May 18, 2015

Folate and Cancer

By cancerconnect

Found in many fruits and vegetables and in supplemental form, folate can play an important role in a well-balanced diet.

Eating a well-balanced, plant-based diet may reduce your risk of developing certain forms of cancer. Research has shown that eating fruits and vegetables rich in folate is associated with a reduced risk of certain types of cancer. Specifically, folate and folic acid have been linked with potential reductions in the risk of breast, colon, rectal, and pancreatic cancers.

What Is Folate?

Folate is a naturally present B vitamin that is water-soluble. Folic acid is the synthetic form of folate; and because foods are sometimes fortified with folic acid, this form makes up a large part of the dietary intake in the United States.

The body absorbs and utilizes folic acid twice as efficiently as it does food sources of folate. Because they play an integral part in making DNA and RNA, folate and folic acid are responsible for producing and maintaining red blood cells. Proper red blood cell production serves important functions, including the prevention of anemia. Folate is also responsible for producing levels of homocysteine (an amino acid in the blood).

Food Sources of Folate

The best food sources of folate are green leafy vegetables such as spinach. Oranges and strawberries are also excellent sources of folate, as are some other fruits. Other foods that are rich in folate are legumes, such as dried peas and beans.

Folic acid was added to the U.S. food supply in the mid-1990s as a way to reduce the amount of neural tube defects in U.S. infants. These folic acid–enriched foods include dried cereal, white rice, and pasta; and the folic acid in these fortified foods is easier to absorb than the folate naturally present in other foods.

Daily Requirements of Folate

To prevent deficiencies in folate, a recommended daily allowance (RDA) has been established. Children between the ages of one and three need 150 micrograms (mcg) of folate per day. From ages four to eight, the RDA is 200 mcg. Teens ages nine to 13 need 300 mcg a day, whereas those 14 and older need 400 mcg. For women who are pregnant, the RDA is 600 mcg; if nursing, 500 mcg.

If one’s diet is lacking in folate or folic acid, the following may occur: increased risk of neural tube defects in infants, anemia induced by folate deficiency (which can occur as weakness), sore tongue, headaches, irritability, memory problems, and behavioral issues. A lack of folate in the blood stream can also cause an increase in homocysteine, which increases the risk of developing heart disease.

People who are pregnant, abuse alcohol, have malabsorption problems, or suffer from kidney or liver disease have an increased need for folate through diet or supplementation. Taking certain medications may also impair folate absorption, which can increase need. These medications include: Dilantin® (phenytoin), Mysoline® (primidone), Fortamet® (metformin), Azulfidine® (sulfasalazine), Dyrenium® (triamterene), Rheumatrex® (methotrexate), and some barbiturates.

Taking large doses of folate or folic acid is not recommended because it may cause a lack of vitamin B12. The upper limit for folate in adults is 1,000 mcg per day unless instructed differently by a physician. A lack of vitamin B12 can present as another form of anemia and if not treated may result in permanent nerve damage.

Reducing Cancer Risk with Increased Folate Intake

Research has shown that a diet lacking in folate appears to increase the risk of developing breast, colon, and pancreatic cancers. The most confirmatory evidence of this was seen in the Nurse’s Health Study, when researchers followed the dietary habits of 88,000 women over a 14-year period. Researchers found that older women (ages 55 to 69) who consumed adequate amounts of folate through diet and a multivitamin had a lower risk of developing colon cancer. Another study found that Chinese women who consumed diets highest in folate or folic acid had a lower risk of breast cancer compared with their counterparts who consumed low amounts of folate. It’s also noted that alcohol negates the positive effect of folate in the diet. Researchers state that although these studies show promising results, more research needs to be done to establish a causal relationship.


Eating a healthy diet rich in fruits and vegetables is an important way to reduce the risk of many disease states such as cancer, heart disease, and stroke. Although research has shown early promising results in regard to a link between folate and a reduced risk of cancer, more research is needed. In the meantime it is recommended that individuals eat between five and nine servings of colorful fruits and vegetables every day to help meet the daily needs for folate. If eating large of amounts of fruits and vegetables is unlikely, supplementing with a daily multivitamin that contains 100 percent of the daily value of folic acid will be sufficient.

Copyright © 2008 The Diet Channel. This article is provided courtesy of The Diet Channel.

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