What is Vitamin B12?
Vitamin B12, also known as cobalamin, is an essential vitamin that plays a pivotal role in the body. It’s a water-soluble vitamin involved in the metabolism of every cell in the human body, specifically affecting DNA synthesis, fatty acid synthesis, and energy production. It’s also key for the function of the nervous system and the production of red blood cells.
Food Sources of Vitamin B12
Vitamin B12 is primarily found in animal products, including:
- Fish and seafood, such as salmon and clams
- Meat, such as beef and liver
- Poultry, like chicken and turkey
- Dairy products, including milk, cheese, and yogurt
- Eggs
Certain fortified foods, like plant-based milk and breakfast cereals, may also contain added B12. Supplements are often recommended for those who cannot obtain enough through diet alone, such as vegetarians and vegans.
Functions and Benefits of Vitamin B12
Vitamin B12 has several important functions in the body:
- Formation of red blood cells and prevention of anemia
- Supporting the health of the nervous system
- Assisting in the synthesis of DNA
- Aid in protein metabolism
Some potential benefits of adequate B12 intake include supporting bone health, preventing macular degeneration, improving mood and symptoms of depression, and supporting healthy hair, skin, and nails.
Deficiency Symptoms of Vitamin B12
B12 deficiency can lead to a variety of symptoms, which may include:
- Fatigue and weakness
- Constipation
- Loss of appetite
- Weight loss
- Numbness and tingling in the hands and feet
- Difficulty maintaining balance
- Depression, confusion, and poor memory
- Soreness of the mouth or tongue
Severe B12 deficiency can lead to a serious condition called pernicious anemia.
Excess Symptoms of Vitamin B12
Vitamin B12 is generally considered safe, even in large doses. The body efficiently excretes excess amounts through urine. There’s no well-established upper intake level for this vitamin. However, some people might experience side effects, such as:
- Dizziness
- Headache
- Anxiety
- Nausea
- Vomiting
Recommended Daily Intake of Vitamin B12
The recommended daily intake of vitamin B12 varies depending on age, sex, and pregnancy status. Here are the recommendations:
- Infants (0-6 months): 0.4 micrograms (mcg)
- Infants (7-12 months): 0.5 mcg
- Children (1-3 years): 0.9 mcg
- Children (4-8 years): 1.2 mcg
- Children (9-13 years): 1.8 mcg
- Adults (14 years and older): 2.4 mcg
- Pregnant women: 2.6 mcg
- Breastfeeding women: 2.8 mcg
Absorption and Interactions of Vitamin B12
Vitamin B12 absorption can be complex and involves stomach acid and a protein made in the stomach called intrinsic factor. Certain conditions and medications that reduce stomach acid or damage the stomach lining—like long-term antacid use or proton pump inhibitors—can interfere with B12 absorption.
Deficiency Diseases or Conditions Related to Vitamin B12
A prolonged deficiency in vitamin B12 can lead to several health conditions, such as:
- Megaloblastic anemia
- Nerve damage
- Depression
- Confusion
- Dementia
Toxicity or Overdose Effects of Vitamin B12
No toxicity or overdose effects are known for vitamin B12. The body can efficiently excrete any excess vitamin B12 through urine.
Special Considerations for Vitamin B12
People who might need extra vitamin B12 include:
- Older adults, who may have less stomach acid and intrinsic factor
- People with pernicious anemia
- People who’ve had gastrointestinal surgery
- People with digestive disorders like celiac disease or Crohn’s disease
- Vegans and strict vegetarians
Additional Facts about Vitamin B12
- The term “cobalamin” comes from the element cobalt found in B12.
- Vitamin B12 is unique because it’s the only vitamin that can only be obtained from animal-derived foods.
- Deficiency is common, especially among older adults and those with certain health conditions or dietary restrictions.
- Vitamin B12 works closely with folate in the body. If the level of one becomes low, it can cause the level of the other to appear high. It’s important to have both checked if a deficiency is suspected.
- Certain seaweeds and algae, such as nori and spirulina, have been studied for their B12 content, but their ability to improve B12 status in humans remains unclear.
Source Links
1. https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
2. https://www.hsph.harvard.edu/nutritionsource/vitamin-b12/
3. https://www.mayoclinic.org/drugs-supplements-vitamin-b12/art-20363663
4. https://www.healthline.com/nutrition/vitamin-b12-benefits