What Is Vitamin B12 Good For?

Vitamin B12 is a water-soluble vitamin required for red blood cell formation, nerve function, and DNA synthesis.

Vitamin B12 is a water-soluble vitamin required for red blood cell formation, nerve function, and DNA synthesis. 

A low level of vitamin B12 is called vitamin B12 deficiency.

Vitamin B12 has many health benefits, including: 

• Red blood cell formation
• Neurological function
• DNA synthesis
• May reduce the risk of heart disease
  • Vitamin B12 affects levels of the amino acid homocysteine
  • High levels of homocysteine can increase the risk of heart disease
• May slow or prevent cognitive decline 
  • Low levels of vitamin B12 deficiency are associated with cognitive decline
• May help maintain energy and endurance
  • Vitamin B12 by itself does not boost energy but low levels of B12 can cause fatigue and weakness, especially in patients who have anemia 
• Essential for development of the neural tube, brain, and spine in a fetus
• Maintaining bone health
• Reducing the risk of macular degeneration
• May reduce symptoms of depression
  • Vitamin B12 can help reduce depression in people who are deficient in the vitamin 
• Can help maintain healthy skin, nails, and hair
  • Low levels of vitamin B12 can cause skin and nail problems, but in people who have normal levels of B12, additional supplementation will not improve skin, nails, or hair

Symptoms of vitamin B12 deficiency include: 

• Anemia
• Fatigue
• Weakness
• Constipation
• Weight loss
• Loss of appetite
• Neurological changes, such as numbness and tingling in the hands and feet
• Balance problems 
• Confusion
• Memory problems
• Dementia
• Depression
• Mouth or tongue soreness

Most people in the U.S. get adequate amounts of vitamin B12, but certain conditions can increase the risk of developing vitamin B12 deficiency, including:

• Older age
• Pernicious anemia
• Gastritis
• Intestinal disorders
• Autoimmune conditions
• Reduced levels of stomach acidity (hypochlorhydria or achlorhydria)
• Vegetarians and vegans who consume no animal foods
• Pregnant and lactating women who follow strict vegetarian diets and their infants
• Certain medications that interfere with the absorption of vitamin B12

Vitamin B12 deficiency is diagnosed with a blood test. 

Other tests may be indicated to determine the cause.

Depending on the severity of vitamin B12 deficiency, low vitamin B12 is treated with: 

• Vitamin B12 injection
• Oral vitamin B12 supplements
• Consuming foods rich in or fortified with vitamin B12