Safety assessment of EPA-rich oil produced from yeast: Results of a 90-day subchronic toxicity study

Fish Oil's Preventive Effect on Two-Stage Skin Carcinogenesis in Swiss Albino Mice: Involvement of NF-ҝB Pathways and Oxidative Stress in a Dose- and Route Dependent Manner

This study investigated the chemopreventive mechanisms of fish oil (FO) at different doses and administration routes in skin carcinogenesis induced by 7,12-dimethylbenz[a]anthracene (DMBA) and croton oil (CO) in Swiss albino mice. Seventy mice were divided into 10 groups, including controls and those receiving FO either orally or topically, with or without the carcinogenesis protocol. Warts were morphologically analyzed. Anatomopathological analysis, qRT-PCR of nuclear factor kappa B (NF-қB) subunits' gene expression, and evaluation of oxidative parameters were conducted. Anatomopathological analysis revealed a presence of invasive squamous cell carcinoma (SCC) in DMBA group. Both oral (500 mg/kg/day) and topical FO treatment showed no signs of cancer, while oral administration at 50 mg/kg/day had no therapeutic effect, and 250 mg/kg/day resulted in low-grade malignancy. Both oral (250 and 500 mg/kg/day) and topical FO significantly reduced NF-кB1 gene expression, alleviated oxidative stress markers, and restored antioxidant enzyme activities compared to the DMBA group. FO shows dose-dependent chemopreventive effects, with oral administration potentially as effective as topical application when using an appropriate dosage. The development of SCC is linked to the stress status and the upregulation of the canonical NF-κB pathway, while FO's chemoprotective effects likely result from its downregulation.

Yarrowia lipolytica, health benefits for animals

The yeast Yarrowia lipolytica has been industrially adopted for docosahexaenoic acid and eicosapentaenoic acid production under good manufacturing practices over 2 decades. In recent years, it has claimed attention for novel biotechnological applications, such as a functional feed additive for animals. Studies have demonstrated that this yeast is safe and has probiotic and nutritional properties for mammals, birds, fish, crustaceans, and molluscs. Animals fed Y. lipolytica enhanced productive and immune parameters, as well as modulated microbiome, fatty acid composition, and biochemical profiles. Additionally, some Y. lipolytica-derived compounds have improved productive performance, immune status, and disease resistance in animals. Therefore, the aim of this review is to identify and discuss research advances on the potential use of this yeast for animals of economic interest. Challenges, opportunities, and trends were identified and envisioned in the near future for this industrially produced yeast. KEY POINTS: • Yarrowia lipolytica has probiotic and nutritional effects in animals. • Lipase2, EPA, and β-glucan from Y. lipolytica have health benefits for animals. • Y. lipolytica is envisioned in terrestrial and aquatic animal production systems.

Effects of eicosapentaenoic acid and docosahexaenoic acid on cardiovascular disease risk factors: a randomized clinical trial

BACKGROUND

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the primary omega-3 fatty acids in fish oil, have been shown to reduce cardiovascular disease (CVD) risk.

OBJECTIVE

This study aimed to examine the independent effects of EPA and DHA on lipid and apolipoprotein levels, as well as on inflammatory biomarkers of CVD risk, using doses often used in the general population.

DESIGN

A blinded, randomized 6-week trial was performed in 121 healthy, normolipidemic subjects who received olive oil placebo 6g/d, EPA 600mg/d, EPA 1800mg/d, or DHA 600mg/d. The EPA was derived from genetically modified yeast.

RESULTS

The subjects tolerated the supplements well with no safety issues; and the expected treatment-specific increases in plasma EPA and DHA levels were observed. Compared to placebo, the DHA group had significant decreases in postprandial triglyceride (TG) concentrations (-20%, -52.2mg/dL, P=0.03), significant increases in fasting and postprandial low-density lipoprotein cholesterol (LDL-C) (+18.4%, 17.1mg/dL, P=0.001), with no significant changes in inflammatory biomarkers. No significant effects were observed in the EPA 600mg/d group. The high-dose EPA group had significant decreases in lipoprotein-associated phospholipase A2 concentrations (Lp-PLA₂) (-14.1%, -21.4ng/mL, P=0.003).

CONCLUSIONS

The beneficial effects of EPA 1800mg/d on CVD risk reduction may relate in part to the lowering of Lp-PLA₂ without adversely affecting LDL-C. In contrast, DHA decreased postprandial TG, but raised LDL-C. Our observations indicate that these dietary fatty acids have divergent effects on cardiovascular risk markers.

Oxidized fish oil in rat pregnancy causes high newborn mortality and increases maternal insulin resistance

Fish oil is commonly taken by pregnant women, and supplements sold at retail are often oxidized. Using a rat model, we aimed to assess the effects of supplementation with oxidized fish oil during pregnancy in mothers and offspring, focusing on newborn viability and maternal insulin sensitivity. Female rats were allocated to a control or high-fat diet and then mated. These rats were subsequently randomized to receive a daily gavage treatment of 1 ml of unoxidized fish oil, a highly oxidized fish oil, or control (water) throughout pregnancy. At birth, the gavage treatment was stopped, but the same maternal diets were fed ad libitum throughout lactation. Supplementation with oxidized fish oil during pregnancy had a marked adverse effect on newborn survival at day 2, leading to much greater odds of mortality than in the control (odds ratio 8.26) and unoxidized fish oil (odds ratio 13.70) groups. In addition, maternal intake of oxidized fish oil during pregnancy led to increased insulin resistance at the time of weaning (3 wks after exposure) compared with control dams (HOMA-IR 2.64 vs. 1.42; P = 0.044). These data show that the consumption of oxidized fish oil is harmful in rat pregnancy, with deleterious effects in both mothers and offspring.

Comparative study of tissue deposition of omega-3 fatty acids from polar-lipid rich oil of the microalgae Nannochloropsis oculata with krill oil in rats

Long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) exert health benefits which are dependent upon their incorporation into blood, cells and tissues. Plasma and tissue deposition of LC n-3 PUFA from oils extracted from the micro-algae Nannochloropsis oculata and from krill were compared in rats. The algal oil provides eicosapentaenoic acid (EPA) partly conjugated (15%) to phospholipids and glycolipids but no docosahexaenoic acid (DHA), whereas krill oil provides both EPA and DHA conjugated in part (40%) to phospholipids. Rats fed a standard diet received either krill oil or polar-lipid rich algal oil by gavage daily for 7 days (5 ml oil per kg body weight each day). Fatty acid concentrations were analyzed in plasma, brain and liver, and two adipose depots since these represent transport, functional and storage pools of fatty acids, respectively. When measuring total LC n-3 PUFA (sum of EPA, docosapentaenoic acid (DPA) and DHA), there was no statistically significant difference between the algal oil and krill oil for plasma, brain, liver and gonadal adipose tissue. Concentrations of LC n-3 PUFA were higher in the retroperitoneal adipose tissue from the algal oil group. Tissue uptake of LC n-3 PUFA from an algal oil containing 15% polar lipids (glycolipids and phospholipids) was found to be equivalent to krill oil containing 40% phospholipids. This may be due to glycolipids forming smaller micelles during ingestive hydrolysis than phospholipids. Ingestion of fatty acids with glycolipids may improve bioavailability, but this needs to be further explored.

Acute appearance of fatty acids in human plasma--a comparative study between polar-lipid rich oil from the microalgae Nannochloropsis oculata and krill oil in healthy young males

Background

The long-chain n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have human health benefits. Alternatives to fish as sources of EPA and DHA are needed. Oil from the micro-algae Nannochloropsis oculata contains a significant amount of EPA conjugated to phospholipids and glycolipids and no DHA. Krill oil contains EPA and DHA conjugated to phospholipids. We compare the appearance of fatty acids in blood plasma of healthy humans after consuming a high fat meal followed by either algal oil or krill oil.

Methods

Ten healthy males aged 18-45 years consumed a standard high fat (55 g) breakfast followed by either algal oil (providing 1.5 g EPA and no DHA) or krill oil (providing 1.02 g EPA and 0.54 g DHA). All participants consumed both oils in random order and separated by 7 days. Blood samples were collected before the breakfast and at several time points up to 10 hours after taking the oils. Fatty acid concentrations (μg/ml) in plasma were determined by gas chromatography.

Results

Fatty acids derived mainly from the breakfast appeared rapidly in plasma, peaking about 3 hours after consuming the breakfast, and in a pattern that reflected their content in the breakfast. There were time-dependent increases in the concentrations of both EPA and DHA with both algal oil (P < 0.001 for EPA; P = 0.027 for DHA) and krill oil (P < 0.001 for both EPA and DHA). The concentration of EPA was higher with algal oil than with krill oil at several time points. DHA concentration did not differ between oils at any time point. The maximum concentration of EPA was higher with algal oil (P = 0.010) and both the area under the concentration curve (AUC) and the incremental AUC for EPA were greater with algal oil (P = 0.020 and 0.006). There was no difference between oils in the AUC or the incremental AUC for DHA.

Conclusion

This study in healthy young men given a single dose of oil indicates that the polar-lipid rich oil from the algae Nannochloropis oculata is a good source of EPA in humans.

Yarrowia lipolytica: safety assessment of an oleaginous yeast with a great industrial potential

Yarrowia lipolytica has been developed as a production host for a large variety of biotechnological applications. Efficacy and safety studies have demonstrated the safe use of Yarrowia-derived products containing significant proportions of Yarrowia biomass (as for DuPont's eicosapentaenoic acid-rich oil) or with the yeast itself as the final product (as for British Petroleum's single-cell protein product). The natural occurrence of the species in food, particularly cheese, other dairy products and meat, is a further argument supporting its safety. The species causes rare opportunistic infections in severely immunocompromised or otherwise seriously ill people with other underlying diseases or conditions. The infections can be treated effectively by the use of regular antifungal drugs, and in some cases even disappeared spontaneously. Based on our assessment, we conclude that Y. lipolytica is a "safe-to-use" organism.

Current evidence for the clinical use of long-chain polyunsaturated n-3 fatty acids to prevent age-related cognitive decline and Alzheimer's disease

An NIH State of the Science Conference panel concluded in 2010 that insufficient evidence is available to recommend the use of any primary prevention therapy for Alzheimer's disease or cognitive decline with age. Despite the insufficient evidence, candidate therapies with varying levels of evidence for safety and efficacy are taken by the public and discussed in the media. One example is the long-chain n-3 (omega-3) polyunsaturated fatty acids (n-3 LC-PUFA), DHA and EPA, found in some fish and dietary supplements. With this report, we seek to provide a practical overview and rating of the level and type of available evidence that n-3 LC-PUFA supplements are safe and protective against cognitive aging and Alzheimer's disease, with additional discussion of the evidence for effects on quality of life, vascular aging, and the rate of aging. We discuss available sources, dose, bioavailability, and variables that may impact the response to n-3 LC-PUFA treatment such as baseline n-3 LC-PUFA status, APOE ε4 genotype, depression, and background diet. Lastly, we list ongoing clinical trials and propose next research steps to validate these fatty acids for primary prevention of cognitive aging and dementia. Of particular relevance, epidemiology indicates a higher risk of cognitive decline in people in the lower quartile of n-3 LC-PUFA intake or blood levels but these populations have not been specifically targeted by RCTs.

Metabolic engineering for the production of clinically important molecules: Omega-3 fatty acids, artemisinin, and taxol

Driven by requirements for sustainability as well as affordability and efficiency, metabolic engineering of plants and microorganisms is increasingly being pursued to produce compounds for clinical applications. This review discusses three such examples of the clinical relevance of metabolic engineering: the production of omega-3 fatty acids for the prevention of cardiovascular disease; the biosynthesis of artemisinic acid, an anti-malarial drug precursor, for the treatment of malaria; and the production of the complex natural molecule taxol, an anti-cancer agent. In terms of omega-3 fatty acids, bioengineering of fatty acid metabolism by expressing desaturases and elongases, both in soybeans and oleaginous yeast, has resulted in commercial-scale production of these beneficial molecules. Equal success has been achieved with the biosynthesis of artemisinic acid at low cost for developing countries. This is accomplished through channeling the flux of the isoprenoid pathway to the specific genes involved in artemisinin biosynthesis. Efficient coupling of the isoprenoid pathway also leads to the construction of an Escherichia coli strain that produces a high titer of taxadiene-the first committed intermediate for taxol biosynthesis. These examples of synthetic biology demonstrate the versatility of metabolic engineering to bring new solutions to our health needs.

Safety assessment of yerba mate (Ilex paraguariensis) dried extract: results of acute and 90 days subchronic toxicity studies in rats and rabbits

Acute toxicity of yerba mate dried extract (YMDE) was investigated in Wistar rats (6/sex/group) from single dose of 2g/kg body weight by intragastric administration and 14days monitoring. Subchronic toxicity was investigated in Wistar rats, by intragastric administration (10/sex/group), and in New Zealand rabbits by oral administration (3/sex/group) of 2g/kg body weight for 12weeks. Toxicological parameters included clinical signs, body weight, water, and food consumption, hematological and serum parameters, and histopathological assessment. Acute YMDE administration showed no effects on survival, clinical observations, macroscopic examination of organs, body weight or food, and water consumption. Sub-chronic administration of YMDE did not change behavior, body weight, and histopatological assessment of stomach, kidney, liver, and small gut. Moreover, most of biochemical and hematological parameters remained unchanged. In summary, the results of our preclinical toxicological investigation are indicative that the YMDE is well tolerated for both single and chronic administration.