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Q: Antioxidants
I pride myself on being somewhat on top of things nutritionally but I'm getting kinda confused lately with all this stuff about antioxidants supposedly not being what they´re cracked up to be. I take a lot of vitamins and minerals but they're saying now (popular press and a healthletter I get) that things like vitamin C and E and selenium maybe don´t really help and in fact may hurt if you take too many. But I also know this kind of thing has happened before in nutrition where some longheld good-for-you thing is called into question, everybody abandons it, then we find out later (like buried on page 36 or something) that the study was majorly flawed.
So what´s the story this time? Expensive urine if I keep taking them or could I actually harm myself? I take 2 grams C, for example, and 250mcg selenium. The MD writer in Time said that 2 grams of C was dangerous. And lastly, even if this lastest news is true, is it true for PLWHIV (People Living With HIV)? We need more, don´t we? (July, 2000)
A: Donna Tinnerello, MS, RD, CD/N responds:
I agree the literature on nutritional supplements is confusing for consumers- and you are so right, the information is continuously changing. Your current regimen of 2 grams of vitamin C and 250mcg of selenium sounds perfectly safe.
There was a recent study on vitamin C above 500 mgs being problematic. The investigators found that people who took 480mgs vitamin C/daily for a year ended up with thickening of the arterial wall. The thinking is that thickened arterial walls create narrower and less elastic blood vessels- and therefore increase the risk for heart disease. This is one study. I spoke by email to the author- it has not yet been published and he is still searching for a journal to publish his work.
Vitamin C is absorbed in the small intestine and excreted in the stool and urine. The kidney reabsorbs from the urine when supplies are low. Absorption is reduced when there is greater than 200 mgs/day. PLWHIV have been taking vitamin C in varying doses since the beginning of the epidemic in doses ranging from the RDA (60mgs) to 20grams/day. It is an antioxidant and our need for and utilization of them increase in the presence of infection (HIV) and injury. We use more when we have fever and inflammation. And if we are malabsorbing we need to take a lot more to get a little. I think 2 grams is the upper limit- and I would divide the doses between AM and PM for best results. A note of caution- Some PLWHIV have chronic or acute bouts of diarrhea- vitamin C supplements can exacerbate diarrhea. Kidney stones are another complication of excess vitamin C.
My number one suggestion, though, is to look at your diet and see what you are getting from your food. Foods rich in vitamin C are usually rich in lots of other nutrients that are not in supplements. Fruits and vegetables are your best bet for C. Supplements are costly and often times we are lead to believe that the nutrients from pills are more effective than food sources- the food supply should be the first line for all nutritional needs. In the case of vitamin C- some is lost in processing so eat some raw and some cooked fruits and vegetables.
Selenium is another antioxidant with good research to back it up. The reason you might hear that it isn’t safe is that taken in excesses it can be immunosuppressive. Most researchers choose an upper limit of 200mcg/day, others say 800mcg. Two hundred milligrams is the amount found in most antioxidant supplement formulas. Brazil nuts are a great source of selenium. In fact, one Brazil nut equals 100 mcgs. Take two a/day and you have met your quota. This is one situation where you can overdose on a mineral by eating too much of a good food, but this is normally not the case.
In the case of certain nutrients like selenium that are immunoprotective- over doing it has the opposite effect. You can also overdose on vitamin A and vitamin D- fat soluble vitamins which you can’t get rid of in the urine.
(Administrator's Note: Useful information on this question [as well as on other vitamins and minerals] can also be found in an article Jennifer wrote in 1996 called Alphabet Soup.)
