Vitamin B12 Deficiency Increases Risk of Depression

Summary: People suffering from vitamin B12 deficiency are 51% more likely to develop depression over a four-year period. However, as a person’s age increased, the risk of depression decreased.

Source: TCD

Scientists from The Irish Longitudinal Study on Ageing (TILDA) have published new research which examines the relationship between folate and vitamin B12 status and its associations with greater prevalence of depressive symptoms in a group of community-dwelling older adults. 

The study, published in the prestigious British Journal of Nutrition, shows that low vitamin B12 status is linked to depressive symptoms, but shows that folate is not associated with depression.

The findings reveal pertinent information for older adults, public health and policymakers to better understand how to identify risk and adopt protective measures to enhance health outcomes for persons aged 50 and over.

Vitamin B status in Ireland

Deficiency and low status of the B-vitamins such as folate and vitamin B12 are highly present in 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.

Some of the negative consequences of low B12 status can include megaloblastic anemia, impaired cognitive function, or damage to the protective covering (myelin sheath) that surrounds the nerve fibers of the brain. 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 study uses data from TILDA, and examines participants aged 50 years and over who were assessed at Wave 1 of the study and who provided measurement of plasma folate and plasma B12 and screening for depression. Researchers observed that those with deficient-low B12 status had a 51% increased likelihood of developing depressive symptoms over 4 years.

Key findings of the study

  • The study finds that low B12 status is associated with a significantly greater risk of depressive symptoms over four-year period, but no such associations were observed for folate.
  • These findings remained robust even after controlling for relevant adjusting factors such as physical activity, chronic disease burden, vitamin D status, cardiovascular disease and antidepressant use.
  • Researchers observed that those with deficient-low B12 status had a 51% increased likelihood of developing depressive symptoms over 4 years in this study.
  • Other factors that influence micronutrient status in older adults included obesity, medication use, smoking, wealth, gender and geographic location.
  • Researcher found that as age increased, the risk of depression decreased.
  • These 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.
  • These observations also provide reassurance for food policy makers that fortification of foods to increase levels of these vitamins could have the potential for benefits in prevention of this condition.

Dr. Eamon Laird, lead author of the study said: “This study is highly relevant given the high prevalence of incident depression in older adults living in Ireland, and especially following evidence to show that one in eight older adults report high levels of low B12 deficiency rates.

This shows a depressed looking woman
Some of the negative consequences of low B12 status can include megaloblastic anemia, impaired cognitive function, or damage to the protective covering (myelin sheath) that surrounds the nerve fibers of the brain. Image is in the public domain

“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 showed 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 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 through the enrichment of food such as breakfast cereals with B12 vitamins and folate.”

Professor Rose Anne Kenny, principal investigator of TILDA, said: “TILDA is exceptional in the breadth of rich data available from its longitudinal dataset, which offers a unique opportunity to conduct strong evidence-based research and spot important changes in a group over time. A major strength of this study is that it is based on a large, nationally representative sample of older adults in Ireland, observed over four years.

“Moreover, researchers examined a well-characterized 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. “

About this depression research news

Author: Press Office
Source: TCD
Contact: Press Office – TCD
Image: The image is in the public domain

Original Research: Closed access.
Low vitamin B12 but not folate is associated with incident depressive symptoms in community-dwelling older adults: a 4 year longitudinal study” by Eamon Laird et al. British Journal of Nutrition


Low vitamin B12 but not folate is associated with incident depressive symptoms in community-dwelling older adults: a 4 year longitudinal study

The objective was to examine the prospective relationship between folate and vitamin B12 (B12) status and incident depressive symptoms in a representative cohort of community-dwelling older people.

This was a longitudinal study utilising the Irish Longitudinal Study on Aging (n =3,849 aged ≥50 years) and investigated the relationship between blood plasma folate and B12 levels at baseline (wave 1) and incident depressive symptoms at 2 and 4 years (waves 2 and 3).

Participants with depression at wave 1 were excluded. A score ≥9 on the Center for Epidemiologic Studies Depression Scale-8 at wave 2 or 3 was indicative of incident depressive symptoms. Plasma B12 and folate concentrations were determined by microbiological assay. B12 status profiles (pmol/l) were defined as: <185, deficient-low; 185 – <258, low normal; >258 – 601, normal and >601 high. Folate status profiles (nmol/l) were defined as: ≤10.0, deficient-low; >10 – 23.0, low normal; >23.0 – 45.0, normal; >45.0, high. Logistic regression models reporting odds ratios were used to analyse the longitudinal association of B-vitamin categories with incident depression.

Both B12 and folate plasma concentrations were lower in the group with incident depressive symptoms vs. non depressed (folate: 21.4 vs. 25.1 nmol/L; P=0.0003); (B12: 315.7 vs. 335.9 pmol/L; P=0.0148). Regression models demonstrated that participants with deficient-low B12 status at baseline had a significantly higher likelihood of incident depression four years later (odds ratio 1.51, 95% CI 1.01-2.27, P=0.043).

This finding remained robust after controlling for relevant covariates including physical activity, chronic disease burden, vitamin D status. cardiovascular disease and antidepressant use. No associations of folate status with incident depression were observed. Older adults with deficient-low B12 status had a 51% increased likelihood of developing depressive symptoms over 4 years.

Given the high rates of B12 deficiency, these findings are important and highlight the need to further explore the low cost benefits of optimising vitamin B12 status for depression in older adults.

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  1. As someone with the MTHFR mutation, I sure hope boosting foods with folate are never created. Ive worked very hard to bring and keep my folate level down so that my homocysteine stays out of the danger zone.

    I do take a B vitamin blend along with plenty of individual B12. I can tolerate only small amts of even the special form of folic acid, taken as a supplement. Please don’t go upping the folate indiscriminately.

  2. In my lifetime of determining the root causes of my mental illness, I have found that vitamin deficiencies, cigarette smoking, mold exposure, and family social dynamics have been critical factors that have impacted my wellness. Doctors and teachers need to help people know themselves better both inside and out. Environmental exposures to toxins makes the fragile chemistry set of our bodies react in negative ways. We need to work towards eliminating unneeded elements from our lives that cause us harm. I feel that the parts of entertainment and media has had a negative impact on the social behaviors of people and there needs to be more discussions about how not to let that affect us. We learn from what we see and hear, but don’t feel the negative affects until we experience them ourselves. We must teach technology to be used effectively and give people incentives to do the right things. For example instead of giving out buying incentives for making purchases, reward people with credits for doing the right thing (like recyling properly ) that don’t expire until they are used. People would earn and learn to do the right things instead of losing time, money and other resources doing the wrong things.

  3. This is an excellent research effort (and medical news effort by Neuroscience that the medical community needs much more of. The medical industrial complex’s failure to properly research and diagnose and treat diet and microbiome and sleep and vital deficiency issues (including those related to Glutathione and Vitamin D3 and Vitamin K2 and Vitamin C and Vitamin B12 and Magnesium and Potassium and Zinc and fiber deficiencies, as well as iatrogenic prescription medication usage, as well as relatively common genetic polymorphisms that may require special supplementation with already biologically activated forms of vitamins such as methyl B12, L5-MTHF, P5P, etc.) is a major reason why psychiatric iatrogenesis is a primary contributor to the third leading cause of death in the U.S. (which is iatrogenesis in general). If the U.S. spent just a fraction of the over $40 billion each year it spends just on iatrogenic psychiatric drugs alone, for properly researching the issues discussed in this and related research efforts we would probably, Lord willing, achieve an absolute revolution in medical efficacy improvement and iatrogenesis reduction.

    Thomas Steven Roth, MBA, MD.

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