Posted 3 years ago

B12 Deficiency – Are you at risk?

Vitamin B12 is a very important nutrient in human health.  Many people associate vitamin B12 with being the energy vitamin, but it is responsible for many more factors in health than just energy.  Vitamin B12 plays an important role in the health of the nervous system, blood system and hormone balance.   Low levels of Vitamin B12 can cause a variety of vague symptoms that many times go undiagnosed.   It is important to be aware or your risk for having a low vitamin B12 level so that you can be on the lookout for potential signs and symptoms of vitamin B12 deficiency.

Signs of B12 Deficiency:

B12 is a critical nutrient for our nervous system.  Deficient levels can cause a whole host of symptoms, including numbness and tingling in the hands and feet, memory problems, depression, and fatigue.   In some cases, these neurological changes can be permanent.

Low levels of Vitamin B12 can also lead to anemia, constipation, changes in menstrual periods, loss of appetite and weight loss.

Where does it come from?

Vitamin B12 is a water-soluble vitamin that we obtain from our diet through foods such as fish, meat, dairy products, and eggs.  The body can store a 2–5-year supply of this vitamin in the liver but prolonged low intake can lead to deficiency.

Who is at Risk? 

Since the main foods that provide Vitamin B12 in our diet are animal sources, vegetarians/vegans are at significant risk for Vitamin B12 deficiency.  For the body to absorb B12 from the foods we eat, it must first bind with intrinsic factor, a substance produced stomach lining cells.  People who have had weight loss surgery are at increased risk for B12 deficiency as our individuals with digestive disease like Chron’s and Celiac disease.   Certain medicines can also cause issues with B12 levels like metformin for diabetes and acid reducing medicines like Prilosec and Pepcid.


B12 levels can be assessed with a blood test.  Most labs will note that a normal level is between 200-900 pg per mL but optimal levels are in the 500-900 pg per mL range.   There are a number of factors that may interfere with B12 lab values such as liver disease or other vitamin deficiencies, so other testing that includes homocysteine and methylmalonic acid levels, can help give a more complete answer.

Replacing Vitamin B12

Vitamin B12 can be given as a supplement in several ways – through an injection in the muscle, as a dissolvable pill or liquid given under tongue or as a pill to be swallowed.  For people with very low B12 levels or who are having serious symptoms from B12 deficiency, the injectable form is the quickest way to replace B12 levels and relieve symptoms.  Those with only mild deficiency or mild symptoms can use either an under the tongue supplement or oral tablets/capsules.  General dose recommendations for at risk individuals are to get 25-100 mcg a day, but  patients who have had weight loss are advised to take 1000 mcg daily.

Nutritional deficiencies, like Vitamin B12 deficiency, can cause a number of serious illnesses that are preventable by getting a balanced diet and monitoring blood levels of individuals that are at risk.  People who are risk for deficiency should consider taking a B12 supplement and be on the lookout for signs that there B12 level is running low.

Dr. Heidi Rula Integrative Oncologist Ironwood Cancer & Research CentersDr. Heidi Rula Joined Ironwood In 2018 To Launch The  Integrative Oncology Program. She Is Board Certified In Family Medicine And Fellowship-Trained In Integrative Medicine. Dr. Rula Has Been A Practicing Physician In The Phoenix Area For Approximately 20 Years And Has Been Recognized By Her Colleagues As One Of Phoenix’s “Top Doctors” On Multiple Occasions.

Dr. Rula has played a key role in bringing integrative medicine to the Valley. She served as the medical director of the University of Arizona Integrative Health Center, where she leads a team of physicians and complementary practitioners in a unique model of integrative primary care that she helped to develop along with Dr. Weil and the UA Center for Integrative Medicine.

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