Investigators keep trying to find health benefits from taking supplements of vitamins A, E, and beta-carotene but keep coming up with the same conclusion: antioxidant supplements do no good and – worse news – appear to cause harm. Here we have the single-nutrient problem again. When in doubt, get nutrients from foods.
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I guess the world needs this. I know that lots of people think glucosamine helps relieve their arthritis pains, especially in the knees, but the science on it is really iffy. Any number of reviews conclude that glucosamine is ineffective but safe as a placebo. Well, at least you can get it now from vegetarian sources, made in China. Reassured? The manufacturer says “Most of the world’s glucosamine is manufactured in China anyway. What we’re doing is supplying a safer and purer glucosamine coming from the same geographical location.”
I’ve been hearing lots of media announcements of the food guide pyramid for old folks produced by Alice Lichtenstein and her colleagues who do research on aging at Tufts University. This one is for adults age 70 and over and is published in the January issue of the Journal of Nutrition. The press announcement from Tufts compares it to the USDA’s MyPyramid of 2005. The differences: even greater emphasis on eating healthfully and staying active (because older adults don’t need as many calories to maintain weight) and, maybe, some supplemental vitamin D (bone health) and vitamin B12 (to overcome losses in absorption ability).
Oops. I owe the American Herbal Products Association an apology for my previous post about its position on irradiation, which I got completely backwards. As Rebecca correctly points out, the AHPA has asked the FDA to deny a petition to allow herbal supplements to be irradiated. Its arguments against this use of irradiation are thoughtful and compelling: the proposed doses of radiation are higher than used on other foods; current good manufacturing practices will keep contaminants under control and irradiation will mask breaches in those practices; and “the United States will become the dumping ground for poor quality herbal ingredients from around the world, since irradiation of herbal ingredients is not permitted in many countries.” Let’s hope the FDA turns down the petition and accepts the AHPA’s arguments. And please accept my apologies.
NOTE: Correction to this post. I must have been asleep when I wrote it. Sorry!
Apparently, the Herbal Products Association has petitioned the FDA to allow herbal supplements to be irradiated at doses high enough to kill contaminating bacteria. The American Public Health Association says this is not a good idea. I don’t think so either, of course. I call irradiation a “late-stage techno-fix,” meaning that it takes dirty products and sterilizes them. Shouldn’t the dietary supplement industry get its act together and produce clean supplements to begin with?
One industry’s tragedy is another person’s dream. In this case, the tragedy is performance-enhancing drug use by baseball players (say it isn’t so). But look what the dietary supplement industry has to say about that problem: what’s bad for baseball is good for us!
Evidence continues to accumulate, little bit by little bit, that fat-soluble antioxidants and antioxidant vitamins–in this case, lycopenes, lutein, and beta-carotene vs. vitamin E–interfere with each other’s absorption. Here’s the short description and here’s the original paper so you can see how the little bits accumulate. For me, the take-home lesson is easy: eat food, not supplements.
Dear Prof. Nestle,
I enjoyed your article in the recent Scientific American and thought that you would be a good person to ask the following:
Food supplements have become a huge fad among people who “work out”.
Protein powders, various lipids, amino acids and dozens of other arcane pills and potions. My step son, who is otherwise a very sensible and educated young man, indulged in some of them (maybe still does) when he lifts weights.
I tried to convince him that a normal, healthy diet is all that one needs. That perhaps these supplements make a difference to competitive athletes who want to shave a few milliseconds off their speed, or add a few pounds to their weight-lifting, but that for a person who just wishes to be fit (even REALLY fit!) they are a total waste of money. One pays tens of dollars per kg or two of protein extract. For a similar cost, relief agencies ship hundreds of times that weight of basically the same material to 3rd world countries.
Moreover, I doubt very much that most of the claims made for them have ever been proven in proper clinical trials. I’m not even sure whether some of the nutrients that are known to be part of normal metabolic pathways cross the plasma membrane that readily. And even if they do, do they provide enough extra to make any detectable difference in performance.
I raised this issue with several colleagues in our Physical Education Faculty…and they seemed equally sceptical about the value of these substances. One of them said that the supplements might help decrease the time at which one reaches a specific level of performance, but not the ultimate level itself.
What might be your thoughts?
My thoughts: I devote a chapter in my book, What to Eat, to the question of supplements. The chapters come with extensive endnotes and references, which may help convince colleagues. My understanding of sports supplements is similar to yours–they give a tiny edge to elite athletes but act as placebos for everyone else. The marketing hype is so over the top that the attorneys for several states are taking them on. But I like to put sports supplements in context: they are generally harmless and are a whole lot better than steroids. Anyone have any additional thoughts on the topic?