Vitamin B12 Usage and Health Benefits

Vitamin B12 is a valuable B vitamin that helps regulate metabolism. Also available as a supplement, vitamin B12 is involved in maintaining the proper functioning of the central nervous system and aiding in the formation of red blood cells. It helps prevent megaloblastic anemia, a type of anemia that makes people weak and tired. Vitamin B12 also plays a major role in the development and proper function of the brain.

Also called cobalamin, vitamin B12 is essential for red blood cell production, brain function, and nerve tissue health. It’s the largest and most structurally complex vitamin. Vitamin B12 naturally occurs in animal products but can be industrially made through bacterial fermentation. Animal products that contain vitamin B12 include dairy products, eggs, meat, and fish.

Health Benefits

Vitamin B12 has numerous health benefits. For instance, it’s known to aid heart health, iron levels, the nervous system, help memory mood, skin, nails, hair, and more.

Heart Health

Research shows that vitamin B12 significantly reduces levels of homocysteine in the blood. This is an essential amino acid that’s associated with increased risks of cardiovascular disease. Studies show that individuals who have moderately raised homocysteine levels have high rates of stroke and heart attack.[iv]

Skin Health

Vitamin B12 helps the nails, hair, and skin. Vitamin B12 deficiency results might lead to reduced hair growth, vitiligo, skin hyperpigmentation, discolored patches, and more.[v]

Brain Health

Research shows that vitamin B12 might help with depression, mood, memory, nervous system function, and brain function. Studies show that people and patients with depression have low vitamin B12 and low folate. Other studies show that lack of vitamin B12 could lead to poor memory.[vi]

Blood Health

Vitamin B12 is an essential vitamin that helps in the production of red blood cells. If the body lacks enough vitamin B12, this might result in unhealthy red blood cells. Lack of enough vitamin B12 is one of the reasons for irregular and extra-large red blood cells. The irregular shape prevents the red blood cells from moving to the bloodstream from the bone marrow. This is what causes megaloblastic anemia.

Over time, anemia might cause fatigue, weakness, and other diseases. This is because the body does not have sufficient red blood cells to carry oxygen to other body organs.[vii]

👨 Man Nutritional Needs

  • 1 to 3 years: 0.9 mcgs per day
  • 4 to 8 years: 1.2 mcgs per day
  • 9 to 13 years: 1.8 mcgs per day
  • 14 to 18 years: 2.4 mcgs per day
  • 19+ years: 2.6 mcgs per day

👩 Woman Nutritional Needs

  • 1 to 3 years: 0.9 mcgs per day
  • 4 to 8 years: 1.2 mcgs per day
  • 9 to 13 years: 1.8 mcgs per day
  • 14 to 18 years: 2.4 mcgs per day
  • 19+ years: 2.6 mcgs per day

Vitamin B12 Deficiency

Vitamin B12 deficiency can cause numbness, weakness, tiredness, and tingling in toes and fingers, and more.[i] Individuals more likely to have vitamin B12 deficiency are older adults who do not produce sufficient hydrochloric acid to naturally absorb the vitamin B12 through food.

People with digestive disorders like celiac disease and Crohn’s disease and people who have had gastrointestinal surgery and weight loss surgery might be deficient in vitamin B12 because of reduced absorption. Following are some health problems you might experience if you don’t take enough vitamin B12.


A person who doesn’t regularly eat animal products, such as Vegans and vegetarians, should ask their health provider to check their B12 levels. Also, excessive consumption of alcohol puts an individual at risk of vitamin B12 deficiency. The body cannot produce sufficient healthy red blood cells when the levels of vitamin B12 are low. This could lead to anemia.[ii]

Irregular Red Blood Cells

Vitamin B12 helps the production of red blood cells. Without enough red blood cells carrying sufficient oxygen to your organs and tissues, the body won’t function properly.[iii] Additional symptoms of vitamin B12 deficiency:

  • Confusion
  • Memory loss
  • Unsteady movements
  • Muscle weakness
  • Yellowish or pale skin
  • Vitiligo
  • Dizziness
  • Shortness of breath
  • Fatigue
  • Tingling or numbness in your feet and hands
  • Anemia
  • Irritability/mood swings
  • Tender tongue
  • Weight loss
  • Irregular heartbeat

Possible Side Effects

While studies have shown there are no risks associated with taking vitamin B12, it’s always important to consult a health provider before you start taking any supplement. The doctor can determine whether it’s a need then.

Studies show vitamin B12 might interact with other medications. According to the NIH (National Institute of Health), the following drugs might interfere with vitamin B12 absorption.[viii]

  • Metformin
  • Histamine h2-receptors
  • Proton pump inhibitors
  • Chloromycetin

Although oral vitamin B12 is safe if taken in recommended amounts for healthy people, injectable vitamin B12 – often used for treating severe deficiencies might cause the side effects below:

  • Vein thrombosis
  • Pulmonary edema
  • Vomiting
  • Nausea
  • Dizziness
  • Headache
  • Skin rash
  • Itching
  • Mild diarrhea[ix]

Also, vitamin B12 might cause rare but severe allergic reactions. This includes difficulty in breathing and swallowing and swelling of the throat, tongue, and face. If this happens, call local emergency services or 911 immediately. Folic acid supplements might interfere with the absorption of vitamin B12. Speak to a health provider if you use folic acid.

You might have to take vitamin B12 alone or separately from these supplements or drugs, maybe one at night and in the morning – to ensure you get the recommended amounts of vitamin B12. Avoid vitamin B12 supplements if you’re allergic or sensitive to cobalt, vitamin B12, or other ingredients.

Dosage And Preparation

The recommended dietary allowance (RDA) is 2.4 micrograms per day. The normal range is 200 picograms per milliliter (pg/ml) to 900 pg/ml. Any amount below 200 pg/ml is considered a deficiency. A doctor should administer a test to measure the levels of vitamin B12.

However, if you have any concerns about not getting sufficient vitamin B12 from natural food, speak to a health professional about taking vitamin B12 supplements. The most suitable supplemental dose for you might depend on factors like medical history, gender, and age.

Ways to Get Your Vitamin B12

You can get adequate vitamin B12 by eating foods that contain this essential micronutrient. Also, you can get your vitamin B12 from supplements; you could take it in capsule or tablet form. You’ll also find vitamin B12 supplements in a liquid extract.

Its recommended you get your vitamin B12 from eating foods because you also get more benefits than just taking vitamin B12 supplements, which is just that, vitamin B12.

Foods Rich in Vitamin B12

Vitamin B12 is found in many meat products. If you regularly eat dairy and meat, it’s easy for you to get sufficient vitamin B12. Below are foods rich in vitamin B12.

  • Animal kidneys and liver – A 100 gram serving of veal, beef, or lamb liver contain 3,500% of the RDA for vitamin B12, while a similar serving of kidneys contains 3,000% of the RDA for vitamin B12.
  • Clams – 100 grams of clams contain 99 mcg of vitamin B12.
  • Sardines – 150 grams of sardines contain 500% of the RDA for vitamin B12.
  • Beef – 100 grams of beef contain 5.9 mcg of vitamin B12.
  • Fortified cereal – one cup of Malt-O-Meal Raisin bran contains 62% of the RDA for vitamin B12.
  • Tuna – 100 grams of cooked tuna contains 10.9 mcg of vitamin B12.
  • Fortified nutritional yeast – 15 grams of nutritional yeast might provide 17.6 mcg of vitamin B12.
  • Trout – a 100-gram of trout has 7.5 mcg of vitamin B12.
  • Salmon – 178 grams of cooked salmon provides over 200% of the RDA for vitamin B12.
  • Fortified non-dairy milk – 240 ml of soymilk has 2.1 mcg or 86% of the RDA for vitamin B12.
  • Milk and other dairy products
  • Eggs – 100 grams has 1.1 mcg or 46% of the RDA for vitamin B12.


People with problems absorbing vitamin B12 from natural food sources might have to take supplements. This includes older patients with intestinal disorders and those with pernicious anemia, as well as those with achlorhydria. Supplements may be taken in a nasal spray or orally. Nevertheless, oral supplements don’t work for those with vitamin B12 deficiency. In such cases, vitamin B12 is injected.

Vegetarians can use supplements to avoid vitamin B12 deficiency because vegan diets remove animal products that naturally provide B12. This is important, particularly while breastfeeding or during pregnancy. Vitamin B12 supplements are available for purchase online and in health food stores.


What is the main benefit of taking vitamin B12?

Vitamin B12 is an essential nutrient that helps keep the blood cells and body’s nerves healthy and helps make the DNA. Also, vitamin B12 helps prevent megaloblastic anemia that makes people weak and tired.

What food is high in vitamin B12?

To increase vitamin B12 amounts in your daily diet, eat foods like eggs, low-fat yogurt, fortified breakfast cereal, fish, chicken, liver, and beef.

What are the symptoms of vitamin B12 deficiency?

Symptoms of lack of vitamin B12 include depression, irritability, disturbed vision, mouth ulcers, a swollen tongue, and a sore throat.

What causes vitaminB12 deficiency?

Vitamin B12 deficiency is often caused by a lack of a compound known as the intrinsic factor, which is caused when the immune system attacks stomach cells and the intrinsic factor is produced. This is called pernicious anemia.

What drugs should you not take with B12?

Some drugs decrease vitamin B12s absorption. These include drugs to treat heartburn (like H2 blockers), anti-seizure drugs (like primidone, phenytoin, phenobarbital), antibiotics (like tobramycin, neomycin, gentamicin), metformin, and colchicine.

Should I take vitamin B12 at night or in the morning?

It depends on whether you’re taking any of the drugs mentioned above. Check the supplements section in our article to find the medications that react with B12. Otherwise, you can take one at night and the other in the morning.

What’s the best vitamin B12 supplement?

You can choose between methylcobalamin and Jarrow Formula’s Methyl B12. Methylcobalamin is much easier to absorb.

Should I take B12 every day?

Yes, the recommended daily allowance (RDA) for B12 for individuals over 14 years is 2.4 micrograms. However, you might want to take less or more depending on your lifestyle, age, and specific situation.



  1. [i] National Institutes of Health, Office of Dietary Supplements. Vitamin B12 Fact Sheet for Consumers. Updated March 30, 2020.
  2. [ii] Johns Hopkins Medicine. Vitamin B12 deficiency anemia. 2020.
  3. [iii] Johns Hopkins Medicine. Vitamin B12 deficiency anemia. 2020.
  4. [iv] Markišić M, Pavlović AM, Pavlović DM. The impact of homocysteine, vitamin B12, and vitamin D levels on functional outcome after first-ever ischaemic stroke. Biomed Res Int. 2017;2017:5489057. doi:10.1155/2017/5489057
  5. [v] Kannan R, Ng MJ. Cutaneous lesions and vitamin B12 deficiency: an often-forgotten link. Can Fam Physician. 2008;54(4):529-532.
  6. [vi] Coppen A, Bolander-Gouaille C. Treatment of depression: time to consider folic acid and vitamin B12. J Psychopharmacol. 2005;19(1):59-65. doi:10.1177/0269881105048899
  7. [vii] Johns Hopkins Medicine. Vitamin B12 deficiency anemia. 2020
  8. [viii] Office of Dietary Supplements. Vitamin B12. Updated 2020.
  9. [ix] Mount Sinai Health System. Vitamin B12 (Cobalamin).