Vitamin B-12 is one of eight B vitamins that make up the B complex. It plays a crucial role in helping your body produce new cells, including red blood cells, which carry oxygen and nutrients throughout your body. B-12 exists in several forms collectively known as cobalamins, which contain the mineral element cobalt. Your body absorbs B-12 from the food you eat with the help of acids and enzymes.
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In food, vitamin B-12 is bound to protein. Your body uses pepsin, an enzyme, to break protein into its component amino acids. The release of pepsin is stimulated by a gastric substance called hydrochloric acid. Pepsin is one of three enzymes that help digest protein, the other two being trypsin and chymotrypsin. If your body is not producing enough pepsin, it would be challenging for you to absorb B-12.
Intrinsic factor is a protein produced by cells in your stomach lining. It is needed for your intestines to absorb B-12. After B-12 is released by hydrochloric acid and pepsin, pancreatic enzymes bind to B-12 for further digestion, then release B-12 for intrinsic factor to bind to it, which then transports it to your bloodstream. Pernicious anemia is when you lack intrinsic factor because your immune system dispatches antibodies to attack intrinsic factor, causing deficiency.
Some individuals do not produce enough acid, pepsin or intrinsic factor to digest sufficient amounts of B-12 from their diet. Sublingual B-12 is available as a dietary supplement and is designed to bypass stomach digestion. You generally allow the sublingual tablet to dissolve under your tongue, where it is transported to your bloodstream by veins under your tongue. This might help improve absorption, if you have gastric issues.
If you have pernicious anemia, it is a lifelong condition. Your body is unable to digest B-12 from the food you eat, making it necessary to supplement. Your doctor will primarily prescribe B-12 injections, which are injected into your muscle and are quickly absorbed into your bloodstream. Alternatives to B-12 injections include transdermal patches that are worn for 24 to 48 hours and slowly release B-12, which is transferred through your skin into your bloodstream.
Because B-12 absorption depends on gastric acids and special enzymes, you increase your risk of developing B-12 deficiency if you consume alcohol frequently, which can destroy these enzymes. Stomach surgeries compromise your ability to absorb B-12 efficiently as well. Consult your doctor regarding your B-12 absorption if you have had stomach surgery.