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How Can You Benefit From Vitamin B12?

Fact Checked

Vitamin B12 Food Sources

Story at-a-glance -

  • Vitamin B12 is a B vitamin found in most animal-based products
  • Vitamin B12 helps in the production of hemoglobin, improvement of nerve strength and regulation of homocysteine levels
  • Read on to learn how you improve your B12 levels through your diet or supplementation

About 92 percent of the American population have some type of vitamin deficiency and unknowingly suffer the consequences.1 One of these is vitamin B12 deficiency, which affects more than 20 percent of the Americans over the age of 50.2 In developing countries, a higher number of patients with this deficiency has been recorded, namely in India, Mexico and some parts of Africa.3

Although this deficiency affects a significant number of people, it is one of the most overlooked conditions. This is mainly due to the number of misdiagnosed or undetected cases because of inaccurate testing, the late onset of symptoms or the overall lack of knowledge about it.4

But why is vitamin B12 necessary? Aside from being essential for cognition and brain health maintenance, it can also help you achieve peak health. Continue reading to learn more about this vitamin and why it's absolutely imperative that you get the recommended amount.

What Is Vitamin B12?

Vitamin B12, or cobalamin, is a B vitamin necessary for cardiovascular and cognitive health. It helps in the production of hemoglobin, improvement of nerve strength and regulation of homocysteine levels.5 Homocysteine is an amino acid produced by the body, which in large amounts can increase the risk of a person for heart attacks and strokes. Vitamin B12 works by making sure that the homocysteine in your blood is successfully expended by your body.6

Unfortunately, the human body cannot produce this vitamin, and mainly depends on your diet to get ample supply. Vitamin B12 is naturally produced by anaerobic microorganisms commonly found in the gastrointestinal tract of animals.7 This means that the majority of B12 sources are either meat or poultry products, which is why many vegetarians and vegans are typically lacking this nutrient.

Vitamin B12 Sources: Where Can You Get It?

Animal products – whether dairy, poultry or meat – are excellent sources of vitamin B12. If you suspect that you're not getting enough vitamin B12 into your system, here are some food products that you should consider adding to your diet (just make sure that you're getting these from high-quality sources to keep yourself safe from chemicals and other harmful materials used in conventional farms):8

Because the bulk of this vitamin's source is meat, people who do not eat meat products may have a higher susceptibility to B12 deficiency. Some of the options for vegans and vegetarians include B12 capsules, sprays and B12 shots. However, you should pay attention to the type of B12 used in these products to make sure that you're getting the form your body needs. Two types of vitamin B12 available in the market are:9

Cyanocobalamin — This is the most popular type of vitamin B12 available because it's cheaper and easier to produce. Cyanocobalamin is normally synthesized in laboratories and does not naturally occur in the human body. Once it is introduced to your system, the body then converts it into methylcobalamin.

Methylcobalamin — This type is said to be the active form of vitamin B12 and is able to remain in the body longer. I recommend looking for B12 supplements that use this type to make sure that your body absorbs the vitamin up front. It's the natural form of this vitamin, so the body isn't required to convert it to another form. It's more easily utilized and is more effective that cyanocobalamin.10

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What Is B12 Deficiency and Is It Serious?

Vitamin B12 deficiency is prevalent in the vegetarian population and the elderly.11 It's been linked to the onset of megaloblastic anemia, brain fog and heart disease. While there have been multiple proposed vegan alternative sources for vitamin B12, like tempeh, spirulina and green leafy vegetables, the amount in these foods are insignificant and do not provide the body with the levels that it requires.12

For older age groups, vitamin B12 is often caused by the decreased ability of the digestive system to absorb nutrients. This means that even if you optimize your diet to contain high amounts of B12, most of it only passes the digestive system unabsorbed. The first thing that becomes noticeable once you have inadequate levels is the changes in brain function.13 Other vitamin B12 deficiency symptoms include the following:

Megaloblastic anemia — This is a type of anemia caused by the body cells' inability to synthesize DNA during red blood cell production. It is often characterized by abnormally sized red blood cells and a lower cell count. Some of the telltale symptoms of megaloblastic anemia include shortness of breath, muscle weakness, nausea and paleness.14

Jaundice — This is often characterized by the abnormal yellowing of the eyes and skin, which is caused by the high amounts of the bilirubin pigment being released from the destruction of the fragile red blood cells brought on by low vitamin B12 levels.15

Memory loss or cognitive difficulties — Studies show that the presence of low to normal levels of B12 in the body can lead to white matter damage in the brain, which then causes major impairment in cognitive function.16

Fatigue — B12-deficient patients feel overwhelming fatigue and tiredness. Some patients even note that they are not able to do menial tasks that they do daily. This may be accompanied by numbness or tingling of the extremities as well.

Optimizing vitamin B12 levels should be one of the top priorities of pregnant women. This is to ensure that you and your child remain healthy, with researchers even noting that vitamin B12 is just as important as folic acid and iron during pregnancy for preventing neural tube defects.17 For women who have suffered miscarriages or have had difficulties in conceiving, low levels of B12 may also be a contributing factor.18

Are You at Risk of Being B12 Deficient?

Diagnosis of vitamin B12 deficiency usually consists of multiple blood tests to determine whether you're in the optimal range. However, the problem with the current B12 blood test used to diagnose deficiency is that it measures both the inactive and active form of B12. This means that even though some patients have higher amounts of inactive B12, they still won't be diagnosed.19

Other tests include a complete blood count and a serum B12 level. Testing homocysteine levels in the blood is another way doctors use to diagnose this deficiency. People who have a predisposition for B12 deficiency may be required to undergo additional screenings. Some of the risk factors for B12 deficiency you should look out for are:20

Crohn's diseaseThis chronic condition is characterized by the inflammation of the digestive system or the gastrointestinal tract. In cases where the inflammation is found in the terminal ileum, the risk for being B12 deficient triples because this is the site for its absorption.21 One of the treatments for this condition is ileocaecal resection, which unfortunately heightens a patient's risk for vitamin B12 deficiency further.22

Tapeworm infestation — Fish tapeworms are the largest parasites in the human body. An infestation is usually caused by eating infected raw or undercooked fish. Once the tapeworms develop inside the intestine, it starts absorbing the nutrients ingested by the patient, one of which is vitamin B12.23

Alcohol abuseAlcoholism makes it hard for the body to absorb vitamin B12 by damaging the gastrointestinal lining, which is responsible for the absorption and distribution of this vitamin.24

Metformin, histamine blockers and proton pump inhibitor use — Metformin is usually prescribed to diabetes patients to help lower their blood glucose levels. Unfortunately, studies show that it can lead to vitamin B12 deficiency.25

Take note that folic acid deficiency and B12 deficiency almost have identical symptoms. If a B12 deficiency is erroneously diagnosed as folic acid deficiency, the symptom of anemia may be treated, but the eventual mental decline, which is only caused by low levels of B12, will still progress.26

If you are affected by any of the conditions mentioned above, it is of utmost importance that you incorporate foods that are rich in B12 into your diet or consider taking B12 supplements. This will not only help you prevent deficiency, but can also keep you away from the serious repercussions that come with this deficiency.

What Is Vitamin B12 Good For?

Aside for vitamin B12's role in cell metabolism, it is also responsible for the regulation of various body processes. Some of the health benefits you'll get if you maintain optimal levels of this vitamin include the following:

Improves depression symptomsVitamin B12 is one of the vitamins essential in the production of serotonin, the brain chemical responsible for mood regulation. Although supplementing B12 may help in lessening the effects of depression, it is still recommended that you consult a health practitioner to help you deal with its symptoms.27

Mitigates the risk for birth defects — Studies show that maintaining optimal levels of B12 is as important as folic acid during pregnancy. It aids in your baby's neural tube, brain and spine development and promotes brain function and blood cell formation.28

Promotes brain health and function — Studies show that patients who have lower levels of B12 have an increased risk for brain volume loss. Additionally, vitamin B12 supplementation has been observed to be neuroprotective for people who have low levels of the vitamin.29

What Are the Other Uses of Vitamin B12?

Vitamin B12 can be used to improve sleep quality and energy levels during the day. Vitamin B12 assists in melatonin production, a hormone responsible for sleep regulation. There have also been claims that it can boost energy levels by assisting in glucose metabolism, although no studies have proven this yet.

However, this may only be applicable for people who are deficient. Some physicians even note that the apparent energy boost that vitamin B12 provides only come from a placebo effect.

Studies Conducted on Vitamin B12

Due to vitamin B12's role in important body processes, many studies have focused on its interaction with other body chemicals. Studies mainly revolve around its role in the prevention of Alzheimer's, heart disease and other conditions.

In a 2012 study, vegetarians and vegans – individuals who have a higher susceptibility to deficiency – were given either a placebo or a vitamin B12 supplement. Those given B12 supplements were observed to have improved blood flow and significant lowering of their homocysteine levels. While this study implies that B12 has a direct benefit for blood flow, it has not yet been proven whether it helps in the prevention of heart attacks, although there are studies that show that it helps with the prevention of stroke.30

For dementia prevention, a study from the University of Oxford showed that elderly people who are at high risk for dementia showed a higher resilience against brain atrophy after B-vitamin treatments, with B12 being pinpointed as the top contributor.31 Furthermore, studies show B12's connection to depression, with deficient patients having a higher risk of developing depression symptoms, even with normal folate and homocysteine levels.32

While this does not mean that all people who are depressed are deficient in B12, studies have proven that it could be a contributing factor for the prevalence of depression in the population.33 Patients who are B12 deficient suffer from other psychiatric abnormalities as well, such as delusions, sleep disturbances and paranoia. 34

What Is the B12 Dosage Advised for Adults and Children?

While the need for this vitamin increases as you age, taking high amounts of vitamin B12 doesn't necessarily mean that you will get above average vitamin B12 levels. On the contrary, physicians have noted that if you take more than the suggested dose, most of the vitamin doesn't get absorbed and ends up wasted.

Adults only require a few micrograms of vitamin B12 daily to have sufficient levels. The recommended dose falls on 2.4 micrograms daily, with pregnant women and breastfeeding women requiring a slightly higher dose at 2.4 and 2.6 micrograms respectively. For infants and children, as well as B12 deficient patients, it is best that you consult a health practitioner regarding the correct dosage.35

Remember that even if you lead a generally healthy lifestyle with a sufficient amount of exercise, you may still be at risk for deficiencies, including vitamin B12. If you're unsure whether you're getting enough of this vitamin into your body, consider getting your levels checked.

Side Effects and Contraindications for B12 Supplementation

In rare cases, patients may observe certain side effects upon using B12 supplements. This is mostly caused by possible drug interactions or allergic reactions to other components of the supplement. Some of these side effects include:36

Nervousness and anxiousness

Headache or migraine


Congestive heart failure

Fluid buildup in the lungs

Some patients can suffer from anaphylaxis or a severe allergic reaction to vitamin B12 supplements, although this is rare, too. This can cause shock, swelling or itching.37 There is also a documented case where a patient suffered from anaphylaxis after an intramuscular injection, but didn't have the same reaction with an oral supplementation.38

Self-prescribing with vitamin B12 supplementation should be avoided, especially if you're taking specific medications or when you're pregnant. Some medications have been observed to cause a reduction in absorption and an increase in the elimination of this vitamin. Some of these medications are:39



Proton pump inhibitors


Note that the opinion of a health practitioner should always be consulted before taking any supplements to make sure whether they are recommended for your case.

Maintain Healthy Vitamin B12 Levels So You Can Ensure Better Cognitive Health

Vitamin B12 may not be as "famous" as other vitamins in the human diet, but it does a great deal for maintaining cognitive health and helping prevent numerous diseases. If you're B12 deficient, providing your body with enough B12 through your diet or a high-quality supplement may not only alleviate your symptoms, but will also lead you closer to a healthier lifestyle.

Frequently Asked Questions (FAQs) About Vitamin B12

Q: What is vitamin B12 used for in your body?

A: Vitamin B12 is essential for red blood cell production, DNA synthesis and homocysteine conversion. It also helps in the maintenance of thought processes, the improvement of depression symptoms and overall promotion of optimal health.40

Q: Do vitamin B12 supplements work?

A: Yes. Vitamin B12 can be taken as supplements and is usually prescribed to people with severe B12 deficiency. However, their effectiveness relies heavily on the digestive system's ability to absorb B12.

Q: When should I take vitamin B12?

A: Vitamin B12-rich foods from animal sources should be a constant part of your diet if you want to make sure that you're getting enough of this nutrient. Hence, vitamin B12 supplementation is especially important for vegetarians, vegans, pregnant women and the elderly. If you fall under any of these categories, consider getting your levels checked for early diagnosis.41

Q: How much vitamin B12 should I take?

A: The recommended dosage for B12 depends on the age of the patient. For adult patients, the recommended dose is 2.4 micrograms, with pregnant and breastfeeding women requiring a slightly higher dose to ensure both the mother's and the child's health.42

Q: Where does vitamin B12 come from?

A: Vitamin B12 is abundant in red meat, poultry and dairy products. For vegetarians and vegans, this can be hard to obtain because of this vitamin is animal-sourced. The best option for them is B12 supplementation to make sure that they are getting adequate amounts of this vitamin.43

Q: Can you get too much vitamin B12?

A: No. Vitamin B12 is a water-soluble vitamin, which means excess amounts of vitamin B12 that enters the body is excreted through the excretory system. While suffering from a vitamin B12 overdose is not something that happens frequently, some people may have adverse reactions to B12 supplements, which can be because of their other components, but not the B12 itself.44

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