Effect of betaine administration on metabolism of hepatic glutathione in rats

Dietary choline and betaine intakes in relation to concentrations of inflammatory markers in healthy adults: the ATTICA study

BACKGROUND

Choline and betaine are found in a variety of plant and animal foods and were recently shown to be associated with decreased homocysteine concentrations.

OBJECTIVE

The scope of this work was to investigate the associations between dietary choline and betaine consumption and various markers of low-grade systemic inflammation.

DESIGN

Under the context of a cross-sectional survey that enrolled 1514 men (18-87 y of age) and 1528 women (18-89 y of age) with no history of cardiovascular disease (the ATTICA Study), fasting blood samples were collected and inflammatory markers were measured. Dietary habits were evaluated with a validated food-frequency questionnaire, and the intakes of choline and betaine were calculated from food-composition tables.

RESULTS

Compared with the lowest tertile of choline intake (<250 mg/d), participants who consumed >310 mg/d had, on average, 22% lower concentrations of C-reactive protein (P < 0.05), 26% lower concentrations of interleukin-6 (P < 0.05), and 6% lower concentrations of tumor necrosis factor-alpha (P < 0.01). Similarly, participants who consumed >360 mg/d of betaine had, on average, 10% lower concentrations of homocysteine (P < 0.01), 19% lower concentrations of C-reactive protein (P < 0.1), and 12% lower concentrations of tumor necrosis factor-alpha (P < 0.05) than did those who consumed <260 mg/d. These findings were independent of various sociodemographic, lifestyle, and clinical characteristics of the participants.

CONCLUSIONS

Our results support an association between choline and betaine intakes and the inflammation process in free-eating and apparently healthy adults. However, further studies are needed to confirm or refute our findings.

Betaine in human nutrition

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.

Dietary betaine modifies hepatic metabolism but not renal injury in rat polycystic kidney disease

We undertook a morphometric and proton nuclear magnetic resonance ((1)H-NMR) study to test the hypothesis that 1% dietary betaine supplementation would ameliorate renal disease in the heterozygous Han:SPRD-cy rat, a model of polycystic kidney disease (PKD) and progressive chronic renal failure. After 8 wk of pair feeding, betaine had no effect on renal cystic change, renal interstitial fibrosis, serum creatinine, serum cholesterol, or serum triglycerides. (1)H-NMR spectroscopy of renal tissue revealed no change in renal osmolytes, including betaine, or renal content of other organic anions in response to diet. (1)H-NMR spectroscopy of hepatic tissue performed to explore the metabolic fate of ingested betaine revealed that heterozygous animals fed the control diet had elevated hepatic levels of gluconeogenic amino acids, increased beta-hydroxybutyrate, and increased levels of some citric acid cycle metabolites compared with animals without renal disease. Betaine supplementation eliminated these changes. Chronic renal failure in the Han:SPRD-cy rat is associated with disturbances of hepatic metabolism that can be corrected with betaine therapy, suggesting the presence of a reversible methylation defect in this form of chronic renal failure.