Omega-3 LC PUFA Contents and Oxidative Stability of Encapsulated Fish Oil Dietary Supplements

A New Generation of Postbiotics for Skin and Scalp: In Situ Production of Lipid Metabolites by Malassezia

Effects of pre- and probiotics on intestinal health are well researched and microbiome-targeting solutions are commercially available. Even though a trend to appreciate the presence of certain microbes on the skin is seeing an increase in momentum, our understanding is limited as to whether the utilization of skin-resident microbes for beneficial effects holds the same potential as the targeted manipulation of the gut microflora. Here, we present a selection of molecular mechanisms of cross-communication between human skin and the skin microbial community and the impact of these interactions on the host's cutaneous health with implications for the development of skin cosmetic and therapeutic solutions. Malassezia yeasts, as the main fungal representatives of the skin microfloral community, interact with the human host skin via lipid mediators, of which several are characterized by exhibiting potent anti-inflammatory activities. This review therefore puts a spotlight on Malassezia and provides a comprehensive overview of the current state of knowledge about these fungal-derived lipid mediators and their capability to reduce aesthetical and sensory burdens, such as redness and itching, commonly associated with inflammatory skin conditions. Finally, several examples of current skin microbiome-based interventions for cosmetic solutions are discussed, and models are presented for the use of skin-resident microbes as endogenous bio-manufacturing platforms for the in situ supplementation of the skin with beneficial metabolites.

Can individual fatty acids be used as functional biomarkers of dairy fat consumption in relation to cardiometabolic health? A narrative review

In epidemiological studies, dairy food consumption has been associated with minimal effect or decreased risk of some cardiometabolic diseases (CMD). However, current methods of dietary assessment do not provide objective and accurate measures of food intakes. Thus, the identification of valid and reliable biomarkers of dairy product intake is an important challenge to best determine the relationship between dairy consumption and health status. This review investigated potential biomarkers of dairy fat consumption, such as odd-chain, trans- and branched-chain fatty acids (FA), which may improve the assessment of full-fat dairy product consumption. Overall, the current use of serum/plasma FA as biomarkers of dairy fat consumption is mostly based on observational evidence, with a lack of well-controlled, dose-response intervention studies to accurately assess the strength of the relationship. Circulating odd-chain SFA and trans-palmitoleic acid are increasingly studied in relation to CMD risk and seem to be consistently associated with a reduced risk of type 2 diabetes in prospective cohort studies. However, associations with CVD are less clear. Overall, adding less studied FA such as vaccenic and phytanic acids to the current available evidence may provide a more complete assessment of dairy fat intake and minimise potential confounding from endogenous synthesis. Finally, the current evidence base on the direct effect of dairy fatty acids on established biomarkers of CMD risk (e.g. fasting lipid profiles and markers of glycaemic control) mostly derives from cross-sectional, animal and in vitro studies and should be strengthened by well-controlled human intervention studies.

Dietary Supplements among Children Ages 0-3 Years in Poland-Are They Necessary?

(1) Background: One of the ways to prevent nutritional deficiencies may be supplementation. Experts have observed the increased use of dietary supplements, not only in adults but also in children. Considering controversies among dietary supplements and possible errors in children's feeding, the goal of our research was to evaluate use and reasons behind supplementation in terms of children's diet analysis. (2) Methods: Our research involved 507 legal guardians of the youngest children (up to 3 years of age) and was conducted via a questionnaire. (3) Results: 79% of all children received dietary supplements. The analysis of children's diets showed a need to implement omega-3 acids and vitamin D supplementation, which was very low in children. On the other hand, vitamin C, vitamin B, vitamin A, and copper levels were extremely high. (4) Conclusions: Popularity of dietary supplements in Polish children aged 0-3 years old is an omnipresent issue. Although the reasoning behind administering nutritional supplements to children seems justified, considering the supply of vitamin D and omega-3 fatty acids, it seems justified to increase parents' knowledge in this regard in terms of the use and means to choose the best supplement possible, as dietary supplementation should always be tailored to individual needs.

Toxicity of oxidized fish oil in pregnancy - a dose response study in rats

INTRODUCTION

Fish oil (FO) supplements are consumed during pregnancy to increase dietary omega-3. However, FO is often oxidized past recommended limits. In rats, a large dose of highly oxidized FO substantially increased newborn mortality, but the effects of human-relevant doses of less oxidized oil are unknown. A dose-response study in rats was conducted to estimate the safe level of oxidation during pregnancy.

METHODOLOGY

Sprague-Dawley rat dams were mated, then individually housed and provided with a gel treatment on each day of pregnancy. Treatment groups differed only in the FO content of the gel; control (no oil), PV5, PV10, and PV40 (0.05ml of FO oxidized to a peroxide value (PV) of 5, 10, or 40meq/kg), or PV40(1ml) (1ml of PV40). A subset of dams was culled on gestational day 20 to enable sampling, and the remainder were allowed to give birth. Newborn mortality was recorded. Offspring were sampled at postnatal days 2 and 21, and dams at day 21.

RESULTS

There were no signs of unwellness during pregnancy. However, there was markedly increased neonatal mortality affecting the PV40(1ml) (12.8%) and PV40 (6.3%) groups, but not the control, PV5, or PV10 groups (1-1.4%). Dietary oxidized FO altered the expression of placental genes involved in antioxidant pathways and the production of free radicals. Conclusions Highly oxidized FO was toxic in rat pregnancy leading to a marked increase in mortality even at a human-relevant dose. We observed no toxic effects of FOs with PV≤ 10meq/kg, suggesting that this is an appropriate maximum limit.

Assessment of the safety of dietary fish oil supplements in terms of content and quality

The fatty acid composition of top-selling fish oil dietary supplements in the markets was compared with the content stated on product label, and their oxidative qualities and heavy metal contents were evaluated in this study. While all the capsule groups (C) confirmed the label information, it was observed that one-third of the syrup groups (S) had less than the specified content. Capsule groups generally had richer EPA and DHA contents than syrup groups in the samples examined. The peroxide values (PV) of all fish oil capsules and syrups were found in the range of 1.97-2.89 mEq/kg and 2.22-18.30 mEq/kg, respectively. As for free fatty acids (FFA) values, the C4, S6, S9, and S10 groups were above the 3% oleic acid limit recommended for high-quality oils. However, thiobarbituric acid reactive substances (TBARs) values were found below 1 mg MA/kg in all groups. All fish oil supplements were within the limits specified in terms of As (0.50-4.19 µg/g), Cd (0.14 µg/g detected for one group, C5), Cu (not detected), Fe (0.32-15.7 µg/g), and Hg (≤ 0.1 µg/g). On the other hand, two fish oil supplements from the capsule group (0.17 for C6 and 1.01 µg/g for C8) and one group from the syrup group (0.29 µg/g for S10) exceeded the recommended limit in terms of Pb (0.1 mg/kg). As a result of the research, it can be concluded that the chemical quality of fish oils in syrup form needs to be improved and their reliability in terms of fatty acid content should be increased. Considering the heavy metals, it seems significant to follow up the fish oil products more strictly.

Quality of Fish-Oil-Based Dietary Supplements Available on the Italian Market: A Preliminary Study

The global market of food supplements is growing rapidly with a large turnover. Fish oil supplements represent a significant part of this turnover as they are believed to have important health benefits. Conversely, there are few papers in the literature about the quality control of fish oil capsules. As prior studies illustrate, a perfect agreement with the label is rarely found, and in some isolated cases, large amounts of soybean oil are also detected, indicating a true adulteration rather than a non-compliance with the label. None of the available studies refer to the Italian market, which ranks first in Europe in the consumption of food supplements. In this present communication, a quality control of fish-oil-based supplements from the Italian market was carried out for the first time. With minor deviations, all results showed substantial agreement with the label. However, the most important conclusion from this research is that compliance with the label is not enough to judge a product of good quality. The analysis of the overall fatty acid composition showed that some supplements have a high level of saturated fatty acids, and therefore they did not undergo a proper purification process. This may represent a safety issue since the purification process also allows the removal of toxic contaminants.

Omega-3 fats in pregnancy: could a targeted approach lead to better metabolic health for children?

The prevalence of childhood obesity is increasing worldwide, and the children of women who are obese during pregnancy are at greatest risk. This risk may be mediated by exaggeration of the normal insulin resistance of pregnancy. Omega-3 (n-3) fats are insulin sensitizing. Supplementation during pregnancy may reduce metabolic risk and adiposity in the children. Though results from animal studies are encouraging, completed clinical trials have not demonstrated this benefit. However, to our knowledge, previous studies have not targeted women who are overweight or obese while pregnant-the group at greatest risk for insulin resistance and most likely to benefit from n-3. In this narrative review, the importance of performing clinical trials restricted to women who are overweight or obese is discussed, as is the potential importance of n-3 dose, oil source and quality, and the timing of the intervention.

An Overview and Therapeutic Promise of Nutraceuticals against Sports-Related Brain Injury

Sports-related traumatic brain injury (TBI) is one of the common neurological maladies experienced by athletes. Earlier the term 'punch drunk syndrome' was used in the case TBI of boxers and now this term is replaced by chronic traumatic encephalopathy (CTE). Sports-related brain injury can either be short term or long term. A common instance of brain injury encompasses subdural hematoma, concussion, cognitive dysfunction, amnesia, headache, vision issue, axonopathy, or even death if remain undiagnosed or untreated. Further, chronic TBI may lead to pathogenesis of neuroinflammation and neurodegeneration via tauopathy, formation of neurofibrillary tangles, and damage to the blood-brain barrier, microglial, and astrocyte activation. Thus, altered pathological, neurochemical, and neurometabolic attributes lead to the modulation of multiple signaling pathways and cause neurological dysfunction. Available pharmaceutical interventions are based on one drug one target hypothesis and thereby unable to cover altered multiple signaling pathways. However, in recent time's pharmacological intervention of nutrients and nutraceuticals have been explored as they exert a multifactorial mode of action and maintain over homeostasis of the body. There are various reports available showing the positive therapeutic effect of nutraceuticals in sport-related brain injury. Therefore, in the current article we have discussed the pathology, neurological consequence, sequelae, and perpetuation of sports-related brain injury. Further, we have discussed various nutraceutical supplements as well as available animal models to explore the neuroprotective effect/ upshots of these nutraceuticals in sports-related brain injury.

Fish oil supplements, oxidative status, and compliance behaviour: Regulatory challenges and opportunities

BACKGROUND

Fish oil supplements that are rich in omega-3 long-chain polyunsaturated fatty acids (n-3 PUFAs). PUFAs are among the most widely-used dietary supplements globally, and millions of people consume them regularly. There have always been public concerns that these products should be guaranteed to be safe and of good quality, especially as these types of fish oil supplements are extremely susceptible to oxidative degradation.

OBJECTIVES

The aim of the current study is to investigate and examine the oxidation status of dietary supplements containing fish oils and to identify important factors related to the oxidation status of such supplements available in the United Arab Emirates (UAE).

METHODS

A total of 44 fish oil supplements were analysed in this study. For each product, the oxidative parameters peroxide value (PV), anisidine value (AV), and total oxidation (TOTOX) were calculated, and comparisons were made with the guidelines supplied by the Global Organization for EPA and DHA Omega-3s (GOED). Median values for each of the above oxidative parameters were tested using the Kruskal-Wallis and Mann-Whitney U tests. P values < 0.05 were chosen as the statistically significant boundary.

RESULTS

The estimate for the average PV value was 6.4 with a 95% confidence interval (CI) [4.2-8.7] compared to the maximum allowable limit of 5 meq/kg. The estimate for the average P-AV was 11 with a 95% CI [7.8-14.2] compared to the maximum allowable limit of 20. The estimate for the average TOTOX value was 23.8 meq/kg with a 95% CI [17.4-30.3] compared to the maximum allowable limit of 26 according to the GOED standards.

CONCLUSION

This research shows that most, although not all, of the fish oil supplements tested are compliant with the GOED oxidative quality standards. Nevertheless, it is clear that there should be a high level of inspection and control regarding authenticity, purity, quality, and safety in the processes of production and supply of dietary supplements containing fish oils.

How To Stabilize ω-3 Polyunsaturated Fatty Acids (PUFAs) in an Animal Feeding Study?-Effects of the Temperature, Oxygen Level, and Antioxidant on Oxidative Stability of ω-3 PUFAs in a Mouse Diet

Substantial studies have shown that ω-3 polyunsaturated fatty acids (PUFAs) have various health-promoting effects; however, there are inconsistent results from animal studies that showed that ω-3 PUFAs have no effects or even detrimental effects. Emerging research suggests that oxidized ω-3 PUFAs have different effects compared to unoxidized ω-3 PUFAs; therefore, lipid oxidation of dietary ω-3 PUFAs could contribute to the mixed results of ω-3 PUFAs in animal studies. Here, we prepared an AIN-93G-based, semi-purified, powder diet, which is one of the most commonly used rodent diets in animal studies, to study the oxidative stability of fortified ω-3 PUFAs in animal feed. We found that lowering the storage temperature or the addition of a certain antioxidant, notably tert-butylhydroquinone (TBHQ), helps to stabilize ω-3 PUFAs and suppress ω-3 oxidation in the animal diet, while reducing the level of oxygen in the storage atmosphere is not very effective. The addition of 50 ppm of TBHQ in the diet inhibited 99.5 ± 0.1% formation of primary oxidation products and inhibited 96.1 ± 0.7% formation of secondary oxidation products, after 10 days of storage of the prepared diet at a typical animal-feeding experiment condition. Overall, our results highlight that ω-3 PUFAs are highly prone to lipid oxidation in a typical animal-feeding experiment, emphasizing the critical importance to stabilize ω-3 PUFAs in animal studies.

What Do Polish Parents and Caregivers Think ofDietary Supplements for Children Aged 3-12?

Background: The aim of this study was to specify the amounts and the types of dietary supplements (DS) taken by children and define the attitudes of caregivers towards DS and towards administering them to children aged 3–12. An analysis of the reasons for using DSs, and of expected benefits and awareness of health risks associated with administering DSs, was conducted. Methods: The online questionnaire collected information on sociodemographic characteristics and use of dietary supplements. Multiple analyses were used to describe the relationship between demographic factors and dietary supplement intake. In particular cases, strength and correlation were also calculated. Results: In total, 54.89% of participants were administering dietary supplements to children at the time of completing the questionnaire—a weak linear relationship (Cramer’s V = 0.21) between child’s age and the child taking dietary supplements. Respondents for whom DSs are equivalents of medicines tend not to see that dietary supplements may cause side-effects and interact. Conclusions: Parents who administer dietary supplements to children show a tendency to have more trust in this type of product than the people who do not do so. It was also confirmed that the people who take dietary supplements transfer their behavioral patterns by also administering them to their children.

Acyl-lipid desaturases and Vipp1 cooperate in cyanobacteria to produce novel omega-3 PUFA-containing glycolipids

BACKGROUND

Dietary omega-3 (n-3), long chain (LC-, ≥ 20 carbons), polyunsaturated fatty acids (PUFAs) derived largely from marine animal sources protect against inflammatory processes and enhance brain development and function. With the depletion of natural stocks of marine animal sources and an increasing demand for n-3 LC-PUFAs, alternative, sustainable supplies are urgently needed. As a result, n-3 18-carbon and LC-PUFAs are being generated from plant or algal sources, either by engineering new biosynthetic pathways or by augmenting existing systems.

RESULTS

We utilized an engineered plasmid encoding two cyanobacterial acyl-lipid desaturases (DesB and DesD, encoding Δ15 and Δ6 desaturases, respectively) and "vesicle-inducing protein in plastids" (Vipp1) to induce production of stearidonic acid (SDA, 18:4 n-3) at high levels in three strains of cyanobacteria (10, 17 and 27% of total lipids in Anabaena sp. PCC7120, Synechococcus sp. PCC7002, and Leptolyngbya sp. strain BL0902, respectively). Lipidomic analysis revealed that in addition to SDA, the rare anti-inflammatory n-3 LC-PUFA eicosatetraenoic acid (ETA, 20:4 n-3) was synthesized in these engineered strains, and ~ 99% of SDA and ETA was complexed to bioavailable monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) species. Importantly, novel molecular species containing alpha-linolenic acid (ALA), SDA and/or ETA in both acyl positions of MGDG and DGDG were observed in the engineered Leptolyngbya and Synechococcus strains, suggesting that these could provide a rich source of anti-inflammatory molecules.

CONCLUSIONS

Overall, this technology utilizes solar energy, consumes carbon dioxide, and produces large amounts of nutritionally important n-3 PUFAs and LC-PUFAs. Importantly, it can generate previously undescribed, highly bioavailable, anti-inflammatory galactosyl lipids. This technology could therefore be transformative in protecting ocean fisheries and augmenting the nutritional quality of human and animal food products.

Aldehydes identified in commercially available ω-3 supplements via 1 H NMR spectroscopy

OBJECTIVES

Cardiovascular disease (CVD) is the leading cause of mortality globally. Studies have suggested that supplementary ω-3 oils may provide cardiovascular protection, although the literature is equivocal. Recently, it has been established that many commercially available ω-3 supplements are unacceptably oxidized, leading to myriad potential health risks. One oxidation product of concern is aldehydes, which have been shown to have mutagenic, cytotoxic, and inflammatory properties that may contribute to many different disease processes, including CVD. The aim of this study was to assess the prevalence of aldehyde contamination in commercially available ω-3 supplements.

METHODS

We tested 12 different ω-3 oils (6 fish, 4 krill, 2 algae), using 1 H-nuclear magnetic resonance scanning. This work is of a pilot nature, as such we randomly selected and purchased 12 different oils over the counter from various local retailers according to the sales representatives' recommendations.

RESULTS

The four krill products contained aldehydes at concentrations between 5.652 (±0.496) and 6.779 (±1.817) mMol/L. Both algae samples contained aldehydes: 1.235 (±0.111) and 1.565 (±0.618) mMol/L. Two of the six fish oils contained aldehydes 1.568 (±0.291) and 4.319 (±2.361) mMol/L. There is currently no standard for aldehyde content nor for labeling of ω-3 supplements. Two-thirds (8 of 12) of the ω-3 supplements tested in this study contained aldehydes. Aldehydes have the potential to precipitate serious health problems even at very low absolute intake volumes. These findings may provide reason for sober reflection.

Examination of marine and vegetable oil oxidation data from a multi-year, third-party database

Fish oil (FO) products constitute good sources of omega-3 fats. Oxidation data from a large third-party database of 1900 + globally-sourced FO samples were assessed. In FO products, for peroxide value (PV), 13.9% exceeded 5 mEq O₂/kg (2.2% >10); for acid value (AcV) 2.1% exceeded 3 mg KOH/g, while for p-anisidine value (pAV) in unflavoured oils, 6.1% exceeded 20, (3.8% >30), and 8.8% exceeded TOTOX limits (26). Additionally, we compared FO with other dietary oils. The FO median PV was similar to those of algal and sunflower oils, 4.8-fold greater than krill oil, and 5.2-fold less than extra-virgin olive oil. The median pAV differed non-significantly among oils. The FO median AcV was similar to those of algal and extra-virgin olive oils, 3.4-fold greater than sunflower oil, and 11.9-fold less than krill oil. This study has provided new insight that retail FO products predominantly meet regulatory guidelines and are comparable in oxidative status to other dietary oils.

Omega-3 Long-Chain Polyunsaturated Fatty Acid Content and Oxidation State of Fish Oil Supplements in New Zealand

Forty-seven fish oil products available on the New Zealand market were analyzed for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content, as well as for oxidative status in a collaborative effort by several analytical laboratories. Of the tested products, 72%, 86% and 77% complied with voluntary industry-set maximum limits on Peroxide Value (PV), para-Anisidine Value (p-AV), and TOTOX, respectively. 91% of the products complied with EPA/DHA content claims. All fish oils complied with a p-AV limit of 30, 98% with a PV limit of 10 meq O2/kg, and 96% with a calculated TOTOX value of 50, which are less stringent limits used by the European and British Pharmacopeia and the Australian authorities. The results are in stark contrast to the very low percentage of fish oil products reported to be in compliance with primary oxidation limits and EPA/DHA content by a recently published assessment of fish oil supplements in New Zealand. Possible reasons for this discrepancy are evaluated and discussed.

Concerns with the Study on Australian and New Zealand Fish Oil Products by Nichols et al. (Nutrients 2016, 8, 703)

n/a.

The impact of essential fatty acid, B vitamins, vitamin C, magnesium and zinc supplementation on stress levels in women: a systematic review

BACKGROUND

Women juggling multiple roles in our complex society are increasingly experiencing psychological stress. Dietary supplementation to manage stress is widespread despite limited supporting evidence. A systematic review of the available literature was undertaken to investigate the efficacy of specific dietary supplements in managing female stress and anxiety.

OBJECTIVES

To identify the impact of essential fatty acids (EFAs), B vitamins, vitamin C, magnesium and/or zinc, consumed as dietary supplements to the daily diet, on female stress and anxiety levels.

INCLUSION CRITERIA TYPES OF PARTICIPANTS

Women aged 18 years and over, who had participated in a study where stress and/or anxiety were assessed.

TYPES OF INTERVENTION(S)

Dietary supplementation with EFAs, B vitamins, vitamin C, magnesium and/or zinc.

TYPES OF COMPARATORS

Supplements, either alone or combined, were compared with either no intervention or placebo.

TYPES OF STUDIES

Randomized controlled and pseudo-randomized trials were included.

OUTCOMES

Stress and anxiety were assessed using self-report or physiological outcome measures.

SEARCH STRATEGY

Published and unpublished studies were sought via MEDLINE (via PubMed), Embase, Scopus, CINAHL, PsycINFO, PsycARTICLES, MedNar, National Institute of Mental Health and the International Association for Women's Mental Health.

METHODOLOGICAL QUALITY

Methodological quality was evaluated using standardized critical appraisal instruments from the Joanna Briggs Institute.

DATA EXTRACTION

Data were extracted using the standardized data extraction instruments from the Joanna Briggs Institute.

DATA SYNTHESIS

Due to heterogeneity of the included studies, narrative synthesis was performed.

RESULTS

Fourteen studies were included in this review. Essential fatty acids were effective in reducing perceived stress and salivary cortisol levels during pregnancy and anxiety in premenstrual women, and anxiety during menopause in the absence of depression, but were ineffective when depression was disregarded. Disregarding the hormonal phase, EFAs were ineffective in reducing stress or anxiety in four groups of women. Combined magnesium and vitamin B6 supplementation reduced premenstrual anxiety but had no effect when used in isolation and did not affect stress in women suffering from dysmenorrhea when combined or used in isolation. Older women experienced anxiety reduction using vitamin B6, but not folate or vitamin B12. High-dose sustained-release vitamin C was effective in reducing anxiety and blood pressure in response to stress.

CONCLUSION

The current review suggests that EFAs may be effective in reducing prenatal stress and salivary cortisol and may reduce anxiety during premenstrual syndrome and during menopause in the absence of depression. Magnesium and vitamin B6 may be effective in combination in reducing premenstrual stress, and vitamin B6 alone may reduce anxiety effectively in older women. High-dose sustained-release vitamin C may reduce anxiety and mitigate increased blood pressure in response to stress.

IMPLICATIONS FOR PRACTICE

Essential fatty acids may be effective in reducing prenatal stress and salivary cortisol levels, and premenstrual or menopausal anxiety in the absence of depression. Combining magnesium and vitamin B6 may reduce premenstrual anxiety and vitamin B6 may reduce anxiety in older women. High-dose sustained-release vitamin C may reduce anxiety and mitigate increased blood pressure in response to stress.

IMPLICATIONS FOR RESEARCH

Investigating supplementation in longer term studies is warranted and should include compliance testing, the use of inert substances as controls and reliable outcome measures.

Nano-encapsulation of fish oil in nano-liposomes and its application in fortification of yogurt

Fish oils have many dietary benefits, but due to their strong odors and rapid deterioration, their application in food formulations is limited. For these reasons, nano-liposome was used to nano-encapsulate fish oil in this study and encapsulated fish oil was utilized in fortifying yogurt. Physicochemical properties of produced yogurt including pH, acidity, syneresis, fatty acid composition, peroxide value as well as sensory tests were investigated during three weeks storage at 4°C. Nano-liposome encapsulation resulted in a significant reduction in acidity, syneresis and peroxide value. The results of gas chromatography analyses revealed that after 21days storage, yogurt fortified with nano-encapsulated fish oil had a higher DHA and EPA contents than yogurt containing free fish oil. Overall, the results of this study indicates that adding nano-encapsulated fish oil into yogurt gave closer characteristics to control sample in terms of sensory characteristics than yogurt fortified with free fish oil.

The PBMC transcriptome profile after intake of oxidized versus high-quality fish oil: an explorative study in healthy subjects

BACKGROUND

Marine long-chain polyunsaturated fatty acids are susceptible to oxidation, generating a range of different oxidation products with suggested negative health effects. The aim of the present study was to utilize sensitive high-throughput transcriptome analyses to investigate potential unfavorable effects of oxidized fish oil (PV: 18 meq/kg; AV: 9) compared to high-quality fish oil (PV: 4 meq/kg; AV: 3).

METHODS

In a double-blinded randomized controlled study for seven weeks, 35 healthy subjects were assigned to 8 g of either oxidized fish oil or high quality fish oil. The daily dose of EPA+DHA was 1.6 g. Peripheral blood mononuclear cells were isolated at baseline and after 7 weeks and transcriptome analyses were performed with the illuminaHT-12 v4 Expression BeadChip.

RESULTS

No gene transcripts, biological processes, pathway or network were significantly changed in the oxidized fish oil group compared to the fish oil group. Furthermore, gene sets related to oxidative stress and cardiovascular disease were not differently regulated between the groups. Within group analyses revealed a more prominent effect after intake of high quality fish oil as 11 gene transcripts were significantly (FDR < 0.1) changed from baseline versus three within the oxidized fish oil group.

CONCLUSION

The suggested concern linking lipid oxidation products to short-term unfavorable health effects may therefore not be evident at a molecular level in this explorative study.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01034423.

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.

Oxidation levels of North American over-the-counter n-3 (omega-3) supplements and the influence of supplement formulation and delivery form on evaluating oxidative safety

The aim of the present study was to evaluate the oxidation status of North American n-3 (omega-3) PUFA nutritional supplements commercially available in Canada and evaluate the influence of product formulation and delivery form on oxidative safety. A total of 171 North American over-the-counter n-3 PUFA nutritional supplements were analysed for oxidation safety. Primary and secondary oxidation and total oxidation (TOTOX) were determined using the American Oil Chemists' Society (AOCS) procedures. Comparisons between supplements' final forms, oil source and n-3 PUFA concentration quartiles, as measures of product formulations and delivery forms, were compared using ANOVA. Of the products successfully tested, 50 % exceeded the voluntary recommended levels for markers of oxidation. Another 18 % of products were approaching the limits with 1-3 years before expiration. Encapsulated products without flavour additives had significantly lower secondary and TOTOX levels than bulk oils and flavoured products (P < 0·05). Children's products had significantly higher primary, secondary and TOTOX levels compared with all other products (P < 0·05). Markers of oxidation did not differ between oil sources (P > 0·05), with the exception of krill oil products having higher secondary oxidation levels than plant-based products (P > 0·05). Markers of oxidation did not differ between n-3 PUFA supplement concentration quartiles. Consumers may be at risk of exposure to higher levels of oxidative products. New regulatory mandates need to be introduced to ensure that all n-3 PUFA products, used as nutritional supplements, regardless of their formulation or delivery form, can be tested for oxidative safety and compliance.

Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA

We evaluated the quality and content of fish oil supplements in New Zealand. All encapsulated fish oil supplements marketed in New Zealand were eligible for inclusion. Fatty acid content was measured by gas chromatography. Peroxide values (PV) and anisidine values (AV) were measured, and total oxidation values (Totox) calculated. Only 3 of 32 fish oil supplements contained quantities of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that were equal or higher than labelled content, with most products tested (69%) containing <67%. The vast majority of supplements exceeded recommended levels of oxidation markers. 83% products exceeded the recommended PV levels, 25% exceeded AV thresholds, and 50% exceeded recommended Totox levels. Only 8% met the international recommendations, not exceeding any of these indices. Almost all fish oil supplements available in the New Zealand market contain concentrations of EPA and DHA considerably lower than claimed by labels. Importantly, the majority of supplements tested exceeded the recommended indices of oxidative markers. Surprisingly, best-before date, cost, country of origin, and exclusivity were all poor markers of supplement quality.

Quality analysis of commercial fish oil preparations

BACKGROUND

Fish oil supplements have grown in popularity in recent years owing to their multiple health benefits, leading to rapid growth in the number of fish oil supplements available for consumers. When choosing a product, it is important that label claims for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are met, especially when a specific dosage is required. In this study the amounts of EPA and DHA in 16 of the top-selling liquid fish oil products from the American marketplace were analysed and compared with their label claims. Peroxide value, a measure of oxidation, was also determined, along with lipid class.

RESULTS

This study found that over half of the supplements did not meet their label claims for EPA and DHA, and a quarter exceeded recommended limits for peroxide value.

CONCLUSION

These results suggest that more stringent regulation is required for fish oil products.

Oxidation of marine omega-3 supplements and human health

Marine omega-3 rich oils are used by more than a third of American adults for a wide range of purported benefits including prevention of cardiovascular disease. These oils are highly prone to oxidation to lipid peroxides and other secondary oxidation products. Oxidized oils may have altered biological activity making them ineffective or harmful, though there is also evidence that some beneficial effects of marine oils could be mediated through lipid peroxides. To date, human clinical trials have not reported the oxidative status of the trial oil. This makes it impossible to understand the importance of oxidation to efficacy or harm. However, animal studies show that oxidized lipid products can cause harm. Oxidation of trial oils may be responsible for the conflicting omega-3 trial literature, including the prevention of cardiovascular disease. The oxidative state of an oil can be simply determined by the peroxide value and anisidine value assays. We recommend that all clinical trials investigating omega-3 harms or benefits report the results of these assays; this will enable better understanding of the benefits and harms of omega-3 and the clinical importance of oxidized supplements.

Oxidised fish oil does not influence established markers of oxidative stress in healthy human subjects: a randomised controlled trial

Intake of fish oil reduces the risk of CHD and CHD deaths. Marine n-3 fatty acids (FA) are susceptible to oxidation, but to our knowledge, the health effects of intake of oxidised fish oil have not previously been investigated in human subjects. The aim of the present study was to investigate markers of oxidative stress, lipid peroxidation and inflammation, and the level of plasma n-3 FA after intake of oxidised fish oil. In a double-blinded randomised controlled study, healthy subjects (aged 18–50 years, n 54) were assigned into one of three groups receiving capsules containing either 8 g/d of fish oil (1·6 g/d EPA+DHA; n 17), 8 g/d of oxidised fish oil (1·6 g/d EPA+DHA; n 18) or 8 g/d of high-oleic sunflower oil (n 19). Fasting blood and morning spot urine samples were collected at weeks 0, 3 and 7. No significant changes between the different groups were observed with regard to urinary 8-iso-PGF2α; plasma levels of 4-hydroxy-2-hexenal, 4-hydroxy-2-nonenal and α-tocopherol; serum high sensitive C-reactive protein; or activity of antioxidant enzymes in erythrocytes. A significant increase in plasma level of EPA+DHA was observed in both fish oil groups, but no significant difference was observed between the fish oil groups. No changes in a variety of in vivo markers of oxidative stress, lipid peroxidation or inflammation were observed after daily intake of oxidised fish oil for 3 or 7 weeks, indicating that intake of oxidised fish oil may not have unfavourable short-term effects in healthy human subjects.