The effect of vitamins B12, B6 and folate supplementation on homocysteine metabolism in a low-income, urbanised, black elderly community in South Africa

Objectives: The aim of this study was to assess the effect of vitamins B12, B6 and folate supplementation at >100% Recommended Dietary Allowances (RDA) for six months on serum homocysteine (Hcy) levels of an elderly urbanised black South African community. Design: An experimental, non-equivalent control group intervention study design was used in a 104 purposively selected sample. Two groups were compared: hyperhomocysteinaemic (hyperHcy) (n = 61) and normo-homocysteinaemic (normoHcy) (n = 43). Setting: Elders attending a day-care centre in Sharpeville, Gauteng, South Africa. Subjects: All subjects were equivalent in age (> 60 years), race (black) and unemployed/pensioner. Outcome measures: The following parameters were determined at baseline and after the six-month supplementation: serum Hcy, vitamins B6, B12 and folate levels, red cell count, mean cell volume, haemoglobin, haematocrit and the nutritional intake of vitamin B6, B12 and folate. Results: A very high incidence (66.36%) of hyperhomocysteinaemia was present in the sample. The mean +/- standard deviation (SD) serum Hcy level in hyperhomocysteinaemic individuals decreased statistically significantly from 25.00 +/- 8.00 umol/l to 18.80 +/- 12.00 umol/l after the intervention. The number of respondents with an increased Hcy level decreased from 100% (baseline) to 67% after the intervention. Conclusions: It is concluded that supplementation of vitamins B6, B12 and folate is an effective Hcy-lowering approach to reduce hyperhomocysteinaemia in an elderly population, and thereby reduce their risk of cardiovascular disease (CVD). Summary The supplementation had a beneficial effect on the respondents' serum vitamin B6 as well as their haemopoiesis (decreased macrocytosis).