Hepatotoxicity upon using niacin to pass a drug test: A case report

B Vitamins, Glucoronolactone and the Immune System: Bioavailability, Doses and Efficiency

The present review deals with two main ingredients of energy/power drinks: B vitamins and glucuronolactone and their possible effect on the immune system. There is a strong relationship between the recommended daily dose of selected B vitamins and a functional immune system. Regarding specific B vitamins: (1) Riboflavin is necessary for the optimization of reactive oxygen species (ROS) in the fight against bacterial infections caused by Staphylococcus aureus and Listeria monocytogenes. (2) Niacin administered within normal doses to obese rats can change the phenotype of skeletal fibers, and thereby affect muscle metabolism. This metabolic phenotype induced by niacin treatment is also confirmed by stimulation of the expression of genes involved in the metabolism of free fatty acids (FFAs) and oxidative phosphorylation at this level. (3) Vitamin B5 effects depend primarily on the dose, thus large doses can cause diarrhea or functional disorders of the digestive tract whereas normal levels are effective in wound healing, liver detoxification, and joint health support. (4) High vitamin B6 concentrations (>2000 mg per day) have been shown to exert a significant negative impact on the dorsal root ganglia. Whereas, at doses of approximately 70 ng/mL, sensory symptoms were reported in 80% of cases. (5) Chronic increases in vitamin B12 have been associated with the increased incidence of solid cancers. Additionally, glucuronolactone, whose effects are not well known, represents a controversial compound. (6) Supplementing with D-glucarates, such as glucuronolactone, may help the body's natural defense system function better to inhibit different tumor promoters and carcinogens and their consequences. Cumulatively, the present review aims to evaluate the relationship between the selected B vitamins group, glucuronolactone, and the immune system and their associations to bioavailability, doses, and efficiency.

Advances in Research on Marine-Derived Lipid-Lowering Active Substances and Their Molecular Mechanisms

Hyperlipidemia (HLP) is a metabolic disorder caused by abnormal lipid metabolism. Recently, the prevalence of HLP caused by poor dietary habits in the population has been increasing year by year. In addition, lipid-lowering drugs currently in clinical use have shown significant improvement in blood lipid levels, but are accompanied by certain side effects. However, bioactive marine substances have been shown to possess a variety of physiological activities such as hypoglycemic, antioxidant, antithrombotic and effects on blood pressure. Therefore, the hypolipidemic efficacy of marine bioactive substances with complex and diverse structures has also attracted attention. This paper focuses on the therapeutic role of marine-derived polysaccharides, unsaturated fatty acids, and bioactive peptides in HLP, and briefly discusses the main mechanisms by which these substances exert their hypolipidemic activity in vivo.

Suspected adverse reactions to performance enhancing dietary supplements: Spontaneous reports from the Italian phytovigilance system

Herbal tonic and adaptogens are often used to improve overall well-being. However, few clinical evidence supports their use and their safety is not known before marketing. In this context, the aim of our study was to analyze the spontaneous reports of suspected adverse reactions (ARs) to performance enhancing herbal dietary supplements collected by the Italian Phytovigilance System. Between March 2002 and September 2020, 110 spontaneous reports were collected, 58 of which related to products containing botanicals, alone or in association. Twenty-three serious reactions were reported, 21 of which required hospitalization, one was life-threatening and another caused disability. Dermatological and cardiovascular reactions were the most frequent. Hepatic ARs were the most serious (9 out of 10). A positive dechallenge was indicated in 69% of cases, while a positive rechallenge occurred in 15%. Concomitant use of other products was present in 18 reports (31%), while predisposing conditions were indicated in 17 (29%). Present data highlight safety concerns on herbal dietary supplements used as cognitive and physical performance enhancers, mainly due to their quality and use without expert supervision. Considering that postmarketing surveillance is not required for these products, spontaneous reports represent the only tool to point out risks related to food supplements.

Niacin increases diet-induced hepatic steatosis in B6129 mice

Nonalcoholic fatty liver disease (NAFLD) is a very common disorder affecting between 20 and 30% of adults in the United States. However, there is no effective pharmacotherapy for treating NAFLD. Niacin, a water-soluble vitamin (B3), at pharmacological doses, decreases hepatic triglyceride (TG) content in NAFLD through inhibition of diacylglycerol acyltransferase 2, a key enzyme that catalyzes the final step in TG synthesis. Alternatively, some studies indicate that niacin induces fatty liver in high-fat diet (HFD)-fed rats. Therefore, in this study we investigated whether niacin is beneficial in treating NAFLD in two strains of mice, C57BL/6J (B6) and B6129SF2/J (B6129) mice, with 20 weeks of HFD feeding. Niacin treatment was started from week 5 until the end of the study. Niacin treatment increased normalized liver weight, hepatic TG content and NAFLD score in HFD-fed B6129 mice but had no impact on B6 mice. Metabolomics analysis revealed that in B6129 mice, 4-hydroxyphenylpyruvic acid (4-HPP), which is associated with fatty acid oxidation, did not change with HFD feeding but significantly decreased with niacin treatment. Lipidomics analysis discovered that the abundance of phosphocholine (PC), which is critical for very low-density lipoprotein (VLDL)-TG production and secretion, was decreased in HFD-fed B6129 with niacin treatment. In conclusion, niacin had no impact on diet-induced NAFLD development in B6 mice but potentiated hepatic steatosis in HFD-fed B6129 mice due to impaired fatty acid oxidation and decreased VLDL-TG production and secretion.