Dietary Cholesterol May Affect Plasma Cholesterol
Keys in the 1950s discovered that dietary triglycerides increase plasma cholesterol more reliably than dietary cholesterol (Chapter 4). At first it seemed to him that any effect of dietary cholesterol was unimportant. In 1965 after more carefully controlled experiments he suggested that plasma cholesterol’s rise was related to the square root of increased dietary cholesterol. Isotope labelled sterol human balance studies in the 1970s showed that as more cholesterol is absorbed, its excretion is increased, and endogenous synthesis decreased by suppression of HMG CoA reductase. In the 1980s research focussed on individual differences in response of plasma cholesterol to dietary cholesterol, but when cholesterol feeds were repeated later in the same subjects, the responses were only partly consistent. One genetic basis for cholesterol responders is the 4/4 genotype of apolipoprotein E.
There has been no clear epidemiological evidence that addition of one egg to a daily diet increases risk of CHD. Years 1965, 1971, 1986, 1999.