1.
A Review of Dietary (Phyto)Nutrients for Glutathione Support.
Minich, DM, Brown, BI
Nutrients. 2019;11(9)
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Glutathione is made up of 3 amino acids (cysteine, glutamic acid and glycine) and plays important roles in the body, including oxidative stress reduction, supporting the immune system and contributing to detoxification processes. Evidence suggests that it is an important marker and target for treatment in many chronic, age-related diseases. This review article explores the evidence of nutritional strategies to improve glutathione status. The authors examine the evidence for supplementation of the precursors of glutathione as well as with various forms of supplemental glutathione itself, and the impacts on glutathione status and clinical impacts. Crucially, the review article provides information on dietary sources of precursors of glutathione and glutathione itself, which will provide Nutrition Practitioners with compelling information for use in clinic. Lean protein, brassica vegetables, polyphenol-rich fruits and vegetables, green tea, herbs and spices and omega-3 rich foods are all discussed in detail.
Abstract
Glutathione is a tripeptide that plays a pivotal role in critical physiological processes resulting in effects relevant to diverse disease pathophysiology such as maintenance of redox balance, reduction of oxidative stress, enhancement of metabolic detoxification, and regulation of immune system function. The diverse roles of glutathione in physiology are relevant to a considerable body of evidence suggesting that glutathione status may be an important biomarker and treatment target in various chronic, age-related diseases. Yet, proper personalized balance in the individual is key as well as a better understanding of antioxidants and redox balance. Optimizing glutathione levels has been proposed as a strategy for health promotion and disease prevention, although clear, causal relationships between glutathione status and disease risk or treatment remain to be clarified. Nonetheless, human clinical research suggests that nutritional interventions, including amino acids, vitamins, minerals, phytochemicals, and foods can have important effects on circulating glutathione which may translate to clinical benefit. Importantly, genetic variation is a modifier of glutathione status and influences response to nutritional factors that impact glutathione levels. This narrative review explores clinical evidence for nutritional strategies that could be used to improve glutathione status.
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Navy Beans Impact the Stool Metabolome and Metabolic Pathways for Colon Health in Cancer Survivors.
Baxter, BA, Oppel, RC, Ryan, EP
Nutrients. 2018;11(1)
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Colorectal cancer (CRC) is one of the leading cause of cancer-related death around the world. Emerging evidence supports that increased consumption of pulses / legumes, such as navy beans, can reduce risk. Consuming navy beans as part of one's diet has been previously shown to positively affect the relationship between a person's gut bacteria and their health status. This study looked at stool samples to assess the impact of navy bean consumption on health based on the by-products of metabolism generated by gut bacteria (metabolites). The study was a 4-week, randomised-controlled trial with overweight and obese CRC survivors and involved consumption of 1 meal and 1 snack daily. People in the intervention group ate 35g of cooked navy bean daily whereas those in the control group had 0g of navy beans. From amongst the hundreds of metabolites identified in both groups, there was a 5-fold increase in ophthalmate for navy bean consumers, which can indicate an increase in glutathione. Glutathione is an antioxidant and detoxifying substance produced in the human liver. It is involved in cancer control mechanisms such as detoxification of xenobiotics (toxins), antioxidant defense, proliferation, and apoptosis. Other interesting results include the metabolism of the amino acid lysine, which supports health immune function, and an increase in plant-based nutrients or phytochemicals in those who consumed navy bean vs the control group. These results are indicative of an acute response to increased navy bean intake, which merit further investigation for improving colonic health after long-term consumption.
Abstract
Colorectal cancer (CRC) is the third leading cause of cancer-related death in the United States and emerging evidence supports that increased consumption of legumes, such as navy beans, can reduce risk. Navy bean consumption was previously shown to modulate host and microbiome metabolism, and this investigation was performed to assess the impact on the human stool metabolome, which includes the presence of navy bean metabolites. This 4-week, randomized-controlled trial with overweight and obese CRC survivors involved consumption of 1 meal and 1 snack daily. The intervention contained 35 g of cooked navy bean or macronutrient matched meals and snacks with 0 g of navy beans for the control group (n = 18). There were 30 statistically significant metabolite differences in the stool of participants that consumed navy bean at day 28 compared to the participants' baseline (p ≤ 0.05) and 26 significantly different metabolites when compared to the control group. Of the 560 total metabolites identified from the cooked navy beans, there were 237 possible navy bean-derived metabolites that were identified in the stool of participants consuming navy beans, such as N-methylpipecolate, 2-aminoadipate, piperidine, and vanillate. The microbial metabolism of amino acids and fatty acids were also identified in stool after 4 weeks of navy bean intake including cadaverine, hydantoin-5 propionic acid, 4-hydroxyphenylacetate, and caprylate. The stool relative abundance of ophthalmate increased 5.25-fold for navy bean consumers that can indicate glutathione regulation, and involving cancer control mechanisms such as detoxification of xenobiotics, antioxidant defense, proliferation, and apoptosis. Metabolic pathways involving lysine, and phytochemicals were also modulated by navy bean intake in CRC survivors. These metabolites and metabolic pathways represent an acute response to increased navy bean intake, which merit further investigation for improving colonic health after long-term consumption.