People who escaped their teen years almost pimple-free may develop persistent adult-onset acne as they get older. Despite the normal increase in androgen levels during puberty, some doctors believe that flare-ups of acne have less to do with androgen levels than with how a person's skin responds to an increase in sebum production or to the bacteria that causes acne. The bacteria Propionibacterium acnes occurs naturally in healthy hair follicles. If too many of them accumulate in plugged follicles, they may secrete enzymes that break down sebum and cause inflammation. Some people are simply more sensitive than others to this reaction. Sebum levels that might cause a pimple or two in one person may result in widespread outbreaks -- or even acute cystic acne -- in another person.
Hey Richard – curious about your thoughts on carbs driving down testosterone. Do you have any studies to that end? I wonder whether the Kitavans had/have low testosterone, despite 70% carb intake? It doesn’t seem immediately obvious to me that carb intake alone would inhibit testosterone, as long as you were getting adequate cholesterol, fat-soluble vitamins, zinc, selenium, etc. to support testosterone levels. These nutrients are often severely lacking in modern diets, as I’m sure you know! So it seems like misplacing causation for correlation to say that modern diets lower testosterone BECAUSE of their high carb levels. (They also have low mineral density, low fat-soluble vitamin levels, low fiber, low polyphenols/antioxidants, high iron, high fluoride/bromide, etc., which all could be confounding factors in the carbs-lower-testosterone hypothesis.)