vitamin b12

Vitamin B-12 is a crucial B vitamin. It is needed for nerve tissue health, brain function, and the production of red blood cells. Cobalamin is another name for vitamin B-12.

Vitamin B-12 is a water-soluble vitamin, like all other B-vitamins.

This means it can dissolve in water and travel through the bloodstream. The human body can store vitamin B-12 for up to four years. Any excess or unwanted vitamin B-12 is excreted in the urine.

Vitamin B-12 is the largest and most structurally complicated vitamin. It occurs naturally in meat products and can only be industrially produced through bacterial fermentation synthesis.


1. Animal Liver and Kidneys

Organ meats are some of the most nutritious foods out there. Liver and kidneys, especially from lamb, are rich in vitamin B12.

A 3.5-ounce (100-gram) serving of lamb liver provides an incredible 1,500% of the RDI for vitamin B12.

While lamb liver is higher in vitamin B12 than beef or veal liver, the latter two contain about 990% of the RDI per 3.5 ounces (100 grams).

Lamb liver is also very high in copper, selenium and vitamins A and B2.

Lamb, veal and beef kidneys are also high in vitamin B12, providing about 1,300% of the RDI per 3.5-ounce (100-gram) serving. They also provide more than 100% of the RDI for vitamin B2 and selenium.

2. Clams

Clams are small, chewy shellfish that are packed with nutrients.

This mollusk is a lean source of protein and contains very high concentrations of vitamin B12. You can get more than 3,300% of the RDI in just 20 small clams.

Clams, especially whole baby clams, also provide great amounts of iron, with almost 300% of the RDI in 20 small clams.

Clams have also been shown to be a good source of antioxidants.

Interestingly, the broth of boiled clams is also high in vitamin B12. Canned broth has been shown to provide 2.7–14.1 mcg of vitamin B12 per 3.5 ounces (100 grams).

3. Sardines

Sardines are small, soft-boned saltwater fish. They’re usually sold canned in water, oil or sauces, though you can also buy them fresh.

Sardines are super nutritious because they contain virtually every single nutrient in good amounts.

A one-cup (150-gram) serving of drained sardines provides more than double the RDI for vitamin B12.

Furthermore, sardines are an excellent source of omega-3 fatty acids, which have been shown to provide many health benefits, such as reducing inflammation and improving heart health.

4. Beef

Beef is an excellent source of vitamin B12.

One grilled flat iron steak (about 186 grams) provides almost 200% of the RDI for vitamin B12.

Also, the same amount of steak contains reasonable amounts of vitamins B2, B3 and B6, as well as more than 100% of the RDIs for selenium and zinc.

If you’re looking for higher concentrations of vitamin B12, it is recommended to choose from low-fat cuts of meat. It’s also better to grill or roast it instead of frying. This helps preserve the vitamin B12 content.

5. Fortified Cereal

This source of vitamin B12 may work well for vegetarians and vegans, as it’s synthetically made and not derived from animal sources.

Although not commonly recommended as part of a healthy diet, fortified cereals can be a good source of B vitamins, especially B12. Food fortification is the process of adding nutrients that are not originally in the food.

For instance, Malt-O-Meal High Fiber Bran Flakes offer up to 137% of the RDI for vitamin B12 in 3/4 cup (29 grams).

The same serving of this cereal also packs 140% of the RDI for vitamin B6 and good amounts of vitamins A, C and E.

Research shows that eating fortified cereals daily helps increase vitamin B12 concentrations.

In fact, one study showed that when participants ate one cup (240 ml) of fortified cereal containing 4.8 mcg of vitamin B12 daily for 14 weeks, their vitamin B12 levels increased significantly.

If you choose to use fortified cereal to increase your vitamin B12 intake, make sure to choose a brand low in added sugar and high in fiber or whole grains.

6. Tuna

Tuna is a commonly consumed fish and great source of nutrients, including protein, vitamins and minerals.

Tuna contains high concentrations of vitamin B12, especially in the muscles right beneath the skin, known as dark muscles. A 3.5-ounce (100-gram) serving of fresh tuna contains almost 160% of the RDI for the vitamin.

This same serving size also packs a good amount of lean protein, phosphorus, selenium and vitamins A and B3. Canned tuna also contains a decent amount of vitamin B12. In fact, one can (165 grams) of light tuna packed in water contains 85% of the RDI.

7. Fortified Nutritional Yeast

Nutritional yeast is a good vegan source of protein, vitamins and minerals.

It’s a species of yeast especially grown to be used as food, not as a leavening agent in bread and beer.

Vitamin B12 is not naturally present in nutritional yeast. However, it’s commonly fortified, making it a great source of vitamin B12.

As with fortified cereals, the vitamin B12 in nutritional yeast is vegan-friendly because it’s synthetically made.

Two tablespoons (16 grams) of nutritional yeast contain up to 130% of the RDI for vitamin B12.

One study added nutritional yeast to the diets of raw-food vegans and found it increased vitamin B12 blood levels and helped reduce blood markers of vitamin B12 deficiency.

8. Trout

Rainbow trout is considered to be one of the healthiest fish there is.

This freshwater species is a great source of protein, healthy fats and B vitamins.

A 3.5-ounce (100-gram) serving of trout fillet offers about 125% of the RDI for vitamin B12 and more than 1,300 mg of omega-3 fatty acids.

The RDI for the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) combined is 250–500 mg.

Trout is also a great source of minerals such as manganese, phosphorus and selenium.

9. Salmon

Salmon is well known for having one of the highest concentrations of omega-3 fatty acids. However, it’s also an excellent source of B vitamins.

A half fillet (178 grams) of cooked salmon can pack more than 80% of the RDI for vitamin B12.

The same serving size also provides an incredible 4,023 mg of omega-3 fatty acids.

Alongside its high fat content, salmon offers a great amount of protein, with about 40 grams in a half fillet (178 grams).

10. Fortified Nondairy Milk

Nondairy milk is popular among those who want a nutritious vegan replacement for dairy milk. While soy, almond and rice milks are not naturally high in vitamin B12, they are usually fortified, making them an excellent source of this vitamin.

One example is soy milk, which can provide up to 45% of the RDI for vitamin B12 in one cup (240 ml). For this reason, fortified nondairy milks could be a great option for those wanting to increase their vitamin B12 intake and avoid deficiency.

Similarly to the vitamin B12 in other fortified sources, the vitamin B12 in nondairy milk is synthetically made, so it’s vegan-friendly.

11. Milk and Dairy Products

Milk and dairy products like yogurt and cheese are great sources of protein and several vitamins and minerals, including vitamin B12.

One cup (240 ml) of whole milk supplies 18% of the RDI for vitamin B12.

Among all kinds of cheeses, Swiss cheese has been shown to have the highest vitamin B12 content. One ounce (30 grams) of Swiss cheese can contain about 16% of the RDI.

Full-fat plain yogurt can also be a decent source. It has even been shown to help improve vitamin B12 status in people who are deficient in the vitamin.

Interestingly, studies have shown that the body absorbs the vitamin B12 in milk and dairy products better than the vitamin B12 in beef, fish or eggs.

For example, a study in over 5,000 people showed that dairy was more effective than fish at increasing vitamin B12 levels.

12. Eggs

Eggs are a great source of complete protein and B vitamins, especially B2 and B12.

Two large eggs (100 grams) supply about 22% of the RDI for vitamin B12, plus 28% of the RDI for vitamin B2.

Research has shown that egg yolks have higher levels of vitamin B12 than egg whites, as well as that the vitamin B12 in egg yolks is easier to absorb. Therefore, it’s recommended to eat whole eggs instead of just whites.

In addition to getting a good dose of vitamin B12, you’ll get a healthy amount of vitamin D. Eggs are one of the few foods that naturally contain it, with 9% of the RDI in two large eggs.

Health Benefits of Vitamin B12

1. Improved heart health

Vitamin B12’s role in promoting heart health may get overlooked, but it’s essential, says Liz Weinandy, RD, a dietician at the Ohio State University Wexner Medical Center in Columbus, Ohio. “Vitamin B12, B6, and folic acid work together help to reduce homocysteine, which is a protein that can build up in blood and damage arterial walls, thus playing a role in heart disease,” she explains. When B12 is low, it can’t do its job effectively, which means your heart is at risk.

2. Pain Relief

Methylcobalamin, a form of Vitamin B12, reduces the clinical symptoms in legs such as paresthesia (an abnormal sensation like tingling or pricking), burning pains, and spontaneous pain.

In one study, methylcobalamin significantly improved symptoms, such as pain and prickling sensation, in patients with neck pain.

Intramuscular cobalamin injection is effective in alleviating low back pain in patients with no nutritional deficiencies. Cobalamin provides effective pain management for mouth ulcers.

Methylcobalamin treatment reduces pain symptoms in neuralgia, diabetic neuropathy, and lower back pain. It improves neuropathic pain.

3. Healthy nervous system

Vitamin B12 benefits your nervous system directly and keeps it in tip-top shape; when this nutrient is in short supply, you may develop that annoying “pins and needles” sensation in your extremities and/or numbness or tingling in the hands, legs, or feet, says Boston-based nutritionist Dana Greene, RD.

This usually occurs with anemia, but that’s not always the case, she says. “Vitamin B12 helps produce the fatty sheath (myelin) that surrounds and protects your nerves.” When you are deficient in B12, your nerve cells can’t function properly.

4. Brain Health

Methylcobalamin (MeCbl) is the most effectively taken form of vitamin B12 in neuronal organelles.

Cobalamin may have a role in the prevention of disorders of brain development and mood disorders as well as Alzheimer’s and vascular dementia in the elderly.

Supplementation of cobalamin is useful in neuronal regeneration. It also repairs the negative effects of ischemia on neurons.

A study on rats with sciatic nerve injuries supports the treatment of peripheral nerve injuries with Cobalamin.

B12 also increases the regeneration of axons and promotes neuronal repair.

5. Your oral health

There are many signs your tongue can reveal about your health, and a B12 deficiency is one of them. A mild deficiency can trigger tongue inflammation (glossitis). Greene says this painful condition can affect how you eat and speak. Your tongue may be red and swollen or look smooth since the tiny bumps along your tongue that contain your taste buds stretch out and disappear.

6. Sleeping Patterns

Cobalamin treatment improves sleep-wake rhythm disorders in human subjects.

It may increase the light sensitivity of circadian rhythms due to decreased melatonin levels.

It’s not normal to struggle falling asleep and wake up in the morning feeling more tired than when you went to bed. Biohacking Insomnia attacks sleep issues from every angle including limbic system repair, hormone levels, and circadian rhythm retraining.

7. Depression

In a randomized trial performed on patients with depression and low normal cobalamin levels, cobalamin supplementation improved depressive symptoms.

Studies have found that prolonged consumption (several weeks to years) may decrease the risk of depression relapse and the onset of clinically significant symptoms in people at risk.

8.Your gut health

We all know that eating enough fiber and drinking enough water are keys to healthy bowel movements, but a vitamin B12 deficiency can also cause constipation, diarrhea, loss of appetite and weight loss, says Will Bulsiewicz, MD, a gastroenterologist

. A vitamin B12 benefit can be a healthy gut. Sometimes these GI symptoms are a result of B12 deficiency, but other times B12 is a marker of an underlying digestive disease. “Vitamin B12 relies on the production of intrinsic factor by the stomach and is absorbed in the last part of the small intestine,” he says.

“Therefore, stomach or small bowel disturbances can create a B12 deficiency.” Crohn’s disease is a classic condition that can present with B12 deficiency, weight loss, and diarrhea. “In this case, it is inflammation of the small bowel from the Crohn’s disease that causes the symptoms, not the B12 deficiency itself,” he says. The exact mechanism by which B12 deficiency causes GI symptoms is still unknown

9. Skin

Topical cobalamin is a new therapeutic option in atopic dermatitis. It is well-tolerable and has low safety risks for both adults and children.

People with a B12 deficiency often look pale or have a slight yellow tinge to their skin (jaundice). Glitches in your body’s red blood cell production affect the size and strength of these cells. They may be too big to travel in your body, resulting in pale skin, Greene says. If they are too fragile, they may break down and cause an excess of bilirubin, which results in an orange-yellow skin tone. But a healthy, non-orange glow is one of the surprising vitamin B12 benefits.

10. Pregnancy and Lactation

One randomized clinical trial states that oral cobalamin supplementation with 250 μg/day throughout pregnancy and early lactation elevates maternal, fetal, and breast milk vitamin B12 levels.

11. Eye Health

Higher homocysteine and decreased B12 levels have been associated with an increased risk of macular degeneration.

One study involved 5,442 women at high risk of cardiovascular disease aged 40 or older, who had been taking B6/B9/B12 for 7 years.

The study found a 34-41% decreased risk of macular degeneration when supplementing with B6/B9/B12 may reduce the risk of macular degeneration.

B12 Deficiency

Vitamin B12 is naturally found in animal foods, including meats, fish, poultry, eggs and dairy. However, it can also be found in products fortified with B12, such as some varieties of bread and plant-based milk.

Unfortunately, B12 deficiency is common, especially in the elderly. You’re at risk of deficiency if you don’t get enough from your diet or aren’t able to absorb enough from the food you eat.

People at risk of a B12 deficiency include:

  • The elderly
  • Those who’ve had surgery that removes the part of the bowel that absorbs B12
  • People on the drug metformin for diabetes
  • People following a strict vegan diet
  • Those taking long-term antacid drugs for heartburn

Here are 9 signs and symptoms of a true vitamin B12 deficiency.

1. Pale or Jaundiced Skin
2. Weakness and Fatigue
3. Sensations of Pins and Needles
4. Changes to Mobility
5. Glossitis and Mouth Ulcers
6. Breathlessness and Dizziness
7. Disturbed Vision
8. Mood Changes
9. High Temperature

Side Effects & Safety

Vitamin B12 is LIKELY SAFE for most people when taken by mouth, applied to the skin, taken through the nose, administered as a shot, or injected into the vein (by IV). Vitamin B12 is considered safe, even in large doses.

Mild itching has been reported in one person who used a specific avocado oil plus vitamin B12 cream for psoriasis.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Vitamin B12 is LIKELY SAFE for pregnant or breast-feeding women when taken by mouth in the amounts recommended. The recommended amount for pregnant women is 2.6 mcg per day. Breast-feeding women should take no more than 2.8 mcg per day. Don’t take larger amounts. The safety of larger amounts is unknown.

Post-surgical stent placement: Avoid using a combination of vitamin B12, folate, and vitamin B6 after receiving a coronary stent. This combination may increase the risk of blood vessel narrowing.

Allergy or sensitivity to cobalt or cobalamin: Do not use vitamin B12 if you have this condition.

Leber’s disease, a hereditary eye disease: Do not take vitamin B12 if you have this disease. It can seriously harm the optic nerve, which might lead to blindness.

Abnormal red blood cells (megaloblastic anemia): Megaloblastic anemia is sometimes corrected by treatment with vitamin B12. However, this can have very serious side effects. Don’t attempt vitamin B12 therapy without close supervision by your healthcare provider.

High numbers of red blood cells (polycythemia vera): The treatment of vitamin B12 deficiency can unmask the symptoms of polycythemia vera.