In the news:
Lutein in Early AMD:
Acid-Suppressors & B12
Lutein May Support Clearer Vision in Early AMD
The macula, located roughly in the center of the retina, is the area of the eye that allows sharp central vision. Lutein and zeaxanthin, known as macular pigments, help to protect the macula from harmful blue light and have anti-inflammatory properties that could be of benefit in the aging retina.
The density of macular pigment has been found to decline as we grow older, and low density appears to be a risk factor for age-related macular degeneration (AMD).
We usually hear about lutein and zeaxanthin in the context of playing a possible role in AMD prevention, or in the context of slowing progression of the disease in those who already have intermediate to advanced stages and don’t consume enough lutein and zeaxanthin. But could these nutrients have a role to play in the early stages of AMD?
To focus on that question, researchers from the UK and the Netherlands conducted a randomized placebo controlled clinical trial in patients with early AMD (1). Study participants were assigned to take 10 mg of lutein daily or placebo, and were followed for a year.
Macular pigment density increased significantly in the lutein group, while no change was seen for placebo. Visual acuity (a measure of clarity or sharpness of vision) didn’t change in the lutein group as a whole, and worsened among placebo-takers.
Since about half the participants had normal or above normal sharpness of vision when the trial began, the researchers looked at those who started out with poor visual clarity. They found that lutein did improve visual acuity among these patients. These promising, although preliminary, findings suggest that the potential role of lutein in early AMD deserves greater attention.
“Acid Reducing” Drugs and Vitamin B12
Millions of Americans use acid-suppressing drugs called proton pump inhibitors (PPIs) for treating conditions such as heartburn, GERD, and peptic ulcers. Long-term use and high doses have been associated with an increased risk of bone fractures and infection with a bacterium called Clostridium difficile. A recent study suggests that users of acid-suppressing medications need to be aware of these drugs apparent effect on vitamin B12 as well.
Vitamin B12, which plays a critical role in forming red blood cells and in brain and nervous system function, can be difficult to absorb for some. Stomach acid is required to release B12 from foods before it’s available to be absorbed. Older people are at greater risk for low B12 because stomach acid output declines with age.
A recent study (2) found that using PPIs for 2 or more years increased the risk of vitamin B12 deficiency by 65%. To a lesser extent, B12 deficiency was also associated with use of histamine-2 receptor antagonists (H2RAs) – another medication that slows the release of stomach acid.
The investigators found these associations when comparing nearly 26,000 patients diagnosed with vitamin B12 deficiency over a 14-year period, with about 184,000 patients without B12 deficiency.
Unlike protein-bound B12 in foods, the form in supplements and B12-fortified foods such as certain breakfast cereals isn’t dependent upon stomach acid to be bioavailable. So it’s a good idea for people taking acid-reducing medications to get B12 from supplements and/or fortified food sources. The Institute of Medicine, in fact, recommends that all adults over the age of 50 obtain the RDA for vitamin B12 from supplements or fortified foods.
For those who have taken these medications for extended periods of time, it may also be wise to speak with a physician about having a blood test to determine B12 blood levels and to discuss the benefits and risks of these medications.
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