Heredity and Heart Disease

A number of my relatives have heart disease so I've been told by my doctor to watch what I eat, exercise, etc. My question is: why does one's heredity put a person at extra risk for heart disease?

Heredity does put one at extra risk for many types of heart disease, most commonly coronary disease, and some other uncommon heart conditions such as cardiomyopathy. From your doctor's advice, the former most likely applies to you.

Our state of health is subject to an intricate interplay between “nature and nurture.” Whereas you cannot alter your heredity, studies are convincing that proper environmental factors, especially lifestyle habits, can significantly impact the expression (i.e. activating vs. silencing) of one's genes.

For example, the U.S. population has not undergone a massive genetic mutation in the past 25 years, and yet poor lifestyle choices have doubled our obesity rate. In you case, there is a very good chance you can overcome your genetics. You can even be healthier than one without the heart disease genes. The choice is yours.