Nutritional-Deficiency Dementia

Compared with Alzheimer's disease, which causes 50% to 60% of dementia cases, nutritional-deficiency dementia accounts for an estimated 5% of cognitive deterioration.



The nutrient deficiencies most closely associated with dementia are the B vitamins: thiamin (B-1), niacin (B-3), folate (folic acid), and vitamin B-12. Of these, folate and B-12 deficiencies are most common. Blood tests to assess their levels are a standard part of the clinical assessment for Alzheimer's disease.



The hallmark of B-vitamin-deficiency dementia is memory loss with possible coordination problems (ataxia).



Some experts have questioned whether B-vitamin deficiencies are a cause or effect of dementia, since individuals with cognitive impairment may not eat well. However, several studies have shown that individuals with dementia and B-12 deficiencies recover when given the vitamin by injection. Other studies have shown mental improvement when people with folate and niacin deficiencies have received supplemental vitamins. But only about 25% of those with dementia due to thiamin deficiency recover completely, while about 50% show partial recovery.



If you suspect a loss of cognitive function, encourage the affected person to take vitamins in consultation with a physician or clinical nutritionist.