by Marion Nestle

Currently browsing posts about: Supplements

Dec 19 2007

Should herbal supplements be irradiated?

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?

Dec 17 2007

Baseball tragedy is supplement industry’s hope?

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!

Oct 22 2007

Antioxidants: Too much of a good thing?

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.

Sep 2 2007

Do Sports Supplements Help?

Today’s question:

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?

Jun 22 2007

FDA Rules for Dietary Supplements

The FDA announced today that manufacturers of dietary supplements will be required to follow Good Manufacturing Practices, meaning that supplements will have to contain precisely what the labels say they contain. What a concept! The supplement industry, concerned about the decline in sales resulting from loss of consumer confidence, has been lobbying for FDA regulation. This could not be more ironic since the supplement industry essentially wrote the legislation that deregulated supplements in the first place, an issue I had a lot of fun discussing in my book, Food Politics.

Jun 18 2007

Foods vs. Supplements

A writer for a women’s magazine asks: If you want to get more of a specific nutrient (lycopene, for example), is it better to take a dietary supplement or to eat foods containing that nutrient? What benefits do you get from eating a whole food that you might miss if you took a supplement instead?

My response: Unless you have been diagnosed with a vitamin or mineral deficiency and need to replenish that nutrient in a great big hurry, it is always better to get nutrients from foods—the way nature intended. I can think of three benefits of whole foods as compared to supplements: (1) you get the full variety of nutrients—vitamins, minerals, antioxidants, etc–in that food, not just the one nutrient in the supplement; (2) the amounts of the various nutrients are balanced so they don’t interfere with each other’s digestion, absorption, or metabolism; and (3) there is no possibility of harm from taking nutrients from foods (OK. Polar bear liver is an exception; its level of vitamin A is toxic). In contrast, high doses of single nutrients not only fail to improve health but also can make things worse, as has been shown in some clinical trials of the effects of beta-carotene, vitamin E, and folic acid, for example, on heart disease or cancer. And foods taste a whole lot better, of course. For more on this, see chapter 37 in What to Eat on “Supplements and Health Food.”

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