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.
People living in non-Mediterranean West Balkan countries have diets with a low n-3 polyunsaturated fatty acid (PUFA) content. Walnuts, a traditional Serbian food, could be an excellent source of n-3 PUFA. The first sub-study evaluated the fatty acid and mineral content of Serbian walnuts, demonstrating that walnuts had the high content of linolenic acid (C18:3, n-3 ALA). The second sub-study assessed the consumption of walnuts (Juglans regia L.) and total n-3-fatty acid intake in apparently healthy Serbian residents, using 24-h dietary recalls (n = 352). An inadequate intake of n-3 fatty acids and a low consumption of walnuts was seen. Additionally, we evaluated the fatty acid profile of healthy Serbian adults (n = 110) and finally, via a randomized intervention 4-weeks study, we assessed the effects of walnut consumption on n-3 fatty acid profile of participants (n = 18). The plasma content of n-3 PUFA was low and the n-6/n-3 ratio was high in our study participants. The n-3 plasma fatty acid profile was improved after 4 weeks of walnut consumption, meaning that ALA, eicosapentaenoic acid, and total n-3 were significantly increased. The results of our study pointed out the potential health benefits of walnuts consumption on amelioration of the n-3 fatty acid profile that should be taken into account in preventive management programs. The higher conversion of ALA to EPA (>10%) in examined study participants, suggests the importance of a moderate walnut consumption.
The fruit juice industry generates pomace as a valuable by-product especially rich in polyphenols, dietary fibers, vitamins, minerals, and unsaturated fatty acids. In the cookies used in this study, 30% of the gluten-free flour was replaced with dried and ground blueberry and raspberry pomace, rich source of polyphenols, dietary fibers, linoleic and alpha-linolenic acid. In order to examine whether the addition of blueberry and raspberry pomace in cookie formulation can have beneficial effects on certain blood parameters and anthropometric measurements, the designed cookies were tested in 20 healthy, normally fed female subjects, aged 30–50 years (41.35 ± 8.58 years) over four-week dietetic intervention study. Significant changes in the composition of fatty acids serum phospholipids, decrease in LDL-cholesterol level (20.16%), increase in adiponectin level (25.52%) and decrease in ALT and AST values were observed, thus indicating that inclusion of cookies containing blueberry and raspberry dried and ground pomace to usual diet might have positive effects on certain cardiovascular risk factors and liver function indicators.