Factors influencing EPA+DHA levels in red blood cells in Japan.

The blood eicosapentaenoic and docosahexaenoic acid (EPA+DHA) concentration is an important inverse risk factor for sudden cardiac death. However, it is not known what kinds of factors influence the EPA+DHA levels in the total phospholipid fraction in red blood cells (RBC EPA+DHA) in Japan, who regularly eat more fish with increasing age. Four hundred and fifty-six healthy individuals (320 men and 136 women, 18 to 70 years old) were recruited between 2002 and 2005. RBC EPA+DHA were measured by gas chromatography and questionnaires were administered. Multivariate analysis indicated that there were significant correlations between RBC EPA+DHA and (i) dietary EPA+DHA (beta=0.31), (ii) age (beta=0.33), (iii) gender (beta=-0.15) and (iv) physical activity (beta=-0.11) but not with body mass index or smoking.

The effect of n - 3 PUFA/gamma-cyclodextrin complex on serum lipids in healthy volunteers--a randomized, placebo-controlled, double-blind trial.

OBJECTIVES: This study was carried out to examine whether serum triglyceride concentrations were decreased by administration of n-3 polyunsaturated fatty acid (PUFA)/gamma-cyclodextrin (gamma-CD) complex-containing capsules as reported previously with n-3PUFA without gamma-CD. STUDY DESIGN: A placebo-controlled double-blind study with healthy subjects (n=35) and hypertriglyceridemic subjects (n=7) of 35-66 years of age was performed. The subjects were randomized to a group (n-3 group) supplemented with n-3PUFA/gamma-CD-containing capsules (660 mg EPA + 280 mg DHA/day) or a control group supplemented with capsules containing essentially no n-3 PUFA for 8 weeks with stratification by sex, age, and serum triglyceride levels in a double blind manner. Fasting blood samples were obtained at the start of administration and 4 and 8 weeks afterward. RESULTS: EPA concentrations in the total phospholipid fraction of red blood cells increased significantly in all subjects in the n-3 group, whereas no changes were seen in the control group. Triglyceride levels were significantly decreased (-17%) in the n-3 group compared with the control group at week 8. The following serum lipids did not significantly change over time: total-cholesterol, low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol. Only two subjects in the n-3 group guessed at the end of the study that their capsules were active. CONCLUSION: n-3 PUFA/gamma-CD complex lowered triglyceride levels in normal and slightly hypertriglyceridemic subjects. There was a possibility that gamma-CD might at least partly cover the smell and aftertaste of fish oil.

The effects of eicosapentaenoic acid-fortified food on inflammatory markers in healthy subjects--A randomized, placebo-controlled, double-blind study.

Epidemiological studies showed that habitual fish intakes were associated with lower blood inflammatory markers. In the present study the effects of a fish oil-containing food on inflammatory markers were investigated in healthy, mostly middle-aged subjects (59 men and 82 women) with normal to mildly elevated triglyceride levels. Study subjects were randomly allocated to two groups in a double-blind manner; one group ingested an eicosapentaenoic acid (EPA)-rich fish oil-fortified drink (0.60 g EPA+0.26 g docosahexaenoic acid/d. EPA group, n=68) for 12 wk. The rest of the subjects took a placebo (control group, n=73). Plasma levels of high sensitivity C-reactive protein (hs-CRP) and soluble tumor necrosis factor-receptors 1 and 2 (sTNF-Rs 1 and 2) were measured at the start and end of intervention. EPA concentrations in the total RBC phospholipid fraction significantly increased by 79% in the EPA group at the end of the study, and they changed very little in the control group (+0.68%). The inflammatory markers did not change in either group. It is likely that fish oil does not change hs-CRP or sTNF-Rs 1 or 2 in subjects without active inflammation.

The relationship between tissue RBC n-3 fatty acids and pulse wave velocity.

Consumption of n-3 fatty acids is well-known to prevent deaths from coronary heart disease. However, not many studies have investigated the effects of n-3 fatty acids on arteriosclerosis in free living subjects. The pulse wave velocity between the brachia and ankles (baPWV) of 161 healthy male subjects was measured and the fatty acid composition of the total phospholipid fraction of their red blood cells (RBC) analyzed. There was a significant inverse correlation between the eicosapentaenoic acid concentrations in the RBC phospholipid fraction and baPWV of the subjects after adjustment for age, pulse rate and diastolic pressure, or further for body mass index, smoking status, diabetes and the ratio of low-density cholesterol to high-density cholesterol. Although baPWV values may not directly indicate arteriosclerosis, the present study suggests that long-term n-3 fatty acid intake is beneficial for the vascular system.