Vitamin B12

Why It Matters

Vitamin B12 is an essential water-soluble vitamin that is a required cofactor for methionine synthase, which drives the methylation cycle that regulates gene expression, neurotransmitter synthesis, and homocysteine clearance. It also serves as a cofactor for methylmalonyl-CoA mutase, which channels fatty acids and amino acids into the citric acid cycle for energy production. A deficit disrupts both neurological function and cellular energy metabolism simultaneously. (source)

Low Vitamin B12: Neurological and Energy Deficit

Low vitamin B12 is commonly linked to low intake and/or absorption. This deficiency is associated with fatigue, muscle weakness, numbness, memory problems, and mood changes. (source, source)

Potential Performance Impact

• Megaloblastic anemia, reducing oxygen transport capacity
• Peripheral neuropathy, impairing proprioception and coordination
• Elevated homocysteine, increasing cardiovascular and vascular risk
• Impaired energy metabolism from disrupted fatty acid oxidation

Optimization

Eat vitamin B12-rich foods: Dietary vitamin B12 intake raises serum B12 levels. (source, source)

Protocol: Consume at least one serving of foods high in vitamin B12 daily. One serving examples: Liver (3 oz), Eggs (3 large eggs), Chicken Breast (3.5 oz), Salmon (3 oz), Beef (3.5 oz).

Avoid smoking: Smoking is associated with decreased vitamin B12 levels. (source, source)

Protocol: If a smoker, take the steps to quit. If not, avoid areas where secondhand smoke is present.

Supplement with a B vitamin complex: Supplementation with vitamin B12 raises serum B12 levels. (source, source)

Protocol: Supplement with a vitamin B complex that has at least 50% of the daily recommendation for each B vitamin.

High Vitamin B12: Liver Dysfunction Signal

Elevated vitamin B12 levels are often associated with supplementation or an indication of underlying liver disease. When liver cells are damaged, they release stored B12 into the bloodstream, artificially elevating serum levels. (source, source)

Potential Performance Impact

• Masking of liver dysfunction that impairs detoxification and recovery
• False reassurance of adequate B12 status when tissue levels are depleted
• Potential indicator of myeloproliferative or hepatic conditions requiring investigation

Optimization

Limit dairy: Dairy is a natural source of vitamin B12. Consumption of dairy is associated with increased B12 levels. Limiting dairy reduces B12 intake. (source, source)

Protocol: Monitor and limit excess intake of dairy products.

Avoid alcohol: Alcohol consumption strains liver cells, the primary storage site of vitamin B12, leading to the release of B12 into the blood. (source, source)

Protocol: Limit consumption to one or two drinks daily, with the goal of less than three per week.

Supplement with milk thistle: Liver inefficiencies are associated with increased serum B12. Milk thistle supports liver health through its hepatoprotective properties. (source, source)

Protocol: Supplement with at least 420 mg of milk thistle daily.