n-3 fatty acids in traditional Inuit diet significantly reduce cardiovascular risk

The traditional diet of the Inuit people of Northern Canada consists primarily of marine foods rich in n-3 fatty acids, a class of polyunsaturated fats that have beneficial effects on cardiovascular (CVD) risk. However, the increasing availability of market foods to the Inuit in the past 20 years has altered the traditional diet, resulting in increased prevalence of risk factors for CVD. In a new study in the American Journal of Clinical Nutrition, Dewailly et al. verified the relationship between plasma concentrations of n-3 fatty acids and CVD risk among a group of 426 Inuit from the villages of Nunavik, Quebec, Canada. Among those who consumed the highest amounts of traditional marine foods, the researchers found high plasma levels of n-3 fatty acids, which was associated with greater high-density lipoprotein (HDL) cholesterol concentrations and lower levels of triacylglycerols.

As part of a 1992 health survey, 179 men and 247 women ages 18-74 years old filled out food frequency questionnaires and attended clinic visits for measurement of their plasma lipid concentrations. Their traditional diet consists primarily of fish and marine mammals such as white whales and seals. Modifications in the Inuit diet, including reduction in consumption of marine foods, have taken place over the past decades. Consequently, older Inuit had higher concentrations of n-3 fatty acids than younger Inuit, and as n-3 fatty acid levels increased, plasma concentrations of HDL cholesterol progressively rose and triacylglycerols fell. The relationships between n-3 fatty acids and total cholesterol and low density lipoprotein (LDL) cholesterol were less consistent. The overall dietary composition of the Inuit is also increased in saturated fat, accounting for some of the apparently high LDL levels in the population. The authors suggests that n-3 fatty acids may change the composition of LDL cholesterol from the less healthful small density type to the more healthful large density type.

At the time of the study, mortality rates from heart disease among the Inuit were 47% of that for the entire province of Quebec, evidence that the Inuit diet may contribute substantial benefits to CVD health. In an accompanying editorial, Connor reviews evidence that deaths from CVD are decreased by * 50% by eating 1 to 2 fish meals per week. Vegetarians can realize some of the same benefits by consuming the n-3 fatty acid precursor alpha-linolenic acid, which is found in canola, soy, flaxseed and walnut oils.

Dewailly, Eric et al. n-3 fatty acids and cardiovascular disease risk factors among Inuit of Nunavik. Am J Clin Nutr 2001;74:464-73.

Connor, William E. n-3 Fatty acids from fish and fish oil: panacea or nostrum? Am J Clin Nutr 2001;74:415-6

This media release is provided by The American Society for Clinical Nutrition to provide current information on nutrition-related research. This information should not be construed as medical advice. If you have a medical concern, consult your doctor. To see the complete text of this article, please go to:

http://faseb.org/ajcn/October/12492-Dewailly2.pdf or http://faseb.org/ajcn/October/13048-Connor2.pdf

For more information, please contact: eric.dewailly@crchul.ulaval.ca or connorw@ohsu.edu

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