Coffee is brain food

People still seem to think that coffee is bad for you. Perhaps it's our assumption that anything that we enjoy can't possibly be good for us. In past columns we've seen that coffee may help improve blood sugar control, lower circulating uric acid, reduce your risk of colon cancer, and is associated with a reduced risk of death from heart disease.

Those are all physical effects; what about mental effects? Researchers in China scoured peer-reviewed journals to find 9 published, prospective studies that not only assessed mental status and cognition using standardized tests, but also asked participants to report on their usual intake of coffee (Clin Nutr 2017;36:730-36). The 9 studies included a total of over 34,000 men and women and lasted from a little less than 2 years up to as many as 28 years. All of the subjects were at least 60 years of age at the start of the study they participated in.

Each study asked its participants to estimate their usual intake of coffee - not caffeinated beverages - and the authors of this study standardized the levels of intake across all 9 studies in three increasing levels of coffee intake: <1 cup of coffee per day, 1-3 cups of coffee per day, and 3 or more cups per day. After taking into account race/ethnicity, gender, age, and other factors, the authors could estimate the risk of specific types of cognitive disorders in relation to the amount of coffee the participants drank.

The outcome argues for moderation: drinking 1-2 cups of coffee per day, as compared to less than 1 cup per day, meant a 22% reduction in risk of dementia, a 16% lower risk of cognitive impairment, and 29% lower risk of Alzheimer's Disease. On the other hand, drinking 3 or more cups of coffee per day actually increased one's risk of cognitive disorders, although the relationship was not considered statistically significant.

These results, as with so many studies, should be taken with a grain of salt: 6 of the 9 studies asked the participants to estimate their own average consumption of coffee, and such self-administered questionnaires are often less than perfectly accurate. Further, a "cup" of coffee may mean one amount in one country, while a different amount in another: the typical cup of coffee in the United States, for example, is larger than the typical cup of coffee in Europe. Finally, the question of whether the coffee was caffeinated or decaffeinated does not appear to have been consistently addressed in the included articles.

What this means for you

Coffee isn't just caffeine - as we've mentioned before, it's the single largest source of antioxidants in the Western diet and also contains minerals and other substances. Whether you drink regular or decaffeinated, it's likely that a moderate amount of coffee will help you keep your mind sharp.

First posted: May 17, 2017