Introduction
Many people often cite epidemiology research as evidence that saturated fat is unhealthy. Although this research has extreme limitations, these people tend to lack the necessary critical thinking skills to discern between correlation and causation.
Ironically, the correlation between saturated fat intake and disease is not as convincing as many people believe. In fact, many rigorous trials have failed to find any correlation at all.
Review
One of the most rigorous and reputable studies ever conducted on this topic was Siri-Tarino et al (1). This study was a meta-analysis that combined data from 21 studies for a total of 347,747 subjects. After examining the nutrient intake of the 11,006 who developed CHD and comparing it to the nutrient intake of those who did not develop CHD, the authors concluded, “there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.”
A large study of 58,453 Japanese men and women concluded that saturated fat, “intake was inversely associated with mortality from total stroke, including intraparenchymal hemorrhage and ischemic stroke subtypes” (2).
A systematic review of prospective cohort studies or randomized trials found that there was insufficient evidence of association between saturated fat intake and coronary heart disease (3).
A report published by the World Health Organization states that “Intake of SFA [saturated fatty acids] was not significantly associated with CHD mortality…” and “SFA intake was not significantly associated CHD events [e.g. heart attacks]…” (4).
On the island of Kitava, citizens consume copious amounts of coconut, which makes saturated fat the most predominant nutrient in their diet. Amazingly, despite consuming enormous amounts of saturated fat, a research study found that, “Stroke and ischaemic heart disease appear to be absent in this population” (5).
A large study of 28,098 subjects concluded that, “individuals receiving more than 30% of their total daily energy from fat and more than 10% from saturated fat, did not have increased mortality. Current dietary guidelines concerning fat intake are thus generally not supported by our observational results” (6).
A trial with 235 postmenopausal women found that, “a greater saturated fat intake is associated with less progression of coronary atherosclerosis” (7).
Conclusions
Contrary to popular belief, there are many epidemiological studies that have failed to find any correlation between saturated fat intake or disease.
References
1 Siri-Tarino P, Sun Q, Hu FB, Krauss RM. Meta-analysis of prospective cohort studies evaluating association of saturated fat with cardiovascular disease. Am J Clin Nutr. Jan 2010.
2 Yamagishi K, et al. Dietary intake of saturated fatty acids and mortality from cardiovascular disease in japanese: the japan collaborative cohort study for evaluation of cancer risk study. Am J Clin Nutr. Aug 2010.
3 Mente A, et al. A Systematic Review of the Evidence Supporting a Causal Link Between Dietary Factors and Coronary Heart Disease. Arch Intern Med. 2009;169(7):659-669.
4 Fats and Fatty Acids in Human Nutrition. Annals of Nutrition and Metabolism, 2009; 55 (1-3).
5 Lindeberg S, Lundh B. Apparent absence of stroke and ischaemic heart disease in a traditional Melanesian island: a clinical study in kitava. J Intern Med. 1993 Mar; 233(3): 269-75.
6 Leosdottir M, et al. Dietary fat intake and early mortality patterns–data from The Malmo Diet and Cancer Study. Journal of Internal Medicine, 2005; 258: 153-165.
7 Mozaffarian D, et al. Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women. Am J Clin Nutr 2004;80(5):1175-84