Where is b12 absorbed in the body

Consequently, symptoms may be mild even when anemia is severe. If severe, anemia causes shortness of breath, dizziness, and a rapid heart rate. Occasionally, the spleen and liver enlarge.

Younger adults who have pernicious anemia due to lack of intrinsic factor are more likely to develop stomach and other gastrointestinal cancers. In people with nerve damage, the legs are affected earlier and more often than the arms.

Tingling is felt in the feet and hands, or sensation in the legs, feet, and hands is lost. Their arms and legs may feel weak. People become less able to tell where their arms and legs are position sense and to feel vibrations.

Mild to moderate muscle weakness develops, and reflexes may be lost. Walking becomes difficult. Some people become confused, irritable, and mildly depressed. Advanced vitamin B12 deficiency may lead to delirium, paranoia thinking that people intend to harm them , and impaired mental function, including dementia. Usually, vitamin B12 deficiency is suspected when routine blood tests detect large red blood cells.

Doctors sometimes suspect it when people have typical symptoms of nerve damage, such as tingling or loss of sensation. If the deficiency is suspected, the level of vitamin B12 in the blood is measured. Usually, doctors also measure the blood level of folate to rule out folate deficiency Folate Deficiency Folate deficiency is common.

Because the body stores only a small amount of folate, a diet lacking in folate leads to a deficiency within a few months. Not eating enough raw leafy vegetables If vitamin B12 deficiency is confirmed in an older person, no other tests are done because the cause, such as low stomach acidity, is usually not serious. In a younger person, other tests, including other blood tests, may be done to determine the cause.

Endoscopy use of a flexible viewing tube to directly examine internal structures may be done to check for destruction of stomach cells that produce intrinsic factor. For infants of vegan mothers, starting vitamin B12 supplements immediately after birth helps prevent vitamin B12 deficiency. Older people with vitamin B12 deficiency benefit from taking vitamin B12 supplements because the deficiency usually results from difficulty absorbing the vitamin from meat. They can absorb the vitamin more easily from supplements than from meat.

Treatment of vitamin B12 deficiency or pernicious anemia consists of high doses of vitamin B12 supplements. If people have the deficiency but no symptoms, the vitamin may be taken by mouth.

Blood tests are done periodically to make sure the vitamin B12 level returns to and remains normal. People who have very low levels of vitamin B12 or symptoms due to nerve damage are usually given vitamin B12 by injection into a muscle. Injections, which may be self-administered, are given daily or weekly for several weeks until the vitamin B12 level returns to normal. Then injections are given once a month indefinitely, unless the disorder causing the deficiency can be corrected.

Anemia usually resolves in about 6 weeks. But if severe symptoms due to nerve damage last for months or years, they may become permanent. In most older people with vitamin B12 deficiency and dementia, mental function does not improve after treatment.

Merck and Co. As a reminder, the chief cells within the stomach will secrete the pepsinogen into the lumen of the stomach. The presence of the hydrochloric acid also provided by the parietal cells is necessary to convert the pepsinogen to pepsin. The functionally active pepsin can then degrade the newly ingested protein source holding onto to the vitamin B Upon this protein degradation, the free vitamin B12 will then proceed as above to be bound to an R-binder or transcobalamin I for entry into the duodenum.

Therefore, regardless of the molecular state of vitamin B12 ingested, it is mostly delivered to the duodenum as a complex with an R-binder. Intrinsic factor is also present in the gastric and intestinal contents that contain the vitamin B12 complexed to R-binders and being delivered to the duodenum.

In addition to the hydrochloric acid secreted from the stomach, the properly functioning parietal cells also secrete intrinsic factor, however nothing is bound to the intrinsic factor at this point. Upon entry into the second segment of the duodenum, the pancreas will secrete additional protease, which will then degrade the R-binders holding onto the vitamin B It is at this point the vitamin B12 will bind to or complex with intrinsic factor for the remainder of its journey to the ileum of the small intestine for absorption.

In fact, the liver's storage of vitamin B12 is significant enough that it could take a year or more before deficiency of vitamin B12 manifests into clinically relevant pathology. About Us Disclaimer Contact Us. Also, you must produce sufficient amounts of intrinsic factor. Other factors include inadequate consumption of Brich foods and over-consumption of alcohol. Drinking too much alcohol can lead to inflammation of the stomach, causing stomach acid to decrease. Thus, absorption of B12 decreases.

Similarly, as you age, the amount of acid in your stomach decreases, which may lead to inadequate B12 absorption. Improving absorption begins with consuming adequate amounts of Brich foods including meat, poultry, fish, eggs, dairy and fortified products. Vitamin B12 is typically found in animal products, so consider taking B12 supplements if you are a vegan. Vitamin B12 supplements are not bound by a protein, so less stomach acid is needed to absorb the vitamin.

If you regularly consume more than the recommended intake of one serving of alcohol per day for women and two for men, cut back on consumption to increase absorption.