Here is a commentary by Dr. Stephen Chaney, professor of nutrition, biochemistry and biophysics at the Univ. of North Carolina, Chapel Hill, medical school. Dr. Chaney is a warm, gracious man (yes, I know him personally 
) and a cancer researcher who has published 80 papers in peer-reviewed medical journals as well as two chapters on nutrition for one of the leading biochemistry textbooks for medical students. His informed perspective is always helpful in separating fact from fiction in the news reports about supplements and dietary recommendations.
Part of the Story
You’ve been hearing a lot of negative news stories about supplements and standard dietary recommendations lately. They are what I call “part of the story.” What I’d like to share is what Paul Harvey calls “the rest of the story.” But first a bit of perspective:
You may have noticed lately that the news media never let the facts get in the way of a good story. That’s because the role of a journalist is to sell newspapers or increase the ratings of their radio or TV station. The journalist craves controversy because that generates interest, which leads to follow-up articles and TV reports.
Scientists also crave controversy to a certain extent. There is no fame in being the 10th person to prove a widely accepted belief. The recognition comes from being the first person to disprove a widely held belief and developing an alternative hypothesis. However, scientists know the rules of the game. That is why you always hear scientists saying that “further studies are needed.” We’re not trying to assure job security. We just know that every study is based on underlying assumptions that may ultimately prove to be false.
Therefore, we don’t want to make dietary recommendations to the public until those recommendations are based on at least 5 or 10 independent studies that all come to the same conclusion. Unfortunately, journalists don’t understand the rules of the game and enjoy creating controversy (see above).
With that perspective behind us, I would like to comment on some of the recent news headlines.
Soy doesn’t decrease the risk of heart disease: What the study actually showed is that adding soy protein or soy isoflavone pills to the diet did not significantly reduce cholesterol levels if nothing else in the diet changed. That is not news.
If you took the time to read down to the end of the article (which, of course, was on the inside page of the paper), you would have read that the experts stated that “using soy protein in place of some of the high fat animal protein in a typical American diet does reduce cholesterol.” That is what we have always been saying and, in fact, forms the basis for the American Heart Association and National Institutes of Health recommendations that “soy protein is part of a heart healthy diet.”
The real take-home message of this article and the message that the scientists were trying to get across (before it was distorted by the journalists) is that you won’t lower cholesterol (and thus decrease your risk of heart disease) by simply sprinkling soy protein on your Big Mac or taking a soy isoflavone pill along with your Big Mac.
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Calcium supplements don’t prevent bone fractures due to osteoporosis: These headlines were particularly curious because when you read the article the experts were quoted as saying that calcium supplementation did actually decrease the incidence of hip fractures, but not some of the other fractures tested.
The experts went on to make the point of saying that the calcium supplements were effective at preventing bone fractures in the sub-group of women who were at highest risk and that the inclusion of both high risk and low risk women in the study confounded the results. Loosely translated this means that if you are starting with dense bones entering menopause (usually because of a combination of genetics, good diet and exercise), the addition of calcium supplements may not be necessary, at least in the short run. However, if you are entering menopause with relatively low bone density, calcium supplementation can be very important.
Finally, the experts were quoted as saying that the calcium supplements worked much better for those who took them regularly than for those who didn’t. That comes under the category of “Duh!”
All of the experts concluded by saying that they still recommended that post-menopausal women get at least 1000-1200 mg of calcium per day. Even if you are taking bone-protective medications, the recommendations are still for 1000 mg of calcium per day.
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Saw Palmetto is ineffective at preventing prostate problems: Suffice it to say that the lead author of this study acknowledged that people shouldn’t change their use of saw palmetto based on his study alone, because its results were opposite to those reported by dozens of earlier studies. Clearly more studies are needed (that’s the scientist in me) because this study may be a fluke.
Low fat diets are ineffective at preventing cancer and heart disease in women: Again, even the headlines were misleading because the study did show that low fat diets slightly decreased the risk of breast cancer.
However, the point to be made here is really that the concept of “low fat diet” has always been an oversimplification. When nutrition experts introduced the concept of low fat diets they were visualizing the American population replacing high saturated fat animal foods with more fresh vegetables, fresh fruits, whole grains, seeds and nuts. What many Americans did, however, was replace the fatty foods with wonder bread, pasta and twinkies.
The real take home message from this study should be to reduce the fat content of the diet slightly, focusing on healthy fats (olive oil, fish oils and unmodified vegetable oils) and healthy carbohydrates (vegetables, fruits and whole grains with a high glycemic index).
Stephen G. Chaney, PhD
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