Vitamin B12, also known as cobalamin, is a water-soluble vitamin that is essential for red blood cell production, normal cellular metabolism and is a key factor in the production of DNA, your unique genetic blueprint. B12 is unique in that it is only naturally found in animal products such as meat, poultry and dairy. However, vegetarian and vegan fortified sources are available [i].
Women and men age 19 and older: 2.4 mcg/day
Vitamin B12 is absorbed by the body in the lower part of the small intestine and requires the protein, intrinsic factor, from the stomach in order to be absorbed. Vitamin B12 requires proper gastrointestinal function in order to be absorbed, and thus gastrointestinal cancers can have a greater risk of vitamin B12 deficiency [i]. Vitamin B12 may have the ability to alleviate certain side effects of chemotherapy including numbness and tingling of the hands and feet, decreased energy levels and cognitive changes also known as “brain-fog” .
Vitamin B12 Deficiencies
Vitamin B12 deficiency is commonly referred to as megaloblastic anemia. Those affected may experience increased weakness, fatigue, and constipation, decreased appetite, weight loss and various neurological issues such as tingling and numbness in the extremities, poor memory and confusion [i, iii]. A B12 deficiency is usually caused by an impairment in the body’s ability to absorbed the vitamin from food sources or poor intake of B12-rich foods [i]. An overall, well-balanced diet will include enough B12 from food sources. B12 fortified foods and a B12 supplement may be recommended for vegans.
** If instructed by a medical professional to take a vitamin or mineral supplement, it is important that these instructions are followed. In some cases, food sources of vitamins and minerals will not be sufficient for addressing nutritional inadequacies. **
Sources of Vitamin B12
Below is a list of the most common food sources of vitamin B12:
- Fortified breakfast cereals
- Some brands of nutritional yeast
- 8 pounds cherrystone clams, scrubbed clean or two 10 ounces cans canned clams and 6 cups of bottled clam juice
- 1 tablespoon unsalted butter
- 2 celery stalks, chopped
- 1 large onion, chopped
- 1 garlic clove, minced
- 2 ½ pounds of potato, peeled and cut into ½ inch pieces
- 1 tablespoon chopped fresh thyme
- 1 bay leaf
- 2 tablespoons cornstarch
- 1 cup heavy cream
- 1 cup 2% milk
- Salt and pepper to taste
- Chopped fresh chives (optional)
- Oyster crackers (optional)
- Bring clams and 4 cups of water to a boil in a large pot. Cook until the clams open, (8-10 minutes, discard any that remain closed). Using a slotted spoon, transfer the clams to a baking sheet and let cool. When able to handle, pull the meat from the shells.
- Chop the clams into bite-size pieces. Strain the broth through a mesh colander. Add additional water so that broth equals 6 cups of fluid. If using canned clams you may skip steps 1 and 2.
- In a large pot, melt butter over medium heat. Add celery, onion and garlic and stir often, cook until onions are translucent (about 10 minutes). Add the reserved broth (or 6 cups of clam juice), potatoes, thyme and bay leaf. Bring the chowder to a simmer and cook until the potatoes are tender (about 20-25 minutes). Stir cornstarch and 2 tablespoons of water in a small bowl to form a slurry. Add the slurry to the chowder base and return to a boil to thicken.
- Remove the pot from the heat to avoid curdling the milk. Remove the bay leaf. Stir in the chopped clams and cream. Season with salt and pepper to taste.
- Garnish with chives and oyster crackers
[i] Vitamin B12: Fact Sheet for Health Professional 2018; https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/#h5.
[ii] King J. Vitamin B12 & Chemotherapy 2017; https://www.livestrong.com/article/205690-chemotherapy-contraindications/.
[iii] Skerrett P. Vitamin B12 Can By Sneaky, Harmful Harvard Health Blog 2013; https://www.health.harvard.edu/blog/vitamin-b12-deficiency-can-be-sneaky-harmful-201301105780.