Supplementation products containing n-3 PUFA from marine sources serve a large market. Although the amount of eicosapentaenoic acid and docosahexaenoic acid in the products is provided by the manufacturer, no or little information is available on their lipid pattern. Therefore, we quantitatively analyzed the fatty acid pattern in the lipid fractions triglycerides, phospholipids, ethyl esters, and free fatty acids in supplementation products by means of solid phase extraction and gas chromatography. Twelve products from the European and U.S. markets containing fish, krill, algal, or plant oil were analyzed. Total n-3 PUFA content ranged from 68 g/100 g fat (fish oil) to 42 g/100 g fat (algal oil) to 17 g/100 g fat (krill oil). On the basis of the n-3 PUFA containing lipid class, the supplements can be separated dominantly in ethyl ester, re-esterified triglyceride, triglyceride, and phospholipid containing products. Algae-based products contained natural triglycerides, krill oils a complex mixture of phospholipids, triglycerides, and free fatty acids, and fish oil products either ethyl esters, re-esterified triglycerides, or triglycerides. Even products of the same class and source showed distinct differences in their lipid pattern. A specification of the lipid composition of n-3 PUFA products would allow distinguishing the different (qualities of) supplements.

Characterizations of the multiple mechanisms determining biological aging are required to better understand the etiology and identify early biomarkers of sarcopenia. Oxylipins refer to a large family of signaling lipids involved in the regulation of various biological processes that become dysregulated during aging. To investigate whether comprehensive oxylipin profiling could provide an integrated and fine characterization of the early phases of sarcopenia, we performed a quantitative targeted metabolomics of oxylipins in plasma of 81-year old subjects from the PROOF cohort with decreased (n = 12), stable (n = 16) or increased appendicular muscle mass (n = 14). Multivariate and univariate analyses identified significant and concordant changes of oxylipin profiles according to the muscle status. Of note, 90 % of the most discriminant oxylipins were derived from EPA and DHA and were increased in the sarcopenic subjects. The oxylipins signatures of sarcopenic subjects revealed subtle activation of inflammatory resolution pathways, coagulation processes and oxidative stress as well as the inhibition of angiogenesis. Heat maps highlighted relationships between oxylipins and the cardiometabolic health parameters which were mainly lost in sarcopenic subjects. This exploratory study supports that targeted metabolomics of oxylipins could provide relevant and subtle characterization of early disturbances associated with muscle-loss during aging.