Release of EPA and DHA from salmon oil – a comparison of in vitro digestion with human and porcine gastrointestinal enzymes

Evaluation of the Metabolite Profile of Fish Oil Omega-3 Fatty Acids (n-3 FAs) in Micellar and Enteric-Coated Forms-A Randomized, Cross-Over Human Study

This study evaluated the differences in the metabolite profile of three n-3 FA fish oil formulations in 12 healthy participants: (1) standard softgels (STD) providing 600 mg n-3 FA; (2) enteric-coated softgels (ENT) providing 600 mg n-3 FA; (3) a new micellar formulation (LMF) providing 374 mg n-3 FA. The pharmacokinetics (PKs), such as the area under the plot of plasma concentration (AUC), and the peak blood concentration (Cmax) of the different FA metabolites including HDHAs, HETEs, HEPEs, RvD1, RvD5, RvE1, and RvE2, were determined over a total period of 24 h. Blood concentrations of EPA (26,920.0 ± 10,021.0 ng/mL·h) were significantly higher with respect to AUC0-24 following LMF treatment vs STD and ENT; when measured incrementally, blood concentrations of total n-3 FAs (EPA/DHA/DPA3) up to 11 times higher were observed for LMF vs STD (iAUC 0-24: 16,150.0 ± 5454.0 vs 1498.9 ± 443.0; p ≤ 0.0001). Significant differences in n-3 metabolites including oxylipins were found between STD and LMF with respect to 12-HEPE, 9-HEPE, 12-HETE, and RvD1; 9-HEPE levels were significantly higher following the STD vs. ENT treatment. Furthermore, within the scope of this study, changes in blood lipid levels (i.e., cholesterol, triglycerides, LDL, and HDL) were monitored in participants for up to 120 h post-treatment; a significant decrease in serum triglycerides was detected in participants (~20%) following the LMF treatment; no significant deviations from the baseline were detected for all the other lipid biomarkers in any of the treatment groups. Despite a lower administered dose, LMF provided higher blood concentrations of n-3 FAs and certain anti-inflammatory n-3 metabolites in human participants-potentially leading to better health outcomes.

DHA bioaccessibility in infant formulas and preschool children milks

Docosahexaenoic acid (DHA, 22:6n-3) is an essential long chain polyunsaturated fatty acid associated with the development of the nervous system that has to be consumed by infants through breast milk or complementary food sources and which consumption is also usually inadequate in preschoolers. In this work, the in vitro bioaccessibility of DHA from two commercial infant formulas (8.9 and 9.1%) and two preschool children milks (6.9 and 7.2%), with similar DHA contents but formulated with different ingredients, was not improved by the presence of egg phospholipids in the product formulation. In addition, the importance of the choice of an age-appropriate in vitro digestion method was demonstrated by comparing the DHA bioaccessibility from the infant formulas by the Infogest 2.0 standardized method and a simulated digestion method specific for infants.

In vitro intestinal digestion of lipids from the marine diatom Porosira glacialis compared to commercial LC n-3 PUFA products

Marine sources of long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) are in high demand for use in health supplements. Mass cultivated marine microalgae is a promising and sustainable source of LC n-3 PUFA, which relieves pressure on natural fish stocks. The lipid class profile from cultivated photosynthetic algae differ from the marine organisms currently used for the production of LC n-3 PUFA. The objective of this study was to compare in vitro intestinal digestion of oil extracted from the cold-adapted marine diatom Porosira glacialis with commercially available LC n-3 PUFA supplements; cod liver oil, krill oil, ethyl ester concentrate, and oil from the copepod Calanus finmarchicus (Calanus® oil). The changes in the free fatty acids and neutral and polar lipids during the enzymatic hydrolysis were characterized by liquid and gas chromatography. In Calanus® oil and the Ethyl ester concentrate, the free fatty acids increased very little (4.0 and 4.6%, respectively) during digestion. In comparison, free fatty acids in Krill oil and P. glacialis oil increased by 14.7 and 17.0%, respectively. Cod liver oil had the highest increase (28.2%) in free fatty acids during the digestion. Monounsaturated and saturated fatty acids were more easily released than polyunsaturated fatty acids in all five oils.

In Vitro and In Vivo Digestibility of Soybean, Fish, and Microalgal Oils, and Their Influences on Fatty Acid Distribution in Tissue Lipid of Mice

The digestion rates of microalgal (docosahexaenoic acid, DHA, 56.8%; palmitic acid, 22.4%), fish (DHA, 10.8%; eicosapentaenoic acid, EPA, 16.2%), and soybean oils (oleic, 21.7%; linoleic acid, 54.6%) were compared by coupling the in vitro multi-step and in vivo apparent digestion models using mice. The in vitro digestion rate estimated based on the released free fatty acids content was remarkably higher in soybean and fish oils than in microalgal oil in 30 min; however, microalgal and fish oils had similar digestion rates at longer digestion. The in vivo digestibility of microalgal oil (91.49%) was lower than those of soybean (96.50%) and fish oils (96.99%). Among the constituent fatty acids of the diet oils, docosapentaenoic acid (DPA) exhibited the highest digestibility, followed by EPA, DHA, palmitoleic, oleic, palmitic, and stearic acid, demonstrating increased digestibility with reduced chain length and increased unsaturation degree of fatty acid. The diet oils affected the deposition of fatty acids in mouse tissues, and DHA concentrations were high in epididymal fat, liver, and brain of mice fed microalgal oil. In the present study, microalgal oil showed lower in vitro and in vivo digestibility, despite adequate DHA incorporation into major mouse organs, such as the brain and liver.

Simulating human digestion: developing our knowledge to create healthier and more sustainable foods

The gold standard for nutrition studies is clinical trials but they are expensive and variable, and do not always provide the mechanistic information required, hence the increased use ofin vitroand increasinglyin silicosimulations of digestion.

Formation of reactive aldehydes (MDA, HHE, HNE) during the digestion of cod liver oil: comparison of human and porcine in vitro digestion models

In this work, we investigated lipid oxidation of cod liver oil during gastrointestinal (GI) digestion using two types of in vitro digestion models. In the first type of model, we used human GI juices, while we used digestive enzymes and bile from porcine origin in the second type of model. Human and porcine models were matched with respect to factors important for lipolysis, using a standardized digestion protocol. The digests were analysed for reactive oxidation products: malondialdehyde (MDA), 4-hydroxy-trans-2-nonenal (HNE), and 4-hydroxy-trans-2-hexenal (HHE) by liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (LC/APCI-MS), and for free fatty acids (FFA) obtained during the digestion by gas chromatography-mass spectrometry (GC-MS). The formation of the oxidation products MDA, HHE, and HNE was low during the gastric digestion, however, it increased during the duodenal digestion. The formation of the oxidation products reached higher levels when digestive juices of human origin were used (60 μM of MDA, 9.8 μM of HHE, and 0.36 μM of HNE) [corrected] compared to when using enzymes and bile of porcine origin (0.96, and 1.6 μM of MDA; 0.16, and 0.23 μM of HHE; 0.026, [corrected] and 0.005 μM of HNE, respectively, in porcine models I and II). In all models, FFA release was only detected during the intestinal step, and reached up to 31% of total fatty acids (FA). The findings in this work may be of importance when designing oxidation oriented lipid digestion studies.

Formation of Malondialdehyde, 4-Hydroxynonenal, and 4-Hydroxyhexenal during in Vitro Digestion of Cooked Beef, Pork, Chicken, and Salmon

Red meat high in heme iron may promote the formation of potentially genotoxic aldehydes during lipid peroxidation in the gastrointestinal tract. In this study, the formation of malondialdehyde (MDA) equivalents measured by the thiobarbituric acid reactive substances (TBARS) method was determined during in vitro digestion of cooked red meat (beef and pork), as well as white meat (chicken) and fish (salmon), whereas analysis of 4-hydroxyhexenal (HHE) and 4-hydroxynonenal (HNE) was performed during in vitro digestion of cooked beef and salmon. Comparing products with similar fat contents indicated that the amount of unsaturated fat and not total iron content was the dominating factor influencing the formation of aldehydes. It was also shown that increasing fat content in beef products caused increasing concentrations of MDA equivalents. The highest levels, however, were found in minced beef with added fish oil high in unsaturated fat. This study indicates that when ingested alone, red meat products low in unsaturated fat and low in total fat content contribute to relatively low levels of potentially genotoxic aldehydes in the gastrointestinal tract.

Effect of broccoli phytochemical extract on release of fatty acids from salmon muscle and salmon oil during in vitro digestion

The aim of the present work was to study the effect of a broccoli phytochemical extract (Br-ex) on the release of fatty acids (FA) from salmon muscle (SM) and salmon oil (SO) duringin vitrodigestion.