Studies in recent years have touted the benefits of antioxidants so often that many people now consider munching dark chocolate and blueberries as much a part of their preventative health diet as getting enough exercise. And this balance may be a good thing, because although blueberries and chocolate may be good for you, they can also be high in calories, so if you eat a lot of them, you probably need all the exercise you can get.
The whole antioxidant craze is based on the idea that they help your body to protect and repair cells by reducing the number of free radicals that cause the damage, leading to aging, tissue damage, and diseases such as cancer. But most studies on antioxidants have been far from definitive, because there have been few accurate tables listing realistic antioxidant values for common foods. Such tables were difficult to create because it is difficult to separate the antioxidants themselves from the rest of the food, and thus determine which benefits come from, say, the tiny percentage of a blueberry that is an antioxidant, and which come from the rest of the blueberry.
Some scientists have tried to standardize antioxidant research by developing the ORAC (Oxygen Radical Absorbance Capacity) scale, a test tube measurement that determines the antioxidant efficiency of foods; in theory, the higher the score, the more antioxidant value a food has. But these foods are all measured by weight, so how do you legitimately compare a food such as grapes (which weigh more because they contain a lot of water) with raisins (which weigh less because they contain very little water), and determine serving sizes of each that can be compared meaningfully?
A study to assess the real preventative value of antioxidants
Researchers from Harvard Medical School and Erasmus Medical Center in Rotterdam, the Netherlands, decided to approach antioxidant research from a new angle. When dealing with the risk of stroke and dementia, do you base your research on individual nutrients (specific antioxidants), or on the total capacity of the subjects’ diet in terms of antioxidants? They followed 5,400 subjects for nearly 14 years, rating their total levels of antioxidant intake as low, moderate, or high.
Their findings indicate that the total level of antioxidants consumed by a person do not seem to have any significant effect on their risk of having a stroke or developing dementia. Furthermore, they found that the bulk of their subjects’ total antioxidant intake came from tea or coffee, which appears to have no effect on one's risk of stroke or dementia. Approximately 600 subjects had a stroke during the study, and another 600 developed dementia, but the researchers failed to find any association between total antioxidant consumption and a lowered risk of either disease.
As study author Elizabeth Devore says, "These results are interesting because other studies have suggested that antioxidants may help protect against stroke and dementia. It’s possible that individual antioxidants, or the main foods that contribute those antioxidants – rather than the total antioxidant level in the diet – contribute to the lower risk of dementia and stroke found in earlier studies."
All antioxidants are not alike
The most valuable finding of the study is that researchers can no longer assume that all antioxidants are equally valuable; in this study 90 percent of the subjects’ antioxidant intake came from coffee and tea, which had no effect on either stroke or dementia. In other words, although as previous studies have indicated, there may be some preventative benefits from following a Mediterranean diet high in antioxidants, the individual foods themselves may be providing more benefits than the isolated antioxidant nutrients in them.
So while eating a Mediterranean diet high in fruits, vegetables, and other antioxidant-rich foods may, in fact, be good for you, and help to prevent certain diseases, consuming similar amounts of antioxidant supplements would probably not have the same effect. This study seems to indicate that the benefit comes from the foods as a whole, not from the percentage of antioxidants they contain.