Older people deficient in vitamin B12 are at greater risk of experiencing depression

In Ireland, one-in-eight older adults are reported to be low in vitamin B12, while low dietary intake and low blood status have been reported throughout all age groups. Picture: File

Older people deficient in vitamin B12 may be at greater risk of experiencing depression, according to a new study by Irish scientists.

Research by scientists from the Irish Longitudinal Study on Ageing (TILDA) at Trinity College Dublin examined the relationship between vitamin B12 and folate — otherwise known as vitamin B9 — and depressive symptoms in a group of older adults over a four-year period.

Researchers observed that those deficient in B12 had a 51% increased likelihood of developing depressive symptoms over the time period of the study. No such associations were observed for deficiencies in folate.

These findings, published today in the  British Journal of Nutrition, held true even after researchers relevant adjusting factors such as physical activity, chronic disease burden, vitamin D status, cardiovascular disease and antidepressant use.

Those behind the study say its findings are relevant given the high occurrence of incident depression and the high levels of low-deficient status of B12 in the older adult population in Ireland.

In Ireland, one-in-eight older adults are reported to be low in vitamin B12, while low dietary intake and low blood status have been reported throughout all age groups.

Consequences

Some of the negative consequences of low levels of B12 can include megaloblastic anaemia, impaired cognitive function, or damage to the protective covering (myelin sheath) that surrounds the nerve fibres of the brain. 

According to the researchers, understanding the link between folate or low B12 status and depression in later life is important as depression is a risk factor for functional decline, admission to residential care and early death.

"There is a growing momentum to introduce a mandatory food fortification policy of B-vitamins in Europe and the UK, especially since mandatory food fortification with folic acid in the US has shown positive results, with folate deficiency or low-status rates of just 1.2% in those aged 60 years and older," said the study's lead author, Dr Eamon Laird

"Our findings should provide further reassurance for policymakers to show that a food fortification policy could offer a potential means to aid the prevention of depressive symptoms in older adults and benefit overall health through the enrichment of food such as breakfast cereals with B12 vitamins and folate.”

Principal investigator of TILDA, Prof Rose Anne Kenny, said that given the rise in loneliness and depression in older adults after the onset of Covid-19 restrictions, the new study highlighted "the importance of increasing B12 intake or supplementation to help mitigate against potential risk factors of depression in older adults."