The first article listed above refers to a study published in the Archives of Internal Medicine, which used data from the Iowa Women’s Health Study. Among the conclusions:
- “When it came to reducing the risk of death, most supplements had no effect on women’s health.”
- “Women who took certain kinds of dietary supplements — vitamin B6, folic acid, magnesium, zinc, copper, iron and multivitamins — faced a slightly higher risk of death than women who did not.”
The study’s lead author has publicly stated that “supplements are not protective against chronic diseases [and] in some cases they may be harmful, especially if used for a long time.”
Attention-grabbing, no doubt. Not surprisingly, the media’s breathless recounting left out some significant information. Read the study in its entirety and a few important details stand out. From a nutritional standpoint:
“Supplement users were more likely to have lower intake of energy, total fat, and monounsaturated fatty acids, saturated fatty acids and to have higher intake of protein, carbohydrates, polyunsaturated fatty acids, alcohol, whole grain products, fruits, and vegetables”.
This isn’t very detailed information. After all, “high intakes of polyunsaturated fatty acids” could refer to diets high in omega 6 fatty acids (not so great from a health standpoint) or omega 3 fatty acids (much better). Similarly, the study does not specify what these women’s main sources of protein were or what their sugar intake looked like (i.e.: ‘higher intake of carbohydrates’ could simply mean they consumed more sugary cereals than non-supplement users). The only nutritional variables the study adjusted for were alcohol, saturated fat, whole grains, fruits, and vegetables.
In the study, researchers also made two crucial points the media completely glossed over:
“An intermediate event, such as CVD or cancer, can induce a change in supplement use and confound the exposure-outcome association”
In other words, it’s very possible that some subjects took supplements as a result of being diagnosed with a condition; in that case, some of the increased risks of death can be attributed to said condition, rather than supplementation.
“It is not advisable to make a causal statement of excess risk based on these observational data.”
Interesting, considering the largely catastrophic and hand-wringing media coverage I came across.
I also take issue with the conclusion that “when it came to reducing the risk of death, most supplements had no effect on women’s health,” as it appears to make many assumptions. The study does not address whether a supplement user who died of cancer could have died sooner had they not taken supplements.
Okay, onto the vitamin E and prostate cancer study. The MSNBC article leads with, “yet another dietary supplement has backfired.”
The problem is not that vitamin E is worthless or “risky”, but rather that taking an isolated pill form of vitamin E is ineffective. Those are two very different concepts.
Let’s consider a food high in vitamin E, like almonds. An almond contains hundreds of beneficial antioxidants and phytonutrients within its food matrix. It is precisely this unique synergy between those compounds and nutrients (like vitamin E) that make almonds healthful. Within that food matrix, vitamin E is effective and does its job. It is precisely this synergy that explains why whole almonds offer more health benefits than slivered ones. A recent study also explained why, for instance, broccoli’s health benefits require eating the actual vegetable in its whole form. Food first!
FYI: Approximately 90 percent of American adults do not meet daily vitamin E recommendations, so be sure to consume nuts, seeds, and/or wheat germ regularly.
To summarize: we are looking at two studies that confirm what many in the nutrition field — including I — have as a core philosophy: get as much of your nutrition from real food, and eat a minimally processed diet. After all, supplementing vitamin B6 in your diet is a moot point if you already get enough and/or your diet is not composed of healthful whole foods to begin with. Additionally, health is cumulative; the way we eat over the course of decades trumps what nutrients we supplement once we enter our sixties.
I also want to point out that this should not be a call to fear supplements. Vitamin D supplementation is crucial in correcting deficiencies. The same goes for B12. Furthermore, omega 3 (DHA and EPA) supplementation has been shown to help reduce cardiovascular risk.