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Signs of Vitamin B Deficiency

The information provided herein does not constitute an expert or medical advice, nor intended to replace such advice.

Health and Wellness

You may have heard about some types of vitamin B, but in reality, there are eight different B vitamins. Each of these vitamins plays a different role in the human body, and they’re all important for your health and wellbeing. A lack of vitamin B can lead to different signs and symptoms that can range in severity.

What happens if you don’t get enough vitamin B? Keep reading to learn more about the signs of low B vitamins.

Functions of B vitamins

Each B vitamin has different functions. According to the Harvard T.H. Chan School of Public Health, the vitamin B complex helps many different enzymes do their jobs correctly. These enzymes are involved in many processes, such as metabolism, oxygen transportation, cell formation, and releasing energy.

Vitamin B6 is involved in the synthesis of new neurotransmitters, which are essential to our brain function. Meanwhile, vitamin B3 plays a role in cell metabolism. Vitamins B9 and B12 are closely related, and they help in the creation of new blood cells and DNA.

Additionally, vitamin B7 or biotin helps create different proteins. These proteins are necessary for many processes. Biotin is commonly known for keeping your nails, skin, and hair healthy.

Since B vitamins are involved in so many processes in the human body, B complex deficiency can lead to a wide range of manifestations. Let’s go over the causes and symptoms of vitamin B deficiency.

Causes of vitamin B deficiency

The main causes of vitamin B deficiency include:

  • Eating an unbalanced diet
  • Excessive alcohol intake that interferes with vitamin absorption
  • Certain medications
  • Diseases that cause intestinal malabsorption
  • Senior adults who don’t eat a balanced diet

According to Johns Hopkins Medicine, the list of diseases that can cause vitamin B deficiency includes celiac disease, chronic pancreatitis, lactose intolerance, Whipple disease, juvenile pernicious anemia, Diphyllobothrium latum infestation, intestinal parasites, among others.

Who is at risk for vitamin B12 deficiency?

Vitamin B12 deficiency is probably the most well-known type of vitamin B deficiency. That’s because anemia is a common B12 deficiency sign. Vitamin B12 is also involved in creating new DNA, and a deficiency can lead to neurological and psychological issues.

According to the Cleveland Clinic, people who don’t consume enough vitamin B12 in their foods have a higher risk of deficiency. This includes vegans and vegetarians, since most sources of dietary B12 come from animal products. Other risk factors for vitamin B12 deficiency include:

  • Gastritis
  • Pernicious anemia
  • Crohn’s’ disease
  • Celiac disease
  • Gastric bypass
  • Excessive alcohol use
  • Certain genetic disorders (transcobalamin II deficiency)

B complex deficiency symptoms

The signs of vitamin B deficiency can range in severity, and they can also affect every person differently. But overall, symptoms of B complex deficiency can include:

  • Fatigue
  • Weakness
  • Sore mouth or tongue
  • Nausea
  • Vomiting
  • Diarrhea
  • Lack of appetite
  • Weight loss
  • Yellowish skin
  • Numbness or tingling of the hands and feet
  • Vision problems
  • Irregular heartbeats
  • Memory loss
  • Concentration difficulties
  • Irritability
  • Depression
  • Unsteady movements or walk
  • Personality changes

Neurological symptoms caused by severe vitamin B deficiency may become irreversible, even after the deficiency has been corrected. It’s very important to seek medical assistance if you suspect that you’re suffering from any type of vitamin deficiency.

Diagnosing vitamin deficiencies isn’t always straightforward, since many different deficiencies can cause similar symptoms. In other cases, deficiency signs are very mild and hard to detect. But it’s very likely that your doctor will order different blood tests to determine the exact cause of the problem so you can receive the right treatment. 

Sources of B vitamins

According to MedlinePlus, you can get B vitamins from foods such as:

  • Fish
  • Poultry
  • Meat
  • Eggs
  • Dairy
  • Leafy greens
  • Beans
  • Peas
  • Fortified cereals and breads

You may also need to take a vitamin B supplement, especially if you follow a vegetarian or vegan diet. People who have diseases that cause intestinal malabsorption could also require additional B vitamin supplementation. Pregnant women and women who are trying to conceive should also take vitamin supplementation to prevent neurological defects in their baby.

It’s important to discuss your dietary requirements with a licensed professional, such as a dietitian. Although rare, it’s possible to develop vitamin B toxicity if you take too many supplements to relieve the effects of low vitamin B.

Visit STDWatch.com now to learn more about many diverse health topics.


B Vitamins - hsph.harvard.edu

Malabsorption - hopkinsmedicine.org

Vitamin B12 Deficiency - my.clevelandclinic.org

B Vitamins - medlineplus.gov

Dr. Andrea Pinto Lopez

Dr. Andrea Pinto Lopez

Jul 06, 2022

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