- 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
- Male and female infertility
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)
- 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:
- vegetarians and vegans
- people aged 60 or over
- people who regularly use PPIs or acid suppressing drugs
- people on diabetes drugs like metformin
- people with Crohn’s disease, ulcerative colitis, celiac or IBS
- women with a history of infertility and miscarriage
Note to vegetarians and vegans: B12 is found ONLY in animal products
B12 is the only vitamin that contains a trace element (cobalt), which is why it’s called cobalamin. Cobalamin is produced in the gut of animals. It’s the only vitamin we can’t obtain from plants or sunlight. Plants don’t need B12 so they don’t store it.
A common myth amongst vegetarians and vegans is that it’s possible to get B12 from plant sources like seaweed, fermented soy, spirulina and brewers yeast. But plant foods said to contain B12 actually contain B12 analogs called cobamides that block intake of and increase the need for true B12 .
The effects of B12 deficiency on kids are especially alarming. Studies have shown that kids raised until age 6 on a vegan diet are still B12 deficient even years after they start eating at least some animal products. In one study , the researchers found:
…a significant association between cobalamin [b12] status and performance on tests measuring fluid intelligence, spatial ability and short-term memory” with formerly vegan kids scoring lower than omnivorous kids in each case.
The deficit in fluid intelligence is particularly troubling, the researchers said, because:
…it involves reasoning, the capacity to solve complex problems, abstract thinking ability and the ability to learn. Any defect in this area may have far-reaching consequences for individual functioning.
I recognize that there are many reasons why people choose to eat the way they do, and I respect people’s right to make their own choices. I also know that, like all parents, vegetarians and vegans want the best for their children. This is why it’s absolutely crucial for those that abstain from animal products to understand that there are no plant sources of B12 and that all vegans and most vegetarians should supplement with B12. This is especially important for vegetarian or vegan children or pregnant women, whose need for B12 is even greater than adults.
Treatment of B12 deficiency
One of the greatest tragedies of the B12 epidemic is that diagnosis and treatment is relatively easy and cheap – especially when compared to treatment of the diseases B12 deficiency can cause. A B12 test can be performed by any laboratory, and should be covered by insurance. If you don’t have insurance, you can order it yourself from a lab like DirectLabs.com  for $60.
As always, adequate treatment depends on the underlying mechanism causing the problem. People with pernicious anemia or inflammatory gut disorders like Crohn’s disease are likely to have impaired absorption for their entire lives, and will likely require B12 injections indefinitely. This may also be true for those with severe B12 deficiency causing neurological symptoms.
Some recent studies have suggested that high dose oral or nasal administration  may be as effective as injections for those with B12 malabsorption problems. However, most B12 experts still recommend injections for people with pernicious anemia and advanced B12 deficiency involving neurological symptoms.
Cyanaocobalamin is the most frequently used form of B12 supplementation in the US. But recent evidence suggests that hydroxycobalamin (frequently used in Europe) is superior to cyanocobalamin, and methylcobalamin may be superior to both – especially for neurological disease.
Japanese studies indicate that methylcobalamin is even more effective in treating the neurological sequelae of B12 deficiency, and that it may be better absorbed because it bypasses several potential problems in the B12 absorption cycle. On top of that, methylcobalamin provides the body with methyl groups that play an role in various biological processes important to overall health.
If you suspect you have B12 deficiency, the first step is to get tested. You need an accurate baseline to work from. If you are B12 deficient, the next step is to identify the mechanism causing the deficiency. This is something you’ll probably need help with from a medical practitioner. Once the mechanism is identified, the appropriate form (injection, oral, sublingual or nasal) of supplementation, the dose and the length of treatment can be selected.
So, next time you or someone you know is “having a senior moment”, remember: it might not be “just aging”. It could be B12 deficiency.