo group. Finally, quality of life, assessed by questionnaire, improved only in the magnesium takers.
Americans Face Dietary Magnesium Gap
Magnesium has anti-inflammatory actions that could improve asthma control, and it may enhance the capacity of the lungs to expand by favorably affecting cell membranes. While not all trials have reported a beneficial response to magnesium, these findings support its use for those with mild to moderate asthma. That’s important because less than half of US adults consume recommended levels of this mineral, according to the last National Health and Nutrition Examination Survey.
Flavonoids May Lower Stroke Risk in Women
Increased intakes of flavonol-rich foods may reduce a woman’s risk of stroke by 20%, according to a new review of studies involving over 110,000 people (2). Flavonols (also known as flavonoids) make up a sub-group of the bioflavonoid family, and are found in a variety of fruits and vegetables such as onions, apples and broccoli – as well as tea.
Dutch researchers conducted a meta-analysis (a review of studies) using data from people who were free of cardiovascular disease or stroke when the studies started. People in these studies were followed from 6 to 28 years, during which time the incidence of stroke was documented. Strokes occur when blood clots or an artery bursts in the brain and interrupts the blood supply to part of the brain. It is the leading cause of disability and the 3rd leading cause of death in the US.
While the researchers caution that more clinical research is needed, they conclude that accumulating evidence supports a role for flavonol-rich foods in maintaining vascular health.
Vitamin D Helps Fend Off Heart Disease and Diabetes in Older People
British researchers conducted the first ever review of studies looking at the relationship between blood levels of vitamin D and cardiovascular disease (CVD), type-2 diabetes and metabolic syndrome. Twenty eight studies were included providing data on nearly 100,000 people (3).
The analysis found that the highest blood levels of vitamin D were associated with a 33% risk reduction in CVD, a 55% reduction in type-2 diabetes, and a 51% drop in the risk of metabolic syndrome, compared with the lowest blood levels.
These findings add to a rapidly expanding body of science supporting the benefits of adequate vitamin D levels. A review that may lead to the establishment of higher recommended intakes is being conducted by the Institute of Medicine.
Complementary Nutritional Support
Part I of the Diabetes and Nutrition series
(see December 2008 issue) discussed the importance of diet and
calories in helping to prevent type 2 diabetes, as well as the
benefits of eating a low glycemic diet for better blood sugar
control. Part II covered essential vitamins and minerals that
can be compromised in diabetics - or those at risk for the disease
- due to poor intake, faster excretion, or greater need (see January
2009 issue). The series concludes with a look at three complementary
alpha lipoic acid, quercetin and polyphenols. Evidence
suggests this trio can play an important role in a diabetic's
nutritional support team.
Protective Properties of Alpha Lipoic Acid
As mentioned in Part II, people with diabetes
have higher levels of oxidative stress which can contribute to
long-term complications. Antioxidants help counter oxidative stress,
alpha lipoic acid is a unique antioxidant. Made in the body
and found in foods such as spinach, broccoli and potatoes, alpha
lipoic acid can scavenge free radicals, and also appears to bolster
levels of the antioxidant enzyme glutathione (1).
Because alpha lipoic appears to be particularly
helpful in protecting nerve cells, it is being studied in neurodegenerative
disorders such as Alzheimer's and Parkinson's disease. A number
of trials (2) have also reported
that high dose alpha lipoic eases symptoms such as pain and numbness
in patients with diabetic neuropathy, a complication of diabetes.
Research in models of diabetic retinopathy
suggests that this antioxidant could have a role in protecting
the eye's retina as well. In one study (3),
giving alpha lipoic early to diabetic mice reduced markers of
oxidative stress, shored up glutathione levels and helped normalize
electrical signals in the retina.
Quercetin is a flavonoid (part of the polyphenol
family of compounds) and is present in a variety of fruits and
vegetables such as onions, apples, citrus fruit, grapes and broccoli.
Consuming plenty of flavonoids, especially quercetin, has been
associated with lower incidence of heart disease and stroke. Quercetin's
apparent ability to counter oxidative stress makes it an attractive
candidate for the diabetic's nutrition arsenal.
In one clinical trial (4),
diabetics had less oxidative damage to DNA within white blood
cells when eating a high vs. a low quercetin diet. If results
from laboratory studies are shown to hold true in people, quercetin
may have a role in visual health as well. Quercetin has been shown
to protect lab-grown human retinal pigment epithelial and cortical
cells during oxidative stress (5).
Procyanidins Support Healthy Vessels, Vision
Procyanidins, plentiful in grapes and cocoa,
have both antioxidant and anti-inflammatory actions. Importantly
for diabetics, procyanidins extracted from pine (Pycnogenol®)
may also help keep blood vessel walls strong and enhance compounds
that help arteries dilate. This source of procyanidins has been
tested in more than 1200 people with retinopathy and diabetic
retinopathy in various trials, with reported results generally
supporting benefit (6).
In a recent double-blind study (7)
of diabetics with hypertension taking ACE inhibitor medication,
58% were able to achieve better blood pressure control at lower
doses of medication after 3 months of Pycnogenol supplementation.
Significant effects on other cardiovascular disease risk factors
were also seen in the pine procyanidin group vs. placebo.
Some Nutrients Can Be a Problem in Diabetes
Twenty-four million Americans - nearly 25%
of those 60 and older - currently suffer from diabetes according
to the Centers for Disease Control. Fifty seven million more have
pre-diabetes which often leads to the full-blown disease. Meeting
vitamin and mineral needs is important for everyone, but for those
with diabetes - or those at risk for this condition - getting
enough of certain nutrients can be a problem. Some nutrients may
be compromised in diabetics due to poor intake, faster excretion,
or greater need.
Vitamin D and B-Vitamin Shortfalls
Vitamin D is important for healthy bones
and for its anti-inflammatory activity, and low levels are common
in adults with type 2 diabetes. Up to 75% of young people with
type 1 may also be deficient in vitamin D according to new evidence
(1). A recent review of studies suggests
that for lowering the risk of type 2 in women, 800 IU of this
vitamin is more effective than 400 IU (2).
People with type 1 & 2 diabetes excrete more
thiamin (vitamin B1,) and have low blood levels compared to those
free of the disease. Researchers report that blood concentrations
of thiamine were decreased by about 75% in type 1 & 2 diabetics
vs. healthy controls (3). Thiamin
plays a role in the body's metabolism of glucose, and low levels
have been found to increase the risk of kidney, nerve and eye
complications in animals.
Low B6 has been observed in those with type
1 and 2, and B6 levels generally decline with age. Older people
are also at risk for sub-optimal levels of B12, a vitamin critical
to proper nerve function. Diabetics have a greater risk for cataract,
and riboflavin (B2) and thiamine have been linked to decreased
risk. In an AREDS analysis, long-term multi use lowered cataract
risk by 16-25%. Many of the participants in this trial were diabetic.
Antioxidants Help Combat Oxidative Stress
Diabetics have higher levels of oxidative
stress - an imbalance between the production of damaging oxygen
compounds and the body's ability to neutralize them. Oxidative
stress contributes to long-term complications in diabetes such
as vision (retinopathy), kidney (nephropathy), nerve (neuropathy)
and heart disease.
Antioxidants such as vitamins
counter oxidative stress. Vitamin
C appears to be particularly
important. Higher blood levels of this vitamin, for example, were
linked to a 62% lower risk of developing diabetes in 21,000 people
followed for 12 years (4). Additionally,
in a large-scale government survey, long-term use of supplemental
and/or a multinutrient, lowered the risk of developing retinopathy
Meaningful Minerals Can Be Missing
Magnesium, which is involved in maintaining
artery health and sensitivity to insulin, is often low in diabetics
with poor blood sugar control. If you are at risk for diabetes,
note that research strongly suggests that better dietary magnesium
intake lowers the risk of developing hypertension, metabolic syndrome
and diabetes itself (6).
and chromium are minerals important for proper insulin function,
and both have antioxidant activity. Urinary loss of zinc
can be higher in type 1 and 2 diabetics (7).
Evidence, too, suggests that chromium supports healthier blood
glucose levels in people who are low in this trace mineral and
have impaired glucose tolerance (8).
Weight is Key to Fending off Type 2 Diabetes
A trio of studies published late last year
in the journal Archives of Internal Medicine shed new light on
the importance of diet in risk of developing type 2 diabetes -
especially the role of calories. The bottom line from all three
studies is that calories trump all else, and that our main goal
in preventing type 2 should be to eat less high-calorie, low-benefit
Fruit Drinks are Culprits; Fruits & Veggies
In the first study (1),
which followed nearly 44,000 Afro-American women for 10 years,
the risk of developing type 2 was 24% higher for those who consumed
two or more soft drinks daily compared with women who drank them
rarely. Sipping fruit drinks was even riskier, with a 31% increased
risk for those drinking them twice daily.
Diet soft drinks as well as grapefruit and
orange juice did not up the risk for diabetes. Unlike other fruit
drinks, these juices contain mostly naturally occurring sugars
which may have different metabolic effects than the high-fructose
corn syrup used to sweeten other juice drinks.
In the second study(2),
blood levels of vitamin C (an indicator of fruit and vegetable
intake) and fruit and veggie consumption were measured in about
22,000 people without diabetes. After a dozen years, those with
the highest vitamin C levels were 62% less likely to develop the
disease. A similar but smaller risk reduction of 22% was observed
for those eating even modest amounts of fruits and veggies.
In the last study(3),
60% of the nearly 49,000 women participants continued with their
regular diet while 40% were assigned to a low fat diet with added
fruits, veggies and grains. Although the diet was not designed
for weight loss, those in the low-fat diet group lost about 5
pounds more over an 8 year period compared to the "usual diet"
group. The researchers concluded that losing weight - rather than
eating less fat - was more important in preventing type 2.
For Diabetics, Recommended Diet May Need Changing
or so suggests a new study(4)
that is one of the longest and largest to assess the impact of
foods with a low glycemic index (GI). Low GI foods don't raise
blood sugar as much as foods with a higher GI.
People with type 2 were assigned to one of
two diets. The first emphasized "brown foods" such as whole grain
bread and breakfast cereal, brown rice and potatoes with the skin
on. This high fiber, high cereal diet is what is usually recommended
for those with diabetes.
The other diet focused on low GI foods which
included beans, peas, lentils, pasta, quickly boiled rice and
certain breads like pumpernickel and rye, as well as oatmeal and
oat bran cereals.
Both diets were low in saturated and trans
fats. Both groups were told to limit their consumption of white
flour and to eat five servings of vegetables and three servings
of fruit daily.
At the end of six months, people on the low
GI diet kept their blood sugar under better control and had slight
reductions in HA1C levels - a measure of blood sugar levels over
time. They also experienced significant increases in "good" HDL
cholesterol, which is good for heart health. That's important
because diabetic men have twice the risk for heart disease and
women four times the risk. Also, drugs used to control type 2
have not shown the expected benefits in terms of reducing heart
The bottom line is that high fiber foods
are fine, but include beans and nuts and try to eat more low GI
Physical Activity isn't Optional - it's a Must!
Physical activity simply means movement of the body that
uses energy. Walking, gardening, briskly pushing a baby stroller, climbing the
stairs, playing soccer or dancing are all good examples of being active.
Being physically active is a KEY element in living a
longer, healthier, happier life. It can help relieve stress, provide an overall
feeling of well-being, and reduce our risk of many chronic diseases such as
heart disease and diabetes. It can also play a major role in weight control, and
may even support better memory in older people.
Get Moving to Prevent & Treat Diabetes
Type 2 diabetes is one of the fastest growing public
health problems worldwide. The relationship between staying physically active
and the risk of developing diabetes has been assessed by a number of clinical
trials. The results from these studies consistently tell us that regular
physical activity reduces the risk of type 2 Diabetes by 15-60%
If you already have diabetes, exercise and better health
go hand in hand. Regular physical activity can help improve blood sugar control,
as well as boost overall fitness and reduce the risk of heart disease and nerve
damage. Exercise counteracts those risks by improving blood flow, increasing the
heart's pumping power and decreasing cholesterol levels.
Physical Activity Fends Off 'Fat Gene' Effects
Becoming overweight often involves many factors from poor
diet to "stress eating", couch potato behavior and genetics. While experts say
there are probably many genetic differences that can influence obesity, one gene
variation that has been linked to excess weight can be overcome by 3-4 hours of
moderate physical activity daily according to a study conducted among the Amish
Scientists believe that about 30% of Caucasians with
European ancestry have a variation in the FTO gene linked to obesity, including
the Amish. That genetic variation can make people more susceptible to gaining
weight, possibly by regulating food intake.
In the study, which involved over 700 Amish, re-searchers determined which
people had the variation of the FTO gene linked to obesity
(2). Among people with the variant, those who got about 3-4 hours of
moderate physical activity a day weighed about 15 lbs. less on average than the
least active people who had the variant. That included such activities as brisk
walking, housecleaning and gardening.
People with the genetic variant were no more likely to be
overweight than those who had a regular version of the gene, so long as they
kept active. "It's only when you're not active that the gene hurts", according
to the researchers. Physical activity - and lots of it - is a way to overcome
the effects of this genetic inheritance.
People with the genetic variant were no more likely to be
overweight than those who had a regular version of the gene, so long as they
kept active. "It's only when you're not active that the gene hurts", according
to the researchers. Physical activity - and lots of it - is a way to overcome
the effects of this genetic inheritance.
Physically Active People Retain Brain Power
A newly reported trial is the first to demonstrate that
exercise can improve the ability to think, reason and remember in older people
with mild cognitive impairment who were at risk for Alzheimer's
In the study, subjects participated in a 6-month
home-based program of physical activity. Some participants received instruction
about physical activity, while others did not. For those that engaged in more
physical activity, the cognitive benefits were not only apparent at the end of 6
months, but also lasted for an additional 12 months. The best part of all, is
the program entailed an increase in physical activity of just 20 minutes per
Science is Strong for the Med Style of Eating
A flood of studies over the past year have increased
support for the Mediterranean (Med) style of eating. Some of the most recent
In Head-to-Head Test, Med Diet Promotes Weight Loss
and is Best for Diabetics
Results from a 2-year trial comparing weight loss
with a low-carb, Med-style or low-fat diet, made the news last month. In
this tightly controlled experiment, 322 overweight people were assigned to 1
of 3 types of diet: a low-fat diet based on American Heart Association
guidelines, a low-carb diet based on the Atkins plan, and a Med style diet.
The biggest weight loss happened in the first 5
months, with people in all 3 groups regaining some of the lost weight as
time went on. At the end of 2 years, the low-fat dieters lost about 6 pounds
while the Med and low-carb groups both lost about 10 pounds.
While the weight loss was modest, it resulted in
improved health markers, and there were subtle differences in the 3 diets
studied. Men seemed to do better on the low-carb diet, losing 11 pounds
versus about 9 on the Med diet. Women fared best on the Med diet, losing
about 14 pounds compared with about 5 pounds on the low-carb eating plan.
For all dieters, the ratio of good to bad cholesterol improved. But among
the 36 diabetic participants, the Med diet had the most favorable effect on
glycemic control. Diabetics had better blood glucose and insulin levels.
What is the Med Style Diet?
The med diet is rich in cereals, wine, fruits,
vegetables, nuts, beans, whole grains, fish and olive oil - foods which
provide carotenoids, vitamins
E, polyphenols, essential minerals, and the
Common foods include pasta, bread (whole grain is
best), rice and couscous, olives, avocados, grapes, eggplant, tomatoes,
peppers, nuts and beans, cheese and yogurt. Moderate consumption of fish and
poultry is encouraged, while red meat is advised only a few times per month.
If you're not yet following the Med style of eating,
the Mediterranean Pyramid, endorsed by the Harvard School of Public Health
and the World Health Organization, can serve as a model to help you get
Insulin Resistance Basics
Insulin is a hormone released from the pancreas that
helps the body use glucose or sugar in the blood. Insulin binds to receptors on
cells like a key would fit into a lock. Once unlocked, glucose can enter cells
to be used as energy or stored for future use. Insulin resistance occurs when
the normal amount of insulin secreted is unable to unlock the doors of muscle,
fat and liver cells. In order to maintain healthy levels of blood glucose, the
pancreas must compensate by making and releasing additional insulin.
Insulin Resistance Leads to Bigger Problems
Eventually the pancreas isn't able to keep up with the
demand for more insulin and excess glucose builds up in the bloodstream setting
the stage for pre-diabetes. Studies have shown that most people with
pre-diabetes go on to develop type 2 diabetes within 10 years if they don't make
Insulin resistance and pre-diabetes also raises the risk
of heart disease. Many people with insulin resistance have excess weight around
the waist (40" for men, 35" for women), low levels of the good HDL cholesterol
(below 40 mg/dL for men, 50 mg/dL for women), high triglycerides (150 mg/dL or
more), high blood pressure (130/85 mm), and small dense LDL particles (the "bad"
cholesterol). This cluster of problems is referred to as the metabolic syndrome
or insulin resistance syndrome.
The Insulin and Memory Connection
At the recent 3rd Annual World Congress on Insulin
Resistance Syndrome in San Francisco, Dr. Suzanne Craft presented cutting edge
research findings on how insulin affects the brain. According to Dr. Craft, how
an older person's body processes insulin can also affect their memory.
Normally, the insulin secreted after eating can enhance
memory. Researchers theorize that this action of insulin evolved to help
primitive people remember where to find food. But while optimal insulin levels
may help us remember the location of our favorite restaurant in today's world,
too much of a good thing may contribute to brain aging and memory impairment
later in life.
The chronically high insulin that occurs when the body is
resistant to insulin can decrease glucose metabolism in certain brain circuits
and provoke inflammation along with free radical damage. Finally, insulin that
is too high may also raise the risk of Alzheimer's by promoting the release of
beta-amyloid and slowing its breakdown. Beta-amyloid is the major protein found
in the plaque and nerve tangles of Alzheimer's patients.
In a series of studies, Dr. Craft and her colleagues
found that an anti-diabetic drug which makes the body more sensitive to insulin
can improve mental function and memory recall in older patients with insulin
resistance, including those diagnosed with early Alzheimer's. Treatments that
can reduce high levels of circulating insulin and improve insulin sensitivity
are promising therapeutic avenues for some older people with impaired memory,
Dr. Craft concluded.
Can You Reverse Insulin Resistance?
Yes! According to Dr. Gerald Reaven who chaired the World
Congress meeting, about 50% of insulin resistance and the metabolic syndrome can
be attributed to underlying genetic susceptibility, while inactivity and being
overweight contribute about 25% each. Physical activity and weight loss make the
body more responsive to insulin. Exercise makes muscle cells more sensitive to
insulin because they need it for energy. And reducing extra fat tissue around
the middle is especially helpful because the fat distributed there is more
Be Active and Eat Well
Results from the 2001 Diabetes Prevention Program, an
NIH-sponsored clinical trial, confirmed that losing weight - even just 5-7% of
your body weight - and walking briskly or riding a bike 5 times weekly, can
reduce the risk of diabetes by 58% in those with pre-diabetes. An estimated 39%
of Americans have some degree of insulin resistance, and it usually has no overt
symptoms. So as we set our health goals for 2006, remember that fighting fatness
and improving fitness isn't optional. It is absolutely essential.
Type-2 diabetes has
tripled in the last 30 years. We've also experienced a dramatic upsurge in
obesity. Experts now use the term "diabesity" to make more people aware of the
connection between these trends: Excess weight makes you more prone to type 2,
and 80% of those who get the disease are overweight when they're diagnosed.
Right now, more than 20 million Americans have blood sugar levels that are
higher than normal but not yet in the diabetic range. Called "pre-diabetes" this
condition can turn into the full-blown disease, especially in those who are
overweight and under-active.
Your Best Defense is
According to one
encouraging study, making realistic changes to your diet and activity level can
greatly reduce your chances of getting type 2 diabetes (1).
The study looked at over 3200 people who were more likely to develop type 2
because their fasting blood sugar levels were too high. After being encouraged
to eat a low fat diet and increase their physical activity, everyone was
assigned to get specific diet and exercise advice, or the drug metformin
(Glucophage) to lower blood sugar. Another group took a placebo.
The incidence of diabetes
went down by 58% in people making lifestyle changes compared to those taking
placebo. For those who got the drug, diabetes decreased by 31%. What's
remarkable about these findings is not just that the lifestyle changes were
better than the drug for preventing diabetes, but that the goals were modest
enough to be reached by most people. The targets were to maintain a weight loss
of at least 7% of initial body weight - that's only 10 lb for a 150 lb woman
for example - and to do moderate physical activity for at least 2 hours
In a follow-up, the
researchers looked at how the lifestyle and drug interventions affected study
volunteers who had metabolic syndrome (MS) in addition to high blood sugar
(2). The syndrome is defined as having 3 or more these characteristics:
thick waist, high triglycerides, low HDL, high blood pressure or high fasting
blood sugar. People with MS have a 5-fold greater risk for diabetes and are 3
times more likely to die of heart attack or stroke. Once again, the lifestyle
changes were more effective than the drug in preventing people who didn't have
MS from developing it. For those who already had MS, the lifestyle changes were
better than the drug in helping the syndrome resolve.
Take Charge of Your
Eating more fiber can help
substantially. Fiber from beans, peas, oats, fruits and vegetables slow down
digestion to help you feel fuller longer. They also slow the entry of glucose
into the bloodstream, helping to dampen insulin output. Eating more of this
fiber helps keep blood levels of LDL cholesterol in check as well. You'll also
want heart-healthy fiber from whole grains, such as wheat cereals, bran and
brown rice. Focus on getting at least 2-3 servings of fish weekly. High intake
of omega-3s from fish correlates with a lower incidence of type 2, and
supplemental amounts in the range of 2-4 grams daily have been shown to bring
down elevated triglycerides (3). Even more
importantly, omega-3s reduce the risk of death from coronary heart disease in
diabetic women (4). Finally, it's wise to take a
complete multi to ensure that you get enough of the many vitamins and minerals
involved in insulin and glucose metabolism such as chromium,
zinc, magnesium and various antioxidants.
Even if you already have
type 2, trimming down and getting active can improve long-term blood sugar
control. And that helps reduce the extra risks that come along with diabetes
such as heart and kidney disease, nerve and vision problems, and even a greater
chance of developing dry eye (5). So let's all
resolve to have our blood glucose checked, tune up our diets and get moving. The
rewards are well worth the effort!
Meta-Analysis: Antioxidants Lower HbA1c In Type 2 Diabetes
Role of Oxidative Stress in Type 2 Diabetes
For almost 25 years, oxidative stress has been considered to play a central part in the type 2 disease process, with over 6,000 related articles published over that time.
Some articles reflect growing evidence that cellular oxidative stress triggers cascades (p38 MAPK) that, in turn, interfere with signaling from the insulin receptor. Other findings suggest that diabetic complications arise from oxidative stress, which is defined as an imbalance of oxidants and antioxidants in the favor of oxidants. Hyperglycemia underlies the development of diabetic complications, most likely due to a greater production of free radicals, more specifically reactive oxygen and nitrogen species.
Combating Oxidative Stress
To combat oxidative stress, a number of trials have investigated administering vitamins C and/or E, since plasma levels of these nutrients are often reduced in those with type 2. In addition, epidemiological studies have found that type 2 individuals with reduced plasma status of vitamins C and E are at increased risk for cardiovascular events.
Antioxidant intervention trials in diabetic patients have not been uniform, however, and this has hindered their interpretation. Recently, researchers conducted a meta-analysis to clarify whether a defective antioxidant network contributes to insulin resistance in diabetes, or to its complications (1).
Databases were searched for randomized, placebo-controlled trials examining the effect of supplemental vitamins E and/or C on glycemic control markers in non-pregnant adults with type 2 diabetes.
The analysis focused upon the effects of these nutrients on 1) plasma glucose and insulin concentrations as an indicator of the ability of the antioxidant to interfere with disease process, and 2) on glycated hemoglobin A1c (HbA1c) as a measure of antioxidant effects on protein modification implicated in disease complications.
Fourteen vitamin E or C intervention studies were identified that met the study inclusion criteria. Collectively, these studies included 572 participants and ranged from 4 weeks to 12 months in duration.
Vitamin C supplementation was from 100 mg to 2 grams daily, while vitamin E supplementation ranged from 200 IU to 1800 IU per day.
Combined analysis revealed that antioxidant supplementation did not affect plasma glucose or insulin levels. However, HbA1c levels (reported in 13 of the 14 studies) were significantly reduced by the supplemental nutrients, suggesting that antioxidants have benefit in protecting against complications of the disease.
Key: Random effects model of meta- analysis of weighted mean difference of HbA1C compared to control group, showing the mean difference for each study and 95% confidence intervals, with the pooled meta-statistic shown as a diamond.
DL pooled effect size = -0.571078 (95% CI = -0.934883 to -0.207273)
HbA1c is the gold standard marker of long term glucose control, and a surrogate for risk of diabetic complications. This analysis found an overall improvement in HbA1c in patients receiving antioxidants (see figure), with the most pronounced effects seen in those getting higher dose vitamin E for at least 2 months.
While some concerns about high dose vitamin E safety have been previously reported, the most recent analysis (Cochrane review) does not support any negative or positive effects on mortality (2).
Microcirculation in Early Retinopathy
Diabetic Retinopathy Expected to Increase
In the next 25 years, the number of Americans living with diabetes will nearly double, increasing from 23.7 million in 2009 to 44.1 million in 2034. Over the same period, spending on diabetes will almost triple, rising from $113 billion to $336 billion, even with no increase in the prevalence of obesity, researchers at the University of Chicago reported in the December, 2009 issue of Diabetes Care.
Those projections portend an increase in the prevalence of diabetic complications as well, including retinopathy. In addition, between 40 and 50% of Americans diagnosed with diabetes already have some stage of diabetic retinopathy, according to the National Institutes of Health.
Procyanidins Studied in Retinopathy
Pine bark extract, a source of dietary procyanidins, has previously been shown to improve objective parameters such as vascular permeability in patients with retinopathies associated with diabetes. [See: Review in EduFacts Vol. 9 No 6]. A new study now reports that pine bark extract may extend vision-saving benefits to diabetics with early stage retinopathy by improving retinal blood flow and inducing regression of edema (1).
Men and women with well-controlled type 2 diabetes for at least four years were recruited into this double-blind, randomized trial. The patients, who had early stages of retinopathy, characterized by mild to moderate retinal edema without hemorrhages or hard exudates in the macula center, received 150 mg of pine bark extract (Pycnogenol®) or placebo daily for three months.
Patients’ visual acuity was assessed using the standard Snellen Chart. Evaluation of diabetic retinopathy was carried out by ophthalmoscopy following pupil dilation, and retinal blood flow was quantitatively evaluated by color duplex scanning. Retinal thickness was determined using high resolution ultra-sound.
Retinal edema score and retinal thickness showed statistically significant improvement as compared to placebo, which showed negligible changes from baseline. Laser Doppler flow velocity measurements at the central retinal artery showed a statistically significant increase from 34 to 44 cm/s in the treatment group as compared to marginal effects in controls. Testing of visual acuity showed significant improvement from baseline (14/20 to 17/20), whereas no change was found in the control group.
The major finding of this study is the reported visual improvement, which was subjectively perceived in 75% of treated patients. According to the lead researcher, the findings suggest that pine bark extract taken in the early stages of retinopathy may enhance retinal blood circulation accompanied by a regression of edema to favorably affect vision.
Steigerwalt R, et al. Pycnogenol® improves microcirculation, retinal edema, and visual acuity in early diabetic retinopathy. J Ocular Pharmacol Therap 25:537-40, 2009.
Diabetes Prevalence is Increasing
Twenty four million Americans - or 8% of the population and nearly 25% of those 60 and older - currently suffer from diabetes according to 2007 prevalence data from the Centers for Disease Control (CDC). The 2007 figure is 3 million higher than 2005 prevalence data. The CDC reported that an additional 57 million had pre-diabetes, a condition that most often precedes a diagnosis of diabetes.
Diabetes can lead to damage of several different tissues, particularly those that are insulin insensitive such as the retina, kidney and nerves. Type 2 diabetes is most common, accounting for 90-95% of all diabetic patients. Both forms cause long-term complications such as neuropathy, nephropathy, cataract and retinopathy. Up to 21% of patients with type 2 diabetes have some signs of retinopathy at time of first diagnosis, and most will develop some degree of retinopathy over time.
The potential role of Pycnogenol (pine bark extract) in the treatment of type 2 diabetes is discussed in a 2008 systematic review (1) from the Ophthalmic Research Group at Aston University in Birmingham England.
Mechanism of Action of Pine Bark Extract
Pycnogenol is the brand name for a standardized extract of bark of the French maritime pine (Pinus pinaster). It contains bioactive procyanidins as does generic standardized pine bark extract. Pine bark extract (hereafter referred to as "Pycnogenol") has been shown to protect endothelial cells against oxidant-induced injury. Pycnogenol promotes a protective antioxidant state by up-regulating important enzymatic and non-enzymatic oxidant scavenging systems. It is a potent natural antioxidant and also has an affinity for proteins such as collagen, which may be responsible for the reduction of pathologically increased capillary permeability observed.
Pycnogenol significantly decreases nitrogen monoxide generation and it is thought that this function may result from a combination of several biological activities including its radical oxygen species and nitrogen monoxide scavenging activity, inhibition of the enzyme nitric oxide syntase (iNOS), and inhibition of iNOS-mRNA expression. Pycnogenol can readily cross the blood-brain barrier to provide antioxidant protection to central nervous system tissue. It is also reported to possess anti-inflammatory action.
Highlighted Clinical Studies
Supplementation of conventional diabetes treatment with 100 mg day) Pycnogenol for 12 weeks has been shown to lower glucose levels, and improve endothelial function (Liu et al., 2004). Glycosylated hemoglobin levels were significantly reduced after 1 month of supplementation. Plasma concentrations of the prostacyclin metabolite, 6-ketoprostaglandin F1, were elevated in both treatment groups, and considerably more pronounced in the Pycnogenol group (p < 0.001).
Pycnogenol is licensed in France for the treatment of diabetic retinopathy. In one investigation, a 6-month double-masked trial of Pycnogenol versus Dexium 500 (calcium dobesilate) was carried out with type 1 and 2 diabetic participants. The pharmacology of Dexium is similar to that of Pycnogenol except that it does not have such a high binding affinity for collagen. Pycnogenol was found to reduce exudates in the eyes of significantly more participants than Dexium. The authors concluded that Pycnogenol might also be beneficial for improvement of visual field loss (Leydhecker, 1986).
Another double-masked, placebo-controlled trial investigated the effect of 150 mg day of Pycnogenol on objective parameters in patients with retinopathies associated with diabetes, atherosclerosis and hypertension (Spadea, 2001). Examination of the ocular fundus showed a significant improvement in those treated with Pycnogenol, as well as improvements in electrophysiology and fluoroangiography measures. The group taking Pycnogenol also experienced a significant reduction in vascular permeability and an improvement in the blood-retinal barrier.
Finally, in a very recent double-blind study (2) of hypertensive type 2 diabetics taking ACE inhibitors, 125 mg of Pycnogenol for 12 weeks was reported to decrease use of ACE inhibitors by 50%. Fifty eight percent achieved blood pressure control, and LDL levels and fasting blood glucose levels were improved vs. placebo.
Pycnogenol® is a registered trademark of Horphag Research Ltd. Use of this product is protected by one ore more of U.S. patents #5,720,956 / #6,372,266 and other international patents.
There's a growing interest in nutrigenomics - the study of how different foods may interact with specific genes to modify the risk of chronic diseases. The underlying premise is that the influence of diet on health is related to individuals' genetic or phenotypic make-up. The aim is to identify the bioactive molecules in the diet that affect health by altering gene expression. As with any emerging field, there are knowledge gaps to close and questions about whether testing and targeted nutrition therapy will be cost effective public health strategies. However knowledge is increasing.
For example, researchers are identifying genotypes that appear to put meat consumers more at risk for colorectal cancer (1), and finding genetic variations that may increase susceptibility to osteoporosis and require early intervention with calcium and other nutrients (2). We've also learned that a common polymorphism of one gene is linked to elevated homocysteine levels and increased risk of heart disease when folic acid intake is low (3,4).
Predicting Who Can Benefit from Vitamin E
Researchers from Israel's Institute of Technology are pursuing another line of inquiry. It's known that people vary in their phenotype of haptoglobin (Hp), a blood protein that attaches to free hemoglobin and is used clinically to assess the rate of red blood cells destruction. Hp is also an antioxidant protein that prevents hemoglobin-induced tissue oxidation. The Hp gene locus is polymorphic, and people can inherit one of 3 different haptoglobin types referred to as Hp 1:1, Hp 2:1 and Hp 2:2. These inherited variations appear to influence response to antioxidant therapy.
The Israeli team tested this hypothesis in the Women's Angiographic Vitamin and Estrogen Trial (WAVE), a prospective study that evaluated the effects of vitamins C and E with or without hormone replacement therapy in treating atherosclerosis in post-menopausal women - a study that failed to find any benefit in taking antioxidants. In analyzing data from this trial, the Israeli researchers found significant benefit of the vitamins in slowing coronary artery stenoses, but only in women with a certain haptoglobin type (5).
Vitamin E May Benefit Haptoglobin 2:2 Diabetics
Hp 2:2 is a very poor antioxidant compared to other Hp types, and Hp 2:2 appears to be predictive of heart disease in diabetics who tend to generate more free radicals. About 40% of diabetics are estimated to have the Hp 2:2 form. In the newest study, the team analyzed serum samples from the Heart Outcomes Prevention Evaluation (HOPE) trial, another trial that showed no benefit for 400 IU vitamin E supplementation on cardiovascular risk in all patients. When analyzed by Hp type, those diabetics with Hp 2:2 who took vitamin E had an apparent 43% reduction in risk of heart attack.
Large Scale Trial Underway
According to the researchers at Technion, a large-scale, 5-year study of some 2000 diabetics with Hp 2:2 is being conducted. If this larger study confirms the results seen so far, vitamin E might represent a way to reduce the risk of CVD and heart attack in a significant proportion of diabetics. It may also help explain the disparity in results from antioxidant trials in recent years.
Other research teams have reported links between Hp 2:2 and refractory hypertension, risk of gestational diabetes and other disorders (7). If further research corroborates the predictive value of haptoglobin type, it may be a useful tool to identifying those who can benefit from targeted nutrition strategies.
In earlier EduFacts communiqués we have summarized reports in the literature evaluating the relationships between dietary intake levels/serum levels of dietary carotenoids and risk of age-related macular degeneration (volume 2, numbers 1, 4, 8, 9, 10, 11, and 14) and cataract (volume 2, number 13; volume 3, numbers 3 and 4). A recent evaluation of the Third National Health and Nutrition Examination Survey (NHANES III) data explored the relationship between diabetes mellitus and serum carotenoid levels (1).
The article points out that diabetes is a condition characterized by oxidative stress. This etiology is hypothesized based on demonstrated increased reactive oxygen species and, lipid peroxidation and increased free radical activity. The authors hypothesize that oxidative stress may result in a lowering of antioxidant concentrations in glucose-intolerant patients.
Phase I of NHANES III was conducted between 1988 and 1991. This was a cross sectional survey using a sophisticated design enabling generalization of results to the non-institutionalized U.S. civilian population. Of the phase I subjects, 1665 had oral glucose tolerance tests yielding valid glucose tolerance status. Patients were classified as: 1) normal, 2) impaired glucose tolerance, and 3) newly diagnosed diabetes according to World Health Organization criteria. Five carotenoids were assayed at the CDC laboratory: alpha-carotene, beta-carotene, cryptoxanthin, lutein /zeaxanthin and lycopene. Covariate-adjusted geometric means of these carotenoids were computed for the 3 groups. The covariates included socio-demographic variables, physical activity, alcohol consumption, dietary intake (single 24-hour recall), vitamin use, serum cholesterol, HDL, BP, body mass index and activity levels.
Beta-carotene levels and lycopene levels (adjusted geometric means) decreased linearly with glucose tolerance status.
The authors concluded that the NHANES III data suggest that serum carotenoid concentrations are associated with insulin-resistance and glucose tolerance status. The ordinal status from normal to impaired to new diabetes showed a linear trend with respect to the levels of beta-carotene and lycopene.
See EduFacts volume 2, number 16 for a summary of another Diabetes-related nutritional study
Investigators from the Beaver Dam Eye Study presented an evaluation of the role of vitamin intake in diabetic retinopathy at the 1998 annual meeting of the Society for Epidemiologic Research in Chicago (1). Past evaluations of The Nutritional Factors in Eye Disease Study (as part of the Beaver Dam eye Study), have provided some evidence of decreased risk of lens opacities associated with increased antioxidant intake (see EduFacts Volume 2, number 7).
In the recent report, the relationship of vitamins C and E (through diet and supplements) and the incidence and progression of diabetic retinopathy was explored. Beaver Dam Eye Study Participants with diabetes at baseline were asked to provide retrospective information on diet and supplements using a modified Block Food Frequency Questionnaire. Of 230 patients with diabetes at baseline, 166 patients provided this information and were followed for 5 years. Incidence and progression of retinopathy were determined by grading of fundus photos.
Incidence of retinopathy was 28% (47 of 166 participants). Odd's Ratios (relative risks) were computed for risk of retinopathy among those at the highest quintile level of each micronutrient vs. those at the lowest quintile level.
Multivariate analysis was performed to control for factors such as gender, insulin use, diastolic BP etc. Relative risk for highest quintile vitamin C intake level vs. lowest quintile was 0.6 - indicating a 40% decrease in risk (p=0.06 for trend). Overall citrus food intake at the highest quintile level had a relative risk of 0.2 compared with lowest quintile intake. This was an 80% reduction in risk (p=0.03). Vitamin E was not associated with lowered risk of retinopathy in this study. The authors suggested further research in this area.
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