Distribution, interconversion, and dose response of n−3 fatty acids in humans

Attention to the role of n-3 long-chain fatty acids in human health and disease has been continuously increased during recent decades. Many clinical and epidemiologic studies have shown positive roles for n-3 fatty acids in infant development; cancer; cardiovascular diseases; and more recently, in various mental illnesses, including depression, attention-deficit hyperactivity disorder, and dementia. These fatty acids are known to have pleiotropic effects, including effects against inflammation, platelet aggregation, hypertension, and hyperlipidemia. These beneficial effects may be mediated through several distinct mechanisms, including alterations in cell membrane composition and function, gene expression, or eicosanoid production. A number of authorities have recently recommended increases in intakes of n-3 fatty acids by the general population. To comply with this recommendation a variety of food products, most notably eggs, yogurt, milk, and spreads have been enriched with these fatty acids. Ongoing research will further determine the tissue distribution, biological effects, cost-effectiveness, and consumer acceptability of such enriched products. Furthermore, additional controlled clinical trials are needed to document whether long-term consumption or supplementation with eicosapentaenoic acid/docosahexaenoic acid or the plant-derived counterpart (alpha-linolenic acid) results in better quality of life.

A systemic review of the roles of n-3 fatty acids in health and disease.

Toray Industries, Inc., Tokyo, Japan Department of Diabetes, Metabolism and Endocrinology, Chiba University Graduate School of Medicine, Chiba, Japan National Center for Geriatrics and Gerontology, Aichi, Japan Department of Internal Medicine and Cardiology, Gifu Prefectural General Medical Center, Gifu, Japan Division of Diabetes and Metabolism, Department of Internal Medicine, Iwate Medical University, Iwate, Japan Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan Center for Integrated Medical Research, Hiroshima University Hospital, Hiroshima, Japan Egusa Genshi Clinic, Hiroshima, Japan Department of Cardiovascular Medicine, Juntendo University, Tokyo, Japan Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan Biomedical Informatics, Osaka University, Osaka, Japan Division of Cardiology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan Department of Community Health Systems Nursing, Ehime University Graduate School of Medicine, Ehime, Japan Department of Vascular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan Department of Vascular Surgery, Saitama Medical Center, Saitama, Japan Chief Health Management Department, Mitsui Chemicals Inc., Tokyo, Japan Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan Department of Neurology, Kita-Harima Medical Center, Hyogo, Japan Department of Internal Medicine, Mizonokuchi Hospital, Teikyo University School of Medicine, Kanagawa, Japan Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan Tsukasa Health Care Hospital, Kagoshima, Japan Faculty of Nutrition, Division of Clinical Nutrition, Kobe Gakuin University, Hyogo, Japan Department of Food and Nutrition, Faculty of Human Sciences and Design, Japan Women’s University, Tokyo, Japan 25 Department of Preventive Cardiology, National Cerebral and Cardiovascular Center, Osaka, Japan Department of Medical Statistics, Toho University, Tokyo, Japan Department of Clinical Innovative Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan Department of Laboratory Medicine, Jikei University Kashiwa Hospital, Chiba, Japan Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, Osaka, Japan Department of Obstetrics and Gynecology, Aichi Medical University, Aichi, Japan 31 Department of Community Medicine, Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan Rinku General Medical Center, Osaka, Japan

https://www.jstage.jst.go.jp/article/jat/advpub/0/advpub_GL2017/_pdf

Japan Atherosclerosis Society (JAS) Guidelines for Prevention of Atherosclerotic Cardiovascular Diseases 2017.

Omega-3 fatty acids and metabolic syndrome: Effects and emerging mechanisms of action

The effects of n-3 fatty acid supplementation in the form of fresh fish, fish oil, and docosahexaenoic acid (DHA) oil on the fatty acid composition of plasma lipid fractions, and platelets and erythrocyte membranes of young healthy male students were examined. Altogether 59 subjects (aged 19-32 yr, body mass index 16.8-31.3 kg/m2) were randomized into the following diet groups: (i) control group; (ii) fish diet group eating fish meals five times per week [0.38 +/- 0.04 g elcosapentaenoic acid (EPA) and 0.67 +/- 0.09 g DHA per day]; (iii) DHA oil group taking algae-derived DHA oil capsules (1.68 g/d DHA in triglyceride form); and (iv) fish oil group (1.33 g EPA and 0.95 g DHA/d as free fatty acids) for 14 wk. The fatty acid composition of plasma lipids, platelets, and erythrocyte membranes was analyzed by gas chromatography. The subjects kept 4-d food records four times during the study to estimate the intake of nutrients. In the fish diet, in DHA oil, and in fish oil groups, the amounts of n-3 fatty acids increased and those of n-6 fatty acids decreased significantly in plasma lipid fractions and in platelets and erythrocyte membranes. A positive relationship was shown between the total n-3 polyunsaturated fatty acids (PUFA) and EPA and DHA intake and the increase in total n-3 PUFA and EPA and DHA in all lipid fractions analyzed. DHA was preferentially incorporated into phospholipid (PL) and triglyceride (TG) and there was very little uptake in cholesterol ester (CE), while EPA was preferentially incorporated into PL. and CE. The proportion of EPA in plasma lipids and platelets and erythrocyte membranes increased also by DHA supplementation, and the proportion of linoleic acid increased in platelets and erythrocyte membranes in the DHA oil group as well. These results suggest retroconversion of DHA to EPA and that DHA also interferes with linoleic acid metabolism.

Incorporation of n‐3 fatty acids into plasma lipid fractions, and erythrocyte membranes and platelets during dietary supplementation with fish, fish oil, and docosahexaenoic acid‐rich oil among healthy young men

OBJECTIVE The present study was carried out to clarify the effects of fish diet, fish oil and docosahexaenoic acid (DHA) rich oil on fasting and postprandial lipid levels in healthy male students. DESIGN The study was a randomized single-blind study with a control and three study groups. SETTING The study was carried out in the Departments of Physiology and Clinical Nutrition of University of Kuopio. SUBJECTS Healthy male volunteers were recruited for the study from the university student population. Fifty-nine subjects entered and 55 completed the study. INTERVENTIONS For 15 weeks the subjects in the fish diet group ate 4.3 +/- 0.5 fish containing meals per week and those in the fish oil and DHA-oil groups ate 4 g oil per day. Fish diet provided 0.38 +/- 0.04 g eicosapentaenoic acid (EPA) and 0.67 +/- 0.09 g DHA, fish oil 1.33 g EPA and 0.95 g DHA and DHA-oil (EPA-free) 1.68 g DHA per day. RESULTS Fasting plasma triglyceride levels decreased in all test groups in 14 weeks when compared to the control group (P < 0.05). Total plasma cholesterol levels did not change but the HDL2/HDL3-cholesterol ratio increased in all test groups by over 50% (P < 0.05). The postprandial total and chylomicron triglyceride responses, measured as areas under the response curve, were lowered in 15 weeks by the fish diet and fish oil (P < 0.05), the same tendency (P < 0.1) being seen in DHA-oil group. CONCLUSIONS These results show that both fasting and postprandial triglyceride concentrations can be decreased with moderate intakes of long-chain n-3 fatty acids either from a fish diet or fish oil and that also pure DHA has a hypotriglyceridemic effect.

O. Pynnonen

Papers

Fish diet, fish oil and docosahexaenoic acid rich oil lower fasting and postprandial plasma lipid levels