Efficacy of DHA and EPA On Serum Triglyceride Levels of Healthy Participants: Systematic Review

Abstract

Background Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are categorized as omega-3 poly unsaturated fatty acids (PUFAs) that are present in fish oil, etc. DHA and EPA omega-3 PUFAs have a well-established fasting serum triglycerides (TG) lowering effect that may result in normal lipidemia in hyperlipidemic patients. In general, omega-3 PUFAs, such as DHA and EPA, can be ingested easily, and because they are highly safe, they are assumed to be suitable for controlling fasting serum TG in the serum of those who do not require drug treatment. To the best of our knowledge, however, almost all systematic reviews on the effects of omega-3 PUFAs on lowering fasting serum TG are directed at patients fulfilling the diagnostic criteria of dyslipidemia. Objectives To review and confirm the preventive effect of omega-3 PUFAs against hypertriglyceridemia or the effect on nondrug treatment in patients with a mild disease, a systematic review was conducted to determine whether there was a fasting serum TG-lowering effect in subjects without disease and those with a slightly higher triglyceride level who consumed DHA and/or EPA orally compared to those with placebo or no intake of DHA and/or EPA. Search Methods We evaluated articles from searches of PubMed (1946-February 2016), Ichushi-Web (1977-February 2016), and J Dream III (JST Plus, 1981-February 2016; JMED Plus, 1981-February 2016). The keywords were set as follows: “DHA” or “docosahexaenoic acid” or “EPA” or “eicosapentaenoic acid” and “TG” or “triglyceride” or “triglycerol” or “triacylglycerol” or “neutral lipid.”. In addition to the literature group obtained by the database search, we included participants not suffering from any disease (i.e., excluding mild hypertriglyceridemia). Eligibility Criteria Before the test selection process, the following inclusion criteria were defined. Participants were healthy men and women including those with mild hypertriglyceridemia (fasting serum TG level, 150-199 mg/dL [1.69-2.25 mmol/L)). Intervention was defined as orally ingested DHA and/or EPA. Comparison was made to placebo intake or no intake of DHA and/or EPA. Results were measured for the fasting serum TG level. The test design was RCT, and quasi-RCT. DOI: 10.14302/issn.2379-7835.ijn-18-2469 Freely Available Online www.openaccesspub.org | IJN CC-license DOI : 10.14302/issn.2379-7835.ijn-18-2469 Vol-3 Issue 2 Pg. no.23 Introduction Cardiovascular disease (CVD) is the leading cause of death worldwide and acts as a major barrier to sustainable human development. To address this major global health concern, in 2011, the United Nations officially recognized several noncommunicable diseases, including CVD, and set up an ambitious plan to dramatically reduce the impact of these diseases in all areas [1]. Hypertriglyceridemia is a type of dyslipidemia characterized by an elevated serum triglycerides (TG] level and has been reported by several prospective studies and randomized controlled trials (RCTs) to be a risk factor for CVD. An increased level of circulating TG is an independent risk factor for the onset of CVD. Hokanson and Austin reported that a fasting serum TG level of 88 mg/dL or more increases the risk of CVD development by 14% and 37% in men and women, respectively [2]. Therefore, lowering or maintaining a low level of fasting serum TG level reduces the risk of CVD. Fatty acids are comprised of lipids, which are present in almost all parts of the human body. Fatty acids are divided broadly into two categories, saturated and unsaturated fatty acids. Unsaturated fatty acids are further classified into two categories: monounsaturated and poly unsaturated fatty acids (PUFAs). The PUFAs are further divided into two categories: the omega-3 series (metabolic cascade starts with α-linoleic acid (ALA)) and omega-6 series (metabolic cascade starts with linoleic acid (LA)). Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) are categorized as omega-3 fatty acids [3]. Certain fatty acids, such as ALA and LA, cannot be synthesized in humans, and thus must be obtained in the diet. ALA, a type of omega-3 fatty acid, is converted into DHA and EPA in the body. DHA and EPA also exist naturally in some foods. LA, which is a type of omega-6 fatty acid, is converted to arachidonic acid (AA). DHA and EPA are derived from ALA by a similar biochemical pathway as AA. Omega-3 fatty acids generally lower fasting serum TG levels and very low-density lipoprotein (VLDL) levels in serum among hyperlipidemic patients. Correspondig author: Yohei Kawasaki, Biostatistics Section, Clinical Research Center, Chiba University Hospital, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba, 260-8677, Japan, Email: [email protected] Running title: Efficacy of DHA and EPA on serum triglyceride levels of healthy participants