Vitamin B12

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a crucial role in various physiological processes within the human body. It is essential for the formation of red blood cells, neurological function, and the synthesis of DNA. Vitamin B12 is unique among the B vitamins as it requires intrinsic factor, a protein produced in the stomach, for optimal absorption. Since the human body cannot produce vitamin B12, it must be obtained through dietary sources or supplements.

Overview

Water-Soluble Vitamin:

Essential Nutrient: Vitamin B12 is an essential nutrient required for the proper functioning of the human body.

Coenzyme: It serves as a coenzyme for various enzymatic reactions.

Unique Absorption Mechanism:

Intrinsic Factor: Vitamin B12 absorption depends on intrinsic factor, a protein produced in the stomach.

Functions of Vitamin B12

Red Blood Cell Formation:

Erythropoiesis: Vitamin B12 is crucial for the production of red blood cells, preventing megaloblastic anaemia.

Neurological Function:

Nerve Myelination: It plays a role in the myelination of nerve fibres, supporting proper neurological function.

Neurotransmitter Synthesis: Vitamin B12 is involved in the synthesis of neurotransmitters.

DNA Synthesis:

Nucleic Acid Synthesis: Vitamin B12 is necessary for the synthesis of DNA, supporting cellular replication.

Homocysteine Metabolism:

Homocysteine Conversion: Vitamin B12, along with other B vitamins, helps convert homocysteine to methionine, reducing the risk of cardiovascular disease.

Dietary Sources of Vitamin B12

Animal Products:

Meat: Beef, pork, lamb, and poultry.

Fish: Salmon, trout, tuna, and sardines.

Shellfish: Clams, oysters, and mussels.

Dairy: Milk, cheese, and eggs.

Fortified Foods:

Fortified Cereals and Plant-Based Milk: Some plant-based products are fortified with vitamin B12.

Supplements:

Vitamin B12 Supplements: Available in various forms, including tablets, capsules, and injections.

Recommended Daily Intake

Varied Requirements: The recommended daily intake varies by age, sex, and life stage. For adults, it is generally around 2.4 micrograms.

Deficiency and Excess

Deficiency Symptoms:

Pernicious Anaemia: A severe deficiency can lead to pernicious anaemia, characterized by fatigue, weakness, and neurological symptoms such as tingling and numbness.

Excess Intake:

Low Risk: Vitamin B12 is water-soluble, and excess amounts are typically excreted in urine, posing a low risk of toxicity.

Interactions and Considerations

Intrinsic Factor:

Intrinsic Factor Production: Conditions affecting intrinsic factor production, such as pernicious anaemia, can impact vitamin B12 absorption.

Medication Interactions:

Proton Pump Inhibitors and H2 Blockers: Long-term use of these medications may reduce vitamin B12 absorption.

Research and Health Benefits

Cognitive Function:

Cognitive Decline: Some studies explore the association between adequate vitamin B12 levels and reduced risk of cognitive decline.

Cardiovascular Health:

Homocysteine Levels: Research suggests that maintaining optimal vitamin B12 levels may help regulate homocysteine levels, reducing cardiovascular risk.