New Irish research has found a strong association between vitamin B12 deficiency and a risk of depressive symptoms.

Scientists from the Irish Longitudinal Study on Ageing (TILDA) examined the relationship between folate and vitamin B12 status and their link to depressive symptoms in a group of older adults living in the community.

Deficiency of B-group vitamins, such as folate and vitamin B12, are common among older people. In Ireland, one in eight older adults are reported to have low B12 status, while low dietary intake and low blood status have been reported throughout all age groups in the Irish population.

A low B12  status can have a number of consequences, such as megaloblastic anaemia, impaired cognitive function or damage to the myelin sheath that surrounds the nerve fibres of the brain.

Examining a potential link between folate or low B12 status and depression in later life is seen as important because depression is a risk factor for functional decline, admission to residential care and early death.

Using data from TILDA, the scientists examined participants aged 50 years and over who were assessed at wave 1 of the study. All were measured for plasma folate and plasma B12. They were also screened for depression.

The study found no link between a low folate status and an increased risk of depressive symptoms. However, a low B12 status was associated with a significantly greater risk of developing depressive symptoms.

In fact, those with deficient or low B12 status had a 51% increased likelihood of developing depressive symptoms over a four-year period.

These findings stood even after other relevant factors were taken into account, such as chronic disease burden, physical activity and antidepressant use.

The scientists said that these findings are important given the high prevalence of incident depression and the high levels of deficient B12 status among older people in Ireland.

They also suggested that the findings should provide reassurance to food policymakers that fortifying foods with B12 could play a potential role in the prevention of depression.

“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.

“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 foods, such as breakfast cereals, with B12 vitamins and folate,”commented the study’s lead author, Dr Eamon Laird.

According to principal TILDA investigator, Prof Rose Anne Kenny, a major strength of this study is that it is based on a large, nationally representative sample of older adults who were observed over a four-year period.

“Moreover, researchers examined a well characterised group and included a wide range of confounding factors including chronic disease, medications, lifestyle factors and other nutrient blood biomarkers to reveal robust findings.

“Given the rise in loneliness and depression in older adults after the onset of Covid-19 restrictions, this study highlights the importance of increasing B12  intake or supplementation to help mitigate against potential risk factors of depression in older adults,” she said.

The study is published in the British Journal of Nutrition and can be viewed here.