Vitamin B12 General Information

What is vitamin B12?

Vitamin B12 is an essential water-soluble nutrient that is instrumental for many important biochemical reactions in your body, such as red blood cell production, converting fat into energy, sustaining healthy nerve cells, and enhancing mental clarity.

Without enough vitamin B12, you may develop severe nervous system disorders and cognitive impairments such as dementia, neuropathy, and mood disorders.

Other illnesses that correlate with vitamin B12 deficiency include fibromyalgia and heart disease.

Pernicious anemia

Pernicious anemia is a type of megaloblastic anemia, meaning that is causes your red blood cells to become engorged and misshapen. Pernicious anemia can result from an autoimmune disorder, or it can occur because of damage to the digestive system, as in chronic gastritis or irritable bowel syndrome (IBS).

Either way, the consequences include inability to absorb vitamin B12 in the digestive tract. As a result, you don’t have enough vitamin B12 to regulate proper production of healthy red blood cells, and you suffer the effects of oxygen depletion in the brain.

Causes and risk factors of vitamin B12 deficiency

Besides pernicious anemia, other causes of vitamin B12 deficiency include not eating enough meat, milk, or fish products containing vitamin B12, submitting to bariatric surgery, taking medicines that inhibit vitamin B12 absorption, and certain autoimmune disorders.

Vitamin B12 deficiency takes years to develop, so it’s important to supplement if you suspect you are a risk factor.

Risk factors for vitamin B12 deficiency include:

  • Veganism
  • Bariatric surgery
  • Diabetes drug metformin
  • GERD medication proton pump inhibitors (PPIs)
  • Autoimmune disorders
  • Inability to produce intrinsic factor, a necessary digestive enzyme for vitamin B12 absorption
  • Gastrointestinal disorders such as Crohn’s disease, celiac disease, and other types of inflammatory bowel disease (IBD)
  • Heliobacter pylori (H. pylori) infection
  • The elderly (the aging process reduces digestive enzymes)
  • Alcoholics


Vitamin B12 deficiency symptoms

Some symptoms of early vitamin B12 deficiency include

  • Frequent forgetfulness
  • Depression
  • Fatigue
  • “Pins and needles” numbness in hands and feet
  • Confused thinking (brain fog)
  • Anxiety

Over time, signs of advanced nerve damage include heart palpitations, difficulty walking, paralysis, burning mouth sensations, eye twitching, vision problems, and autonomous nervous system malfunctioning.

Unless treated, vitamin B12 deficiency can be fatal.

Testing for vitamin B12 deficiency

The majority of the vitamin B12 you ingest is stored in your liver, to remain dormant for several years. The rest, known as “active” vitamin B12, enters your blood supply and assists in various biochemical functions.

This is the type of vitamin B12 that counts. For optimum health, and to avoid symptoms of deficiency, you must have adequate levels of active vitamin B12.

Since standard blood tests measure total vitamin B12 levels, but don’t isolate active vitamin B12, you should not rely on lab tests alone. If you notice symptoms like fatigue, depression, memory loss, and painful tingling in the hands and feet (all common symptoms of vitamin B12 deficiency), then start supplementing with vitamin B12 immediately.

Where to get vitamin B12

There is no upper limit for vitamin B12, so you may take as much as you like for increased stamina, cognitive health, and metabolic integrity.

Many doctors prescribe vitamin B12 shots for long-term deficiency. For maximum vitamin B12, over-the-counter (OTC) vitamin B12 supplements are helpful to take in addition to vitamin B12 shots or as a gentle substitute.