Elevated concentrations of plasma ω-3 polyunsaturated fatty acids among Alaskan

Eskimos

Parkinson, Cruz, Heyward, Bulkow, Hall,Barstaed, and Connor, 1994

Presented by Emily McCarney and Melissa Pomeroy

Background Information• Fish and marine mammal

oils are a natural source of ω-3 FAs

• Ex. Eicosapentaenoic acid (20:5ω-3) and docosahexaenoic acid (22:6ω-3)

• Low concentrations of arachidonic acid (20:4ω-6)

• In normal platelet metabolism, arachidonic acid thromboxane A2 (vasoconstrictor and platelet-aggregation)

• Vasoconstriction is the narrowing of blood vessels

Background Information Cont…

• Platelet-aggregation or clumping can cause severe clots or too little clot formation

• In vascular endothelial cells, arachidonic acid prostaglandin 2 (inhibits platelet aggregation)

• These together may induce an antithrombotic state with lower platelet aggregation and prolonged bleeding time

• Antithrombotic state is a reduction of thrombus (clotting factors)

Recent studies have shown..• High dietary intake of EPA

has been positively correlated with low incidence of coronary heart disease and thrombosis (clotting factors)

• Fish oils rich in ω-3 FAs can reduce cholesterol, triglycerides, and ischemic heart disease

• When linoleic acid is consumed, it is converted to arachidonic acid in the body

• Blood vessel cells then convert this to prostoglandin by use of an endoperoxidase

• This reaction inhibits platelet aggregation and allows blood to flow without constriction or obstruction

This study examines..• 80 members of 2 Yupik

Alaskan Eskimo communities, ages 4-40

• The differences between the two communities concerning ω-3 and ω-6 intake & variation when compared to a non-native control group from Oregon

• Plasma FA composition and bleeding times were measured for all study groups

Eskimo Populations

• Bering Sea Coastal• Higher frequency of consuming

“traditional” foods such as marine fish, marine mammals, birds, and items cooked in seal oil

• Kuskokwim River • Higher frequency and variation of

salmon, other fresh-water fish, and slightly higher land mammal consumption

• Better access to store-bought Western foods

*In general, adults ate more of these traditional foods than children

Experimental Procedure• 80 participants were randomly chosen, 40 in each community

from 4 different age groups (4-8, 12-14, 17-20 & 30-40) with 5 males and 5 females per age group

• Those taking anticoagulants were excluded• Detailed dietary information was collected, as illustrated in

Table 1• Medical histories were also taken• Bleeding time and blood counts were determined by a

regional hospital in Bethel, AK• Fatty acid analyses of blood plasma were determined by gas-

liquid chromatography at the Oregon Health Sciences University

Results • Markedly high concentrations of ω-3 FAs were found in both

Alaskan populations when compared to the Oregon population (EPA and DHA specifically)

• EPA was 6.8 times higher in the River population and 13 times higher in the coastal population than the Non-native Oregon group

• EPA and DHA were significantly higher in the Coastal population than the River population

• The River pop. had higher ω-6 levels than coastal, specifically linoleic and linolenic acids whereas the coastal pop. had higher ω-3 levels than the river pop.

Table 2

DHAEPAAA

More Results• No significant differences

were found in concentrations of arachidonic acid between the two villages

• There was a pattern of increasing ω-3s with increasing age among all Native participants

• Positive associations were found between arachidonic acid and both EPA and DHA

• A negative correlation was found for DHA and γ-linolenic acid in the coastal village & less extreme in the river village

• Adults only: Negative links found with linoleic acid & arachidonic acid, EPA & DHA

• Children have no correlation between linoleic acid and other FAs

Conclusions• Salmon consumption & increased concentrations of EPA and

arachidonic acid have a positive correlation

• EPA and the consumption of marine fish with seal oil are also positively associated

• Approximately 44% of the study members claim to have the tendency for prolonged bleeding times

• 88% of the river pop. & 98% of the coastal pop. showed normal bleeding times

• Only 3 of the participants had longer than normal bleeding times

• These abnormal times were not due to high total ω-3 FAs

• No statistical correlation between bleeding time and total ω-3, EPA, total ω-3 FAs, arachidonic acid