We’re all on the lookout for magic bullets. Especially attractive is the idea of a powerful nutrient (in a food or capsule) that turns out to be a “natural” cure or preventive—for colds, for cancer, for obesity.
The belief in magical nutrients is not farfetched. The discovery that certain diseases could be cured by correcting vitamin or mineral deficiencies—such as scurvy with vitamin C and rickets with vitamin D—led to the development of modern nutritional science. Taking this one step further, experts in the last half century developed nutrient guidelines in hopes of helping prevent disorders such as heart disease and hypertension.
The focus on individual nutrients has had downsides, however. These were discussed in an editorial in the Journal of the American Medical Association by two Harvard researchers—Drs. Dariush Mozaffarian and David Ludwig. I use some of their points in my lectures to graduate students:
- With a few exceptions (such as calcium and sodium), individual nutrients have, at most, small effects on chronic diseases. That’s one reason why nutrient-based guidelines for reducing the risk of chronic diseases have had minimal success—and many unintended consequences. Notably, advice to cut down on all kinds of fat proved not to be beneficial, and led many people to eat more “low-fat,” sugary and refined-grain products.
- It’s nearly impossible for people to make practical use of advice about specific nutrients. For instance, who can keep track of daily intake of saturated fat, fiber, protein, vitamins, minerals and so on? And who can deal sensibly with guidelines to eat more, or less, carbohydrates, which are found in most foods—everything from oats, broccoli and yogurt to bread, cookies and table sugar?
- The important thing is to focus on wholesome whole foods and “healthy eating patterns.” That takes us back to old-fashioned advice to eat more fruits, vegetables, whole grains and fish. These are more than just the sum of their individual nutrients. Limit highly processed foods (even if they are fortified and make health claims), fast foods and sugary drinks.
Diets based on whole foods tend to be low in salt, trans fat, saturated fat, refined carbs and added sugars; higher in minerals, vitamins, fiber, unsaturated fat, antioxidants and other beneficial compounds. Plus, they’re more filling. Thus, according to the JAMA authors, “a focus on foods increases the likelihood of consuming more healthy nutrients and fewer calories and decreasing chronic disease risk, whereas the opposite has arguably occurred through decades of nutrient-focused guidelines.” That’s not advice processed-food manufacturers want to hear.