The Seven Countries book: Keys’s 10-year report on diet, cholesterol and heart deaths
In 1980 Ancel Keys and 15 co-investigators published the 10-year report of the Seven Countries Study, which compared coronary deaths among middle-aged men in 16 cohorts. A Japanese supplement maker’s page on oleic acid cites the report as a source.
What the study did and found
Harvard University Press published “Seven Countries: A Multivariate Analysis of Death and Coronary Heart Disease” in 1980, written by Ancel Keys and 15 co-investigators. The study followed 16 cohorts of mostly rural men aged 40–59 in seven countries, with the same methods in every centre (Keys et al., 1980).
The book is the 10-year follow-up report. Cohort saturated-fat intake tracked coronary death rates while total fat did not: Crete and Japan had very low coronary rates at about 40% and 10% of calories from fat (Pett et al., 2017).
Why it is cited
The one referring page recorded here is an oleic acid page on Wakasa no Himitsu, the site of the Japanese supplement maker Wakasa Seikatsu, whose reference note 2 links to the record.
The multi-country design matches the book, but the page stretches it: it uses the record to back a claim that oleic acid may help prevent heart disease, and its olive oil finding comes from a 1986 paper, not the 1980 report (Keys et al., 1986).
The diet findings compare cohort averages, so they cannot show that a man’s own diet set his risk. Only middle-aged men took part, and saturated fat lost significance once serum cholesterol entered the 1980 model (Pett et al., 2017).
At 15 years, cohort cholesterol and blood pressure explained three-quarters of the variance in coronary death rates (Keys et al., 1984); by 50 years these rates differed 6.7-fold between cohorts (Kromhout et al., 2018).
The topic today
WHO’s 2023 guideline advises cutting saturated fat to 10% of energy (World Health Organization, 2023), and a 2020 Cochrane review found that doing so reduced combined cardiovascular events by 17%, with little or no effect on deaths (Hooper et al., 2020).
For the current picture, see our explainer The Seven Countries Study: Diet and Heart Deaths in 1980.