Vitamin B12 deficiency increases risk of depression in older people – study

TCD researchers find 51 per cent increased likelihood of developing symptoms

Low levels of vitamin B12 can significantly increase the risk of depression in older people, according to new research from Trinity College Dublin.

Academics from The Irish Longitudinal Study on Ageing (Tilda) at Trinity found that older people who had deficits of the vitamin had a 51 per cent increased likelihood of developing depressive symptoms over four years, according to the study.

The findings, contained in the study just published in the British Journal of Nutrition, are significant given the high occurrence of depression and the high levels of B12 deficiency in the older adult population in Ireland.

One in eight older adults in Ireland are reported to have low levels of B12, while low dietary intake and low blood status of the vitamin has been reported across all age groups.


The findings offer new information for older adults, public health doctors and officials, and policymakers “to better understand how to identify risk and adopt protective measures to enhance health outcomes for older adults”, the study says.

Low levels of vitamin B12 can result in anaemia, impaired cognitive function or damage to the protective covering around the nerve fibres of the brain.

The study of people aged 50 and over found that folate, vitamin B9, was not associated with depression.

“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,” the researchers said.

Food fortification

The academics said that the findings should offer reassurance to health officials and politicians involved in food policy about the importance of encouraging people of the potential benefits of eating more foods with higher levels of the vitamin to prevent depression.

Vitamin B12 is found in meat, fish, eggs, dairy products, yeast extract and fortified foods.

Dr Eamon Laird, lead author of the study and a senior research fellow in medical gerontology, said that there was "growing momentum" to make fortification of foods with B vitamins in Europe and the UK mandatory given the positive results seen in the US.

“Our findings should provide further reassurance for policy makers 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,” said Dr Laird.

This could be done through the enrichment of food such as breakfast cereals with B12 vitamins and folate, he said.

Prof Rose Anne Kenny, principal investigator of Tilda, said that given the risk in loneliness and depression in older adults since the onset of Covid-19 restrictions, this study showed the importance of increasing B12 intake or supplements to help mitigate against potential risk factors of depression in older adults.

Simon Carswell

Simon Carswell

Simon Carswell is News Editor of The Irish Times