There are no Magic Bullets!

By Wendy Gordon

Maybe something strange was in the air, but February seemed to be the month for media debunking of conventional nutrition wisdom. Over the space of seven days the following headlines appeared in my local paper: "The skinny on weight loss drug: it's not a quick fix;" "less fat, more fruit may not ward off disease;" "calcium role in prevention may be limited;" "fears about mercury needlessly scare folks off fish;" "study finds nutritionals do little to ease arthritic pain;" and my favorite, "study turns tables on salt: restricted diet may be fatal."

Whew! I feel like Woody Allen in Sleeper, when he wakes up from a fifty-year slumber to be told "hot fat and chocolate are good for you." Come to think of it, I also read a story that week about a study indicating that eating one-third of a chocolate bar per day prevents heart disease.

In reality, a closer look shows that all these studies raise more questions than they ask. None of them completely disprove the theses they tested, but they do poke holes in the smug assumptions of many health professionals as well as the patients who listen to them. There are no right answers. There are no magic bullets. Let me go through these studies, one by one.

"Weight loss drug may not be a quick fix," measured the effects of a prescription drug, Orlistat, which has been in use since 1999 and may soon be sold as an over the counter drug. It's been shown to produce a 5-10% weight loss, which is a drop in the bucket for most seriously obese people. Unsurprisingly, its mode of action produces unpleasant side effects (anal leakage, anyone?) in 70% of users. Vitamins A, D, E and K leak out along with the fat, so users need to take supplements to make up for the loss. Doctors note that to lose weight, dieters also need to eat fewer calories and exercise more.

Yet you know that if Orlistat is approved, people will rush to buy it, forgetting about all those diet, exercise and vitamin supplement caveats. Why do all that boring stuff when you can pop an expensive ($2-$3 a day) magic bullet in their mouths?

"Less fat, more fruit may not ward off disease" probably garnered the most publicity of any of these headlines. This study followed 20,000 post-menopausal women for seven years. The study asked them to eat only 20% of their daily calories from fats, with at least five servings of fruits and vegetables and six servings of grains per day. They compared the rate of three diseases -colon cancer, breast cancer, and heart disease - with 29,000 non-dieting peers. The results showed no significant changes in the rates of any of the diseases between the two groups. That's the headline. Reading more closely (and between the lines) reveals much more ambiguous results.

First of all, there is no way of accurately measuring how closely these women followed their dietary recommendations. They didn't live in a lab for seven years, and no matter how much nutrition counseling they got at the medical center, serving size remains a subjective thing, especially when people eat out or prepare complicated recipes. Nor is there any guarantee of complete truthfulness among the study participants. I remember one of my son's friends filling out a "sexual activity questionnaire" at his middle school. This twelve year old boy claimed to be "having sex" forty times a week! I always wondered whether this, and similar claims, were conveyed seriously to terrified teachers at some conference. People lie about their eating habits as much as they lie about sex.

Even if one takes the study results at face value, they are more complicated than they initially appear. The study indicated that refined carbohydrates (those no-nos on high protein diets) do not increase blood sugar, insulin resistance, cholesterol, or triglycerides. Apparently those women who made the most serious cuts in fat intake showed a 15-20% reduction in invasive breast cancer. The women who reduced their intake of saturated and trans fats lowered their heart disease risk by 18%. So perhaps the recommended changes weren't drastic enough. Or, perhaps dietary habits in childhood and younger adulthood are more significant. Perhaps seven years was not long enough to notice a change. Nothing in the study indicated that we shouldn't continue to eat more fruits, vegetables and grains while limited saturated fats.

"Calcium: role in prevention may be limited." This study tracked 36,000 post-menopausal women for seven years, giving half of them 1000 mg calcium and 400 units of vitamin D per day, while the other half received sugar pills. Both groups had the same rate of colon cancer and overall broken bones, and the supplemented group's risk of kidney stones increased by 17%. What the headlines don't tell you is that supplemented women over 60 showed a 21% lower risk of hip fractures. Since hip fractures are one of the most serious consequences of osteoporosis, this strikes me as a significant finding. Also, 29% fewer hip fractures occurred in women of all ages who "took at least 80% of their pills." This implies that a sizable percentage of the participants didn't even follow the protocols of the study! So how can researchers draw any credible conclusions from it? The researchers also emphasize the importance of a high calcium diet and weight bearing exercise. No allowance was made for variance in either of these factors, or intake of other nutrients that inf luence calcium metabolism. Again, nothing in this study indicates you should stop taking your calcium pills - just that it's not a magic bullet.

"Nutritionals do little to ease arthritic pain." This study followed 1583 osteoarthritis patients who were given one of five treatment protocols: glucosamine; chondroitin; both of those together; Celebrex (which is known to have adverse side effects); and a placebo. Of these options, only the Celebrex produced definitive improvement. The combo of the other two supplements helped those patients in the most pain. In the small print, you find out that the form of glucosamine used was glucosamine hydrochloride, rather than the glucosamine sulfate form that is popular in Europe.

Clearly a trial with glucosamine sulfate, as well as a closer look at the supplement combo, is warranted. This study dealt only with osteoarthritis, not with rheumatoid arthritis, which is more debilitating, and could conceivably respond better to supplementation. This study leads me to question the efficacy of glucosamine and chondroitin, but not to dismiss it altogether.

"Fears about mercury needlessly scare folks off of fish." This article reports that federal advisories issued two years ago recommending that pregnant women and children limit their intake of certain types of fish and shellfish (due to mercury contamination), are scaring these groups off a highly nutritious food. They mention a 15 year long study in the Seychelle Islands, where residents eat an average of 11 fish meals per week, which shows no adverse effects. However, they do not bother to compare the mercury content of the local fish to that in the U.S., though. This article makes the valid point that people have overreacted to mercury concerns- to their overall dietary detriment.

Lastly, what about that "sodium restricted diet may be fatal" headline? This article refers to a "large government sponsored clinical trial" (how large and with whom they don't bother to say) in which participants who restricted daily sodium intake to less than 2300 mg were 37% more likely to die of cardiovascular disease. The scientists involved had some interesting theories to explain this phenomenon, and the results certainly prove what we already know: sodium metabolism is complex. Without further information, though, I see no reason either to throw out your salt shaker or embrace it. Better to enjoy salt in moderation and check your blood pressure regularly.

In summary, I'd suggest reading these nutritional news stories the same way you should read any story you see in the paper: with an open mind and a critical eye. There are two sides to almost every story.