I was thrilled to read the National Institutes of Health study that found so many benefits to drinking coffee. What are your thoughts on this?
Dr. Michael Murray: My first thought was to chuckle. The impact of many foods on our health is completely individualized. In other words, one person’s food is another person’s poison, and this is certainly the case with coffee. One of the major drawbacks in conventional medical research is that it assumes we are all alike. It’s becoming more and more clear that we aren’t.
The Science: Each of us has unique biochemical traits that determine who we are and how we interact with food (and drugs). One of the major determinants of biochemical individuality is a family of enzymes known as the cytochrome P450 enzymes. These play a critical role in metabolizing food components, detoxifying drugs and cancer-causing compounds, and regulating hormones. Differences in the P450 enzymes can explain why some people can smoke without developing lung cancer, or why certain individuals are more susceptible to the harmful effects of pesticides and other toxic chemicals.
Differences in P450 enzyme activity can also explain the health effects of your diet. For example, let’s take a look at the research on the effects of coffee consumption on heart disease. The research has been mixed: one study finds no correlation between coffee consumption and high blood pressure or heart disease, while the next shows a strong link to coffee consumption and the risk of heart disease. Why are the two so different? It depends on the group being studied and the manner in which most subjects in the group metabolize caffeine or gain benefit from the antioxidant compounds in coffee.
One study published in the Journal of the American Medical Association looked at the way in which people metabolized caffeine and then examined heart attack rates. When the researchers divided the group according to whether they possessed an enzyme that quickly metabolizes caffeine, or a different enzyme that metabolizes it more slowly, suddenly the picture on the impact of caffeine intake and heart attack became very clear. People who break down caffeine rapidly decrease their risk of a heart attack by drinking coffee, while slow caffeine metabolizers dramatically increase their risk! Drinking four cups a day of coffee was associated with a 17 percent decrease risk in fast metabolizers and a 260 percent increased risk in slow metabolizers.
So, should you be drinking more coffee? How do you know if you are a fast or slow metabolizer? If caffeine makes you feel a bit nervous, irritable, hyper, anxious, or depressed, or if it causes insomnia, you are likely a slow metabolizer. If you are a fast metabolizer, you can tolerate caffeine. Remember, though, that one cup produces better protection against a heart attack than drinking two or more cups, and when you get above four cups, you start losing any real benefit.
Coffee can be source of beneficial antioxidants and healthful in low quantities if it works for your body. Otherwise, choose decaf, but keep in mind that even decaf still has levels of caffeine that can be a problem for some people. Lastly, coffee’s health benefits pale in comparison with the benefits provided by many other foods, most notably chocolate, berries, and other richly colored fruit and vegetables. —S&H
Michael Murray is the author of The Encyclopedia of Natural Medicine.