Complications of vitamin B12 deficiency

Vitamin B12 Deficiency

Vitamin B12 is an important vitamin of the B group of vitamins. It is also called cobalamin and it plays an important role in the proper brain and nervous system functioning and in the formation of blood.

It is found in foods of animal origin, like shellfish, meat (especially liver), chicken and other poultry, eggs, milk, and dairy products. By eating these foods a person guarantees an adequate intake of B12. However, vegans, who do not eat meat, fish, dairy products, or eggs, are at risk of developing B12 deficiency and must take supplements.

Most common symptoms of vitamin B12 deficiency are tiredness and fatigue. Depression and memory impairment are also possible symptoms of this deficiency.

Complications

When the body does not receive proper amounts of vitamin B12, it starts producing abnormally large red blood cells that do not function properly.

This deficiency can manifest as anemia and have symptoms and complications commonly associated with other types of anemia. These include tiredness, lethargy, and problems with the heart like tachycardia and heart failure. In cases of severe anemia, patients need to be admitted to a hospital where their lung and heart functions can be monitored.

Vitamin B12 deficiency can affect the nervous system and lead to complications like blurred vision, memory loss, tingling, and difficulty walking or speaking.

This deficiency can also cause temporary infertility, which is reversed as soon as the body receives adequate amounts of B12.

In pregnant women who have B12 deficiency there is a risk of neural tube defect for the baby. This condition affects growth and development. Baby can be at risk of spina bifida, where the spine is not developed properly, and anencephaly, a condition that affects the baby’s skull and brain.

Causes of vitamin B12 deficiency include difficulty absorbing vitamin B12 from food, lack of intrinsic factor (e.g., because of pernicious anemia), surgery in the gastrointestinal tract, prolonged use of certain medications (e.g., metformin or proton pump inhibitors, discussed in more detail below in the section on interactions with medications), and dietary deficiency. Because people who have difficulty absorbing vitamin B12 from food absorb free vitamin B12 normally, their vitamin B12 deficiency tends to be less severe than that of individuals with pernicious anemia, who cannot absorb either food-bound or free vitamin B12.

Certain congenital conditions, such as hereditary intrinsic factor defects and congenital vitamin B12 malabsorption (Imerslund-Gräsbeck disease), can also cause severe vitamin B12 deficiency.
The effects of vitamin B12 deficiency can include the hallmark megaloblastic anemia (characterized by large, abnormally nucleated red blood cells) as well as low counts of white and red blood cells, platelets, or a combination; glossitis of the tongue; fatigue; palpitations; pale skin; dementia; weight loss; and infertility.
Neurological changes, such as numbness and tingling in the hands and feet, can also occur. These neurological symptoms can occur without anemia, so early diagnosis and intervention is important to avoid irreversible damage.
In addition, some studies have found associations between vitamin B12 deficiency or low vitamin B12 intakes and depression. In pregnant and breastfeeding women, vitamin B12 deficiency might cause neural tube defects, developmental delays, failure to thrive, and anemia in offspring.
Because the body stores about 1 to 5 mg vitamin B12 (or about 1,000 to 2,000 times as much as the amount typically consumed in a day), the symptoms of vitamin B12 deficiency can take several years to appear.

Typically, vitamin B12 deficiency is treated with vitamin B12 injections, because this method bypasses any barriers to absorption. However, high doses of oral vitamin B12 might also be effective. A 2018 Cochrane review included three randomized controlled trials (RCTs) that compared very high doses (1,000–2,000 mcg) of oral with intramuscular vitamin B12 for vitamin B12 deficiency in a total of 153 participants. The evidence from these studies, although of low quality, showed that the ability of high oral doses of vitamin B12 supplements to normalize serum vitamin B12 was similar to that of intramuscular vitamin B12.

✓ Fact confirmed: Vitamin B12 Fact Sheet for Health Professionals National Institutes of Health (NIH) Office of Dietary Supplements (ODS); March 9, 2022

Psychologically, this deficiency can lead to depression, anxiety, irritation, mania, psychosis and personality changes.

Some of the signs that may indicate that a person has vitamin B12 deficiency include itching, stinging or tingling of the tongue, especially around the edges or on the tip, sharp and sudden pain in the palm of a hand, white spots on the skin due to absence of melanin, sores in the corners of the mouth, twitching of facial muscles, especially around the eye, pain in the face, short breath, migraine, tingling in thighs, memory loss, irritation, depression.

Vitamin B12 deficiency is treated by administering supplements of this vitamin. In milder cases, it can be part of a B group of vitamins supplement or taken individually in form of a pill, but in severe cases, it is usually injected.