The essential fatty acid alpha-linolenic acid (ALA) is present in high amounts in oils such as flaxseed, soy, hemp, rapeseed, chia, and perilla, while stearidonic acid is abundant in echium oil. ALA is metabolized to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by desaturases and elongases in humans. The conversion of ALA to EPA and DHA is limited, and these long-chain n−3 polyunsaturated fatty acids (PUFAs) are mainly provided from dietary sources (fish and seafood). This review provides an overview of studies that explored the effects of dietary supplementation with ALA in obesity and related diseases. The obesity-associated changes of desaturase and elongase activities are summarized, as they could influence the metabolic conversion of ALA. Generally, supplementation with ALA or ALA-rich oils leads to an increase in EPA levels and has no effect on DHA or omega-3 index. According to the literature data, stearidonic acid could enhance conversion of ALA to long-chain n−3 PUFA in obesity. Recent studies confirm that EPA and DHA intake should be considered as a primary dietary treatment strategy for improving the omega-3 index in obesity and related diseases.

The plant-derived α-linolenic acid (ALA) is an essential n-3 acid highly susceptible to oxidation, present in oils of flaxseeds, walnuts, canola, perilla, soy, and chia. After ingestion, it can be incorporated in to body lipid pools (particularly triglycerides and phospholipid membranes), and then endogenously metabolized through desaturation, elongation, and peroxisome oxidation to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with a very limited efficiency (particularly for DHA), beta-oxidized as an energy source, or directly metabolized to C18-oxilipins. At this moment, data in the literature about the effects of ALA supplementation on metabolic syndrome (MetS) in humans are inconsistent, indicating no effects or some positive effects on all MetS components (abdominal obesity, dyslipidemia, impaired insulin sensitivity and glucoregulation, blood pressure, and liver steatosis). The major effects of ALA on MetS seem to be through its conversion to more potent EPA and DHA, the impact on the n-3/n-6 ratio, and the consecutive effects on the formation of oxylipins and endocannabinoids, inflammation, insulin sensitivity, and insulin secretion, as well as adipocyte and hepatocytes function. It is important to distinguish the direct effects of ALA from the effects of EPA and DHA metabolites. This review summarizes the most recent findings on this topic and discusses the possible mechanisms.

Lifestyle modifications are the main support of nonalcoholic fatty liver disease (NAFLD) therapy. Weight loss is one of the primary goals in NAFLD, but the effects of different calorie-restricted diets remain unclear. Thus, we evaluated the effects of two calorie-restricted diets—the Mediterranean diet (Med diet) and low-fat diet—on liver status, cardiometabolic markers, and fatty acid profiles in patients with NAFLD. Twenty-four overweight/moderately obese men were randomly assigned to consume one of these diets. Lipid levels, glucose, insulin, liver enzymes, steatosis, and fatty acid profiles of serum and erythrocytes phospholipids were assessed. After 3 months, all participants had a significant weight loss (>9%), with improvements in waist circumference, body fat %, index of visceral adiposity (VAI), lipid accumulation product, fatty liver (FLI), and hepatic steatosis (HSI) index (p < 0.001). Both diets significantly lowered triglycerides, total and LDL-cholesterol, liver enzymes, fasting glucose, insulin, and HOMA-IR index. Fatty acid profiles were enhanced after both diets, with a significantly decreased n-6/n-3 ratio. Participants on the Med diet had higher levels of HDL-cholesterol and monounsaturated and n-3 docosahexaenoic acids in serum phospholipids and lower levels of saturated fatty acids, triglycerides, TG/HDL ratio, and FLI when compared to participants on the low-fat diet. Our results indicate that dietary patterns and calorie restriction represent central therapeutic issues in the improvement of obesity-related cardiometabolic alterations that are involved in the mechanism of hepatic steatosis. The Med diet may contribute to disease treatment even more than the low-fat diet since it leads to decreased saturated and increased monounsaturated and n-3 polyunsaturated fatty acid status and improved FLI in NAFLD patients.

Polyunsaturated fatty acids (PUFAs) are necessary for overall health. The two PUFAs families, n-6 and n-3 fatty acid are physiologically and metabolically distinct. Proportion of PUFAs in serum and erythrocyte phospholipids is an important determinant of both health and disease, and depends on endogenous metabolism controlled by genetic polymorphisms and dietary intake. Both n-3 and n-6 PUFAs are processed to powerful promoters of eicosanoids synthesis at the cyclooxygenase and lipoxygenase level. Evidence from observational and intervention studies suggest that n-3 PUFAs are cardioprotective, perhaps through their anti-inflammatory, anti-arrhythmic, lipid-lowering, and antihypertensive effects. In contrast, dietary n-6 PUFAs have pro-inflammatory effect. Low n-3 and elevated n-6 PUFAs levels were found in patients with cancer on different sites. The present review will focus on the current knowledge related to PUFAs intake and status in health and disease, with reference to the Serbian population.

The aim of this study was to analyze the effects of a 4-week-long consumption of glucomannan-enriched, aronia juice-based supplement on anthropometric parameters, membrane fatty acid profile, and status of antioxidant enzymes in erythrocytes obtained from postmenopausal women with abdominal obesity. Twenty women aged 45–65 with a mean body mass index (BMI) of 36.1 ± 4.4 kg/m²and waist circumference of 104.8 ± 10.1 cm were enrolled. Participants were instructed to consume 100 mL of supplement per day as part of their regular diet. A significant increase in the content of n-3 (P<0.05) polyunsaturated fatty acids in membrane phospholipids was observed, with a marked increase in the level of docosahexaenoic fatty acid (P<0.05). Accordingly, a decrease in the n-6 and n-3 fatty acids ratio was observed (P<0.05). The observed effects were accompanied with an increase in glutathione peroxidase activity (P<0.05). Values for BMI (P<0.001), waist circumference (P<0.001), and systolic blood pressure (P<0.05) were significantly lower after the intervention. The obtained results indicate a positive impact of tested supplement on cellular oxidative damage, blood pressure, and anthropometric indices of obesity.

The fatty acid composition of serum phospholipids were analyzed in 20 patients with alcoholic liver cirrhosis (11 with malnutrition and 9 with acceptable nutritional status); 25 healthy age and sex-matched adults were used as controls. Cirrhotic patients showed higher levels of palmitic acid and total saturated fatty acids than healthy subjects. Total n-6 and n-3 polyunsaturated fatty acids (PUFA), and levels of linoleic, dihomo-gama linolenic, arachidonic, and docosahexaenoic acid were significantly lower (p<0.001) in patients with alcoholic cirrhosis compared to healthy controls. Significant changes were also found between patients stratified according to nutritional status. In particular, the sum of n-3 PUFA was significantly lower (p<0.001) and ratio of n-6/n-3 fatty acids was higher (p<0.01) in malnourished patients when compared to the patients with acceptable nutritional status. Furthermore, important changes in the levels of saturated fatty acids, palmitoleic and oleic acid and long-chain PUFA were found in well-nourished patients with alcoholic cirrhosis as well. Our present data confirmed evidence that malnutrition is one of the factors that led to lower levels of polyunsaturated fatty acids in patients with alcoholic liver cirrhosis. PUFA supplementation in the latter needs further investigation.