You know all about fish oil and heart health, but that’s just the tip of the iceberg for these healthful fats.

Understanding your genetic clock and how to slow it down For many years, it was thought that cells were immortal if provided an ideal environment. That belief was discarded in the early 1960s when Leonard Hayflick, PhD, observed that human fibroblasts in tissue culture wouldn’t divide more than about 50 times. Hayflick found that if he froze the cells after 20 divisions, they would “remember” that they had 30 doublings left after they thawed.