Yes, they're both B vitamins. Yes, they're both needed to make new cells. And yes, not getting enough of either vitamin in your diet can lead to anemia. While there are several similarities between vitamin B-12 and folic acid, there are also a number of differences. Knowing the differences between the two B vitamins might help you understand the individual importance of getting both in your diet.
One of the major differences between vitamin B-12 and folic acid are its primary food sources. Vitamin B-12 is predominantly found in animal foods such as meat, poultry, fish, eggs and milk. In fact, if you are a vegan -- someone who doesn't eat any animal products -- you may need to take vitamin B-12 supplements to meet your daily needs. While you can meet some of your daily folic acid needs eating chicken and eggs, better food sources include dark green vegetables, fruits, beans, nuts and seeds. The one food similarity both folic acid and vitamin B-12 share is that beef liver is the best source for both.
Functions in the Body
Both vitamin B-12 and folic acid are necessary for DNA synthesis and red blood cell formation. But vitamin B-12 has an additional role in your body; it is necessary for proper neurological function. Not getting enough vitamin B-12 in your diet can cause neurological problems such as tingling and numbness in your hands and feet. Folic acid plays an important role for women of childbearing age, especially during pregnancy. Women need adequate intakes of folic acid before and during pregnancy to prevent neural tube defects.
From Food to Bloodstream
How your body gets the vitamin B-12 and folic acid from the food you eat to your bloodstream also differs. The vitamin B-12 found in food is bound to a protein. The acid and enzymes in your stomach help break the bond between the protein and vitamin B-12, readying it for absorption. But before that happens, it must first bond with a substance secreted in your stomach called intrinsic factor. The vitamin B-12 and intrinsic factor are then transported to your small intestines, where the vitamin is absorbed into your bloodstream. Folic acid does not require as many steps to get into your bloodstream as vitamin B-12. When folic acid hits your stomach, it is hydrolyzed and then absorbed in your small intestines.
Signs of Deficiency
Deficiency symptoms differ between the two vitamins. If you're not getting enough vitamin B-12 in your diet, symptoms might include fatigue, weakness, loss of appetite, weight loss and constipation, in addition to the neurological symptoms. You might also experience depression, confusion or problems with your memory if your vitamin B-12 levels are low. While you may also experience fatigue with inadequate intakes of folic acid, additional deficiency symptoms might include heart palpitations, irritability and shortness of breath. Folic acid deficiency can also cause changes to your hair and skin, as well as fingernail discoloration.
Not getting enough vitamin B-12 or folic acid can cause megaloblastic anemia, which is when your body produces abnormally large red blood cells. However, there is an additional anemia that is only associated with vitamin B-12 known as pernicious anemia, which is an anemia caused by a lack of intrinsic factor. Because you cannot absorb vitamin B-12 from food without intrinsic factor, the only treatment for pernicious anemia is vitamin B-12 pills or shots.