Vitamin B-12 distinguishes itself from other vitamins with several unique characteristics. For example, it's the only water-soluble vitamin stored in your body. It's also produced by bacteria, so it's primarily found in animal foods, such as fish, meat, poultry and dairy products. In its natural form, vitamin B-12 is attached to a protein, which means it's digested differently than other vitamins. This difference also limits the amount you can absorb at one time.
Vitamin B-12 Basics
Your body depends on vitamin B-12 to make DNA, synthesize red blood cells and keep nerves working. Lack of the vitamin results in anemia and potentially irreversible neurological problems, reports the Office of Dietary Supplements. While most people consume the recommended dietary allowance -- 2.4 micrograms daily -- malabsorption may cause a deficiency. Before your body can absorb the vitamin B-12 you get from food, it must be separated from its attached protein. This step happens in your stomach and depends on stomach acid and digestive enzymes that work in your stomach.
Consume Frequent But Smaller Portions
After vitamin B-12 is separated from its protein, it binds with another substance produced by your body called intrinsic factor. The amount of vitamin B-12 you can absorb is limited by the availability of intrinsic factor. The Office of Dietary Supplements reports that you won't have enough intrinsic factor left to absorb vitamin B-12 after consuming 1 to 2 micrograms of the vitamin, which is the amount you'll get from a cup of yogurt or a serving of beef. You’ll optimize absorption by consuming smaller amounts of vitamin B-12 at every meal rather than eating a large portion of B-12-rich food at one meal.
Choose Fortified Foods
You can increase the amount absorbed by choosing foods that are fortified with vitamin B-12. The synthetic form of B-12 used to fortify foods, and to make supplements, is not attached to a protein. As a result, it doesn’t need to go through the extra digestive steps in your stomach, and it's easier to absorb. Most ready-to-eat cereals and some brands of soy milk and meat substitutes are fortified with B-12. The amount varies, however, so check the labels to see how much is in the brand you buy.
Watch Acid-Reducing Products
Antacids neutralize stomach acid, while proton pump inhibitors shut down the production of stomach acid. Without stomach acid, you won’t absorb vitamin B-12 from foods. You should take antacids an hour after you eat, according to MedlinePlus. If you take proton pump inhibitors, drink cranberry or grapefruit juice with your meals because their acidity may offset the lack of stomach acid and improve vitamin B-12 absorption, suggests the University of Michigan Health System. If you take any medications that alter your stomach's acidity, however, talk to your doctor about the best way to ensure you get enough vitamin B-12.