This week’s note feels like a retrograde step. I thought concerns about dietary cholesterol were behind us, but this week’s paper has tried to resurrect them. The introduction to the paper noted that the Scientific Report of the 2015 Dietary Guidelines Advisory Committee stated that “cholesterol intake need not be limited because there is only a weak relationship between cholesterol intake and serum [blood] cholesterol concentrations” and that “egg consumption should be considered part of a healthy diet” (Ref 1). However the Scientific Report of the 2020 Dietary Guidelines Advisory Committee cautioned “it seems prudent to recommend lower intake of foods high in dietary cholesterol”, while calling for additional research” (Ref 2). The authors may have taken the call for more research as an invitation.
Dietary cholesterol is only found in foods of animal origin – meat, fish, eggs and dairy products. An attack on dietary cholesterol is concomitantly an attack on animal foods. Ancel Keys was the first researcher to systematically investigate whether cholesterol in food had an impact on cholesterol in the blood and he concluded unequivocally that it did not. His most definitive quotation on the matter was “There’s no connection whatsoever between cholesterol in food and cholesterol in the blood. None. And we’ve known that all along. Cholesterol in the diet doesn’t matter at all unless you happen to be a chicken or a rabbit” (Ref 3).
This week’s paper was called “Associations of dietary cholesterol, serum cholesterol, and egg consumption with overall and cause-specific mortality: Systematic review and updated meta-analysis” (Ref 4). The lead author was Zhao, from China.