Almost every day I read about a new medical study that says I would be healthier if, for example, I ate more fish, drank red rather than white wine, took enchinacea, or began practicing yoga. Do such studies represent a significant body of knowledge that I should pay attention to?
An article in the May Consumer Reports Health shed some light on this question. It discussed the widely publicized medical study that showed, contrary to expectations, that “raising HDL (good) cholesterol with drugs did nothing to protect against heart attacks.” This, the article said, was surprising because observational studies had shown that people with lower levels of HDL had more heart attacks than those with higher levels of HDL. An observational study, however, shows only a correlation between two variables (e.g., level of HDL and number of heart attacks). The new result came from a randomized clinical study, using one group of patients who receive a given treatment and a “control group” of patients who do not. Unlike an observational study, such a study can show whether or not, for example, higher HDL actually prevents heart attacks. The article went on to emphasize that “we should almost never rely on the results of observational studies, which can only suggest associations with disease but not prove them.”
Taking a broader view, it would seem preferable to keep healthy by a method that is simple, reliable and doesn’t require constant revision and fine-tuning. We do, after all, have such a method available: simply follow the humdrum standard advice we’ve heard all our lives about eating sensibly, exercising regularly, and having recommended medical tests and exams. Doing this and foregoing the endless calibration of our behavior to the latest research results will be far less stressful, make it more likely that we’ll stick to the method, and allow more time for fulfilling pursuits. From this point of view, the media’s constant updates on the latest observational studies are counterproductive.
Something for people to think about from Gary Gutting’s opinion piece, “Trying to Live Forever.” Correlation and association are not causation. Your life isn’t one-dimensional. You do a variety of things and are exposed to a variety of environmental factors! Why should the lives of study participants be any different?
Edited to add: I do in fact tend to eat more paleo than not and I also participate in Crossfit. But I also cycle to school and the grocery store, and I walk frequently. I do Crossfit because intense exercise acts as my anti-depressant, and I eat paleo because I’m gluten-sensitive (if you’re curious- migraines, not celiac) and because I appreciate the slow and local food movements.