Caleb Finch: USC Davis School of Gerontology

Human lifespans have increased remarkably from the 20 year life expectancy (LE) of the great apes. The normative 40 y LE of pre-industrial peoples has recently risen to about 80 y in privileged populations during the last 200 years. I propose that diet and infections are key to understanding both demographic transitions. During human evolution, human ancestors shifted from a largely plant based diet to include larger amounts of animal tissues and cholesterol intake that observed in the extant great apes. Exposure to infections also increased because of consumption of raw tissues and from close contact with feces not observed in great apes which rarely use the same night nest. In 2004, Craig Stanford and I hypothesized that “meat-adaptive genes” enabled these transitions (Q Rev Biol. vol 79, 2004). Apolipoprotein E is a candidate for pleiotropic genes with influences on blood lipids, innate immunity, and brain development; the apoE3 allele that increases LE spread in human populations about 225,000 years ago. I will further discuss the possible role of apoE alleles and other genes in supporting the recent increase in LE during post 18th century improvements of diet and reduction of infections.