Originally published December 17, 2002. Updated October 16, 2014.
Nutrigenomics is a fascinating field concerned with determining how to tailor nutritional recommendations to individuals based on their genetic makeup. Right now research is in its infancy, but investigators are looking into how the nutrients in our diets act at the molecular level to prevent or promote certain diseases, and how our individual genetic makeup influences this process.
We already know that genes can determine how our bodies respond to certain foods and nutrients. For example, lactose intolerance stems from a genetic variant that prevents the body from making an enzyme. In turn, this enzyme deficiency interferes with digestion of milk sugar. Affected individuals develop gas, bloating or nausea when they drink milk. Similarly, some people who develop type 2 diabetes can bring the disorder entirely under control by changing their eating habits while others cannot (even when they faithfully follow prescribed diets). The difference may be in their genes. Here’s another interesting example: a study of lung cancer rates in China found that people at lowest risk were genetically deficient in an enzyme that metabolizes certain nutrients in cruciferous vegetables. In this case, the abnormality seems to be beneficial, possibly enabling those affected to get better cancer protection from these vegetables. Clearly, variations in genetic makeup from person to person determine how we assimilate, metabolize, store and excrete nutrients and how these processes affect our health.
The more we learn about how nutrients act at the genetic level to protect against cancer or other diseases, the better able physicians will be to tailor their recommendations to the individual. In other words, this promising field is still in its infancy. I’ve seen no persuasive evidence that, at this time, it can be applied successfully to improve the health of the average person.
In the meantime, your best bet is a diet that emphasizes a variety of fruits, vegetables, whole grains, and monounsaturated fats. Get regular exercise. And don’t forget to attend to your emotional and spiritual health.
Andrew Weil, M.D.