The time it takes to feel results from a B-12 injection can vary depending on the individual and the severity of the deficiency
Finally, pernicious anemia is an autoimmune disease that affects B12 absorption and can result in a deficiency of this vital nutrient
However, major expert groups have looked at the research and concluded that: The evidence is not sufficient to show that screening every adult without symptoms for vitamin D deficiency clearly improves outcomes such as fractures, heart disease or cancer

People with symptoms of vitamin B12 deficiency It is a good idea for anyone with the following signs and symptoms of a vitamin B12 deficiency or pernicious anemia to consult a doctor: People with gastrointestinal issues Conditions that affect the gastrointestinal tract may affect vitamin B12 release or absorption, including: pernicious anemia, which can lead to gastric atrophy, or damage to the stomach fish tapeworm infestation bowel or pancreatic cancer folic acid deficiency overgrowth of bacteria in the small intestine diabetes thyroid disease Crohns disease celiac disease chronic pancreatitis People who have undergone gastrointestinal surgery, including weight loss, may have fewer cells necessary to secrete stomach acid and intrinsic factor
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