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Vitamin supplementation and other variables affecting serum homocysteine and methylmalonic acid concentrations in elderly men and women
- Source :
- Journal of the American College of Nutrition. 15(4)
- Publication Year :
- 1996
-
Abstract
- An elevated serum concentration of the metabolite, homocysteine (Hcys): 1) can indicate folate or vitamin B12 deficiency, 2) is an independent risk factor for vascular disease. The metabolite, methylmalonic acid (MMA), is elevated in deficiency of vitamin B12, but not folate. The purpose of this study was to determine the effect of self-selected vitamin supplementation and other variables on serum Hcys and MMA concentrations in elderly men and women.Serum concentrations of Hcys, MMA, folate and vitamin B12 were measured for elderly volunteers, age 68-96 years, and compared for those consuming (26 men, 25 women) and not consuming (24 men, 25 women) self-selected vitamin supplements.Compared with the nonsupplemented group, the supplemented group had lower mean serum MMA (208 +/- 162 vs. 241 +/- 98 nmol/L [+/- SD]) and Hcys (9.5 +/- 2.6 vs. 11.2 +/- 2.7 mumol/L); and higher serum vitamin B12 (391 +/- 174 vs 292 +/- 107 pmol/L), and serum folate (46 +/- 15 vs. 24 +/- 10 nmol/L) p0.05. Among all 100 subjects, the prevalence of serum vitamin B12221 pmol/L (300 pg/mL) was 18; MMA271 nmol/L, 16; Hcys16.2 mumol/L, 3; folate5.0 nmol/L, none. Based on serum vitamin B12221 nmol/L with elevated serum MMA, vitamin B12 deficiency was probable in seven subjects, of whom two were supplemented. All three subjects with elevated serum Hcys had elevated serum MMA as well, suggesting vitamin B12 deficiency or renal insufficiency. A stepwise linear regression model for serum Hcys explained 61.7% of the variance, and included (in order) serum creatinine, folate, vitamin B12, albumin, age and body mass index (BMI). A model with serum MMA replacing serum vitamin B12 explained 64.1% of the variance in serum Hcys. Folate did not enter the model for supplemented subjects, supporting a "threshold effect": serum Hcys was inversely related to serum folate at lower serum folate (nonsupplemented subjects), but at higher serum folate (supplemented subjects), the relationship was flat. In supplemented subjects, serum Hcys was still related to vitamin B12 status, confirming that tissue deficiency of the vitamin was present.Results showed potential usefulness of serum MMA and Hcys in identifying subclinical or tissue deficiency of vitamin B12. Clinicians should be aware of the risk of vitamin B12 deficiency in older people and of current screening algorithms using serum metabolites. These elderly volunteers had generally good folate status; nevertheless, some subjects seemed likely to benefit from an improvement in folate status that would reduce their serum Hcys within the normal range. The role of serum creatinine in the normal range in predicting serum Hcys, a vascular disease risk factor, remains unexplained.
- Subjects :
- Vitamin
Male
medicine.medical_specialty
Homocysteine
Metabolite
Methylmalonic acid
Medicine (miscellaneous)
Folic Acid Deficiency
chemistry.chemical_compound
Folic Acid
Internal medicine
medicine
Humans
Cyanocobalamin
Vitamin B12
Prospective Studies
Risk factor
Aged
Aged, 80 and over
Nutrition and Dietetics
business.industry
Patient Selection
food and beverages
Vitamin B 12 Deficiency
B vitamins
Endocrinology
chemistry
Food, Fortified
Linear Models
Female
business
Methylmalonic Acid
Subjects
Details
- ISSN :
- 07315724
- Volume :
- 15
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- Journal of the American College of Nutrition
- Accession number :
- edsair.doi.dedup.....c7e827b63de8d3c87cae394445762593