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Uses, benefits, and side effects of vitamin B-12 shots

Vitamin B12 shots are injections that a doctor may recommend to address a nutrient B12 deficiency, particularly if the body has trouble absorbing the vitamin.

Vitamin B12 deficiency can cause a variety of health issues, from fatigue to permanent neurological abnormalities.

A doctor may recommend oral vitamin B12 supplementation or injections if a person’s vitamin B12 levels are low owing to a medical condition.

Injections are typically used by people who have difficulty absorbing vitamin B12 or who have had stomach surgery. Shots allow the body to absorb vitamin B12 without having to pass it thru the digestive system.

The necessity of maintaining proper vitamin B12 levels is discussed in this article, as well as the benefits and risks of vitamin B12 shots.

Vitamin B12

vitamin B-12 shots

Vitamin B12 is a water-soluble vitamin that is important for a variety of biological activities, including:

  • nerve cells
  • red blood cells
  • DNA production

Megaloblastic anaemia can make a person feel fatigued and weak if they don’t get enough vitamin B12.

Vitamin B12 can be found in a variety of foods, including:

  • dairy products
  • nutritional yeast
  • some fortified foods
  • meat
  • fish
  • eggs

Vitamin B12 binds to protein molecules in animal-based diets. Stomach acid separates it from the protein during digestion, and a chemical called intrinsic factor causes the bloodstream to absorb it.

A condition known as autoimmune atrophic gastritis causes some people’s bodies to produce insufficient stomach acid or intrinsic factor. Vitamin B12 shots may be required for these people to lower their risk of deficiency, which can develop to pernicious anaemia.

Those who have had gastrointestinal surgery and whose digestive system is unable to absorb vitamin B12 properly may also require shots.

What dosage of vitamin B12 do We require?

The recommended dietary allowances (RDAs) for vitamin B12 are listed in the table below. The RDA is the minimal daily quantity required by the majority of healthy people in a certain group.

GroupAmount
0–6 months0.4 micrograms (mcg)
7–12 months0.5 mcg
1–3 years0.9 mcg
4–8 years1.2 mcg
9–13 years1.8 mcg
14+ years2.4 mcg
Pregnant people2.6 mcg
People who breastfeed2.8 mcg

A doctor, on the other hand, may provide advice on an individual’s specific needs.

Vitamin B12 shots

Vitamin B12 shots are a type of supplement that contains cyanocobalamin, a synthetic form of vitamin B12.

The shot will be administered by a doctor into the muscle. If they inject it into a vein, the body may lose a high amount of it through urine.

Cyanocobalamin is available in three different forms: liquid, tablet, and capsule. Certain foods, such as cereals, may be fortified with vitamin B12 in a synthetic form.

Who needs vitamin B12 shots?

Vitamin B12 injections can only be obtained with a prescription after a clinical diagnosis of low levels. Because the human liver accumulates vitamin B12 throughout time, low levels are uncommon in most healthy persons.

Some people, however, are at a higher risk of deficiency and may benefit from vitamin B12 injections or tablets.

Those suffering from vitamin B12 deficient symptoms

A doctor should be seen if you have symptoms of vitamin B12 deficiency or pernicious anaemia.

The following are some of the signs and symptoms:

  • difficulty thinking and remembering
  • fatigue
  • heart palpitations
  • pale skin
  • weight loss
  • infertility
  • numbness and tingling in the hands and feet
  • dementia
  • mood changes
  • a sore tongue
  • low appetite
  • constipation

Vitamin B12 deficiency risk factors

The following risk factors can increase the chance of developing vitamin B12 deficiency:

  • high alcohol consumption
  • older age
  • pernicious anemia
  • atrophic gastritis, which refers to inflammation in the stomach
  • Helicobacter pylori infection
  • celiac disease
  • Crohn’s disease
  • a history of gastrointestinal surgery
  • following a plant-based diet
  • pancreatic insufficiency
  • AIDS
  • some hereditary conditions that affect vitamin B12 absorption

Those suffering from gastric people

Vitamin B12 release and absorption may be affected by gastrointestinal conditions.

These are some of them:

  • pernicious anemia, which can lead to gastric atrophy, or damage to the stomach
  • fish tapeworm infestation
  • bowel or pancreatic cancer
  • folic acid deficiency
  • overgrowth of bacteria in the small intestine
  • celiac disease
  • Crohn’s disease

People who have had gastrointestinal surgery, such as weight loss surgery, may have less of the cells that secrete stomach acid and intrinsic factor. Vitamin B12 absorption may be affected as a result of this.

Older adults

According to research published in 2015, vitamin B12 deficiency is more common in people over the age of 60, and certain people may benefit from vitamin B12 injections.

The researchers discovered that disorders linked to decreased stomach acid production, such as gastric atrophy, are more common in older persons. Low stomach acid also encourages the growth of some bacteria, which depletes vitamin B12 reserves.

Vegans and vegetarians

Because vitamin B12 is mostly found in animal sources, people who eat a plant-based diet are more likely to be vitamin B12 deficient.

In a 2010 study of 689 males, researchers discovered that those who ate a plant-based diet had greater rates of vitamin B12 insufficiency. Compared to just 1% of people who ate meat, over half of vegans and 7% of vegetarians had inadequate vitamin B12 levels.

Vitamin B12 is transferred to the infant through the placenta and breast milk, thus vegetarians and people who are pregnant may need to take supplements or eat fortified foods. If the baby is exclusively breastfed, he or she may not get enough vitamin B12. This can result in long-term and serious neurological problems.

A doctor may propose injections in rare circumstances, but research shows that taking extra vitamin B12 by mouth is just as beneficial as getting an injection in a muscle. It is also less expensive.

Benefits

Vitamin B12 shots may be recommended by a doctor for people who are at risk of deficiency or its repercussions.

Vitamin B12 injections may help to lower your risk of developing the following conditions:

  • heart disease
  • stroke
  • neurological disorders
  • problems with thinking and memory
  • vision loss
  • infertility
  • neural tube defects in children born to those with a vitamin B12 deficiency

Risks

Because the risk of toxicity or overdose is low, there is no upper limit for vitamin B12 intake. Vitamin B12 injections, on the other hand, may have unintended consequences.

If a person has any of the following symptoms, or if they persist or worsen, they should get medical help:

  • pain, redness, or itching at the site of the injection
  • mild diarrhea
  • a swelling sensation in the body
  • temporary itching of the skin

There may also be a risk of:

Anyone experiencing trouble breathing, hives, or swelling should seek immediate medical attention. They could be suffering from anaphylaxis, a life-threatening allergic reaction.

Drug interactions

Certain drugs may interact with vitamin B12. Before obtaining a vitamin B12 shot, people should always tell their doctor about all prescription and over-the-counter medications they are taking.

The following are some of the most regularly prescribed drugs that may interact with vitamin B12:

  • H2 receptor antagonists
  • metformin
  • proton pump inhibitors

Medical disorders and allergies

Before having a vitamin B12 shot, anyone with allergies or medical issues should always consult a doctor.

Shots of vitamin B12 may not be appropriate for those who have a history of:

  • hypokalemia, or low potassium levels
  • deficiencies in other nutrients, particularly folic acid and iron
  • sensitivity to vitamin B12
  • Leber’s disease, which affects the optic nerve
  • kidney problems

Conclusion

While most people obtain enough vitamin B12 from their diet, some people do not. This could be caused by low intrinsic factor levels in the digestive system, a digestive disease, or eating a plant-based diet.

The American Dietary Guidelines for 2020–2025 propose that vitamin B12 and other nutrients be met first and foremost through food.

If dietary sources are inadequate, a doctor may prescribe supplementation in the form of tablets or injections, depending on the cause of the deficiency.

Sources:

  • https://www.ncbi.nlm.nih.gov/books/NBK441923/
  • https://rarediseases.info.nih.gov/diseases/10310/autoimmune-atrophic-gastritis
  • https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2933506/
  • http://lpi.oregonstate.edu/mic/vitamins/vitamin-B12
  • https://www.medicalnewstoday.com/articles/318216
  • https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=579bd1fe-51a1-403f-a422-0fb701aab57d
  • https://www.sciencedirect.com/topics/food-science/recommended-dietary-allowance
  • https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
  • https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6494183/
  • https://pubmed.ncbi.nlm.nih.gov/25756278/

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