Effects of vitamin B12, folate, and vitamin B6 supplements in elderly people with normal serum vitamin concentrations

Naurath, H J; Joosten, Etienne; Riezler, Reiner; Stabler, Sally P.; Allen, R. H.; Lindenbaum, John

doi:10.1016/s0140-6736(95)92113-3

Cited by 262 publications

(127 citation statements)

References 22 publications

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“…This in turn suggests that folic acid supplementation to the effect of 400 mg per day may have little impact on the normal population Hcy levels. It has been shown the supplementation of elderly individuals (Naurath et al, 1995) and South African men (Ubbink et al, 1995) with doses similar to those used in this study (1.0±1.1 mg), resulted in a signi®cant decrease in mean Hcy values to a similar degree as in our study of healthy normal individuals.…”

Section: Discussionsupporting

confidence: 83%

Unpredictable intra-individual variations in serum homocysteine levels on folic acid supplementation

Santhosh-Kumar

et al. 1997

Eur J Clin Nutr

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Objective: To determine if changes in serum homocysteine values during folic acid supplementation can identify objectively healthy subjects with subclinical folate de®ciency. Design: Blood drawn and processed in a regimented fashion from fasting subjects. Serum homocysteine values determined by gas chromatography-mass spectrometry twice before and on days 5 and 8 of daily folic acid supplementation. Setting: Outpatient University Hospital Clinical Research Center, Denver, Colorado. Subjects: Subjectively healthy adults with normal hematologic and biochemical screening tests. Intervention: Folic acid 1 mg daily for eight consecutive days. Results: Homocysteine values of the group fell signi®cantly during folic acid supplementation. Values presupplementation were 7.8 AE 1.8 and 7.4 AE 2.4 mmol/L while values on days 5 and 8 of supplementation were 6.5 AE 2.2 and 6.3 AE 2.2 mmol/L. However, the homocysteine values of any given individual varied up to 60% (rises up to 7 mmol/L and falls of 5 mmol/L) during folic acid supplementation despite the controlled circumstances of blood handling, and an assay coef®cient of variation of 8%. Conclusions: Although group values of serum homocysteine fall during folic acid supplementation, intraindividual variation is so great that subjects with subclinical folate de®ciency can not be identi®ed using this study design. Furthermore, these data suggest than an individuals homocysteine values vary enough that single values must be interpreted with caution.

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Section: Discussionsupporting

confidence: 83%

Unpredictable intra-individual variations in serum homocysteine levels on folic acid supplementation

Santhosh-Kumar

et al. 1997

Eur J Clin Nutr

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“…Estimates of the potential public health impact of folate deficiency might be expected to rise if such functional folate determinations are used to assess adequate intake. Approximately 30-35% of elderly individuals have metabolic evidence of folate deficiency (elevated homocysteine), with low folate intake as the primary cause (46); supplementation with folate, B 6 , and B 12 reduced homocysteine levels back to the normal range in 92% of those studied (63).…”

Section: Discussionmentioning

confidence: 99%

Folate deficiency causes uracil misincorporation into human DNA and chromosome breakage: Implications for cancer and neuronal damage

Blount

Mack

Wehr

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

1,263

889

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Folate deficiency causes massive incorporation of uracil into human DNA (4 million per cell) and chromosome breaks. The likely mechanism is the deficient methylation of dUMP to dTMP and subsequent incorporation of uracil into DNA by DNA polymerase. During repair of uracil in DNA, transient nicks are formed; two opposing nicks could lead to chromosome breaks. Both high DNA uracil levels and elevated micronucleus frequency (a measure of chromosome breaks) are reversed by folate administration. A significant proportion of the U.S. population has low folate levels, in the range associated with elevated uracil misincorporation and chromosome breaks. Such breaks could contribute to the increased risk of cancer and cognitive defects associated with folate deficiency in humans.

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“…Our hypothesis was based on the assumption that the previously reported lack of association with prognosis might be due to the low sensitivity for total vitamin B 12 as a measure of vitamin B 12 status, making it a poor screening test for deficiency (Naurath et al, 1995;Herrmann et al, 2000Herrmann et al, , 2003Herrmann et al, , 2005. Over the years different serum markers, isolated and in combination, have been evaluated trying to obtain an optimal screening test for deficiency.…”

Section: Discussionmentioning

confidence: 99%

Holotranscobalamin and methylmalonic acid as prognostic markers following an acute myocardial infarction

Aarsetøy

Valente²,

Reine

et al. 2007

Eur J Clin Nutr

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Objective: To evaluate whether low levels of holotranscobalamin (holoTC) or elevated levels of methylmalonic acid (MMA), both indicators of vitamin B 12 deficiency, might predispose to new cardiovascular events following an acute myocardial infarction (MI). Design: A prospective prognostic study. Setting: One hospital center in Stavanger, Norway. Subjects: A total of 300 patients admitted with an acute MI. Methods: Registration of new TnT positive coronary events (defined as TnT40.05 mg/l and a typical MI pattern) and/or cardiac death during a median follow-up time of 45 months. Results: We compared the recurrence of events in the lowest quartile of holoTC (Q1o73.9 pmol/l) to the event rate above the 25% percentile (Q2-4). For methylmalonic acid (MMA) the same comparison was carried out for the upper quartile (Q4X0.24 mmol/l) as compared with the event rate below the 75% percentile (Q1-3). After 18 and 45 months of follow-up, the odds ratio (OR) for Q1 vs Q2-4 for holoTC was 1.15 (95% confidence interval (CI) 0.91-1.46, P ¼ 0.25) and 1.05 (95% CI 0.86-1.29, P ¼ 0.64), respectively. For MMA the OR for Q4 vs Q1-3 was 0.95 (95% CI 0.76-1.19, P ¼ 0.67) after 18 months and 1.01 (95% CI 0.83-1.23, P ¼ 0.90) after 45 months. Conclusion: This study showed no increased risk of future cardiovascular events associated with low levels of holoTC or high levels of MMA following an acute MI.

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Effects of vitamin B12, folate, and vitamin B6 supplements in elderly people with normal serum vitamin concentrations

Cited by 262 publications

References 22 publications

Unpredictable intra-individual variations in serum homocysteine levels on folic acid supplementation

Unpredictable intra-individual variations in serum homocysteine levels on folic acid supplementation

Folate deficiency causes uracil misincorporation into human DNA and chromosome breakage: Implications for cancer and neuronal damage

Holotranscobalamin and methylmalonic acid as prognostic markers following an acute myocardial infarction

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