Betaine in human nutrition

Abstract

Betaine is distributed widely in animals, plants, and microorganisms, and rich dietary sources include seafood, especially marine invertebrates ( approximately 1%); wheat germ or bran ( approximately 1%); and spinach ( approximately 0.7%). The principal physiologic role of betaine is as an osmolyte and methyl donor (transmethylation). As an osmolyte, betaine protects cells, proteins, and enzymes from environmental stress (eg, low water, high salinity, or extreme temperature). As a methyl donor, betaine participates in the methionine cycle-primarily in the human liver and kidneys. Inadequate dietary intake of methyl groups leads to hypomethylation in many important pathways, including 1) disturbed hepatic protein (methionine) metabolism as determined by elevated plasma homocysteine concentrations and decreased S-adenosylmethionine concentrations, and 2) inadequate hepatic fat metabolism, which leads to steatosis (fatty accumulation) and subsequent plasma dyslipidemia. This alteration in liver metabolism may contribute to various diseases, including coronary, cerebral, hepatic, and vascular diseases. Betaine has been shown to protect internal organs, improve vascular risk factors, and enhance performance. Databases of betaine content in food are being developed for correlation with population health studies. The growing body of evidence shows that betaine is an important nutrient for the prevention of chronic disease.

Mitochondrial dysfunction and oxidative stress in the pathogenesis of alcohol- and obesity-induced fatty liver diseases

“…Betaine, a natural antioxidant, functions as an osmolyte and a methyl donor for the remethylation of homocysteine, "the bad thiol" [192], back to methionine [193]. Hyperhomocysteinemia is associated with steatosis presumably through induction of endoplasmic reticulum stress and activation of SREBPs leading to increased hepatic synthesis and uptake of triglycerides and cholesterol [194].…”

Phosphatidylcholine functional foods and nutraceuticals: A potential approach to prevent non‐alcoholic fatty liver disease

“…Dietary choline deficiency has multiple implications for human health, including birth defects, neurological dysfunction and the development of fatty liver [20]. With respect to steatosis, or fatty liver, choline deficiency has been shown to play an important role.…”

Dietary methyl-consuming compounds and metabolic syndrome

“…Betaine is derived from either diet or the conversion of choline by choline oxidase. 17 It has an important role in maintaining the methionine-homocysteine cycle, not only for its direct participation in the methylation of homocysteine to form methionine, but also for its metabolites that contribute to the formation of 5,10-methylenetetrahydrofolate, the precursor of 5-methyltetrahydrofolate. 18,19 Because all of the methyl consumers from either endogenous or exogenous sources share the same pool of labile methyl donors, it is conceivable that an increase in any methyl consumer(s) may influence not only the methylation of other methyl consumers due to its increasing demand for labile methyl groups.…”