Ask Dr. Louise

A few years ago, one of my patients, a retired Marine mentioned how he had been suffering from shooting and burning pains in his legs and feet for the last few years, and although his doctor tried several different pain medicines, none had really helped. Then one day his feet and legs stopped hurting so much. 

“The only thing I did differently that week was start a new vitamin that happened to have a lot of vitamin B12 in it. Week after week, I kept expecting the pain to come back, but it’s been over 6 months and I’m still mostly pain-free. But I still take that vitamin, just in case.”

Vitamin B12 is a water-soluble B vitamin that helps your nerves work and also helps your body make new red blood cells, which can prevent a certain type of anemia. A deficiency in vitamin B12 can show up as fatigue, weakness, depression or pain in your feet or hands. The most common factors that contribute to vitamin B12 deficiency are age, diet and medicines. 

According to the National Institutes of Health (NIH), vitamin B12 is found mostly in animal proteins, such as fish, meat, poultry, eggs, milk, and milk products. 

Most healthy adults get enough vitamin B12 in their diet; those who don’t either don’t have much animal protein in their diet or aren’t able to absorb vitamin B12 very well. 

Strict vegetarians may not get enough animal protein in their diet to satisfy the recommendation of 1 to 2 mcg daily of vitamin B12. Others become deficient because they cannot absorb it very well, like the elderly, those who have had gastric bypass surgery and people who take certain medicines.

The most common cause of vitamin B12 deficiency is not being able to absorb enough of it from your food. This can be due to a condition called atrophic gastritis, which affects 10-30% of the elderly. Atrophic gastritis interferes with the ability to absorb vitamin B12 from your food because it decreases secretion of digestive juices such as gastric acid. 

Gastric acid is critically important in being able to absorb vitamin B12, which is usually attached to animal proteins like ground meat or chicken. Without enough stomach acid, your body can’t break down the proteins enough for the vitamin B12 to be absorbed into your body. 

Most people who can absorb vitamin B12 well only require 1 or 2 mcg daily. If you are over 70, take medicine for heartburn or an ulcer or have had gastric bypass surgery, you may need more than that. 1000-2000mcg daily of vitamin B12 as an oral or a sublingual tablet can overcome poor absorption. 

Medicines that can contribute to poor absorption and deficiency of vitamin B12 include acid-reducing medicines such as Prilosec® (also known as omeprazole), Prevacid® (also known as lansoprazole), Protonix® or Nexium®. Older acid-blocking medicines which also impair absorption of vitamin B12 include Zantac® (ranitidine), Pepcid® or Axid®. Metformin, a common pill for diabetes can also interfere with your body’s ability to absorb vitamin B12. 

A deficiency in vitamin B12 can show up as fatigue, weakness, depression or pain in your feet or hands. If you are noticing these symptoms, talk to your doctor. Vitamin B12 deficiency can be detected with a blood test. Your doctor or medical provider can advise you if you need tested, and which supplement would be best for you to take, and how much.

Here are 4 tips on getting enough vitamin B12

1. Include fortified breakfast cereals in your diet if you are vegetarian or vegan. Since vitamin B12 isn’t found in plant foods, the National Institutes of Health (NIH) suggests including fortified breakfast cereals in your diet as an alternative source of vitamin B12 if you are vegetarian or vegan.

2. Stomach acid helps you absorb vitamin B12 from your food. To avoid becoming deficient in vitamin B12, minimize your use of medicines that work to reduce stomach acid, including Prilosec® (also known as omeprazole), Prevacid® (also known as lansoprazole), Protonix®, and Nexium®, along with older medicines like Tagamet® (cimetidine), Zantac® (ranitidine), Pepcid® (famotidine) or Axid® (nizatidine).

3. Oral and sublingual vitamin B12 supplements are inexpensive and don’t require a prescription. Most people with vitamin B12 deficiency can safely take 1000-2000 mcg daily of vitamin B12 as a supplement. 

4. Avoid the timed-release or long-acting products of vitamin B12, because they may not be as well absorbed as immediate release forms.

There’s more information about vitamin B12 at the NIH website www.nih.gov. 

Dr. Louise Achey, Doctor of Pharmacy is a 39-year veteran of pharmacology and author of Why Dogs Can’t Eat Chocolate: How Medicines Work and How YOU Can Take Them Safely. Your questions and comments are always welcome at www.AskDrLouise.com.

©2018 Louise Achey