Do you need a vitamin B12 supplement?

b12 vitamin

Walk into any drugstore, supermarket, or big box store and you’ll be able to buy vitamin B12 supplements. Whether you need one or not, they are often promoted for improving memory loss, depression, neuropathy, or for preventing a possible deadly anemia associated with vitamin B12 deficiency.

The question is should you take a vitamin B12 supplement, what are signs of a B12 deficiency, and how much B12 would you need to take for maintenance or a deficiency?

A brief history of vitamin B12

Vitamin B12 has a rather interesting history.  It was the last of the vitamin B complex family to be discovered and was considered challenging at that. Before its discovery in 1926, a disease called pernicious anemia, a condition where the body is unable to make enough healthy red blood cells, not only caused patients to become tired and weak but also could be lethal.  In fact, Mary Todd Lincoln, wife of President Abraham Lincoln, is suspected to have died from pernicious anemia, long before its discovery. Annie Oakley, a famous markswoman known for her sharpshooting, did perish from pernicious anemia caused by the body’s inability to absorb B12 from the intestine, the same year it was discovered. It wasn’t until many years later that scientists learned how to treat pernicious anemia with injections of B12.

People who have a deficiency of B12 but not in the form of pernicious anemia can usually be treated but eating more B12-rich foods.

Why vitamin B12 is an essential nutrient

Cobalamin is the chemical name for vitamin B12 and is considered an essential B vitamin. Your body is unable to make vitamin B12 on its own therefore you must get it from food sources that contain it. This essential nutrient helps keep your brain and nerves healthy, makes DNA and red blood cells, and helps lower levels of homocysteine, an amino acid that when elevated, is linked to dementia, heart disease, stroke, and osteoporosis.

Your main dietary source of vitamin B12 is animal-based foods of beef, liver, clams, poultry, fish, fortified cereals, eggs, cheese, yogurt, milk, and fortified plant-based dairy alternatives like soy, almond, or rice.

In order to absorb and digest vitamin B12, it has to be freed up from the food that contains it. Acids in your stomach help this process by binding to a protein called intrinsic factor produced by cells in the stomach lining.

Why some people may have a deficiency of vitamin B12

There are multiple reasons why someone may develop vitamin B12 deficiency with growing older is the main cause. It’s estimated that 3.2% of people over the age of 50 have very low B12 levels and up to 20% may have a borderline deficiency. Aging causes us to produce less stomach acid which means the less intrinsic factor is made and therefore making it harder to extract B12 from food. People who are unable to make enough intrinsic factors and therefore are unable to absorb any B12 from the intestine will likely go on to develop pernicious anemia.

Other causes of vitamin B12 deficiency include:

  • Following a vegan diet that allows no animal-based foods
  • Weight loss surgery
  • Autoimmune diseases such as Crohn’s or celiac disease that attaches the stomach lining or gastrointestinal lining
  • Taking heartburn medications like proton-pump inhibitors that suppress stomach acid necessary for food to release B12 or taking the diabetes drug, Metformin, may also interfere with B12 absorption

There are several signs of a B12 deficiency:

  • Balance problems
  • Depression
  • Extreme fatigue or muscle weakness
  • Memory loss or confusion
  • Numbness or tingling in hands or legs brought on by nerve damage
  • Anemia

Checking for vitamin B12 deficiency

For most people who eat a balanced diet that includes animal foods, a vitamin B12 deficiency is rare. But if you are exhibiting signs of possible B12 deficiency or are 65 years of age or older, a simple blood test can check B12 levels confirming the status of your levels. In fact, some doctors will automatically check vitamin B12 levels in all patients starting at age 65 and then every three to four years. The blood test will look for markers of anemia, low levels of B12, and high levels of homocysteine and methylmalonic acid (MMA) to make a determination of a deficiency or not.

Generally, a normal level of vitamin B12 in the blood is between 190 and 950 picograms per milliliter (pg/mL).  It’s considered borderline if you test between 200 to 300 pg/mL and low is any number less than 200 pg/mL.

Treating vitamin B12 deficiency

Depending on whether you have low levels of vitamin B12 due to poor food choices or pernicious anemia will depend on the treatment recommended.

If your B12 deficiency is due to a lack of eating animal products or using too many heartburn medications, you may be told to simply increase your intake of more B12-rich foods. You may also be advised to take an over-the-counter B12 supplement of 1,000 micrograms daily if B12 is borderline low or MMA is borderline high. Once the level returns to normal, the supplement can either be reduced or stopped.

It’s recommended to take the natural form of a B12 supplement which is methylcobalamin and not the synthetic form which is cyanocobalamin since cyanocobalamin may impair kidney functioning.

If your B12 deficiency is due to pernicious anemia, B12 injections may be required since B12 supplements may not work.

Anyone with concerns of having a B12 deficiency should discuss with their doctor first whether to take a B12 supplement or not. Supplements are generally inexpensive and can help safeguard a possible deficiency if animal-based foods are not eaten very often or a person is a vegan.

Do you need a vitamin B12 supplement?
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Dr. David Samadi

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1 comment

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  • Hi,

    I have been taking this B-12 for few months.

    It does help my condition as you explain in this article.

    Thanks a lot for this valuable information.



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Dr. David Samadi