B-12, one of the siblings of the B-complex family, is an important vitamin that may be overlooked among the many vitamins we need. It may be difficult to remember what vitamins are needed for what functions of the body and worry about our ability to ingest it all. Afterall, we can only eat so much food and unfortunately, the nutrient-scarce foods usually win the fight of who gets to be eaten. However, B-12 is not a particularly tough nutrient to consume, as its food sources are mostly animal based. For reasons explained below, absorption may be compromised.
This is why regular blood work is important to keep us afloat of our nutritional status and ensure we are not deficient in any vital nutrients.
B-12 is a water soluble vitamin (meaning you will urinate any extra out) that contains the mineral cobalt in its chemical structure. Methylcobalamin is the metabolically active form of B-12 (which means it will be absorbed more efficiently), while cyanocobalamin and hydroxycobalamin are the inactive forms and will only become active after they’re converted to methylcobalamin. Vitamin B-12 is required for the development, myelination (aka insulation), and function of the central nervous system (CNS); healthy red blood cell (RBC) formation; and DNA synthesis.
When you eat a food rich in B-12, the B-12 actually needs to be separated from the food protein in order for it to be absorbed in the body. This separation process begins in the mouth when food is mixed with saliva. It’s also separated and released by hydrochloric acid and gastric protease (aka an enzyme) in the stomach. This is why proton pump inhibitors (PPIs), the medication that lowers stomach acid production for those suffering from heartburn, may contribute to B-12 deficiency. The freed B-12 then combines with an intrinsic factor, a protein that helps transport the B-12 from the duodenum (initial segment of the small intestine) to the ileum (final segment of the small intestine) for final absorption.
One can assess their B-12 status through bloodwork by measuring serum/plasma vitamin B-12, methymalonic acid (MMA), or homocysteine levels. If a B-12 deficiency is evident, food sources or supplements can be taken to boost your level. Rich food sources include animal products, such as beef, fish, poultry, eggs, and dairy products. Not many plant sources contain B-12, but fortified breakfast cereals and nutritional yeast contain B-12 that has high bioavailability (which means it’s optimal for absorption.)
Causes of B-12 deficiency include dietary deficiency (vegans or vegetarians may be at risk for B-12 deficiency due to this reason due to their lack of animal food consumption), difficulty absorbing B-12 from food due to genetic mutations, lack of intrinsic factor (older adults are at risk for decreased production of intrinsic factor and secretion of hydrochloric acid in the stomach,) surgery in the gastrointestinal (GI) tract, GI disorders such as celiac disease or Crohn’s disease, and prolonged use of certain medications like PPIs and metformin for diabetes. Signs and symptoms of B-12 deficiency include low counts of white blood cells and platelets, glossitis of the tongue, fatigue, palpitations, pale skin, dementia, weight loss, infertility, numbness and tingling in the hands and feet, and megaloblastic anemia. This type of anemia occurs when low B-12 levels cause a reduction of RBC formation and prevent them from developing properly. Instead of the cells being small and round in shape, they develop into larger and more oval in shape. This irregularity causes an inability for the RBC to move from the bone marrow into the bloodstream, preventing optimal transport of RBC to vital organs. As a result, fatigue and weakness can occur.
Eating a varied diet can include many vitamins and minerals that are necessary for your body to function optimally. A varied diet includes healthy proteins, vegetables, fruits, and complex carbohydrates. These can all contribute to providing everything you need to feel and move your best!
Melissa Papir Kolb is a registered dietitian working in long-term care nutrition in Washington Heights. She works with middle-aged/elderly residents to provide nutrition that can help boost their quality of life. She loves to write about nutrition in her spare time. She can be reached at [email protected].
