In the news: Vitamin C & Exercise, Veggies & Breast Health
Vitamin C May Help Overweight Exercisers
If you are cutting calories and moving more to shed some weight, the findings of a new study might be news you can use. The study reports that daily supplements of vitamin C may decrease heart rate during moderate exercise, helping exercisers feel less exertion and fatigue .
In this small but carefully conducted trial, 20 obese men and women were put on a calorie-restricted diet and assigned to receive either 500 mg of vitamin C daily or a placebo over a 4 week period. The diet was also controlled for vitamin C content.
At the beginning and end of the trial, the volunteers used a treadmill for 60 minutes at 50% intensity of predicted maximal oxygen consumption – the maximum capacity of an individual’s body to transport and use oxygen during exercise.
There was no difference in breathing between the groups, and they both lost similar amounts of weight. However the vitamin C takers had, on average, 11 fewer heartbeats per minute during exercise compared to those taking a placebo.
The group getting vitamin C also reported feeling that the treadmill session took less effort and that they felt less fatigue, as assessed by a questionnaire and by a scale that rates perceived exertion.
Perceived exertion – how hard you feel like your body is working – typically correlates with heart rate: If one is lower, the other is likely to be lower too. The researchers suggest that their findings could be a factor in helping people stick to their exercise routine, since both calorie cutting and physical activity are needed for effective weight loss.
Cruciferous Veggies May Improve Survival For Breast Cancer Patients
Members of the cabbage family, called cruciferous vegetables, include greens like mustard, collard, kale, and bok choy, cauliflower, broccoli, Brussels sprouts, turnips, watercress, radishes and more.
These veggies are well known for providing nutrients that we’re all familiar with, such as fiber, carotenoids (e.g. lutein) and folic acid. But they are also a unique source of lesser-known compounds called glucosinolates.
When digested, glucosinolates are turned into other compounds (isothiocyanates and indoles) that have anti-cancer properties. High intakes of crucifers have been associated with a lower risk of lung and colorectal cancer in some population-health studies.
Evidence linking these veggies to breast or prostate cancer has been limited. However, the newly published findings of a collaborative research project between Vanderbilt University and scientists at Shanghai Centers for Disease Control and Prevention, suggest that eating more of these veggies may benefit women who’ve had breast cancer
The researchers monitored nearly 4,900 Chinese breast cancer survivors, analyzing their diets at 6, 18 and 36 months post-diagnosis.
They found that women who ate higher amounts of crucifers during the first 3 years after being diagnosed with cancer had a higher rate of survival.
Compared to women eating the least crucifers, those who had the highest daily intake had a 62% lower risk of dying from breast cancer, and a 35% reduced risk of breast cancer recurrence.
Chinese women typically eat higher amount of crucifers than do their American counterparts. They also eat different kinds of crucifers – more bok choy, turnips and greens, while broccoli and Brussels sprouts are the most common crucifers eaten by American women. Putting more crucifers on the menu might benefit all of us, especially women with a history of breast cancer.
- Huck CJ, et al. Vitamin C status and perception of effort during exercise in obese adults adhering to a calorie-reduced diet. Nutr [Epub June 5, 2012].
- Xiao SO, et al. Cruciferous vegetable consumption linked to improved breast cancer survival rates. Presented at the Annual Conference of the American Association for Cancer Research, Chicago, April 3, 2012.