You are probably aware of vitamin B12’s importance in preventing fatigue, but a new Swedish study suggests it may play an important role in keeping your brain young.
Swedish researchers discovered that total brain volume losses were lower among individuals with higher vitamin B12 levels, whereas the opposite was true of those with increased homocysteine levels. (1) Scientists concluded vitamin B12 and homocysteine levels might be useful markers of brain aging in older adults, and if so, B12 supplementation may be preventative.
This study was remarkable in that it tracked a large number of participants (501) over a significant period of time (six years), as well the novel approach of looking at vitamin levels as a predictor of cognitive decline.
Because low vitamin B12 status and elevated homocysteine normally go hand in hand, it is challenging to separate one from the other. What is the relationship between the two? B12 and several other B vitamins are known to suppress homocysteine. B12 helps the body convert homocysteine into the essential amino acid methionine. But if you’re B12-deficient, this reaction cannot take place and your homocysteine levels begin to climb. High homocysteine levels are linked with cognitive impairment and dementia, as the VITACOG study revealed.
The 2010 “VITACOG study” found that homocysteine-lowering B vitamins (folate, B6 and B12) slowed brain atrophy as much as seven-fold in elderly individuals with mild cognitive impairment (MCI). (2) MCI is frequently a precursor to Alzheimer’s disease. Not only did the vitamins significantly reduce brain shrinkage but they did so in the regions of the brain most affected by Alzheimer’s disease. (3) Several other studies have yielded similar findings. (4, 5, 6, 7, 8)
Vitamin B12 deficiency is not an insignificant problem in North America. In 2000, the American Journal of Clinical Nutrition indicated that up to 39 percent of the population may be suffering from B12 deficiency.(9) With Alzheimer’s rates skyrocketing along with other neurodegenerative diseases, the role of vitamin B12 deserves a closer look.
Vitamin B12 Deficiency May Be Grossly Underdiagnosed
Your body needs vitamin B12 to transform food into energy, synthesize DNA, and manufacture healthy new red blood cells. B12 is the only vitamin containing the trace element cobalt, hence its scientific name “cobalamin.” It helps maintain nerve cells and robust conduction of nerve impulses. It plays a role in building and maintaining the myelin sheath—the protective covering around your nerves. Therefore, low vitamin B12 levels can adversely affect nearly every cognitive function.
Vitamin B12 deficiency can factor into fatigue, mood issues such as depression and anxiety, insomnia, neuropathy, cognitive impairment and dementia. Some studies now suggest B12 deficiency may be as common among younger people as the elderly.
B12 deficiency is often missed for three reasons. First, it’s not routinely tested. Second, the American reference range is too low. (10) Third, standard serum B12 blood tests tend to underdetect B12 deficiency.
In the US, normal B12 reference ranges are defined as 200 to 900 picograms per milliliter (pg/mL). This is the minimal level to keep you from developing pernicious anemia, but not enough to prevent other health problems. It is well-established by science that many people with B12 levels between 200 and 350 pg/mL (11) experience distinct B12 deficiency symptoms, especially cognitive ones. (12) The B12 range recommended in many other countries is significantly higher. For example, Japan’s minimum is 500 pg/mL—more than twice the minimal acceptable level of the US.
Studies show an alarming 50 percent of patients with diseases related to vitamin B12 deficiency have normal B12 levels when tested. (13) Why is this? Traditional vitamin B12 tests that measure total serum B12 have limited sensitivity, but there are now better options. Holotranscobalamin (holoTC) and methyl malonic acid (MMA) have higher sensitivity and specificity and are considered better biomarkers of B12 status because they measure “active B12”—the amount available to the cells of your body. (14, 15)
Primary Causes and Symptoms of B12 Deficiency
Vitamin B12 is available only from animal-based foods such as meat, poultry, dairy, eggs, fish and organ meats. Plants don’t need vitamin B12 so they don’t make it. Therefore, people who avoid meat products—such as vegans and vegetarians—without supplementing their vitamin B12 are at higher risk for deficiency. Studies consistently find that up to 50 percent of vegetarians and 80 percent of vegans are deficient in vitamin B12 (16, 17), and it may be taking a toll on their health.
In 2002, the Oxford Vegetarian Study showed that while overall mortality was the same between vegetarians and non-vegetarians, vegetarians had 2.2 times the death rate from mental and neurological diseases. (18) The effects of B12 deficiency on children are especially alarming. Studies show kids raised until age six on a vegan diet are still B12 deficient years after they start eating some animal products. Adolescents with insufficient B12 do indeed demonstrate cognitive impairment. (19)
Other individuals at high risk of B12 deficiency include smokers, alcoholics, those with kidney disorders, and anyone with gastrointestinal problems, dysbiosis or gut inflammation. Certain drugs can interfere with B12 absorption, including metformin and proton pump inhibitors (20), and pregnant women have an increased need for B12.
Even if you do consume meat products, you are not immune to B12 deficiency. It’s estimated that malabsorption is the underlying factor about 60 to 70 percent of the time. (21) Malabsorption may also explain why some vegetarians do NOT show lower levels of B12. Vitamin B12 absorption is complex and involves multiple steps. B12 may not be sufficiently extracted from your foods or adequately absorbed from your gut for one of the following reasons:
- Insufficient stomach acid: A significant amount of stomach acid is required to properly break down food and free up B12. Once liberated, B12 can then bind to intrinsic factor and be absorbed in the terminal ileum, which is the last section of your small intestine. Vitamin B12 absorption can go awry anywhere in that process. If stomach acid is inadequate, intrinsic factor cannot be liberated from the lining of your stomach so B12 cannot be absorbed.
- High detoxification: If the body has an increased need for B12 because of major detoxification activity, B12 deficiency can develop. Vitamin B12 and folate play enormous roles in methylation or phase two detoxification in the liver. If your B12 levels are low, your detoxification will be compromised.
- Autoimmunity: Pernicious anemia is an autoimmune condition in which intrinsic factor is deficient, preventing B12 absorption. This is a very serious type of B12 deficiency that requires immediate and ongoing B12 replacement.
General symptoms of vitamin B12 deficiency are outlined below. Symptoms develop over a number of years, changing and evolving as the condition worsens. Since deficiency can lead to irreversible neurological damage, early diagnosis is essential.
- Chronic fatigue, lack of energy
- Muscle aches and weakness
- Joint pain
- Poor memory, concentration and overall cognitive function
- Mood changes, depression, anxiety
- Digestive problems, nausea, diarrhea, cramping, diminished appetite
- Poor dental health, bleeding gums, mouth sores
- Inflamed, red cracked tongue
- Tingling or numbness in hands or feet
- Arrhythmias, palpitations or other heart problems
- Difficulty breathing, shortness of breath
Dietary Tips for Increasing Your B12
The best way to increase your vitamin B12 stores is by bumping up your consumption of naturally vitamin B12-rich foods. These include organic pastured dairy products and eggs, pasture-raised meats and poultry, organ meats and wild-caught fish. Vitamin B12 can be found to some degree in fortified plant foods like nutritional yeast and grain products, but most of these are not as bioavailable as natural animal sources.
A common myth amongst vegetarians and vegans is that it’s possible to get plenty of B12 from plant sources like seaweed, fermented soy, spirulina and brewer’s yeast. However, those plants don’t contain actual vitamin B12 but rather analogs (called cobamides) that may block intake of and increase the need for real B12. (22) If you’re a vegetarian who consumes some eggs and dairy, you may be able to maintain adequate vitamin B12 levels, but you should get yourself tested regularly. If you’re a strict vegan, however, you face more of a challenge.
Tempeh and nori seaweed (23, 24) contain small amounts of bioactive B12. If you don’t eat these foods on a regular basis, then you will likely need to take a vitamin B12 supplement and monitor your B12 levels. According to some, raw or freeze-dried nori may be better than conventionally dried as some of the B12 appears to be destroyed in the drying process. Spirulina is not a good source of B12.
Choose Your Vitamin B12 Supplements Carefully
Functional medicine physician Dr. Evan Hirsch recommends maintaining your B12 levels between 500 and 1500 pg/mL. If your B12 levels fall below 500 pg/mL in spite of dietary changes, I would strongly encourage your consideration of a supplement. When it comes to B12 supplements, how do you know what to take?
Supplements come in oral and sublingual tablets, as well as intramuscular injections. Injections are more expensive and require a doctor’s order. Studies show that oral B12 is effective for individuals with normal absorption. (25) If you have malabsorption issues, then sublingual tablets or B12 shots would be a better way to go. Sublingual B12 is more absorbable than oral and an excellent place for anyone to start.
Oral B12 also comes in various forms, the two most common being cyanocobalamin and methylcobalamin. Cyanocobalamin is the most frequently found form but is inferior in quality to methylcobalamin, especially for neurological benefits. Cyanocobalamin is cheap synthetic chemical (100 times cheaper than methylcobalamin) used only in low-end products in which the vitamin is attached to a cyanide molecule. On the other hand, methylcobalamin contains no cyanide and is more easily absorbed and assimilated.
Japanese studies indicate methylcobalamin actually promotes nerve regeneration. (26) Additionally, methylcobalamin provides your body with methyl groups that play critical roles in many biological processes.
Vitamin B12 must be balanced with the other B vitamins because they can displace each other off of receptor sites, creating even more B vitamin deficiencies—which is the last thing you want! Make sure to take a good multivitamin or B-complex that includes methylfolate (folate is vitamin B9). Don’t confuse folic acid with folate—folic acid is another cheap, laboratory-derived synthetic used in supplements and fortified foods, while folate is the premium natural form of the vitamin.
Vitamin B12 deficiency is often missed, which can have serious consequences for your health. If you do not consume animal products, you almost certainly need to be taking supplemental B12 and at the very least be monitoring your B12 levels regularly. Regardless of your age, if you are experiencing “senior moments,” one of the first and easiest things you can do is to check your vitamin B12 level—leave yourself a sticky note so you won’t forget. (As your levels improve, you’ll be more likely to remember.)