Plasma Docosahexaenoic Acid Research Articles

Enrichment of (n-3) Fatty Acids of Suckling Rats by Maternal Dietary Menhaden Oil

The study was undertaken to determine whether the content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in neonatal rats can be increased through milk provided by lactating mothers fed a diet containing 20% menhaden oil (experimental group), in comparison with a group fed a 20% corn oil diet (control group). The test diets were isocaloric and provided 41% of total energy as fat. Coinciding with 3-9% higher maternal body weight gain throughout the lactation period with the menhaden oil diet, the suckling rats in the experimental group at the ages of 3-9 d gained 5-10% more weight than did their control counterparts. When compared with corn oil, maternal dietary menhaden oil induced not only a higher weight percentage but also higher concentrations (microgram/mL) of EPA, DHA and total (n-3) fatty acids in milk, plasma, platelets and erythrocytes of neonates. These changes were accompanied by lower arachidonic and linoleic acid levels. EPA and DHA were detected in all three blood components of the control group, whose corn oil diet contained linolenic acid but not longer chain (n-3) fatty acids. This finding, together with the higher DHA to EPA ratios found in the three blood components than in the milk of the experimental group, suggests that neonatal rats possess the enzymes necessary for producing DHA from EPA and linolenate by desaturation and elongation mechanisms.

Effect of Fish Oil and Safflower Oil in Common Japanese Diet on Human Plasma Fatty Acid Composition

The influence of fish oil and safflower oil contained in the common Japanese diet as the main dietary polyunsaturated fatty acid source on plasma fatty acids in ten female student volunteers (21-22 years old) was investigated. The subjects were divided into two groups and fed the experimental diets for five days. The total daily fat intake in the fish diet and safflower oil diet was 54.4 g and 56.2 g, respectively, and the fat derived from fish and safflower oil was 16 g and 23 g, respectively. The proportion of linoleic acid was reduced in the plasma of subjects fed the fish diet and increased in the plasma of subjects fed the safflower oil diet. The plasma levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were significantly elevated in the fish diet group. The ratio of EPA/arachidonic acid (AA) was higher, and those of n-6/n-3 and n-9/n-3 were lower in the plasma of subjects fed the fish diet when compared to the results obtained from plasma of subjects fed the safflower oil diet. From these results, it seems likely that fish oil in the common Japanese diet is a favorable source of plasma EPA and DHA even in such short term supplementation and with such a small amount of daily consumption.

Alterations in Plasma Fatty Acid Composition in Psoriatic Patients

The cause of enormous accumulation of arachidonic acid (AA) in the epidermis of psoriasis (a benign epidermal hyperproliferative disease) patients is unknown. As an initial step to elucidate the reason, the fatty acid composition in whole plasma lipid extract of psoriatic and normal subjects, male and female separately, was studied by gas chromatography. The results revealed a decrease in plasma linoleic acid (LA), a major component of whole plasma fatty acid, in both male and female psoriatic patients as the only statistically significant finding. A statistically significant decrease in AA in psoriatic plasma as reported previously was not confirmed in males. The results suggest that plasma LA in psoriatic patients is selectively incorporated into epidermis and transformed into AA there, so as to meet the great demand of psoriatic epidermis for AA. However, another possibility is also considered that a decrease in LA itself is the cause of psoriasis, since animals fed an essential fatty acid-deficient diet show psoriasis-like skin and their epidermal DNA synthesis is increased. Interestingly, increased tendency of plasma docosahexaenoic acid (DCHA) level in psoriatic patients was also found, which has not been reported before. Just as indomethacin exacerbates psoriasis, DCHA, which was shown to be a strong competitive inhibitor of AA conversion to prostaglandins, may be involved in the development of psoriasis.