Currently browsing posts about: Antioxidants

I’m often asked about Açaí, the latest miracle fruit that is supposed to cure whatever ails you.

If this is a miracle, it’s one that must be enjoyed by the company that makes MonaVie brand Açaí, which sells for about $40 a bottle.  I had heard about Açaí and was not overly impressed.  But then I got an e-mail from a MonaVie enthsiast who was so convinced of its benefits that he sent me the research.

Here’s one of the studies. It looks formidible but its conclusions are simple.  In translation: MonaVie contains antioxidants.  The antioxidants in MonaVie act like antioxidants in the test tube and in the body, and they work better than potato starch, which has no antioxidants. Why am I not surprised? This is a study sponsored by the manufacturer.

You can read about this study and the rest of fuss over this juice in the March 12 New York Times. It’s in the Style Section (where else?).  The bottom line: all juices have antioxidants and most are a lot cheaper than MonaVie.

As for weight-loss claims: This month’s Nutrition Action Healthletter explains how to analyze Internet advertising, using Açaí as an example of truth-bending.

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.

Which fruit has the most antioxidants? The latest report says blueberries, followed by cranberries, apples, red grapes, and finally green grapes. What? Pomegranates don’t even make the top five? In this case, who knows? The investigators were testing a new assay method and those were the only fruits they examined. Never mind. It doesn’t matter. A fundamental principle of nutrition is variety. In this case, variety means that it’s good to eat different kinds of fruits and vegetables. Each contains its own unique complement of antioxidants and other nutrients and if you eat a variety of foods, you are likely to get all the ones you need and not overdo on any.

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.

A comment posted yesterday under the Label category asks whether it is possible to rank foods: “The idea that I’m trying to express is some measure that shows that 100 calories of, say, broccoli sauteed in olive oil is healthier than 100 calories of shortbread cookies or 100 calories of potato chips, even if they happend to have the same number of fat grams.”

I have philosophical as well as practical problems with this kind of approach. First, the practical: Foods contain 40 to 50 components known to be required in the human diet and hundreds more (antioxidants, for example) that are not considered essential but have effects on health. All foods except sugar–which has calories but no nutrients–have lots of different nutrients, but in different proportions. Once you get beyond soft drinks, the situation gets really complicated. Many groups have taken this on: Center for Science in the Public Interest, Hannaford supermarkets, the Australian Heart Foundation, for example. I think they are way too complicated and the cut points set up a slippery slope. If you rank foods high because they contain vitamins, all companies have to do is add vitamins to their products to make them rank higher.

Philosophically, I much prefer the “eat less, move more, eat lots of fruits and vegetables, and don’t eat too much junk food” approach. Because there are so many different nutrients to keep track of, and because foods have nutrients in different proportions, eating lots of different kinds of relatively unprocessed foods takes care of nutritional needs. Keeping junk foods (highly processed by definition) to a minimum means that you don’t have to worry about the nutritional details and can enjoy what you eat.

Thanks for asking!

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.”