Vitamin B12 helps in various body functions, including carbohydrate and fat synthesis. Some side effects, include mild diarrhea, skin rash, dizziness, itching, nausea, headaches, vomiting, sensation swelling, pulmonary edema, vein thrombosis, and polycythemia vera.

Vitamin B12 is needed for various body functions and developments. Most people get enough of this vitamin from the regular foods they eat; however, some people may experience its deficiency, which is rarely detected at an early stage. Serious deficiency could result in nerve damage, anemia, and stomach problems. The doctors often recommend an oral or injection of vitamin B12 for people with deficiency. Let’s consider the possible side effects of too much intake of the vitamin.

What is Vitamin B12?

This vitamin is a water-soluble vitamin that helps the body perform various functions, such as fat and carbohydrate synthesis, to make new proteins and provide energy. It also helps in nerve cell health, the formation of red blood cells, and neurological functions. It is mostly found in animal-based foods since it binds itself to food protein molecules. During digestion, this vitamin is separated from the protein to be absorbed into the bloodstream. The acid in the stomach aid in this separation, and another substance known as the intrinsic factor is needed to enhance absorption. It means that vitamin B12 deficiency could result from a poor diet lacking the vitamin or the body’s inability to absorb it.

Since Vitamin B12 is water-soluble, it is often absorbed in the ileum and then used for making red blood cells and DNA. The vitamins not utilized are stored in the liver, meaning individuals taking on vitamin B12 supplements may take more than the body requires.

Side effects of excess intake of Vitamin B12

An oral intake of the vitamin at recommended dosages is healthy and recommended for people with deficiency. However, an injection of vitamin B12, used under severe deficient conditions, can result in some side effects, including mild diarrhea, skin rash, dizziness, itching, nausea, headaches, vomiting, sensation swelling, pulmonary edema, vein thrombosis, and polycythemia vera.

Additionally, it can cause a rare allergic reaction called anaphylaxis-which includes swelling of the tongue, face, throat, and problems breathing and swallowing. This condition is serious, and one is advised to call an emergency line should experience them. Vitamin B12 supplements are recommended for people taking vitamin C, metformin, colchicine, H2 blockers, proton pump inhibitors, and chloramphenicol. If you are under these medications, you may need to alternate them with the timing of your vitamin B12 supplements. For example, if you are taking the medication in the morning, you can take the supplements in the evening. It is also advisable to avoid vitamin B-12 supplements if you are allergic or sensitive to cobalt or any other elements in the supplements.

Signs and Symptoms of Vitamin B12 Deficiency

The symptoms of vitamin B12 resemble signs of other illnesses and can take some time before the doctors point out the main problem. Nevertheless, some of the common signs to look for could signify a lack of the vitamin. If you experience persistent fatigue, lethargy, decreased cognitive function, depression or irritability, constipation, headache, feeling faint, mouth ulcers, heart palpitation, paraesthesia, swollen tongue, or vision changes.

The Risk Factor of Vitamin B12 Deficiency

Certain avoidable and unavoidable factors can exacerbate vitamin B12 deficiency. These factors hinder the normal functioning of intrinsic factors that promote the absorption of the vitamin. These factors include:

  • Smoking
  • Medical prescriptions, such as type 2 diabetes drugs and antiacids
  • Alcohol abuse
  • Endocrine-related disorders, such as thyroid disorder or diabetes

Gastrointestinal issues- these issues could result in a malfunction of the gastrointestinal tract, inhibiting the absorption or the release of vitamin B12. It means individuals with disorders like Crohn’s disease or celiac disease have an increased risk of vitamin B12 deficiency. The gastric bypass could also reduce the number of cells needed to secrete adequate intrinsic and stomach acid necessary for vitamin B12 absorption.

Research also suggests that a greater number of older adults experience a deficiency of this vital vitamin. Older adults may have a decreased stomach acid production, providing a perfect environment for the growth of certain bacteria that uses vitamin B12, thus limiting the amount available for the body. The institute of medicine proposes that adults above age 50 take vitamin B12 shots, supplements, or eat a fortified food. These methods will make the vitamin readily available for absorption in the body.

Vegetarians or vegans are also at risk of vitamin B12 deficiency since the vitamin is chiefly found in meat, fish, dairy, and eggs. Most vegetarians and vegans could benefit from vitamin B12 shots or supplements to meet their requirements.

Pregnant women and breastfeeding mothers could also experience a deficiency in vitamin B12 since their intake involves taking for the baby. Infants with vitamin B12 deficiency may develop severe neurological issues.

The Correct Dosage of Vitamin B12

The National Institute of Health provides the recommended amounts of the vitamin for various categories of people as follows:

  • Individuals from ages 14 and above can take 2.4 micrograms (mcg)
  • Pregnant women should take up to 2.6 mcg daily
  • Breastfeeding mothers should have a daily intake of 2.8 mcg

Individuals over the age of 50 do well to eat adequate vitamin B12 or consider taking supplements containing 100 mcg of the vitamin. Food rich in vitamin B12 includes eggs, fish, cheese, liver, shellfish, red meat, and kidney.

When You See a Doctor

If you realize adverse effects upon beginning vitamin B12 supplement intake, discontinue the consumption immediately. If the effects do not subside after discontinuing, you should then seek medical attention from your doctor. The doctor would give the best course of action to improve your absorption of vitamin B12 free of negative side effects.

The Bottom Line

Lack of vitamin B12 can be corrected by taking foods rich in the vitamin, an injection of vitamin B12, or an oral intake of supplements. Sometimes intake of these supplements can result in adverse side effects. You can correct them by stopping to take the supplements. If the symptoms continue, it is recommended you see a doctor for further medical examination. Generally, vitamin B12 is safe when taken in the correct dosage

Nutritionist. Bluffton University, MS

In today's world, people's eating and exercise patterns have changed, and it is often lifestyle that is the cause of many diet-related illnesses. I believe that each of us is unique – what works for one does not help another. What is more, it can even be harmful. I am interested in food psychology, which studies a person's relationship with their body and food, explains our choices and desires for specific products, the difficulty of maintaining optimal body weight, as well as the influence of various internal and external factors on appetite. I'm also an avid vintage car collector, and currently, I'm working on my 1993 W124 Mercedes. You may have stumbled upon articles I have been featured in, for example, in Cosmopolitan, Elle, Grazia, Women's Health, The Guardian, and others.

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