vitamin B12
Julie Hambleton
Julie Hambleton
April 16, 2024 ·  4 min read

Signs of Vitamin B-12 Deficiency You Should Never Ignore

One of the most crucial, though often overlooked, vitamins to our health is vitamin B-12. Without enough vitamin B-12 in our diets, we can feel tired, have trouble focusing, and so much more. Unfortunately, it is estimated that approximately 15% of the general population is deficient. These are the signs of vitamin B-12 deficiency and what you should do to prevent it.

What Is Vitamin B-12?

the word VITAMIN B-12 . Medical concept. the medicine
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Vitamin B-12, also known as Cobalamin, is a vitamin that is found naturally in most animal products. It is necessary for the formation of red blood cells and DNA. Its requirement for red blood cells means that it is a necessary vitamin in transporting other nutrients around the body and providing us with energy. Vitamin B-12’s involvement in DNA formation also makes it important for cognitive development and functioning. It is a key component in the function and development of both brain and nerve cells. (1) Vitamin B-12 first binds to the proteins in the foods that we eat. From there, enzymes and hydrochloric acid in our stomach break down those foods and unbind the vitamin B-12 into its free form. Once it is free, it then binds with a protein called intrinsic factor so that our small intestine can absorb it into our bloodstream later on in the digestive process.

Read: The Vitamin Deficiency Up to 80% of People Have

What Foods Contain Vitamin B-12?

Natural sources of Vitamin B12 (Cobalamin) for normalization of sleep; ensuring normal brain function; supporting the respiratory system; alzheimer's deasease treatment. Top view
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As already mentioned, vitamin B-12 is found naturally in animal-based foods. It may also be found in other non-animal products that have been fortified with the vitamin. You will also find it in enriched nutritional yeast, fortified breakfast cereals, and enriched soy or rice milk. It can be found in small amounts in nori, however, it depends on where the seaweed came from among other factors. The following is a list of foods that contain vitamin B-12 naturally (2):

  • Fish and shellfish
  • Liver 
  • Red meat
  • Poultry 
  • Eggs
  • Dairy products (milk, cheese, yogurt)

How Much Do You Need?

Vitamin B complex consists of 8 types of vitamin B B1 thiamine B2 riboflavin B3 niacin B5 pantothenic acid B6 Pyridoxine , B7 biotin , B9 Folic, B12 Cobalamin,
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The amount of daily dietary vitamin B-12 that you need depends on your age and also your situation. In general, adults need about 2.4 micrograms of it each day. Pregnant and lactating women, however, will need more. Adequate vitamin B-12 status in pregnant and lactating women is crucial to the cognitive development of the growing fetus and baby. Older adults will also need to monitor their status of the vitamin as stomach acid tends to decrease with age. Lower stomach acid makes it harder for the vitamin to be absorbed into the bloodstream.

Read: Cherries Are the Bedtime Snack You Didn’t Know You Needed

What Causes Deficiency?

Medical concept meaning VITAMIN B12 DEFICIENCY with sign on the sheet.
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Most adults in the United States are not vitamin B-12 deficient. Deficiencies are seen in greater numbers in minority populations and in lower-income populations. Most cases of vitamin B-12 deficiency are caused by intestinal malabsorption. If you are unable to properly absorb the vitamin from the food you eat into your bloodstream, you will be deficient. (3) Most malabsorption problems can come from low stomach acid or also a lack of the intrinsic factor required for the small intestine to absorb it.

The most common reasons for malabsorption problems are:

Doctor and holographic bowel scan projection with vital signs and medical records. Concept of new technologies, body scan, digital x-ray, abdominal organs, modern medicine
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  • Pernicious anemia (lack of intrinsic factor)
  • Food-bound vitamin B-12 malabsorption disorder
  • Atrophic gastritis (chronic inflammatory disease of the stomach)

Other causes include stomach surgeries, celiac disease, and other small intestine disorders, pancreatic insufficiency, vegan and vegetarian diets, alcoholism, AIDS, and long-term use of acid-reducing drugs. Most doctors will recommend people who follow a vegan or vegetarian diet take a vitamin B-12 supplement. Without the consumption of meat and other animal products, reaching your vitamin B-12 intake needs is extremely difficult. 

Read: People who eat some cheese, yogurt, or chocolate every day have a lower risk of heart disease, study finds

Signs of Vitamin B-12 Deficiency

Vitamin B12 deficiency infographic, 3d medical vector illustration on white background
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The body will give you hints if you are lacking in adequate vitamin B-12. The trick is you just need to know what to listen for. These symptoms are often mild and progress gradually, so you must listen carefully. Pale skin, weakness, and fatigue are the big three. Along with these come difficulty focusing or difficulty participating in your normal activities. In some extreme cases, people can struggle to walk. They may also develop delirium and paranoia and even dementia. Other symptoms when deficiency becomes worse can include (4):

  • Tingling in the hands and/or feet
  • Loss of sensation in the legs, hands, or feet
  • Shortness of breath
  • Rapid heart rate
  • Dizziness
  • Confusion and irritability
  • Depression

Read: Taking a Daily Nap? You’re Not Lazy, You’re Just Doing Your Body Good

How To Test For It

Doctor holding a test blood sample tube with Vitamin B12 test on the background of medical test tubes with analyzes
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Diagnosis of vitamin B-12 deficiency is done usually by a blood test but also occasionally doctors will perform an endoscopy. If red blood cells are large, the doctors will suspect a B-12 deficiency. From there, what the doctors decide to do or look for next depends on your age, biological sex, and health status. If you are low, the doctors will suggest some dietary changes and likely supplementation. In the case of those who lack the intrinsic factor to absorb the vitamin, they may require you to have vitamin B-12 injections. Vitamin B-12 is a water-soluble vitamin, meaning that it is very difficult to overdose when taking supplements. This is because your body just gets rid of any excess that it doesn’t need through the urine.

Keep Reading: 14 Fish You Could Consider Never Eating


  1. Vitamin B12.” Harvard T Chan School of Public Health. Harvard University. Accessed July 8, 2022.
  2. Vitamin B12.” Office of Dietary Supplements. National Institute of Health. Updated March 9, 2022. Accessed July 08, 2022.
  3. Vitamin B12.” Linus Pauling Insitute | Micronutrient Information Center. Oregon State University. Accessed July 08, 2022.
  4. Vitamin B12 Deficiency.” Merck Manuals. Larry E. Johnson, MD, Ph.D. November 2020.