Overview
Vitamin B9, also known as folate or folic acid, is one of 8 B vitamins. All B vitamins help the body convert carbohydrates into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body use fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly. Folic acid is the synthetic form of B9, found in supplements and fortified foods, while folate occurs naturally in foods. We will refer to both terms interchangeably below.
All the B vitamins are water-soluble, meaning that they must be taken each day as the body does not store them .
Folic acid is crucial for proper brain function and plays an important role in mental and emotional health. It aids in the production of DNA and RNA, the body’s genetic material, and is especially important when cells and tissues are growing rapidly, such as in infancy, adolescence, and pregnancy. Folic acid also works closely with vitamin B12 to help make red blood cells and help iron work properly in the body.
Vitamin B9 works with vitamins B6 and B12 and other nutrients to control blood levels of the amino acid homocysteine. High levels of homocysteine are associated with heart disease.
It is fairly common to have low levels of folic acid. Alcoholism, inflammatory bowel disease, and celiac disease can cause folic acid deficiency. Also, certain medications may lower levels of folic acid in the body. Folic acid deficiency can cause poor growth, tongue inflammation, gingivitis, loss of appetite, shortness of breath, diarrhea, irritability, forgetfulness, and mental sluggishness.
Pregnant women need more folic acid to lower the risk of neural tube birth defects, including cleft palate, spina bifida, and brain damage. Neural tube defects are birth defects caused by abnormal development of the neural tube, a structure that eventually gives rise to the brain and spinal cord. Since folic acid has been added to many grain foods in the U.S., such as bread and cereal, neural tube defects have decreased dramatically.
Birth Defects
As mentioned, pregnant women who don’t get enough folic acid are more likely to have children with birth defects. Pregnant women should get 600 mcg of folic acid per day. Women who plan to become pregnant should make sure to get the recommended 400 mcg per day, since many neural tube defects can happen shortly after conception, before a woman even knows she is pregnant.
Studies show that women who take folic acid supplements before conception and during the first trimester may reduce their risk of having children with neural tube defects by 72 – 100%. Folic acid may also help prevent miscarriage, although the evidence isn’t clear.
Heart Disease
Folate may help protect the heart through several methods. First, there is some evidence that getting enough folic acid in your diet can reduce your risk of heart disease, although this evidence is based on population studies and not more definitive clinical trials.
Also, many studies suggest that people with high levels of the amino acid homocysteine are roughly 1.7 times more likely to develop coronary artery disease and 2.5 times more likely to have a stroke than those with normal levels. B complex vitamins, especially vitamins B9, B6, and B12, help lower homocysteine levels.
Age-related Hearing Loss
One study suggests that folic acid supplements help slow the progression of age-related hearing loss in elderly people with high homocysteine levels and low folate in their diet. It isn’t known whether healthy seniors would benefit.
Age-Related Macular Degeneration
One large study found that women who took 2,500 mcg of folic acid along with 500 mg of vitamin B6 and 1,000 mcg of cyanocobalamin (vitamin B12) daily reduced their risk of developing AMD, an eye disease that can cause loss of vision.
Depression
There are myriad causes for depression but some studies show that 15 – 38% of people with depression have low folate levels in their bodies, and those with very low levels tend to be the most depressed. Supplementation of folate and other nutrients through food or food-based supplements may assist this condition.
Cancer
Folic acid in the diet seems to protect against the development of some forms of cancer, particularly cancer of the colon, as well as breast, cervical, pancreatic, and stomach. However, this evidence is based on population studies that show people who get enough folate in their diet have lower rates of these cancers. Researchers don’t know exactly how folate might help prevent cancer. Some think that folic acid keeps DNA healthy and prevents mutations that can lead to cancer. Low dietary intake of folate may increase the risk of developing breast cancer, particularly for women who drink alcohol. Regular use of alcohol — more than 1 ½ to 2 glasses per day — is associated with higher risk of breast cancer. One large study, involving over 50,000 women who were followed over time, suggests that adequate intake of folate may reduce the risk of breast cancer associated with alcohol.
Dietary Sources
Rich sources of folate include spinach, dark leafy greens, asparagus, turnip, beets, and mustard greens, Brussels sprouts, lima beans, soybeans, beef liver, brewer’s yeast, root vegetables, whole grains, wheat germ, bulgur wheat, kidney beans, white beans, lima beans, mung beans, salmon, orange juice, avocado, and milk.
Safety limits
The Council for Responsible Nutrition recommends an upper limit of 1,000 µg (1.25 mg) per day.
Sources
University of Maryland Medical Center
The Council for Responsible Nutrition
