What You Should Know About Vitamin B12 Benefits, Dosage, And Side Effect!
vitamin b12 benefits
Vitamin B12 is:
A water-soluble vitamin that is naturally present in some foods added to others, and available as a dietary supplement and a prescription medication. Vitamin B12 exists in several forms and contains the mineral cobalt, so compounds with vitamin B12 activity are collectively called “cobalamins”. Methylcobalamin and 5-deoxyadenosylcobalamin are the forms of vitamin B12 that are active in human metabolism.
It is required for proper red blood cell formation,
neurological function, and DNA synthesis. Vitamin B12 functions as a cofactor for methionine synthase and L-methylmalonyl-CoA mutase. Vitamin B12, bound to protein in food, is released by the activity of hydrochloric acid and gastric protease in the stomach. When synthetic vitamin B12 is added to fortified foods and dietary supplements, it is already in free form and, thus, does not require this separation step.
Free vitamin B12 then combines with intrinsic factor,
- A glycoprotein secreted by the stomach’s parietal cells, and the resulting complex undergoes absorption within the distal ileum by receptor-mediated endocytosis.
- Approximately 56% of a 1 mcg oral dose of vitamin B12 is absorbed, but absorption decreases drastically when the capacity of intrinsic factor is exceeded (at 1–2 mcg of vitamin B12).
Pernicious anemia is,
- An autoimmune disease that affects the gastric mucosa and results in gastric atrophy.
- This leads to the destruction of parietal cells, achlorhydria, and failure to produce intrinsic factor, resulting in vitamin B12 malabsorption.
- If pernicious anemia is left untreated, it causes vitamin B12 deficiency, leading to megaloblastic anemia and neurological disorders, even in the presence of adequate dietary intake of vitamin B12.
Vitamin B12 status is typically assessed,
- Via serum or plasma vitamin B12 levels.
- Values below approximately 170–250 pg/mL (120–180 picomol/L) for adults indicate a vitamin B12 deficiency.
However,
- Evidence suggests that serum vitamin B12 concentrations might not accurately reflect intracellular concentrations. An elevated serum homocysteine level (values >13 micro mols/L) might also suggest a vitamin B12 deficiency.
- However, this indicator has poor specificity because it is influenced by other factors, such as low vitamin B6 or folate levels.
- Elevated methylmalonic acid levels (values >0.4 micromol/L) might be a more reliable indicator of vitamin B12 status because they indicate a metabolic change that is highly specific to vitamin B12 deficiency.
How Well You Absorb Vitamin B12 is The Key?
Vitamin B12 needs the presence of an enzyme in the intestinal tract called “intrinsic factor” to be absorbed as hydrochloric acid, pepsin, vitamin B6 and calcium. Vitamin B12 absorption also depends on a properly functioning thyroid gland.
Autoimmune reactions prevent the absorption of vitamin B12 as well. One form of vitamin B12 is cyanocobalamin, which is generally found in supplements and is used as a food additive. This form is easily converted to other forms of the vitamin. Other forms include transcobalamin, hydroxycobalamin, 5-deoxyadenosylcobalamin, methylcobalamin, and adenosylcobalamin.
Facts About Vitamin B12:
- Vitamin B12 is Probably best known for its numerous health benefits, particularly providing increased energy.
- Necessary for converting stored carbohydrates into glucose which produces energy and leads to a decrease in fatigue and lethargy in the body.
- B12′s ability to instantly boost energy levels is by far the most common and most powerful benefit of taking vitamin B12 supplements. The recommended therapeutic amount is 1000 micrograms a day.
- Essential for the healthy development of red blood cells in the body.
- Deficiency can ultimately result in a blood disorder known as anemia which can cause permanent and severe nerve and brain damage.
- Another one of the best-known benefits of vitamin B12 is that it has been shown to increase energy thus helping promote weight loss.
- One recent study showed that as many as 40% of adults suffered from some form of Vitamin B12 deficiency.
- High vitamin B12 level in elderly people has also been shown to protect against brain atrophy or shrinkage, associated with Alzheimer’s disease and impaired cognitive function.
Also,
- Aside from maintaining healthy red blood cells and the nervous system, vitamin B12 is needed in order for our bodies to absorb folic acid (also known as vitamin B9) which helps release energy.
- B12 normally plays a significant role in the metabolism of every cell of the body allowing for energy production which is why taking vitamin B12 for energy is so popular.
Vitamin B12 Found in Non-Vegan Foods:
Although vegetarians often say that all nutrients can be obtained on a non-meat diet, getting enough vitamin B12 is difficult without meat and other high-quality protein sources. The problem is that the general public believes that if they switch to a vegetarian diet and feel better, then the vegetarian diet must be working.
A vitamin B-12 deficiency takes about 5 years to appear because the body’s natural stores of the vitamin will be used up first. According to the U.K. Vegan Society, the only reliable vegan sources of vitamin B12 are foods fortified with B12 and B12 supplements.
Although,
small amounts of vitamin B12 may be found in spirulina, blue-green algae, and barley grass, substantial amounts can be found in animal proteins such as liver, shellfish, kidney, muscle meats, fish, and dairy products. Also, laboratory tests find that these substances do not have biological activity in humans.
Recommended Intakes:
Intake recommendations for vitamin B12 and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine (IOM) of the National Academies (formerly National Academy of Sciences).
DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and gender, include:
-
Recommended Dietary Allowance (RDA):
- The average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
-
Adequate Intake (AI):
- Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
-
Estimated Average Requirement (EAR):
- The average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
-
Tolerable Upper Intake Level (UL):
- Maximum daily intake unlikely to cause adverse health effects.
Table 1 lists the current RDAs for vitamin B12 in micrograms (mcg). For infants aged 0 to 12 months, the FNB established an AI for vitamin B12 that is equivalent to the mean intake of vitamin B12 in healthy, breastfed infants.
| Age | Male | Female | Pregnancy | Lactation |
|---|---|---|---|---|
| 0–6 months* | 0.4 mcg | 0.4 mcg | ||
| 7–12 months* | 0.5 mcg | 0.5 mcg | ||
| 1–3 years* | 0.9 mcg | 0.9 mcg | ||
| 4–8 years* | 1.2 mcg | 1.2 mcg | ||
| 9–13 years* | 1.8 mcg | 1.8 mcg | ||
| 14+ years* | 2.4 mcg | 2.4 mcg | 2.6 mcg | 2.8 mcg |
* Adequate Intake.
Sources of Vitamin B12:
1. Food:
Vitamin B12 is naturally found in animal products, including fish, meat, poultry, eggs, milk, and milk products. Vitamin B12 is generally not present in plant foods, but fortified breakfast cereals are a readily available source of vitamin B12 with high bioavailability for vegetarians.
Some nutritional yeast products also contain vitamin B12. Fortified foods vary in formulation, so it is important to read the Nutrition Facts labels on food products to determine the types and amounts of added nutrients they contain.
Several food sources of vitamin B12 are listed in Table 2.
Table 2: Selected Food Sources of Vitamin B12:
| Food | Micrograms (mcg) per serving |
Percent DV* |
|---|---|---|
| Clams, cooked, 3 ounces | 84.1 | 3,504 |
| Liver, beef, cooked, 3 ounces | 70.7 | 2,946 |
| Trout, rainbow, wild, cooked, 3 ounces | 5.4 | 225 |
| Salmon, sockeye, cooked, 3 ounces | 4.8 | 200 |
| Trout, rainbow, farmed, cooked, 3 ounces | 3.5 | 146 |
| Tuna fish, light, canned in water, 3 ounces | 2.5 | 104 |
| Nutritional yeasts, fortified with 100% of the DV for vitamin B12, 1 serving | 2.4 | 100 |
| Cheeseburger, double patty, and bun, 1 sandwich | 2.1 | 88 |
| Haddock, cooked, 3 ounces | 1.8 | 75 |
| Beef, top sirloin, broiled, 3 ounces | 1.4 | 58 |
| Milk, low-fat, 1 cup | 1.2 | 50 |
| Yogurt, fruit, low-fat, 8 ounces | 1.1 | 46 |
| Cheese, Swiss, 1 ounce | 0.9 | 38 |
| Beef taco, 1 soft taco | 0.9 | 38 |
| Breakfast cereals, fortified with 25% of the DV for vitamin B12, 1 serving | 0.6 | 25 |
| Ham, cured, roasted, 3 ounces | 0.6 | 25 |
| Egg, whole, hard-boiled, 1 large | 0.6 | 25 |
| Chicken, breast meat, roasted, 3 ounces | 0.3 | 13 |
2. Dietary supplements:
In dietary supplements, vitamin B12 is usually present as cyanocobalamin, a form that the body readily converts to the active forms methylcobalamin and 5- deoxyadenosine cobalamin. Dietary supplements can also contain methylcobalamin and other forms of vitamin B12.
Existing evidence does not suggest any differences among forms with respect to absorption or bioavailability. However, the body’s ability to absorb vitamin B12 from dietary supplements is largely limited by the capacity of intrinsic factors. For example, only about 10 mcg of a 500 mcg oral supplement is actually absorbed in healthy people.
In addition to oral dietary supplements,
vitamin B12 is available in sublingual preparations as tablets or lozenges. These preparations are frequently marketed as having superior bioavailability, although evidence suggests no difference in efficacy between oral and sublingual forms
3. Prescription medications:
Vitamin B12, in the form of cyanocobalamin and occasionally hydroxocobalamin, can be administered parenterally as a prescription medication, usually by intramuscular injection. Parenteral administration is typically used to treat vitamin B12 deficiency caused by pernicious anemia and other conditions that result in vitamin B12 malabsorption and severe vitamin B12 deficiency.
Also,
- Vitamin B12 is available as a prescription medication in a nasal gel spray formulation, a product marketed as an alternative to vitamin B12 injections that some patients might prefer.
- This formulation appears to be effective in raising vitamin B12 blood levels in adults and children, although it has not been thoroughly studied in clinical settings.
Vitamin B12 Deficiency:
Vitamin B12 deficiency occurs when there are inadequate levels of vitamin B12 in the body. This important vitamin is necessary for the production of red blood cells and the healthy functioning of the nervous system.
A deficiency of B12 will keep the body from producing enough quantities of blood, and it will increase the rate of blood cell destruction. It is very important to treat because it can originate problems in the nervous system.
The signs of vitamin B12 deficiency will be appearing slowly over time since the levels of this vitamin absorbed lower down and the amount of B12 sorted is continually used. Common symptoms of this deficiency include breathlessness, weakness, pallor, bad resistance to infections, and tiredness.
Symptoms of Vitamin B12 deficiency are characterized by:
- Megaloblastic anemia.
- Fatigue.
- Weakness.
- Constipation.
- Loss of appetite.
- And weight loss.
- Neurological changes, such as numbness and tingling in the hands and feet, can also occur.
- Additional symptoms of vitamin B12 deficiency include difficulty in maintaining balance.
- Depression.
- Confusion.
- Dementia.
- Poor memory.
- And soreness of the mouth or tongue.
The neurological symptoms of vitamin B12 deficiency can occur without anemia, so early diagnosis and intervention are important to avoid irreversible damage.
During infancy, signs of a vitamin B12 deficiency include:
- Failure to thrive.
- Movement disorders.
- Developmental delays.
- and megaloblastic anemia.
Many of these symptoms are general and can result from a variety of medical conditions other than vitamin B12 deficiency.
Typically, vitamin B12 deficiency is treated with,
Vitamin B12 injections since this method bypass potential barriers to absorption. However, high doses of oral vitamin B12 may also be effective. The authors of a review of randomized controlled trials comparing oral with intramuscular vitamin B12 concluded that 2,000 mcg of oral vitamin B12 daily, followed by a decreased daily dose of 1,000 mcg and then 1,000 mcg weekly and finally, monthly might be as effective as intramuscular administration.
Overall,
an individual patient’s ability to absorb vitamin B12 is the most essential factor in determining whether vitamin B12 should be administered orally or via injection. In most countries, the practice of using intramuscular vitamin B12 to treat vitamin B12 deficiency has remained unchanged
Folic acid and vitamin B12:
- Large amounts of folic acid can mask the damaging effects of vitamin B12 deficiency by correcting the megaloblastic anemia caused by vitamin B12 deficiency without correcting the neurological damage that also occurs.
- Moreover, preliminary evidence suggests that high serum folate levels might not only mask a vitamin B12 deficiency but could also exacerbate the anemia and worsen the cognitive symptoms associated with vitamin B12 deficiency.
- Permanent nerve damage can occur if vitamin B12 deficiency is not treated. For these reasons, folic acid intake from fortified food and supplements should not exceed 1,000 mcg daily in healthy adults.
Groups at Risk of Vitamin B12 Deficiency:
The main causes of vitamin B12 deficiency include vitamin B12 malabsorption from food, pernicious anemia, postsurgical malabsorption, and dietary deficiency. However, in many cases, the cause of vitamin B12 deficiency is unknown. The following groups are among those most likely to be vitamin B12 deficient.
I. Older adults:
- Atrophic gastritis, a condition affecting 10%–30% of older adults, decreases the secretion of hydrochloric acid in the stomach, resulting in decreased absorption of vitamin B12.
- Decreased hydrochloric acid levels might also increase the growth of normal intestinal bacteria that use vitamin B12, further reducing the amount of vitamin B12 available to the body.
Individuals with atrophic gastritis are unable to absorb the vitamin B12 that is naturally present in food.
Most, however, can absorb the synthetic vitamin B12 added to fortified foods and dietary supplements. As a result, the IOM recommends that adults older than 50 years obtain most of their vitamin B12 from vitamin supplements or fortified foods. However, some elderly patients with atrophic gastritis require doses much higher than the RDA to avoid subclinical deficiency.
II. Individuals with:
A. pernicious anemia:
Pernicious anemia, a condition that affects 1%–2% of older adults, is characterized by a lack of intrinsic factor. Individuals with pernicious anemia cannot properly absorb vitamin B12 in the gastrointestinal tract.
Pernicious anemia is usually treated with intramuscular vitamin B12. However, approximately 1% of oral vitamin B12 can be absorbed passively in the absence of intrinsic factor, suggesting that high oral doses of vitamin B12 might also be an effective treatment. 
B. Gastrointestinal Disorders:
Individuals with stomach and small intestine disorders, such as celiac disease and Crohn’s disease, may be unable to absorb enough vitamin B12 from food to maintain healthy body stores.
Subtly reduced cognitive function resulting from early vitamin B12 deficiency might be the only initial symptom of these intestinal disorders, followed by megaloblastic anemia and dementia. vitamin b12 benefits
C. Individuals who have had gastrointestinal surgery:
Surgical procedures in the gastrointestinal tract, such as weight loss surgery or surgery to remove all or part of the stomach, often result in a loss of cells that secrete hydrochloric acid and intrinsic factor. This reduces the amount of vitamin B12, particularly food-bound vitamin B12, that the body releases and absorbs.
Surgical removal of the distal ileum also can result in the inability to absorb vitamin B12. Individuals undergoing these surgical procedures should be monitored preoperatively and postoperatively for several nutrient deficiencies, including vitamin B12 deficiency.
III. Vegetarians:
Strict vegetarians and vegans are at greater risk than Lacto-ovo vegetarians and nonvegetarians of developing vitamin B12 deficiency because natural food sources of vitamin B12 are limited to animal foods.
Fortified breakfast cereals and fortified nutritional yeasts are some of the only sources of vitamin B12 from plants and can be used as dietary sources of vitamin B12 for strict vegetarians and vegans. Fortified foods vary in formulation, so it is important to read the Nutrition Facts labels on food products to determine the types and amounts of added nutrients they contain.
IV. Pregnant and lactating women who follow strict vegetarian diets and their infants:
Vitamin B12 crosses the placenta during pregnancy and is present in breast milk. Exclusively breastfed infants of women who consume no animal products may have very limited reserves of vitamin B12 and can develop vitamin B12 deficiency within months of birth. Undetected and untreated vitamin B12 deficiency in infants can result in severe and permanent neurological damage. vitamin b12 benefits
The Academy of Nutrition and Dietetics recommends
- Supplemental vitamin B12 for vegans and Lacto-ovo vegetarians during both pregnancy and lactation to ensure that enough vitamin B12 is transferred to the fetus and infant.
- Pregnant and lactating women who follow strict vegetarian or vegan diets should consult with a pediatrician regarding vitamin B12 supplements for their infants and children.
Here’re some of the Claimed benefits of Vitamin B12:
Vitamin B12 has numerous health benefits and can help your body in various ways. Here’s a look at the different benefits offered by Vitamin B12: vitamin b12 benefits
1. Keeping your nervous system healthy:
One of the most important benefits of Vitamin B12 is the maintenance of the nervous system. It is needed for myelination of the building of myelin sheaths. Myelin sheaths provide protection to the nerves, and without them, you are prone to permanent nerve damage. vitamin b12 benefits
2. Prevention of anemia:
The vitamin is essential for the production of healthy red blood cells, which are responsible for carrying oxygen throughout the body. Deficiency of the vitamin can lead to the formation of abnormally large red blood cells that are not able to function properly. Those who have anemia as a result of the deficiency of the vitamin usually experience overall weakness and lethargy.
3. Energy and endurance:
Due to its role in energy metabolism, vitamin B12 is frequently promoted as an energy enhancer and an athletic performance and endurance booster. These claims are based on the fact that correcting the megaloblastic anemia caused by vitamin B12 deficiency should improve the associated symptoms of fatigue and weakness. However, vitamin B12 supplementation appears to have no beneficial effect on performance in the absence of a nutritional deficit.
4. Treats Depression:
Vitamin B12 is regarded to promote the activity of neurotransmitters and hormones that can influence your emotional state and mood. These hormones add Dopamine, Serotonin, and Melatonin. Patients with depression are often prescribed Vitamin B12 supplements as it can set off serotonin ‘happy hormone’ production and uplift their mood.
5. Healthy Skin, And Hair:
Vitamin B12 is vital for DNA and RNA synthesis and cell reproduction. Our skin, hair, and nails undergo a process of constant growth and renewal, which is why they need enough amount of B Vitamins, especially B12 for maintaining healthy growth. Deficiency of Vitamin B12 can lead to dry skin, wrinkles, acne, brittle hair and nails, and skin problems just like dermatitis.
6. Weight loss:
Vitamin B12 is also called the ‘Energy Vitamin’ since it can give an instant and real energy boost. It can speed up the metabolism process, thus burning more calories and improving the rate of weight loss. It also increases the overall energy levels in the body, allowing you to increase your level of physical activity and exercise.
7. Encourages Healthy Pregnancy:
Compared to typical adults, pregnant women need a higher amount of Vitamin B12 to make red blood cells, maintain a healthy nervous system, release energy from food, and to process folic acid. B12 deficiency can cause birth defects and even miscarriage. The RDA (Recommended Dietary Allowance) of Vitamin B12 for pregnant girls is 2.6 mcg per day, and it’s important that this requirement is met.
8. Helps you to Sleep Better:
– Vitamin B12 improves the production of Melatonin, a hormone that facilitates healthy sleep patterns. This is particularly beneficial for older adults, as with age their body becomes less efficient in making this hormone. Vitamin B12 can help in increasing Melatonin production allowing older people to sleep better.
9. Lowers homocysteine levels:
B12 has been shown to lower homocysteine levels. An elevated homocysteine level has been associated (not causal) with stroke, heart disease, diabetes, and Alzheimer’s dementia. This implication is very exciting and promising.
10. Boost Immune System:
This vitamin provides support to the immune system and promotes proper functioning. It helps to decrease the inflammatory state of an inflamed immune system. vitamin b12 benefits
Scientifically, What are some effects of vitamin B12 on health?
Scientists are studying vitamin B12 to see how it affects health. Here are several examples of what this research has shown.
Heart disease:
Vitamin B12 supplements (along with folic acid and vitamin B6) do not reduce the risk of getting heart disease. Scientists had thought that these vitamins might be helpful because they reduce blood levels of homocysteine, a compound linked to an increased risk of having a heart attack or stroke.
Dementia:
As they get older, some people develop dementia. These people often have high levels of homocysteine in the blood. Vitamin B12 (with folic acid and vitamin B6) can lower homocysteine levels, but scientists don’t know yet whether these vitamins actually help prevent or treat dementia.
Energy and athletic performance:
Advertisements often promote vitamin B12 supplements as a way to increase energy or endurance. Except in people with a vitamin B12 deficiency, no evidence shows that vitamin B12 supplements increase energy or improve athletic performance.
Health Risks from Excessive Vitamin B12:
The IOM did not establish a UL for vitamin B12 because of its low potential for toxicity. In Dietary Reference Intakes:
Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline, the IOM states that “no adverse effects have been associated with excess vitamin B12 intake from food and supplements in healthy individuals”.
Interactions with Medications:
Are there any interactions with vitamin B12 that I should know about? Yes. Vitamin B12 can interact or interfere with medicines that you take, and in some cases, medicines can lower vitamin B12 levels in the body. Here are several examples of medicines that can interfere with the body’s absorption or use of vitamin B12
- Chloramphenicol: an antibiotic that is used to treat certain infections.
- Proton pump inhibitors: such as omeprazole (Prilosec®) and lansoprazole (Prevacid®), are used to treat acid reflux and peptic ulcer disease.
- Histamine H2 receptor antagonists, such as cimetidine (Tagamet®), famotidine (Pepcid®), and ranitidine (Zantac®), are used to treat peptic ulcer disease.
- Metformin: a drug used to treat diabetes.
Tell your doctor, pharmacist, and other health care providers about any dietary supplements and medicines you take. They can tell you if those dietary supplements might interact or interfere with your prescription or over-the-counter medicines or if the medicines might interfere with how your body absorbs, uses, or breaks down nutrients.
Summing Up:
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Disclaimer: “Nothing in this article makes any claim to offer cures or treatment of any disease or illness. If you are sick please consult with your doctor.”
References:
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