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Additionally, folic acid has also been found to improve the memory of older people. There is some evidence that deficiency in folic acid may increase the risk of dementia, especially Alzheimer's disease and vascular dementia, but there is debate about whether it lowers risk of cognitive impairment in the older population. Folic acid supplementation is shown to lower blood homocysteine levels, while folic acid deficiency can lead to a condition of high levels of homocysteine (Hcy) in the bloodstream called hyperhomocysteinemia (HHcy). HHcy is related to several vascular diseases such as coronary artery disease, peripheral vascular disease, and stroke.