Older people with low blood levels of folate (vitamin B9) are 68 percent more likely to develop dementia and have a higher rate of death from any cause.
Serum folate levels with aging tend to decline, with studies showing one-in-five older adults is deficient.
Therefore, concentrations of folate should be regularly measured to prevent deficiency or correct the issue.
Folate deficiency could harm cognitive function and nerve signalling in the brain, leading to dementia in later life.
However, only a few studies have looked at the idea of low folate as a risk factor for dementia.
The condition takes time to progress and so it has been difficult to prove if folate deficiency is a consequence of dementia or vice versa.
Folate deficiency and dementia
For this reason, a research team examined the association between folate deficiency and increased risk of dementia, as well as likelihood of dying from any cause.
They analysed 27,188 medical records of adults aged 60 to 75 with no history of dementia and followed them for 10 years.
Nearly 13 percent of participants were low in folate, a serum level below 4.4 ng/ml.
The results showed that folate deficient people were at a greater risk of dementia and more likely to die from any cause.
After eliminating factors such as taking folic acid supplements, vitamin B12 deficiency, diabetes, cognitive decline, depression, and smoking, folate deficiency increased the risk of dementia by 68 percent and tripled the odds of dying from any cause.
The authors explain that folate deficiency can elevate the levels of an amino acid called homocysteine.
High levels of homocysteine can damage blood vessels and so reduce blood flow to the brain, leading to vascular dementia.
The process causes oxidative damage to DNA and makes brain cells age quickly and die.
The authors concluded:
“Serum concentrations of folate may function as a biomarker used to modify the risks of dementia and mortality in old age.
The implications for public health policy appear to be to reliably monitor serum concentrations of folate in older adults and treat deficiency for preventative measures and/or as part of implemented therapeutic strategies while regularly reviewing patients’ clinical outcomes.”
A study suggests that both low and high levels of folate are linked to autism, a neurodevelopmental disorder, the signs of which include repetitive or unusual behaviour, social impairment, and abnormal communication.
The study was published in the journal Evidence Based Mental Health (Rotstein et al., 2022).