People concerned about senile dementia should make sure they are eating plenty of leafy vegetables. A new study has found that folate deficiency is associated with a dramatically higher risk of developing dementia. Like folic acid, folate is a water-soluble form of vitamin B9. Both can be taken as supplements or in their natural form in leafy vegetables such as spinach, turnip greens, lettuces, dried beans, peas and other foods.

The new research, done at King's College London, Institute of Psychiatry and Chonnam National University Hospital in the Republic of Korea, tracked the development of dementia in 518 people over the age of 65 over a two-year period.

Tests were carried out at the start and end of the two-year period to identify subjects with dementia. At the same time, blood tests were taken to assess levels of folate, vitamin B12 and the protein homocysteine. The idea was to find out if dementia risk was associated with higher or lower levels of any of these three substances.

Previous studies have shown that high levels of homocysteine are associated with cardiovascular disease.

At the start of the two-year period, almost one in five people in the study had high levels of homocysteine, while 17% had low vitamin B12 levels and 3.5% were folate deficient.

On the other hand, the higher the level of folate a person had, the higher his or her Vitamin B12 levels and the lower their homocysteine level.

By the end of the study, 45 people had developed dementia. Of these, 34 had Alzheimer's disease, seven had vascular dementia and four had other types of dementia. People who were folate deficient at the beginning of the study were almost 3.5 times more likely to develop dementia. Dementia was also more likely in people whose folate levels fell and homocysteine levels rose during the 2 year study. The authors of this study, published online ahead of print in the Journal of Neurology Neurosurgery and Psychiatry, suggest that folate deficiency and other changes in micronutrients could be linked with the other signs that are known to precede dementia, including weight loss and low blood pressure.