Vitamin A deficiency enhances docosahexaenoic and Osbond acids in liver of rats fed an α-linoleic acid-adequate diet

Impact of polyunsaturated fatty acid supplementation on assisted reproductive technology outcomes: a systematic review

This review explores the impact of polyunsaturated fatty acid (PUFA) supplementation in women undergoing assisted reproductive technology (ART) on reproductive outcomes. A systematic search of English peer-reviewed journals was carried out using MEDLINE, EMBASE, and the Cochrane Library to identify articles published from January 1978 to 2021. The primary outcomes assessed included pregnancy and live birth rates. Secondary outcome measures included: (i) implantation rate; (ii) fertilisation rate; (iii) number of oocytes retrieved; (iv) number of metaphase II (MII) oocytes; (v) blastocyst conversion; and (vi) embryo quality. A total of 4 randomised control trials (RCTs) met the inclusion criteria. There is a lack of high-quality research to support widespread dietary supplementation with PUFAs in women undergoing ART. Prior to its clinical recommendation, there is a need for well-designed RCTs to facilitate an in-depth understanding of PUFA supplementation in women undergoing ART.

The Application of Lactobacillus reuteri CCM 8617 and Flaxseed Positively Improved the Health of Mice Challenged with Enterotoxigenic E. coli O149:F4

The aim of our study was to monitor the effects of dietary synbiotics on experimentally infected mice. Sixty mice were divided into the following three groups: negative control group C1, positive control group C2 (mice infected with enterotoxigenic Escherichia coli O149:F4_NAL), and experimental group LF (Lactobacillus reuteri CCM 8617_RIF + 10% flaxseed + E. coli O149:F4_NAL). Supplements were administered for 42 days. Microbiological, hematological, and biochemical analyses, electrophoretic analysis of lactate dehydrogenase (LDH) isoenzymes, and analysis of fatty acids using gas chromatography and isotachophoresis were performed. We recorded higher numbers of jejunal and ileal lactic acid bacteria, lower Enterobacteriaceae counts in the feces of the animals, and an increased production of organic acids in the synbiotic-fed group. The supplements applied favored n-3 polyunsaturated fatty acid (PUFA) metabolism and inhibited n-6 PUFA metabolism; thus, they influenced the n-6 to n-3 and eicosapentaenoic to arachidonic acid ratios. Additionally, the incorporation of n-3 PUFAs to the cell membrane decreased the activity of LDH, transaminases, and alkaline phosphatase. Results obtained in our study indicate the positive effect of continuous supplementation of combination of probiotic cheese enriched with L. reuteri CCM 8617_RIF and crushed flaxseed on composition of intestinal microflora and alleviation of the course of infection induced by pathogenic bacterium E. coli O149:F4_NAL.

Alternative retinoid X receptor (RXR) ligands

Retinoid X receptors (RXRs) control a wide variety of functions by virtue of their dimerization with other nuclear hormone receptors (NRs), contributing thereby to activities of different signaling pathways. We review known RXR ligands as transcriptional modulators of specific RXR-dimers and the associated biological processes. We also discuss the physiological relevance of such ligands, which remains frequently a matter of debate and which at present is best met by member(s) of a novel family of retinoids, postulated as Vitamin A5. Through comparison with other natural, but also with synthetic ligands, we discuss high diversity in the modes of ligand binding to RXRs resulting in agonistic or antagonistic profiles and selectivity towards specific subtypes of permissive heterodimers. Despite such diversity, direct ligand binding to the ligand binding pocket resulting in agonistic activity was preferentially preserved in the course of animal evolution pointing to its functional relevance, and potential for existence of other, species-specific endogenous RXR ligands sharing the same mode of function.

Omega-3 and omega-6 polyunsaturated fatty acids: Dietary sources, metabolism, and significance - A review

Linoleic acid (LA) (n-6) and α-linolenic acid (ALA) (n-3) are essential fatty acids (EFAs) as they cannot be synthesized by humans or other higher animals. In the human body, these fatty acids (FAs) give rise to arachidonic acid (ARA, n-6), eicosapentaenoic acid (EPA, n-3), and docosahexaenoic acid (DHA, n-3) that play key roles in regulating body homeostasis. Locally acting bioactive signaling lipids called eicosanoids derived from these FAs also regulate diverse homeostatic processes. In general, ARA gives rise to pro-inflammatory eicosanoids whereas EPA and DHA give rise to anti-inflammatory eicosanoids. Thus, a proportionally higher consumption of n-3 PUFAs can protect us against inflammatory diseases, cancer, cardiovascular diseases, and other chronic diseases. The present review summarizes major sources, intake, and global consumption of n-3 and n-6 PUFAs. Their metabolism to biosynthesize long-chain PUFAs and eicosanoids and their roles in brain metabolism, cardiovascular disease, obesity, cancer, and bone health are also discussed.

Spaceflight Activates Lipotoxic Pathways in Mouse Liver

Spaceflight affects numerous organ systems in the body, leading to metabolic dysfunction that may have long-term consequences. Microgravity-induced alterations in liver metabolism, particularly with respect to lipids, remain largely unexplored. Here we utilize a novel systems biology approach, combining metabolomics and transcriptomics with advanced Raman microscopy, to investigate altered hepatic lipid metabolism in mice following short duration spaceflight. Mice flown aboard Space Transportation System -135, the last Shuttle mission, lose weight but redistribute lipids, particularly to the liver. Intriguingly, spaceflight mice lose retinol from lipid droplets. Both mRNA and metabolite changes suggest the retinol loss is linked to activation of PPARα-mediated pathways and potentially to hepatic stellate cell activation, both of which may be coincident with increased bile acids and early signs of liver injury. Although the 13-day flight duration is too short for frank fibrosis to develop, the retinol loss plus changes in markers of extracellular matrix remodeling raise the concern that longer duration exposure to the space environment may result in progressive liver damage, increasing the risk for nonalcoholic fatty liver disease.

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Several studies have reported that the status in omega-3 polyunsaturated fatty acid (PUFA) and the omega-3/omega-6 PUFA ratio are positively related to bone health. This study aimed at examining the relationship between the status of different PUFAs and bone strength expressed by the stiffness index (SI) among indigenous women in northern Canada and Greenland, whose diets are rich in PUFAs compared to those of non-Aboriginals. Our study includes 118 Inuit women from Nuuk (Greenland), 195 Inuit women from Nunavik (Canada), and 249 Cree women of from East James Bay (Canada). Projects in Nunavik and in the Cree communities had a cross-sectional design and the Greenland project, a longitudinal design. The content of some PUFAs phospholipids of erythrocyte membranes was measured after transmethylation by gas chromatography coupled with a flame ionization detector. Stiffness index was measured by ultrasound at the right calcaneus with a water-bath Achilles Lunar instrument (Greenland) or an Achilles Insight instrument (Nunavik, East James Bay). Relations between SI and various PUFAs were studied using multiple linear regression analyses. Eicosapentaenoic acid (EPA) was positively and significantly associated with SI (log), even after adjustment for several confounders and covariates in all three projects. A high EPA status, resulting mainly from the consumption of fatty fish or marine mammal fat, seems to have a positive effect on bone strength measured by ultrasonography among Aboriginal women from three different populations.

Animal products, diseases and drugs: a plea for better integration between agricultural sciences, human nutrition and human pharmacology

Eicosanoids are major players in the pathogenesis of several common diseases, with either overproduction or imbalance (e.g. between thromboxanes and prostacyclins) often leading to worsening of disease symptoms. Both the total rate of eicosanoid production and the balance between eicosanoids with opposite effects are strongly dependent on dietary factors, such as the daily intakes of various eicosanoid precursor fatty acids, and also on the intakes of several antioxidant nutrients including selenium and sulphur amino acids. Even though the underlying biochemical mechanisms have been thoroughly studied for more than 30 years, neither the agricultural sector nor medical practitioners have shown much interest in making practical use of the abundant high-quality research data now available. In this article, we discuss some specific examples of the interactions between diet and drugs in the pathogenesis and therapy of various common diseases. We also discuss, using common pain conditions and cancer as specific examples, how a better integration between agricultural science, nutrition and pharmacology could lead to improved treatment for important diseases (with improved overall therapeutic effect at the same time as negative side effects and therapy costs can be strongly reduced). It is shown how an unnaturally high omega-6/omega-3 fatty acid concentration ratio in meat, offal and eggs (because the omega-6/omega-3 ratio of the animal diet is unnaturally high) directly leads to exacerbation of pain conditions, cardiovascular disease and probably most cancers. It should be technologically easy and fairly inexpensive to produce poultry and pork meat with much more long-chain omega-3 fatty acids and less arachidonic acid than now, at the same time as they could also have a similar selenium concentration as is common in marine fish. The health economic benefits of such products for society as a whole must be expected vastly to outweigh the direct costs for the farming sector.

Dietary n-6 and n-3 polyunsaturated fatty acids: from biochemistry to clinical implications in cardiovascular prevention

Linoleic acid (LA) and alpha linolenic acid (ALA) belong to the n-6 (omega-6) and n-3 (omega-3) series of polyunsaturated fatty acids (PUFA), respectively. They are defined "essential" fatty acids since they are not synthesized in the human body and are mostly obtained from the diet. Food sources of ALA and LA are most vegetable oils, cereals and walnuts. This review critically revises the most significant epidemiological and interventional studies on the cardioprotective activity of PUFAs, linking their biological functions to biochemistry and metabolism. In fact, a complex series of desaturation and elongation reactions acting in concert transform LA and ALA to their higher unsaturated derivatives: arachidonic acid (AA) from LA, eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) from ALA. EPA and DHA are abundantly present in fish and fish oil. AA and EPA are precursors of different classes of pro-inflammatory or anti-inflammatory eicosanoids, respectively, whose biological activities have been evoked to justify risks and benefits of PUFA consumption. The controversial origin and clinical role of the n-6/n-3 ratio as a potential risk factor in cardiovascular diseases is also examined. This review highlights the important cardioprotective effect of n-3 in the secondary prevention of sudden cardiac death due to arrhythmias, but suggests caution to recommend dietary supplementation of PUFAs to the general population, without considering, at the individual level, the intake of total energy and fats.