Editing Ancel Keys (section)

===Seven Countries Study===
{{Main|Seven Countries Study}}
His interest in diet and cardiovascular disease (CVD) was prompted, in part, by seemingly counter-intuitive data: American business executives, presumably among the best-fed people, had high rates of [[heart disease]], while in post-war Europe CVD rates had decreased sharply in the wake of reduced food supplies.  Keys postulated a correlation between [[cholesterol]] levels and CVD and initiated a study of Minnesota businessmen (the first prospective study of CVD).<ref name=Keys_1963>{{cite journal |vauthors=Keys A, Taylor HL, Blackburn H, Brozek J, Anderson JT, Simonson E |title=Coronary heart disease among Minnesota business and professional men followed 15 years |journal=Circulation |volume=28 |issue= 3|pages=381–395 |date=September 1, 1963|pmid=14059458 |doi=10.1161/01.cir.28.3.381|doi-access=free }}</ref> At a 1955 expert meeting at the World Health Organization in Geneva, Keys presented his diet-lipid-heart disease hypothesis.<ref>{{cite web|title=Famous Polemics on Diet-Heart Theory|author=Henry Blackburn|publisher= School of Public Health, University of Minnesota|url=http://www.epi.umn.edu/cvdepi/essay.asp?id=33|archive-url=https://web.archive.org/web/20140327233831/http://www.epi.umn.edu/cvdepi/essay.asp?id=33|archive-date=March 27, 2014}}</ref><ref name=Keys_1980>{{cite book | last = Keys | first = Ancel| title = Seven Countries: A Multivariate Analysis of Death and Coronary Heart Disease |url=https://archive.org/details/sevencountriesmu0000keys | url-access = registration | publisher = Harvard University Press | year = 1980 | isbn = 978-0-674-80237-7 }}</ref> As part of his argument, he presented a correlation between deaths from heart disease and percentage of fat in the diet that featured six countries.<ref>{{Cite journal|last=Keys|first=A.|date=July 1953|title=Atherosclerosis: a problem in newer public health|journal=Journal of the Mount Sinai Hospital, New York|volume=20|issue=2|pages=118–139|issn=0099-9695|pmid=13085148}}</ref> His rationale and conclusions were heavily critiqued by two other epidemiologists.<ref>{{Cite journal|last1=Yerushalmy|first1=J.|last2=Hilleboe|first2=H. E.|date=July 15, 1957|title=Fat in the diet and mortality from heart disease; a methodologic note|journal=New York State Journal of Medicine|volume=57|issue=14|pages=2343–2354|issn=0028-7628|pmid=13441073}}</ref>

After observing in southern Italy the highest concentration of centenarians in the world, Keys hypothesized that a Mediterranean-style diet low in animal fat protected against heart disease and that a diet high in animal fats led to heart disease. This finding helped Keys initiate a long-term observational study, known as the [[Seven Countries Study]], which appeared to show that serum cholesterol was strongly related to [[coronary artery disease|coronary heart disease]] mortality both at the population and individual levels.<ref>Kromhout D: "Serum cholesterol in cross-cultural perspective. The Seven-Countries Study". ''Acta Cardiol'' 1999;54:155–158</ref><ref name=Katan>Katan MB, Beynen AC.  "Linoleic acid consumption and coronary heart disease in U.S.A. and U.K." ''Lancet''. 1981 Aug 15;2(8242):371</ref>

Keys had concluded that saturated fats as found in milk and meat have adverse effects, while unsaturated fats found in vegetable oils had beneficial effects. Keys stated that of the 12,000 men in seven countries studied in 1960, those least likely to develop cardiovascular disease lived in [[Crete]].<ref>[http://www.nytimes.com/1998/02/10/science/personal-health-pass-the-wine-and-olive-oil-and-other-lessons-from-crete.html "Personal Health; Pass the Wine and Olive Oil, and Other Lessons From Crete"]. nytimes.com. Retrieved May 4, 2024.</ref>

After Keys' retirement from the [[University of Minnesota]] in 1972, his protege Henry Blackburn, MD became director of the Laboratory of Physiological Hygiene.<ref>{{cite web |title=Blackburn, Henry « Heart Attack Prevention |url=http://www.epi.umn.edu/cvdepi/bio-sketch/blackburn-henry/ |website=University of Minnesota |access-date=March 28, 2020}}</ref>  Blackburn continued research on the role of lifestyle including diet in the cause and prevention of heart disease. The department played an active role in multicenter trials of the 1970s–80s and population strategies of surveillance and preventive interventions in Minnesota.