Vitamin b12 uses and side effects
- Vitamin B12, or cobalamin, is a vital water-soluble nutrient that supports the production of red blood cells, maintains healthy nerve function, and aids in DNA synthesis—making it essential for overall health and well-being.”While it is naturally found in animal-based foods, it is also available as a supplement and in fortified foods for those who are deficient or at risk of deficiency.This article provides a comprehensive overview of the uses, benefits, and potential side effects of vitamin B12, as well as information on dosage and the best food sources
Vitamin B12 belongs to the B-complex family of vitamins and uniquely contains the trace mineral cobalt, which is essential for its biological activity.”which is essential for its biological activity.”It is required for:Red blood cell productionNeurological functionDNA synthesis and repairEnergy metabolismThe body cannot produce vitamin B12 on its own, so it must be obtained from dietary sources or supplements.The liver serves as the main storage site for vitamin B12, and a deficiency can take several years to manifest due to the body’s ability to retain reserves.
Natural Sources of Vitamin B12
Vitamin B12 is primarily found in animal products. Common dietary sources include:
Meat: beef, lamb, pork
Poultry: chicken, turkey
Fish: salmon, tuna, sardines, trout
Dairy: milk, cheese, yoghurt
Eggs
Fortified products—such as plant-based milks, breakfast cereals, and nutritional yeast
—can provide vitamin B12, especially important for vegetarians and vegans, who are more susceptible to deficiency and may require supplementation or fortified options in their diet.
Recommended Daily Intake
According to the National Institutes of Health (NIH), the recommended daily intake (RDI) for vitamin B12 varies by age and condition:
Infants (0–12 months): 0.4–0.5 mcg
Children (1–8 years): 0.9–1.2 mcg
Teens (9–18 years): 1.8–2.4 mcg
Adults: 2.4 mcg
Pregnant women: 2.6 mcg
Breastfeeding women: 2.8 mcg
Health Benefits and Uses of Vitamin B121
Red Blood Cell Formation and Anaemia Prevention
1. Vitamin B12 plays a key role in producing healthy red blood cells, helping to prevent certain types of anaemia that can cause fatigue and weakness.”A deficiency can cause megaloblastic anaemia, characterised by large and immature red blood cells that cannot function properly. Common symptoms include tiredness, physical weakness, and difficulty breathing.”
2. Supports Brain and Nerve Function
Vitamin B12 is essential for forming the myelin sheath that insulates and protects nerves. A deficiency can result in various neurological issues, including”:Numbness and tinglingBalance issuesMemory lossCognitive declineIn severe cases, long-term deficiency may cause irreversible nerve damage.
3. May Improve Mood and Symptoms of DepressionVitamin B12 is involved in the synthesis of neurotransmitters like serotonin and dopamine. Low B12 levels have been linked with a higher risk of depression. Supplementation may help improve mood, especially in individuals who are deficient.
4. Supports Bone Health and May Prevent OsteoporosisLow B12 levels have been associated with decreased bone mineral density, especially in older adults. This may increase the risk of osteoporosis and fractures.
5. Improves Heart Health by Lowering HomocysteineHigh levels of homocysteine, an amino acid, have been linked to an increased risk of heart disease. Vitamin B12, along with B6 and folate, helps convert homocysteine into methionine, reducing cardiovascular risk.
6. Boosts Energy LevelsAlthough vitamin B12 does not directly provide energy, it helps convert food into glucose, the body’s primary energy source. Deficiency often leads to fatigue and weakness, which may be relieved through supplementation.
7. Supports Healthy Skin, Hair, and NailsVitamin B12 plays a role in cell production, which is essential for healthy skin, hair, and nails. Deficiency may cause dermatological symptoms like hyperpigmentation, nail discolouration, and hair thinning.
8. May Aid in Preventing Birth DefectsAdequate B12 levels are crucial during early pregnancy. Deficiency can increase the risk of neural tube defects and miscarriage. Pregnant women, especially vegetarians, should ensure adequate intake.
9. Supports Eye HealthVitamin B12 may help reduce the risk of age-related macular degeneration (AMD) by lowering homocysteine levels, which are associated with eye damage.
Signs and Symptoms of Vitamin B12 Deficiency
Vitamin B12 deficiency may develop slowly and show subtle symptoms at first. Common signs include:
- Fatigue
- Weakness
- Pale or jaundiced skin
- Heart palpitations
- Breathlessness
- Cognitive difficulties (e.g., memory loss, confusion)
- Numbness and tingling in the hands and feet
- Mood changes (e.g., irritability, depression)
- Glossitis (inflamed tongue) and mouth ulcers
- Blurred vision
If left untreated, the deficiency can cause permanent nerve damage and neurological disorders.Causes of Vitamin B12 DeficiencyPernicious anaemia: an autoimmune condition that interferes with B12 absorption
Gastrointestinal issues: Crohn’s disease, coeliac disease, gastritis Surgeries: gastric bypass or bowel resection Dietary insufficiency: especially in vegans or vegetarians
Alcohol abuse Ageing: absorption declines with age.
Medications: proton pump inhibitors, metformin
Vitamin B12 Supplements
Vitamin B12 supplements are a
vailable in several forms:
Cyanocobalamin: synthetic form, commonly used in supplements
Methylcobalamin: a naturally occurring, active formHydroxocobalamin: often used in injections
Adenosylcobalamin: another active form in human metabolism
They come as:Oral tablets or capsules
Sublingual (under the tongue) forms
Nasal spraysInjections (for those with severe deficiency or malabsorption)
Side Effects and Risks of Vitamin B12Is Vitamin B12 Safe?
Vitamin B12 is considered safe, even at high doses, because it is water-soluble and excess amounts are excreted in urine.Possible Side Effects
Though rare, side effects may include:
Mild diarrhoeaItching or skin rash
- Headache
- Nausea
- Dizziness
- Anxiety (rare)
In cases of injectable B12:Pain or redness at the injection site
- Swelling
- Allergic
- reaction (anaphylaxis) –
- extremely rareDrug InteractionsVitamin B12 may interact with the following medications:
Metformin: used for diabetes; may reduce B12 absorption
Proton pump inhibitors (PPIs): reduce stomach acid necessary for B12 absorptionHistamine-2 receptor antagonists also reduce stomach acid.
Chloramphenicol: an antibiotic that may affect blood cell production Nitrous
oxide: repeated exposure may inactivate B12.Before beginning any supplement, it’s important to consult a healthcare professional—particularly if you’re taking medications or managing existing health conditions.
Who Should Consider Supplementation?
Vegans and vegetariansOlder adults (over 60)People with digestive disordersPregnant or breastfeeding womenPeople taking long-term medications that affect absorptionIndividuals who have undergone GI surgeryRegular blood tests can help detect a deficiency early, and a doctor can recommend appropriate treatment.