What is Vitamin B12?

Vitamin B12 (cobalamin) is a crucial nutrient for red blood cell production, neurological function, and DNA synthesis. It plays a vital role in methylation, working alongside folate to regulate homocysteine levels, support cellular repair, and aid in detoxification.

Since the body doesn’t produce B12, it must be obtained from diet or supplements. Naturally found in animal products like meat, dairy, and eggs, B12 is an essential nutrient for those following vegetarian or vegan diets, as plant-based sources are limited.

A B12 deficiency can lead to anemia, fatigue, nerve damage, and cognitive issues, making it an important marker for overall health.

Factors That Influence B12 Levels

1. Dietary Sources

Vitamin B12 is found in meat, poultry, fish, eggs, and dairy products. Those who avoid animal products may need fortified foods or supplements to maintain adequate levels.

2. Absorption Issues

Certain conditions can impair B12 absorption, including:

• Pernicious anemia, an autoimmune disorder affecting B12 uptake.
• Crohn’s disease and celiac disease, which damage the gut lining.
• Gastric surgery, such as weight loss surgery, which reduces the stomach’s ability to absorb B12.

3. Age and Deficiency Risk

Older adults are at a higher risk of B12 deficiency due to decreased stomach acid production, which is necessary for B12 absorption.

Healthy Vitamin B12 Levels

Normal levels range from 300–900 pg/mL, but levels above 400 pg/mL are ideal for optimal health.

Effects of Low B12 Levels

• Fatigue and weakness: Due to its role in red blood cell production, low B12 can cause anemia and energy depletion.
• Neuropathy: Deficiency can damage the nervous system, leading to tingling, numbness, and poor coordination.
• Cognitive decline: B12 is essential for brain function—low levels have been linked to memory loss and difficulty concentrating.

Effects of High B12 Levels

• While high B12 is usually harmless, it may indicate liver disease, kidney dysfunction, or excessive supplementation.