By Eric Uthus
Most people, especially women, associate folic acid as a vitamin needed during pregnancy. The need for this vitamin is crucial during pregnancy. However, folic acid has numerous beneficial actions and is needed at all times regardless of age, by both female and male. A high folic acid intake is considered heart healthy. Recently folic acid has been in the news as needed to help prevent osteoporosis. The reason for these claims is that folic acid lowers homocysteine.
Homocysteine is a naturally occurring compound that is made in our bodies. Normally, the amount of homocysteine in our bodies (as typically measured in blood) is low because it is metabolized (changed) to other compounds which are necessary. There are four B-vitamins (B6, B12, choline and folic acid) that are necessary for this metabolism to continue. If there is a lack of one or more of these vitamins, homocysteine increases.
Of these four vitamins, folic acid has been most studied in its relation to homocysteine, specifically in relation to heart disease. However, diets that are low in folic acid are thought to make individuals prone to increased risk of cancer. Low intake of folic acid results in elevating the levels of homocysteine.
In heart disease, homocysteine is thought to cause damage to blood vessels resulting in atherosclerosis, or hardening of the arteries. In the case of cancer, the damage is to DNA; severe damage to the cellular process can eventually lead to cancer. Another mechanism by which low folic acid intake increases the risk of cancer is that folic acid is required for making and repairing DNA. The third way folic acid may influence cancer risk is that the lack of folic acid can affect the turning "on" or "off" of genes. Specifically, if oncogenes (cancer genes that cause normal cells to change into cancerous tumor cells) are turned on and/or tumor suppressor genes (genes that can suppress the development of cancer) are turned off, cancer may result.
The story of folic acid and cancer (or other diseases such as cardiovascular disease or osteoporosis) is not simply that a low folic acid will result in any of these diseases. There are many other contributing factors such as genetic background and interaction with other nutrients and non-nutrients. For example alcohol consumption has been shown to alter folic acid metabolism and increase cancer susceptibility. Thus, the risk of cancer in someone who has a low folate intake is further increased if he/she also consumes alcohol.
Furthermore, there are other nutrients including selenium, calcium, and many vitamins, that are important in preventing cancer. The body has many lines of defense to ward off disease. However, the lack of any essential nutrient will stress our bodies and make us less resistant to disease.
Thus, the best advice is, as nutritionists repeat often - eat well balanced meals that contain plenty of fruits and vegetables (green leafy vegetables, dry beans and peas, and fortified cereals and grain products are good sources of folic acid). This diet will ensure that you receive the nutrients you need. Additionally, this type of diet - high in fruits and vegetables - will result in fewer calories from fat and simple carbohydrates. A good diet, along with regular exercise is the best advice to offer and the best advice to follow.