As discussed previously, elevated homocysteine levels are a risk factor for cardiovascular disease and possibly cancer, dementia and adverse pregnancy outcomes. Homocysteine is synthesised from methionine and under normal cellular conditions is quickly metabolised back to methionine via the enzyme methionine synthase, or to cysteine via the enzyme cystathione β-synthase. These two conversions are dependent on vitamin B12 and folate (in the form of tetrahydrofolate) or vitamin B6, respectively. Evidence suggests that deficiency of these vitamins results in decreased activity of the key metabolising enzymes, which causes accumulation of homocysteine. It is this elevation in homocysteine concentration (both cellular and plasma) that results in tissue and cell damage, and ultimately leads to disease. Research has suggested that supplementation of folic acid, vitamin B6 and vitamin B12 are effective at reducing elevated levels of homocysteine.
For example, researchers1 used a randomised double blind design study to investigate the effects of B-vitamin fortified breakfast cereal on the homocysteine status of 189 healthy 50 to 85 year old individuals. The subjects did not previously consume fortified breakfast cereal or take vitamin supplements and had no history of cardiovascular disease. Subjects were assigned to consume either 0.24L of breakfast cereal fortified with 440 µg folic acid, 1.8 mg vitamin B6 or 4.8 µg of vitamin B12 or a placebo cereal (unfortified) for 12 weeks. The results showed that those subjects fed the fortified cereal had significantly lower levels of homocysteine and significantly higher levels of B vitamins (adjusted from baseline) than those who consumed the placebo cereal. These results suggest that in healthy individuals, fortified breakfast cereal is an effective strategy to decrease homocysteine concentrations.
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