In class, we discuss a Finnish study that showed that male smokers eating a lot of fruits and vegetables developed less cancer than men who did not. We also consider that antioxidant supplements produce negative results in a variety of health studies, in some actually increasing the incidence of cancer. One meta-analysis of all of the supplement studies reports that “supplementation was dose-dependently associated with an increased risk of death.” In other words, supplements of one or a few antioxidants at best have no effect and frequently have harmful effects.
A recent Norwegian study decided to see if getting the same dose of antioxidants that proved harmful in supplement form also was harmful if eaten as food. They recruited a group of male smokers and divided them into three groups. One eating a typical Norwegian diet, one eating a regular diet plus three kiwis a day, and one eating an antioxidant-rich diet. They made the interesting observation that Norwegians get most of their antioxidants from coffee (as opposed to fruits and vegetables) so, in order to control the daily dose of antioxidants in these three diets, they limited all to 3 cups of coffee a day.
The volunteers were followed over the course of a year, taking a break over Christmas, Easter, and for summer vacation, periods when they might be tempted not to follow their assigned diet. The earlier antioxidant supplement studies tested daily dosages of 2 grams of vitamin C or 5 grams of vitamin E, so the antioxidant-rich arm of this study matched those doses. This antioxidant-rich diet also increased the participants’ calorie intake by close to 500 calories a day. This should, on average, have caused a weight gain of about 6.5 pounds in each of the men in this group. However, no weight gain was seen, indicating that healthy foods has a different effect on metabolism than not-so-healthy foods.
In the end, eating large amounts of antioxidant-rich foods did not have any negative health effects. In other words, unlike a beta-carotene supplement, an antioxidant-rich diet will not increase the incidence of cancer in male smokers. Of course, this study supports the earlier observation that antioxidant-rich foods reduces the incidence of lung cancer in male smokers. Those on the kiwi diet also ate much more vitamin C than did those on the typical Norwegian diet. Surprisingly though, the vitamin C levels in their blood did not increase. Smoking uses up vitamin C so the researchers theorized that the extra vitamin C balanced out needs created by smoking. This may be one of the ways that the antioxidant-rich diet protects: It overcomes deficits caused by poor life style or environmental challenges.
Modern science much prefers carefully constructed studies with strictly limited variables. As it result, it prefers to test isolated supplements such as vitamin E or beta-carotene rather than testing a diet composed of thousands of different antioxidants. However, it increasingly appears that it is going to be impossible to use this reigning paradigm of “evidence-based medicine” when it comes to nutrition and health. There are simply too many co-factors and other essential variables at play in the health effects of food and in understanding the importance of a healthy diet.
Finally, I should add that, in my opinion at least, this study does not show that supplements are bad. Instead, it shows that a steady diet of real food is needed for health. Supplements, if well made (e.g., bioidentical, without sugars, dyes and other chemicals) may then be added to fit the individual’s need. For instance, smokers may well benefit from both a very healthy diet and a vitamin C supplement to overcome the negative effects of smoking (of course, with the ultimate goal of quitting smoking). Supplements should simply not be used in the belief that they can make up for a poor diet nor should they be used in high doses without a well-defined individual need for that dose.
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