In a small study, 266 older adults with mild cognitive impairment (aged 70+) received a daily dose of 0.8 mg folic acid, 0.5 mg vitamin B₁₂ and 20 mg vitamin B₆ or a placebo for two years. Those treated with B vitamins had significantly lower levels of homocysteine at the end of the trial (high homocysteine is a known risk factor for age-related cognitive decline and dementia). Moreover, this was associated with a significantly slower rate of brain shrinkage.

However, while there were significant effects on homocysteine level, brain atrophy, and executive function, it wasn’t until results were separated on the basis of baseline homocysteine levels that we get really dramatic results.

It was the group with high homocysteine levels at the start of the study who really benefited from the high doses of B vitamins. For them, brain atrophy was cut by half, and there were clear benefits in episodic memory, semantic memory, and global cognitive function, not just executive function. Among those with high baseline homocysteine who received the placebo, significant cognitive decline occurred.

The level of B vitamins in the supplements was considerably greater than the recommended standard. However, caution must be taken in dosing yourself with supplements, because folic acid can have negative effects. Better to try and get your diet right first.

A longer and larger follow-up study is now planned, and hopefully that will tell us if such treatment can keep MCI developing into Alzheimer’s.