Vitamin B12 is not produced by plants or animals, but by microbes covering the earth. In the past, we probably obtained B12 by drinking from a mountain stream or a well. Studies suggest that vegetarians in developing countries, who drink purified water, may be at higher risk. Nowadays, we usually chlorinate our water to kill bacteria. Most of us no longer have much B12 in our water, but we also don’t have much cholera. This is an advantage of living in a more hygienic world. However, vegetarians living in slums in less developed regions seem to have fewer B12 problems. In general, the cleaner our meals, the less B12 we consume. Our fellow apes, like gorillas, obtain all the Vitamin B12 they need from their own feces. I prefer supplements. So how much should we take, what type is best, and how can we determine if we have a B12 deficiency?
The Benefits of Vitamin B12
We cannot take B12 intake lightly. If we don’t get enough, it can lead to a variety of digestive, blood, brain, and nervous system disorders.
In many case reports, it is detailed how B12 can be life-changing. For example, a 47-year-old woman suffered from psychosis for five years. She had been treated with antipsychotics, had cognitive impairments, and reported visual hallucinations. After it was revealed that the patient had been strictly vegan for seven years, a Vitamin B12 supplementation was started, and her symptoms disappeared. She had lost years of her life in a psychotic state – apparently just because she didn’t want to take a supplement.
A Vitamin B12 supplement is mandatory for anyone following a plant-based diet, and, as I will discuss later, for anyone over the age of 65.
Vitamin B12 Deficiency: Symptoms and Treatment
As I discuss in my video The Symptoms of Vitamin B12 Deficiency, it can cause everything from bloating and chronic diarrhea to shortness of breath and swollen, red, painful feet. It can also cause Parkinson’s-like symptoms, darkening of the skin (which was resolved with a supplement), and bilateral useless hand syndrome, a condition I had never heard of before.
A B12 deficiency can also manifest in various neurological symptoms – such as numbness and tingling in the hands and feet, muscle cramps, dizziness, cognitive impairment, difficulty walking, and erectile dysfunction – as well as in fatigue and psychiatric symptoms such as depression and psychosis.
How can a B12 deficiency be treated? With B12 supplements or B12-fortified foods.
Recommended Dosage of Vitamin B12
The official stance of associations and government bodies is categorical and clear: a Vitamin B12 supplement is necessary for anyone following a vegetarian diet, including those consuming eggs and dairy products, and I would also extend this to flexitarians who eat only a few servings of meat per week.
Who else should ensure a regular and reliable source of Vitamin B12 by supplementing their diet with B12 supplements or B12-fortified foods? Those who have undergone bariatric surgery (which can sometimes impair absorption), those following a plant-based diet, and all individuals over the age of 65.
As I discuss in my video The Optimal Vitamin B12 Dosage for Adults, adults under 65 years should take at least one supplement of 2,000 µg (mcg) per week, preferably as a chewable tablet, sublingually, or as a liquid supplement on an empty stomach, or at least one supplement of 50 µg (mcg) daily. As we age, our ability to absorb Vitamin B12 may decrease. Therefore, the supplementation for individuals over 65 years likely should be increased to up to 1,000 µg (mcg) per day, as I explain in my video The Optimal Vitamin B12 Dosage for Children, Pregnancy, and Seniors.
Pregnant and lactating women can simply follow my recommendation of 50 µg (mcg) daily for non-pregnant adults or take 2,000 µg (mcg) per week, possibly divided into two doses to enhance absorption. Once weaned, infants can start with 5 µg (mcg) per day. From age 4 to 10, children can take half of the adult dose of 25 µg (mcg) per day, then from 11 years of age, they can take 50 µg (mcg) daily or 2,000 µg (mcg) per week.
Note that these doses are specific to cyanocobalamin, the preferred form of Vitamin B12 supplement. (I discuss cyanocobalamin compared to methylcobalamin further below.)
The Best Food Sources for Vitamin B12
If you need additional B12 but don’t want to take supplements, you will need to rely on B12-fortified foods Three separate servings of B12-fortified foods per day, each ideally containing at least 190 percent of the „daily value“ on the nutrition label of the product. As I discuss in my video The Healthiest Food Sources for Vitamin B12, B12-fortified nutritional yeast is a common source, and there are all kinds of other B12-fortified options on the market, including plant-based meats and milks, breakfast cereals, and even energy drinks.
The Worst Food Sources for Vitamin B12
What about various algae-like products such as spirulina, advertised as natural sources of Vitamin B12? Not only do they contain no B12 absorbable by humans, but they may also contain B12 analogs – similar molecules that can even block the absorption of real B12!
Can Vitamin B12 Cause Side Effects?
You don’t need to worry about taking too much Vitamin B12. It is water-soluble. At worst, you will just get expensive urine. However, injectable forms can trigger acne.
Methylcobalamin vs. Cyanocobalamin
There are two main types of Vitamin B12: Methylcobalamin, marketed as Methyl B12, and Cyanocobalamin, usually marketed simply as Vitamin B12. Methylcobalamin is more expensive, so it must be better, right? Wrong.
As I discuss in my video The Best Type of Vitamin B12: Cyanocobalamin or Methylcobalamin, due to its high stability, Cyanocobalamin is the most commonly used form. Methylcobalamin is less stable and is particularly prone to being destroyed by light.
The only major exception, however, could be kidney failure. Methylcobalamin may be better for people with impaired kidney function. It has been speculated that oral methylcobalamin or injected hydroxycobalamin may also be preferable for smokers, although this has not been confirmed yet.