Vitamin B12, also known as cobalamin, is a vital nutrient with the largest and most complex chemical structure among all vitamins. What makes it truly unique is that it's the only vitamin containing a metal ion, cobalt. This essential vitamin plays a crucial role in numerous bodily functions, and deficiency can lead to a wide range of health issues.

Where Does B12 Come From?

Naturally, Vitamin B12 is found in higher amounts in animal products such as meat, poultry, fish (including shellfish), and to a lesser extent, dairy products and eggs. Notably, plant foods do not contain B12, though it is often fortified in cereals. The body primarily stores B12 in the liver.

Why is B12 So Important?

B12 is indispensable for several critical bodily processes:

• DNA Production: It is essential for the production of DNA.
• Red Blood Cell Formation: B12 is needed to make hemoglobin found in red blood cells.
• Nerve Health: It is crucial for nerve health and function, as it helps produce myelin.
• Metabolic Reactions: Along with folate, B12 is necessary for the function of the enzyme methionine synthase, which converts homocysteine into methionine—the amino acid the body uses for methylation reactions. This prevents excess levels of homocysteine.
• Energy Production: B12 is also involved in the production of energy.

Are You Getting Enough B12?

The recommended daily allowance (RDA) for adults is only 2.4 micrograms a day. However, despite this small requirement, insufficient levels are surprisingly common. According to the NIH, about 12.5% of all adults over the age of 19 have insufficient blood levels, and among older adults, up to 43% can have deficient levels. Blood B12 levels naturally tend to decline with age. Vegans often need B12 supplementation.

Signs and Symptoms of B12 Deficiency

The symptoms of B12 deficiency can be wide-ranging and affect multiple systems in the body. If you experience any of these, it's worth discussing with your doctor:

• Fatigue or feeling weak
• Macrocytic anemia, often accompanied by pale or yellow skin
• Poor cognitive function and increased risk of dementia, possibly related to high homocysteine
• Neuropathy, manifesting as numbness and tingling in hands and feet; trouble walking or speaking normally
• Vision problems
• Mood disturbances, including depression, irritability, paranoia, and delirium
• Osteoporosis, often linked to elevated homocysteine
• Loss of appetite
• Nausea, vomiting, diarrhea
• Weight loss
• Headaches
• Unhealthy skin, hair, and nails

Why Do Deficiencies Occur?

Several factors can lead to B12 deficiency:

• Dietary Factors: A lack of B12 in the diet can occur in vegetarians and vegans. Infants of vegan women may also be at risk if the mother's diet or breast milk lacks sufficient B12 during fetal development and in breast milk.
• Digestive Issues: Many digestive issues contribute to deficiency, primarily malabsorption. This can occur in seniors due to a lack of hydrochloric acid (HCl), or in individuals with digestive conditions such as celiac disease, Crohn’s disease, and pancreatic disorders. SIBO (Small Intestine Bacterial Overgrowth) is also a cause.
• Gastrointestinal Surgery: Individuals who have undergone gastrointestinal surgery, including bariatric surgery for weight loss (which affects the stomach or stomach and small intestine), may experience a deficiency. If the stomach is removed or part of it, HCL and intrinsic factor production can be affected. If part of the small intestine (ileum) where B12 is absorbed is removed, it also impacts absorption.
• Medical Conditions: Pernicious anemia, an autoimmune condition affecting stomach mucosa so that the parietal cells in the stomach do not produce intrinsic factor, is a significant cause. Other conditions include H. pylori infection of the stomach, causing low stomach acid, advanced HIV infection, fish tapeworm infection, and inherited disorders of B12 absorption and transport.
• Medications: Certain medications can interfere with B12 absorption, such as Metformin, hydrochloric acid blocking drugs (PPIs and H3 receptor antagonists), and colchicine.
• Liver Disorders & Alcoholism: Liver disorders can lead to deficiency since the liver stores B12. Alcoholism is also a cause.

Diagnosis and Treatment

B12 deficiency is diagnosed through a blood test, specifically by checking serum B12 and methylmalonic acid. 

When it comes to supplements, there are different forms:

• Cyanocobalamin: This is a synthetic compound available in supplement and injectable forms, but it must be converted into one of its active forms. Clinical nutritionists and integrative doctors rarely use this outdated form.
• Natural Forms: These include hydroxocobalamin, adenosylcobalamin, and the most common form, methylcobalamin. Although hydroxocobalamin needs to be converted to the active forms, which are methylcobalamin and 5-deoxyadenosylcobalamin. Our clinic uses the methylcobalamin form for supplements, as well as for injection and intravenous use.

Supplements can be administered orally (in the form of capsules, tablets, gummies, and liquids), sublingually, or through subcutaneous (SubQ) or intramuscular (IM) injections.

Safety of B12 Supplements

Vitamin B12 is generally considered very safe and well tolerated. Even at high doses, vitamin B12 is generally regarded as safe because the body does not store excess amounts.

If you suspect you may have a B12 deficiency, consult your healthcare provider for proper diagnosis and personalized treatment recommendations.

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