Confusion at the Vitamin Counter
Nutrition Action Health Letter
Center for Science in the Public Interest, Nov. 2007
THE RISK OF TOO MUCH
Folic Acid
In the 90’sthe evidence was clear that folic acid lowers the risk of neural tube defects.
High doses of folic acid do not cut the risk of cancer, heart attacks and stroke.
Data indicates adequate folic acid (400 mcg.) protects against certain cancers.
An abundance of folic acid might accelerate carcinogenesis (more than 400 mcg.)
Colorectal cancer rates rose when companies added folic acid to foods.
Large quantities given to people with existing cancers may rev up the cancer.
Folic acid may accelerate growth of precancerous lesions of colorectal, prostate, and breast cancer that tend to occur as we age.
Folic acid in leafy green vegetables shouldn’t be of concern as it’s les efficiently absorbed than supplements.
Bottom Line- If you take a multivitamin with 400 mcg. of folic acid, don’t eat additional foods supplemented with folic acid.
Selenium - The Nutritional Prevention of Cancer Study (NPC)
A trial in1983 showed 200mcg of selenium/day increased squamous cell skin cancers.
10% more selenium takers than placebo takers developed diabetes after 8 years.
Dr. Marshall of Roswell Park Cancer Inst. doesn’t recommend taking selenium supplements.
Bottom Line - Don’t take a multivitamin with more than 70 mcg of selenium.
THE RISK OF TOO LITTLE
Vitamin D
MUSCLES AND BONES
Studies show people may be getting too little Vitamin D.
Current RDA is 200 IU, there is a recommendation now for 1000 IU a day for adults.
To prevent bone fractures in older adults, 400 IU showed no effect.
The National Osteoporosis Foundation claims the amount needed is 800-1000IU/day.
800-1000IU/day is also the minimum for improving muscle performance & preventing falls by enlarging fast-twitch muscle fibers.
D may also be affecting balance because it has effects in the brain.
BEYOND BONES
Breast, prostate & colon cancer risk is lowered with higher levels of D .
Diabetes risk is 64% lower in those with higher levels of D (needed for insulin secretion.)
Periodontal disease is reduced with higher levels of D which reduces inflammation.
Mental Function - Low D contributes to poor mental function in the elderly.
Multiple Sclerosis risk was 62% lower in those with highest Vit. D levels.
Bottom Line - Shoot for 1.000 IU/day of Vit. D3 from your multivitamin & extra supplement combined.