Author
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MASON, JOEL - HNRCA |
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Submitted to: Journal of Nutrition
Publication Type: Review Article Publication Acceptance Date: 12/1/2002 Publication Date: 3/1/2003 Citation: MASON, J.B. BIOMARKERS OF NUTRIENT EXPOSURE AND STATUS IN ONE-CARBON ("METHYL") METABOLISM. JOURNAL OF NUTRITION. 2003. Interpretive Summary: Technical Abstract: One-carbon metabolism is a network of interrelated biochemical reactions that involve the transfer of one carbon groups from one compound to another. The co-enzymes necessary for several of these reactions include the B-vitamins, folate, B12, B6 and riboflavin (B2) whereas important intermediary compounds in this schema include methionine and choline. There has been a renewed interest in one-carbon metabolism over the past several years, engendered by recent insights which indicate that modest dietary inadequacies of the abovementioned nutrients, of a degree insufficient to cause classical deficiency syndromes, may still contribute to important diseases such as neural tube defects, cardiovascular disease and cancer. Traditional means of assessing nutrient exposure with food frequency questionnaires, and nutrient status with plasma and urine vitamin assays has some genuine validity and utility. Assessing the concentration of appropriate intermediary compounds, such as plasma homocysteine for folate and methylmalonic acid for B12, provides further insights because they appear to add a degree of sensitivity that does not exist with the more traditional assays. There may also be value in developing measures which integrate the status of all these nutrients and express it as a functional `methylation capacity¿ of the individual. Plasma or tissue concentrations of S-adenosylmethionine and S-adenosylhomocysteine, and genomic DNA methylation are two potential candidates in this regard although a much work has yet to be done to define the nature of these relationships. |
