Studies on Inuit Populations and Cardiovascular Health
Landmark Bang & Dyerberg Studies (1970s)
The foundational research on Inuit populations demonstrated dramatically lower coronary heart disease mortality (5.3% in Greenland Inuit males aged 45-65 years versus 40.4% in the USA during the 1970s), attributed to their traditional marine-based diet extraordinarily high in omega-3 fatty acids. 1
Key Findings from Greenland Expeditions
Bang & Dyerberg's 1970 sled expedition to Igdlorssuit village (500 km north of the Arctic Circle) studied Inuit hunter-fishermen and their wives aged 40+ years, finding all plasma lipoprotein concentrations lower than Danes except HDL-cholesterol, which was higher. 1
The dietary difference was striking: LC n-3 PUFA intake accounted for 13.1% of total fatty acids among Inuit versus only 0.8% among Danes, while n-6 PUFA was 5% versus 10% respectively. 1
Plasma n-6 PUFA concentrations in Inuits were 30-50% lower than Danes, while LC n-3 PUFA concentrations were five to ten times higher. 1
Critically, Inuit women who emigrated to Denmark had lipoprotein concentrations similar to Danes rather than Greenland Inuits, arguing strongly for dietary environmental factors over genetic protection. 1
Mechanistic Cardiovascular Benefits Identified
Inuits demonstrated markedly low platelet aggregation and prolonged bleeding time compared to Western populations. 1
The protective factors identified included: favorable lipid profile, lower platelet aggregation, low prevalence of obesity, hypertension, and absence of diabetes—despite being very heavy smokers. 1
Anti-thrombotic mechanisms included EPA increasing production of inactive thromboxane A3 (TBXA3), decreasing thromboxane A2 (TBXA2), increasing anti-thrombin III concentrations, improving erythrocyte deformability, and decreasing blood viscosity. 1
Modern Prospective Cohort Studies
2001 Nunavik Study (Canadian Inuit)
This cross-sectional study of 426 Inuit aged 18-74 years found geometric mean plasma phospholipid concentrations of EPA at 1.99%, DHA at 4.52%, and combined EPA+DHA at 6.83% of total fatty acids. 2
N-3 fatty acids were positively associated with HDL-cholesterol and inversely associated with triglycerides and total-to-HDL cholesterol ratio, supporting cardiovascular benefit. 2
However, total cholesterol, LDL cholesterol, and plasma glucose paradoxically increased as n-3 fatty acid concentrations increased, demonstrating complex metabolic effects. 2
No significant associations were found between n-3 fatty acids and blood pressure or plasma insulin. 2
2020 Greenland Prospective Cohort (First of Its Kind)
This landmark 2020 study represents the first-ever prospective cohort examining whether marine omega-3 fatty acids actually protect Inuit against cardiovascular disease—and surprisingly found no protective association. 3
The study followed 2,924 adult Greenlanders for a median of 9.7 years, with 216 experiencing their first CVD event (8.3 events/1000 person-years). 3
No association between EPA+DHA and CVD risk was detected (IRR = 0.99 per percentage point EPA+DHA increase, 95% CI: 0.95-1.03, p = 0.59). 3
Similarly, no association was found with ischemic heart disease risk (IRR = 1.03,95% CI: 0.97-1.09) or stroke risk (IRR = 0.98,95% CI: 0.93-1.03). 3
The study could exclude CVD risk reduction larger than 21% for individuals at the 75th EPA+DHA percentile compared to the 25th percentile, suggesting any protective effect is modest at best. 3
This null finding occurred despite the population having extraordinarily high omega-3 levels, raising questions about whether the original Bang & Dyerberg hypothesis holds in contemporary Inuit populations experiencing dietary westernization. 3
Autopsy and Pathological Studies
1996 Greenland Autopsy Study
Routine autopsies from Nuuk and Ilulissat (representing 26% of deaths) analyzed 104 specimens for cardiovascular pathology and dietary biomarkers. 4
High amounts of mono-unsaturated and omega-3 polyunsaturated fatty acids were confirmed in adipose tissue, with reduced atherosclerotic lesions found in coronary arteries. 4
Liver selenium analyses confirmed expected high intake among Greenlanders. 4
Blood pressure levels calculated from renovascular pathology indicated levels similar to industrialized countries, yet some protective factor appeared to offset the expected hypertensive effect on coronary arteries. 4
Important Contaminant Findings
Methyl mercury levels in organs were generally high among Greenlanders. 4
PCB concentrations in organs were higher than other populations, raising concerns about the risk-benefit balance of traditional marine diets. 4
Critical Interpretation and Clinical Implications
The Paradox of Modern Evidence
The striking discrepancy between the 1970s observational data showing dramatic cardiovascular protection and the 2020 prospective cohort showing no protection suggests either: (1) confounding factors in the original studies, (2) dietary westernization has eliminated the protective effect, or (3) genetic or lifestyle factors beyond omega-3 intake were responsible for the original observations. 3, 1
Dietary Context Matters
The traditional Inuit diet provided omega-3 intake equivalent to 2.5-4 grams EPA+DHA daily from whole marine foods, far exceeding typical supplementation doses. 5, 6
The 2000 Mayo Clinic review noted that 850 mg/day omega-3 fatty acids reduced sudden cardiac death by 45% and all-cause mortality by 20% in the GISSI-Prevention trial, but this was in a Western population with baseline low omega-3 status. 5
Contemporary Relevance
CVD incidence rates are rising in Inuit populations concurrent with westernization of diet, suggesting the protective effect (if real) requires the complete traditional dietary pattern, not just high omega-3 intake. 3
The 2012 review concluded that nonfish sources of omega-3 PUFA vary in their capacity to regulate blood levels and CVD risk factors, emphasizing that fatty fish-derived EPA and DHA are more effective than plant-based sources. 6