Vitamin B Deficiency: Symptoms, Causes And Treatments (2024)

B vitamins are “water soluble vitamins that are needed for red blood cell metabolism, DNA metabolism, energy and cognitive function,” says Erin Ellis, N.D., a naturopathic doctor based in Gilbert, Arizona.

B vitamins help certain enzymes work properly by releasing energy from carbohydrates and fat, as well as breaking down amino acids and transporting oxygen around the body. B vitamins also have a direct impact on your energy levels, brain function and cell metabolism.

There are eight B vitamins, collectively called B complex vitamins:

• Thiamine (B1): Assists in the growth and function of various cells
• Riboflavin (B2): Assists in the growth of cells, energy production and the breakdown of fats
• Niacin (B3): Helps release energy from food, create cholesterol and fats and create and repair DNA
• Pantothenic acid (B5): Helps break down fats and perform other metabolic functions
• Vitamin B6 (pyridoxine): Helps enzymes perform various functions, supports brain and immune health
• Biotin (B7): Helps enzymes break down fats, carbohydrates and proteins from food
• Folate (B9): Helps form DNA and RNA and assists in protein metabolism
• B12 (cobalamin): Assists in forming red blood cells and DNA

Different B vitamins yield different deficiency levels, for example, in the U.S., research indicates that approximately 6% of adults younger than 60 years have vitamin B12 deficiency, and around 20% of those older than 60 have a deficiency^[1]Hunt A, Harrington D, Robinson S. Vitamin B12 deficiency. BMJ. 2014;349:g5226. . However, thiamin and folate deficiencies are quite rare across the country.

While the causes of deficiency can vary from vitamin to vitamin, common causes include:

• Inadequate intake due to certain diets
• Malabsorption due to certain conditions (such as Crohn’s disease)
• Interactions with certain medications
• Alcohol abuse
• Certain genetic disorders

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Symptoms of B12 deficiency – B12 institute

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Those who eat primarily a vegetarian diet are at risk of a B vitamin deficiency, since meat products are a high source of certain B vitamins, notes Dr. Ellis. For vitamin B12 in particular, research notes that people of low socioeconomic status, women and non-Hispanic Blacks are more at risk of a deficiency.

Additionally, people with one or more of the risk factors listed below are more prone to vitamin B12 deficiency specifically, according to research:

• Gastric or small intestine resections
• Inflammatory bowel disease
• Metformin use for more than four months
• Proton pump inhibitors or histamine H2 blocker use for more than 12 months
• Vegans and/or strict vegetarians
• Adults older than 75 years

“Supplements are a great way to boost the levels of all B vitamins in the B complex, however, intramuscular (IM) injections or IV therapy are also beneficial ways to get your B vitamins,” says Dr. Ellis.

The symptoms of B vitamin deficiencies vary depending on the B vitamin.

However, the symptoms of B12 deficiency in particular (which can carry a higher risk rate of deficiency than other B vitamins) include:

• Anemia
• Fatigue
• Weakness
• Pale yellow skin color
• Mouth ulcers and canker sores
• Constipation
• Vision disturbances
• Balance issues, difficulty walking
• Tingling in hands and legs
• Memory loss, confusion
• Dementia
• Depression
• Seizures
• Vision loss

The top sources of B vitamins, according to Dr. Melanie Keller, N.D., a naturopathic doctor in Los Angeles, include:

• Meat, especially liver from beef, pork, lamb or chicken
• Seafood, like salmon, is rich in several B vitamins, while oysters, clams and mussels are a stellar source of vitamin B12 specifically
• Poultry, like chicken and turkey, are most notable for their niacin (vitamin B3) and pyridoxine (vitamin B6) content
• Eggs are one of the top sources of biotin
• Dairy products, like milk, provide ample riboflavin
• Legumes are most notable for their high folate content
• Leafy greens, which stand out for their folate (B9) content
• Seeds and nutritional yeast, which contain B vitamins and are often fortified with them as well

“Review your diet and supplementation with your doctor to assess B vitamin intake and, or, consider taking a B complex [supplement],” says Dr. Keller.

“While even at large doses, vitamin B12 is generally considered to be safe because the body does not store excess amounts, but taking high levels of vitamin B6 from supplements for a year or longer can cause severe nerve damage, leading people to lose control of their bodily movements,” she adds, emphasizing the importance of getting tested for B vitamin deficiency at your doctor’s office before attempting to self-treat.

While deficiencies are relatively rare for a number of B vitamins, if vitamin B12 deficiency specifically is left untreated, it could lead to:

• Nerve and brain damage
• Increased risk of stomach cancer
• Infertility (although this may be reversed with treatment)
• Heart and lung conditions

Other B vitamin deficiencies to watch for include folate—especially during pregnancy. “If left untreated, folate deficiency may result in serious birth defects in the spinal cord and brain of a developing fetus, which are called neural tube defects,” says Dr. Keller. It can also cause severe complications due to depriving tissues of oxygen.