I just posted about a study that found people with high cholesterol and high blood pressure have a substantially higher risk of dying from heart disease. How do you get high cholesterol? This study* found that eating cholesterol (in the form of egg yolks) substantially increases serum cholesterol:
Effect Of Dietary Cholesterol On Serum Cholesterol In Man, American Journal of Clinical Nutrition, June 1972
The purpose of the work reported here was to examine the effect that … cholesterol has when the composition of the diet is otherwise the same as that customarily consumed in the United States.
Subjects: 56 male inmates at Holmesburg prison in Pennsylvania. This was a very controlled study.
There were 4 diet groups. All contained the same amount of calories, fat (40%, same polyunsaturated-to-saturated fat ratio of 0.3), protein, and carbohydrate. They differed by the amount of cholesterol, provided by dried egg yolk. (One large egg contains about 212 mg cholesterol.):
Group 1: 0 mg cholesterol
Group 2: 106 mg/1000 calories
Group 3: 212 mg/1000 calories
Group 4: 317 mg/1000 calories
The intervention part of the study lasted 42 days. Those who ate the most cholesterol experienced the greatest increase in serum cholesterol, a 25% increase over their baseline cholesterol-free diet:
The ingestion of cholesterol resulted in an elevation of the serum cholesterol. This increase was linear over the entire range of sterol feeding. Each 100 mg cholesterol in 1,000 kcal of diet resulted in approximately a 12 mg/100-ml increase in serum cholesterol. The highest level of cholesterol that was fed approximates that in the United States diet. The subjects receiving this diet showed a 40 mg/100-ml rise in serum cholesterol.
It is proposed that relatively greater importance should be given to dietary cholesterol as a determinate of the serum cholesterol level in the United States population.
* I saw this on McDougall’s forum. It was posted by Jeff Novick, McDougall’s resident dietitian.