Because B12 comes from animal sources, vegans and vegetarians typically have the lowest B12 intake. This often results in B12 deficiency which is associated with higher homocysteine levels in the blood . Elevated homocysteine is a risk factor for heart disease, stroke and osteoporosis.[2]
Women who are pregnant have an increased need for Vitamin B12. Deficiency of B12 during pregnancy has been associated with risk of preterm birth. Adequate folate intake in a healthful diet during early pregnancy may reduce the risk of serious brain or spinal cord birth defects. Folate, B12 and choline are especially important to promote normal brain development. [3,4,5]
About one third of people with Type 2 Diabetes who take a biguanide medication may develop vitamin B12 deficiency. Research demonstrates that B12 deficiency is a factor in a common complication of diabetes called peripheral neuropathy, which responds to B12 supplementation.[6]
As acidity decreases in the stomach due to use of antacids , PPIs or H2 blockers used for GERD or acid reflux, less Intrinsic Factor is made by the body which reduces absorption of B12. This also happens when the stomach lining gets thinner as people grow older.[7,8]
The most well-known autoimmune disease associated with B12 deficiency is Pernicious Anemia. Over time, antibodies destroy the Intrinsic Factor or the cells in the stomach that make it. Other autoimmune diseases like thyroiditis or vitiligo increase the risk of developing Pernicious Anemia - which requires injections of B12 prescribed by healthcare practitioners to treat effectively.[9]
There are over 200,000 gastric bypass surgeries performed in the US every year. Many of the most popular surgeries remove the part of the stomach that makes Intrinsic Factor which causes a lifelong dependence on B12 supplementation.[10,11]
