Vitamin B12 Supplement Facts: Do You Need to Take One?

Vegans, vegetarians and older adults over 65 are those most at risk and may benefit greatly from dietary supplementation.

When concentrations in the body are low you may feel tired, numbness or tingling, light headedness, low appetite, trouble with balance, cognitive impairment, cardiovascular issues and depression.

Here, we'll break down the topic of B12 supplementation and explore the most common subjects often discussed when it comes to this much needed nutrient.

A vitamin B12 supplement is typically available in sublingual forms. This means it's ideally placed under the tongue, where it can mix with saliva and rapidly enter the system.

For this reason, it’s usually found as lozenges, chewables, liquid drops or sprays as opposed to a vitamin that you swallow whole.

Once dissolved in the mouth, most will enter the bloodstream directly through the mucus membranes. Since it tends to bypass the GI tract, it can be great for older adults or those with digestive disorders or low stomach acid.

Vitamin B12 isn't made by the body but needs to be replenished regularly from food sources like meat, dairy, eggs and seafood.

The highest sources are organ meats and shellfish, especially liver and clams.

But, because protein-bound B12 in these foods can be harder to break down, carnivores also might also need to supplement. Digestive enzymes can also help in this arena. Absorption rate may likewise be limited in older adult meat eaters who tend to produce less of the necessary "intrinsic factor" required to assimilate it.

B12 is not present in plant-based foods, so sometimes, food products and milk alternatives are fortified with this vitamin.

Fortified nutritional yeast is a common example in which B12 (in the form of cyanocobalamin) is added along with other B-vitamins.

There are some plant-based foods like tempeh, dried shiitake, nori and chlorella that can contain B12. However, this is only because they uptake B12 from the cultures in growing mediums or contain the bacteria that create it. Because amounts can vary widely, they are not considered reliable sources.

Since B12 is produced by bacteria, some vegans speculate that a healthy gut microbiome can likewise generate its own B12, especially in the colon where the highest microbial density exists.

However, B12 first enters the small intestine where major absorption occurs in the ileum, rather than the colon. So, some argue that this makes it unavailable for nutrient uptake. It would be interesting in the future to see more research on this theory.

Vitamin B12 is measured in micrograms (mcg or μg).

The Recommended Dietary Allowances (RDA) for adults is 2.4 micrograms (mcg) per day, and 2.6 micrograms for pregnancy and 2.8 micrograms for lactation.

Older adults over 65 may require more like 10 to 12 mcg/day as the body's ability to absorb it declines with age.

You will likely notice that most B12 supplements offer serving amounts way over the recommended daily requirements.

Often thousands of micrograms (mcg) over. Extra strength supplements can be up to 2,500 to 5,000 mcg per serving.

This is primarily because the percentage absorbed is usually a very small percentage of the total ingested

Higher doses help to ensure adequate uptake, especially if you are malnourished in this essential vitamin.

Because B12 is a water-soluble vitamin, it is very hard to overdose on a vitamin B12 supplement. Any excess is often excreted via the urine. Therefore, large doses are generally considered non-toxic.

In rare cases, extremely high amounts may cause nausea or gastrointestinal upset.

The best way to confirm if you have a vitamin B12 deficiency is to get tested by a healthcare professional.

This often involves a simple blood test for serum B12, which is usually accompanied by measuring your homocysteine and methylmalonic acid levels. Usually, when elevated serum homocysteine is over 15 micromol/L and methylmalonic acid (MMA) is over 0.271 micromol/L there is a B12 deficiency.

If you happen to notice any of the related symptoms, it is definitely a good idea to do such testing to rule out the possibility.

You can try eating more foods rich in B12 to correct deficiencies but in most cases, supplementation can be necessary to replenish this very important nutrient.