Vitamin B12 is a water-soluble vitamin that is part of the B-complex responsible for energy metabolism, red blood cell formation and neurological functioning. Vitamin D is a fat-soluble vitamin that is best known for having an interdependent relationship with calcium to aid in its absorption for the building and maintenance of strong bones and teeth. Vitamin D is also linked to improving immunity and decreasing inflammation. It is possible to become deficient in either one or both of these vitamins.
Deficiency of Vitamin B12
Vitamin B12 is a water-soluble vitamin, which means we need to consume this vitamin daily from food and supplementation. When taken in excess, it is excreted daily in the urine. Some people -- particularly older adults, those with pernicious anemia and those with reduced levels of stomach acidity or intestinal disorders -- have difficulty absorbing vitamin B12 and as a result, vitamin B12 deficiency is common, affecting between 1.5 percent and 15 percent of the general population, according to Medline Plus. Signs and symptoms of deficiency include fatigue, weakness, constipation, weight loss and neurological changes. Groups at risk for B12 deficiency include vegetarians, those with pernicious anemia, pregnant and lactating women and those who have had gastrointestinal surgery, including gastric bypass.
Deficiency of Vitamin D
Vitamin D is a fat soluble vitamin, which means the body stores any excess in its fatty tissue and liver. We can obtain vitamin D from dietary sources and synthesize it from direct sunlight. A vitamin D deficiency can occur when intake is lower than recommended levels over time, exposure to sunlight is limited, the kidneys cannot convert vitamin D to its active form or absorption of vitamin D from the digestive tract is inadequate, according to the National Institutes of Health. Symptoms of a vitamin D deficiency can include bone loss and muscle weakness. Bone loss can lead to osteopenia and osteoporosis over time, which can lead to an increased risk for fractures.
Lab Testing and Diagnosis
Vitamin deficiencies can be diagnosed by blood work and evaluation. Patients who experience signs and symptoms of a deficiency should consult their health-care provider, who will provide the appropriate testing. Treatment of a vitamin B12 and D deficiency includes taking such vitamins, usually at a higher dosage for a period of time and then repeating the blood work to assess if levels have reached a therapeutic range. Sometimes, vitamin B12 deficiencies may need to be treated with intramuscular injections of vitamin B12.