Vitamin B12 (Cobalamin) Deficiency

Vitamin B12 is needed by every cell in your body. It helps make red blood cells, keeps nerves healthy, supports DNA production, and powers energy inside cells. When B12 runs low, symptoms can show up almost anywhere: tiredness, brain fog, numbness, mood changes, or worse. Deficiency is common, often missed, and can cause serious problems if ignored.

Why B12 Deficiency Causes So Many Different Symptoms

B12 works in two main ways:

1. It lowers homocysteine (an amino acid linked to heart disease when high).

2. It helps build and maintain the myelin sheath, the protective coating around nerves.

Without enough B12, nerves misfire, red blood cells become large and weak (megaloblastic anemia), and cells struggle to make energy or repair themselves. Because every cell uses B12, low levels can create a wide range of seemingly unrelated complaints. The body rarely has just one cause for illness. B12 shortage often combines with stress, poor diet, gut issues, or other imbalances.

Vascular and Blood-Related Symptoms

B12 deficiency causes large, immature red blood cells (megaloblastic anemia), leading to fatigue, weakness, shortness of breath, and pale skin. It also raises homocysteine, increasing the risk of:

• Atherosclerosis (hardened arteries)

• Blood clots (deep vein thrombosis)

• Heart attack

• Stroke

  
  

Neurological Symptoms of B12 Deficiency

Nerves and brain are especially sensitive to low B12. Common signs include:

• Numbness, tingling, or burning in hands, feet, legs, or arms

• Loss of sensation (trouble feeling pain, touch, or temperature)

• Balance problems or feeling unsteady when walking

• Muscle weakness, stiffness, or spasms

• Brain fog, poor memory, confusion, trouble concentrating

• Mood changes: depression, irritability, anxiety, paranoia

• Personality shifts or extreme cases of mania/psychosis

• Headaches, blurred vision, tremors

• Symptoms that mimic Parkinson’s, multiple sclerosis, or dementia

These can start mild and slowly worsen. Many patients improve noticeably with B12 therapy even when other nerve conditions are present.

B12 and Baby’s Brain Development

Pregnant or breastfeeding women need extra B12. Low levels raise the risk of neural tube defects in the baby, developmental delays, and long-term neurological issues. A mother’s deficiency can affect the child’s brain growth before birth and during early months. Infants with severe deficiency may fail to thrive (poor growth and development).

Other Common Signs

Because B12 affects every cell, symptoms can include:

• Bone loss or increased fracture risk

• Constipation or digestive slowdown

• Loss of appetite

• Sore, red, or smooth tongue

• Unexplained weight gain or loss

These can appear alone or together with neurological or blood issues.

Who Is at Highest Risk for B12 Deficiency?

Certain groups are more likely to become low in B12:

• People with anemia - Iron deficiency or megaloblastic anemia often overlaps with B12 shortage.

• Autoimmune thyroid conditions - Hashimoto’s or Graves’ disease frequently cause absorption problems and low B12.

• Bariatric surgery patients - Gastric bypass or sleeve surgery removes or bypasses stomach areas that produce intrinsic factor and acid, both needed for B12 absorption. Many patients need lifelong B12 injections.

• Depression or mood disorders - Low B12 is linked to depression, poor memory, and fatigue. Higher B12 levels often predict better response to treatment.

• Elderly adults - Atrophic gastritis (stomach lining thinning) reduces acid and intrinsic factor. H. pylori infection (common in older adults) worsens this. Long-term acid blockers (tums) also block absorption.

• Gastrointestinal disorders - Crohn’s disease (especially ileum involvement), celiac disease, gluten sensitivity, and IBS impair absorption. Over 80% of celiac/gluten-sensitive patients show low B12 at some point.

• Infertility and recurrent miscarriage - B12 deficiency is common in women struggling to conceive or carry pregnancies. Correcting it often improves outcomes.

• Pernicious anemia - An autoimmune attack on stomach cells stops intrinsic factor production. Affects 1–2% of adults (higher over age 60). Untreated, it causes irreversible nerve damage. Injections are the best treatment.

• Vegans and vegetarians - B12 comes almost exclusively from animal products. Fortified foods help, but most long-term plant-based eaters become deficient without supplements.

Summary

Vitamin B12 deficiency is sneaky, widespread, and often overlooked. Standard blood tests miss many cases because “normal” ranges are too broad. Symptoms can mimic other conditions (depression, MS, Parkinson’s, chronic fatigue) yet improve dramatically with proper B12.

At Jones Chiropractic & Functional Medicine we look beyond lab numbers. We consider symptoms, diet, gut health, and absorption issues. If you’re tired, foggy, numb, moody, or just not yourself, B12 deficiency could be part of the puzzle. Testing (serum B12, methylmalonic acid, homocysteine) plus a trial of bioavailable B12 often brings clear answers and relief.

Disclaimer: The content presented on this website serves educational and informational purposes and is not meant to replace professional medical advice, diagnosis, or treatment. Consult your doctor for any inquiries concerning medical conditions. Do not disregard or delay seeking professional medical advice based on information obtained from this website.