By: Yirong Wang
So, what is nutrigenomics?
It is the study of nutrients and bioactive components in our diet interact with our genome to turn on and off gene expression. Imagine diseases are light bulbs and genes are the filaments, then the food you eat is the switch to turn on the disease genes. This happens when the nutrients in our food interacting with the genes in two ways: 1) they function directly as “switches” and 2) they modify genetic materials. Both ways can decide whether the disease genes will be turned on or off. More important, both of them are inheritable. The metaphor of nutrigenomics sheds light on how heritability accounts for the effects of grandmaternal diet on the health outcomes of the next generation.
The high-fat diet, which represents over-nutrition, during the pre-conceptional period and pregnancy, causes an increase in body size as well as insulin sensitivity in the next generation. The insulin-related trait is inheritable through the paternal lineage. That means if my grandma on my father’s side had a high-fat diet during her pregnancy, my sister and I may be larger in body size and have a greater risk of disease compared with our friends. Alternatively, the low-fat maternal diet will have a protective effect on the offspring’s health. This whole cycle will repeat if my hypothetical sister inherits these traits and has children.
A low-protein diet will also have a detrimental effect on the offspring’s health. The Dutch Famine Study first illustrated this point. Researchers found that fetal reprogramming occurred in the early stage of development. At this point, there were inadequate nutrients available, thus the fetus reprogrammed its DNA to adapt to the poor nutritional state and the birth resulted in low birth weight. In early life, the low-protein offspring have certain health advantages. However, an age-dependent impairment in glucose tolerance will occur. Furthermore, if the low-protein offspring are exposed to an environment of better nutrition, or more often, a junk food enriched environment, their risks of disease increase remarkably. This mechanism may account for the double effect of under-nutrition and obesity in the developing countries.
Is there a perfect diet for the mothers-to-be? Yes and no! Balance is the crucial take-home message. An unbalanced diet, either too much or too little, will have several metabolic impairments. These nutrients will interact with your genome to change your genetic make-up and pass this information to several generations. However, don’t panic because it’s not hopeless. The switch that turns diseases on or off is in your hands. As long as you are eating a balanced diet that is full of variety and have a positive attitude, your family is still on the right track to a healthy and happy life. Remember, YOU can control what you eat and make a difference.