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Understanding the link between vitamin B12 and depression

Understanding the link between vitamin B12 and depression

Deficiency of vitamin B12 can have a poor effect on the brain
man eating vitamin b12 rich foods
Representational image | Shutterstock

At 30, Rishu Sharma, a planning engineer from Mumbai, felt a tingling sensation and numbness in his legs. This, along with dizziness and brain fog continued for a year. He was also feeling low and glum.  

Dispirited, he confessed to not having enough drive to even share how he was feeling with anyone. With time, these issues aggravated, and he also began to experience an increased heart rate accompanied by palpitations.   

That was when he decided to seek medical help wherein he was advised a full body health check-up and certain blood routines including a complete blood test, serum vitamin B12, and homocysteine level test.  His doctor then diagnosed him with vitamin B12 deficiency and indicated that it was the culprit causing his depressive mood. 

“It was a shock to me that vitamin B12 deficiency led me to a depressed state,” Sharma recalls. He was given an oral supplement of vitamin B12 with a tweaked diet plan and was asked to check his levels quarterly.  

What you need to know about this water-soluble vitamin 

Vitamin B12, also called cobalamin, is a water-soluble vitamin and belongs to the B group of vitamins. “It is important for developing and maintaining the nervous system, DNA synthesis and the formation of red blood cells,” says Sushma Jaiswal, nutritionist, and founder of Swasthya Nutrition in Bengaluru.  

A 2019 study to understand the neurological benefits of B vitamins, showed the significant role played by cobalamin in the health of one’s nervous system. Some findings:  

  • Protection of neurons:  It is involved in the formation of a fatty acid sheath around the nerve axon, which helps in the transfer of signals from neuron to neuron in the brain. This helps individuals to think and move in purposeful and coordinated ways. 
  • Production of neurotransmitters: The vitamin helps in the synthesis of neurotransmitters such as dopamine, serotonin, and norepinephrine through a biochemical process known as methylation, which is important for one’s overall mental health.  

“This vitamin is an important nutrient for nerve health. It is important for the conversion of homocysteine (a naturally occurring amino acid) to methionine (amino acid) and the synthesis of myelin sheath for the protection of neurons,” says Dr Gajanan Kulkarni, Neuropsychiatrist at Apollo hospital based in Bengaluru.  

How does Vitamin B12 deficiency occur? 

As per Jaiswal, “Low blood levels of this vitamin, can happen because of poor diet or improper absorption of the vitamin’s levels by the body. It is commonly found in animal products like eggs, meat, shellfish, and dairy products. Therefore, people who follow a vegan or vegetarian diet may not get enough vitamin B12 in their body through their diet.”  Hence, vitamin B12-fortified products and milk products in the diet are advisable for this group.  

Explaining another reason behind low levels of vitamin B12, Jaiswal says that impaired absorption occurs due to the impairment of a special protein called the intrinsic factor that binds vitamin B12 so that it can be absorbed in the intestines.  

Does a lack of vitamin B12 cause depression 

A 2013 survey based in Finland showed the association between vitamin B12 deficiency and major depressive disorder. The result of this survey, published in the journal BMC Psychiatry, showed that 20% of individuals with mental health conditions had low serum vitamin B12 levels.  

A 2021 clinical study on twins by the Emory School of Medicine, US, showed an increased level of homocysteine in twins with major depressive disorders. It showed that low vitamin B12 levels result in the deposition of toxic amino acids in the brain, which leads to a decrease in the production of neurotransmitters. 

Experts suggest that those with unhealthy dietary patterns have a higher risk of depression because of low levels of vitamin B12. A December 2021 study from Trinity College, Dublin, explored the relationship between vitamin B12 and folate levels and depressive symptoms in adults aged 50 and older. It showed that individuals with low levels of the vitamin had a 51% higher chance of depression over four years. Moreover,  it revealed that one in eight older adults has low vitamin B12 levels, making this a relevant concern for ageing adults. 

How to diagnose Vitamin B12 deficiency  

The diagnosis of vitamin B12 deficiency is based on the symptoms of the individuals.  

Megaloblastic anemia (presence of large red blood cells in the bone marrow), impaired balance, problems in walking, and impairment in memory are symptomatic of this deficiency. Vitamin B12 levels can be checked through blood tests such as vitamin B12 serum, homocysteine and hemoglobin and complete blood count, says Dr Kulkarni.  

If the vitamin level is below 148pg/L, a person is suffering from vitamin B12 deficiency.  

 If the vitamin level is between 148-221pg/L, the person has insufficient vitamin B12, which is considered as borderline safe. It is very common to have insufficient levels without clinical symptoms, and modification in the diet can help to increase the level of vitamin B12, he adds. 

Treatment of vitamin B12 deficiency-related depression 

If a person has improper absorption of vitamin B12, he will need to take injections of vitamin B12 and a high-dose supplement of vitamin B12 serum, says Jaiswal. 

Vegetarians and vegans can modify their diet by including vitamin B12-fortified grains, yogurt, cheese, low-fat milk, green leafy vegetables, she adds. 

Older adults with vitamin B12 deficiency will likely be prescribed vitamin B12 supplements and multivitamins with vitamin B12. 

In cases where vitamin B12 supplement and diet modification are not enough to improve the mental health of the person, the doctor will prescribe some anti-depressants.  

 “It has been shown that the vitamin B12 supplement along with anti-depressants improves treatment outcomes of anxiety, depression, and cognitive functions,” says Dr Kulkarni. 

Wholesome nutrition an answer 

Vitamin B12, an essential vitamin, is synthesized by bacteria and is mainly found in animal products. There is no biological process of production of vitamin B12 in the human body.  

It is believed that vitamin B12 along with folic acid may help in the prevention of mental and neurological disorders such as dementia, mood behaviour. The combination is vital for the healthy functioning of the central nervous system. Severe deficiency of this vitamin is also responsible for another condition, known as anemia.  

Diet modification is the most common way to manage the deficiency in mild cases. However, intervention is needed in case of severe deficiency.  

Foods rich in vitamin B12 are meat, poultry, seafood, eggs, and dairy products, and fortified food such as bread with vitamin B12. Including enough of these food products in one’s diet, helps maintain optimal levels of this crucial vitamin. 

Individuals with medical conditions such as lactose intolerance who cannot consume milk or dairy products, need to consult their physician who will advise them on the right dose of vitamin B12 supplements and multivitamins. 

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3 Responses

  1. Wow ! good one hasn’t thought, how B12 vitamin is so essential . Well written in a lucid manner.

    1. Thanks Prashant for your positive feedback! Please keep reading Happiest Health for more such stories and share them with your friends and loved ones.

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