Editor’s note: This is the only vitamin that is missing from a vegan diet as right now, this vitamin shows up in only animal derived foods. Yeast, a single cell fungus, contains high amounts of vitamin B12. But vegans may shun this good food source. So vegans would be better off taking vitamin B12 supplements.
編者註：這是目前素食主義者飲食中唯一缺少的維生素，這種維生素僅在動物源性食物中出現。 酵母是一種單細胞真菌，其中含有大量的維生素B12。 但是素食主義者可能會避免這種良好的食物來源。 因此，素食主義者最好服用維生素B12補充劑。
- May 11, 2019
- 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 can improve your B12 levels through diet or supplementation
Table of Contents
- What Is Vitamin B12?
- Vitamin B12 Sources: Where Can You Get It?
- What Is B12 Deficiency and Is It Serious?
- Are You at Risk of Being B12-Deficient?
- What Is Vitamin B12 Good For?
- What Are the Other Uses of Vitamin B12?
- Studies Conducted on Vitamin B12
- Side Effects and Contraindications for B12 Supplementation
- Maintain Healthy Vitamin B12 Levels so You Can Ensure Better Cognitive Health
- Frequently Asked Questions (FAQs) About Vitamin B12
A significant portion of Americans have some type of vitamin deficiency and unknowingly suffer the consequences.1 One of these is vitamin B12 deficiency, which affects 3.2% of Americans over the age of 50, with another possible 20% borderline deficient.2 Citizens of developing countries have it worse — in some cases, they have B12 deficiency throughout their entire life.3
Although vitamin B12 deficiency affects a significant number of people, particularly the elderly and those in developing countries, it is one of the most overlooked conditions. This is mainly due to lack of curiosity regarding this subject, relegating a B12 deficiency diagnosis as a last possibility for a variety of health issues.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 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 produce hemoglobin, improve nerve strength and regulate homocysteine levels.5,6,7 Homocysteine is an amino acid produced by the body, which in large amounts can increase the risk for heart attacks and strokes. Vitamin B12 works by making sure that your body uses the homocysteine in your blood.8
Unfortunately, the human body cannot produce vitamin B12, 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.9 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 you’re not getting enough vitamin B12 into your system, here are some foods you should consider adding to your diet (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):10
- Raw, organic grass fed milk
- Organic free-range chicken
- Wild Alaskan salmon
Because the bulk of this vitamin’s source is meat, people who do not eat meat products may be more susceptible to B12 deficiency. Options for vegans and vegetarians include B12 capsules and 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 are:11
- Cyanocobalamin — This is the most popular type of vitamin B12 available because it’s cheaper and easier to produce. Cyanocobalamin is synthesized in laboratories and does not naturally occur in the human body. Once it is introduced to your system, your body then converts it into methylcobalamin.12
- Methylcobalamin — This type is the active form of vitamin. I recommend looking for B12 supplements that use this type because research shows that this form of vitamin B12 has been used to manage pain, promoting nerve health and addressing sleep-wake rhythm problems.13
What Is B12 Deficiency and Is It Serious?
Vitamin B12 deficiency is prevalent among vegetarians and the elderly.14 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 amounts in these foods are insignificant and do not provide the body with the levels that it requires.15
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 passes the digestive system unabsorbed.
The first noticeable symptoms of vitamin B12 deficiency are changes in mood, fatigue, weight loss and tingling in your limbs.16 Other symptoms include the following:
- Megaloblastic anemia — This is a type of anemia caused by your cells’ inability to synthesize DNA during red blood cell production, inhibiting nuclear division. Some of the telltale symptoms of megaloblastic anemia include shortness of breath, muscle weakness, nausea and palpitation.17
- Jaundice — This is 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 cells18 brought on by low vitamin B12 levels.19
- 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 causes major impairment in cognitive function.20
- 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.21 Additional research shows that B12 deficiency is linked to poor growth and neurodevelopment of infants.22
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 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.23
Other tests include a complete blood count and a serum B12 level. Testing homocysteine levels in the blood is another way to diagnose this deficiency. People who have a predisposition for B12 deficiency may be required to undergo additional screenings. Some risk factors for B12 deficiency you should look out for are:24
- Crohn’s disease — A study published in 2015 notes that patients who have Crohn’s disease are generally more deficient in vitamin B12.25 One of the treatments for this condition is ileocaecal resection, which unfortunately heightens a patient’s risk for vitamin B12 deficiency further.26
- 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 B12.27
- Alcohol abuse — Alcoholism makes it hard for the body to absorb vitamin B12.28
- 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.29
Take note that folic acid deficiency and B12 deficiency almost have identical symptoms. If a B12 deficiency is erroneously diagnosed as folic acid deficiency, anemia may be treated, but the eventual mental decline, which is only caused by low levels of B12, will still progress.30
If you are affected by any of the conditions mentioned above, it is of utmost importance that you incorporate foods rich in B12 into your diet or consider taking B12 supplements. This not only will help raise your B12 levels, but also can help prevent serious repercussions that come with this deficiency.
What Is Vitamin B12 Good For?
Aside from 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:
- Improves depression symptoms — Patients diagnosed with depression have been shown to have low vitamin B12 levels. Research indicates that supplementing with vitamin B12 may help improve management of depression.31,32
- Mitigates the risk for birth defects — Studies show that maintaining optimal levels of B12 is as important as folic acid during pregnancy, as it aids in the infant’s brain development.33
- Promotes brain health and function — Research indicates that patients who have lower levels of B12 have an increased risk for brain volume loss. Additionally, vitamin B12 supplementation has been observed to help boost cognitive function.34
What Are the Other Uses of Vitamin B12?
Vitamin B12 can be used to improve sleep quality by assisting in melatonin production, a hormone responsible for sleep regulation.35 Supplementation may also boost your energy levels, as a study has found that severe B12 deficiency can reduce physical endurance.36
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 lowers the risk of heart attacks, although there are studies showing it helps reduce the chances of stroke.37,38
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.39
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.40 While this does not mean that all depressed people are deficient in B12, studies have shown that it is a contributing factor for the prevalence of depression.41 Patients who are B12-deficient suffer from other psychiatric abnormalities as well, such as delirium, schizophrenia and psychosis.42
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 side effects include:43
- 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.44 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.45
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:46
- Proton pump inhibitors
- H2 receptor antagonists
Note that you should seek the opinion of your health practitioner 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 not only may alleviate your symptoms, but also will 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.47
Q: Do vitamin B12 supplements work?
A: Yes. Vitamin B12 can be taken as supplements and are 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.
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.48
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 as a supplement are excreted through the excretory system. On the other hand, the body stores vitamin B12 that it gets from natural sources. Most of this vitamin B12 is found in substantial amounts in the liver.
If you were to stop getting vitamin B12 in your body, it would take up to five years for your body to be completely depleted of it.49 Suffering from a vitamin B12 overdose is highly unlikely, and “no clear toxicity has been reported from daily oral consumption of B12 in doses up to 100 µg,” according to the book “Epigenetics: The Death of the Genetic Theory of Disease Transmission.”50