Vitamin B12

We really liked this article by Chris Kresser about vitamin B12 and the risks involved with having a B12 deficiency. Evie, the nurse practitioner at our office, now offers single B12 shots and B12 shot packages. Talk to her at you next visit about getting one!

What do all of these diseases have in common?

Alzheimer’s, dementia, cognitive decline and memory loss (collectively referred to as “aging”)
Multiple sclerosis (MS) and other neurological disorders
Mental illness (depression, anxiety, bipolar disorder, psychosis)
Cardiovascular disease
Learning or developmental disorders in kids
Autism spectrum disorder
Autoimmune disease and immune dysregulation
Cancer
Male and female infertility

Answer: they can all mimic the signs and symptoms of vitamin B12 deficiency.

B12 deficiency: an invisible epidemic

B12 deficiency isn’t a bizarre, mysterious disease. It’s written about in every medical textbook and its causes and effects are well-established in the scientific literature.

However, B12 deficiency is far more common than most health care practitioners and the general public realize. Data from the Tufts University Framingham Offspring Study suggest that 40 percent of people between the ages of 26 and 83 have plasma B12 levels in the low normal range – a range at which many experience neurological symptoms. 9 percent had outright deficiency, and 16 percent exhibited “near deficiency”. Most surprising to the researchers was the fact that low B12 levels were as common in younger people as they were in the elderly.

That said, B12 deficiency has been estimated to affect about 40% of people over 60 years of age. It’s entirely possible that at least some of the symptoms we attribute to “normal” aging – such as memory loss, cognitive decline, decreased mobility, etc. – are at least in part caused by B12 deficiency.

Why is B12 deficiency so under-diagnosed?

B12 deficiency is often missed for two reasons. First, it’s not routinely tested by most physicians. Second, the low end of the laboratory reference range is too low. This is why most studies underestimate true levels of deficiency. Many B12 deficient people have so-called “normal” levels of B12.

Yet it is well-established in the scientific literature that people with B12 levels between 200 pg/mL and 350 pg/mL – levels considered “normal” in the U.S. – have clear B12 deficiency symptoms. Experts who specialize in the diagnosis and treatment of B12 deficiency, like Sally Pacholok R.N. and Jeffery Stewart D.O., suggest treating all patients that are symptomatic and have B12 levels less than 450 pg/mL. They also recommend treating patients with normal B12, but elevated urinary methylmalonic acid (MMA), homocysteine and/or holotranscobalamin (other markers of B12 deficiency).

In Japan and Europe, the lower limit for B12 is between 500-550 pg/mL, the level associated with psychological and behavioral manifestations such as cognitive decline, dementia and memory loss. Some experts have speculated that the acceptance of higher levels as normal in Japan and the willingness to treat levels considered “normal” in the U.S. explain the low rates of Alzheimer’s and dementia in that country.

What is vitamin B12 and why do you need it?

Vitamin B12 works together with folate in the synthesis of DNA and red blood cells. It’s also involved in the production of the myelin sheath around the nerves, and the conduction of nerve impulses. You can think of the brain and the nervous system as a big tangle of wires. Myelin is the insulation that protects those wires and helps them to conduct messages.

Severe B12 deficiency in conditions like pernicious anemia (an autoimmune condition where the body destroys intrinsic factor, a protein necessary for the absorption of B12) used to be fatal until scientists figured out death could be prevented by feeding patients raw liver (which contains high amounts of B12). But anemia is the final stage of B12 deficiency. Long before anemia sets in, B12 deficiency causes several other problems, including fatigue, lethargy, weakness, memory loss and neurological and psychiatric problems.

B12 deficiency occurs in four stages, beginning with declining blood levels of the vitamin (stage I), progressing to low cellular concentrations of the vitamin (stage II), an increased blood level of homocysteine and a decreased rate of DNA synthesis (stage III), and finally, macrocytic anemia (stage IV).

Why is B12 deficiency so common?

The absorption of B12 is complex and involves several steps – each of which can go wrong. Causes of B12 malabsorption include:

intestinal dysbiosis
leaky gut and/or gut inflammation
atrophic gastrits or hypochlorhydria (low stomach acid)
pernicious anemia (autoimmune condition)
medications (especially PPIs and other acid-suppressing drugs)
alcohol
exposure to nitrous oxide (during surgery or recreational use)

This explains why B12 deficiency can occur even in people eating large amounts of B12-containing animal products. In fact, many of my patients that are B12 deficient are following a Paleo diet where they eat meat 2-3 times a day.

In general, the following groups are at greatest risk for B12 deficiency: