Folic acid (also known as folate), is a type of B vitamin that is involved in the process of making proteins. It is necessary for the successful construction and repair of DNA and for normal cell division. Without it, cells can’t divide properly and can turn cancerous. During cell division—the process our body uses to grow and renew its organs and tissues–the DNA contained in the center of each cell must replicate itself. In other words, it must make an exact copy of itself.
Mistakes can, and do, happen all the time during this replication process. Certain chance mistakes can turn the messages in DNA traitorous. Instead of dispatching communications for health, it may accidentally spawn messages for cancer. Folic acid helps to protect your DNA from making the mistakes that can lead to cancer. Think of it as an automated editor. This may explain why low levels of folic acid in the body are associated with a significantly increased risk of breast cancer.
In a 1992 study from the University of Vermont, researchers found that DNA mistakes, or mutations, increase with age and cigarette smoking. They also discovered that folate helps to prevent those mutations, including mutations that increase the risk of breast cancer.
Alcohol causes folate levels to drop. Women who drink alcohol and have low folate levels seem to have a particularly high risk for developing breast cancer. Harvard University conducted a very large prospective study, called the Nurses’ Health Study, which followed 88,818 women from 1980 to 1996. A prospective study is one that follows the subjects into the future; it is considered one of the best study designs for obtaining significant and reliable information. This study found that the women, who had the highest risk of developing breast cancer, drank at least 15 grams of alcohol a day and had low folate levels.

Good Sources of Folate
Folic acid is found in high concentrations in eggs, asparagus, whole wheat, deep-green leafy vegetables, and brewer’s yeast. It’s also found in certain meats and fish. But eating large amounts of meat and fish is a double-edged sword, since they considerably increase your risk of breast cancer due to the environmental toxins that they absorb, concentrate, and store.
You can also take folic acid as a supplement. About 400 milligrams (mg) a day is all you need. As with all good things, don’t take too much folate. The Physicians’ Desk Reference for Nutritional Supplements reports no incidences of folate overdosing in the medical literature, but taking too much folic acid can be a problem for people who have a vitamin B12 deficiency. When vitamin B12 levels are very low and supplemental folate is given, the neurological problems and damage associated with low B12 can worsen.
Birth control pills, alcohol, and nonsteroidal anti-inflammatories (such as aspirin and ibuprofen) lower folate levels. So, if you take any of these medications or drink alcohol regularly, make sure you take supplemental folic acid.
VITAMIN B12 (Cobalamin)
The other B vitamin that has been shown to protect against breast cancer is vitamin B12. Vitamin B12 is known as “Nature’s most beautiful cofactor,” because its crystalline structure is a stunning dark red, like that of a rare ruby. Vitamin B12 works with folic acid, so it’s also a fundamental part of the DNA construction and repair team. Without it, the quality of DNA would never pass inspection. B12 is vitally important for keeping your DNA messages correct and free from cancer-inducing mistakes. Research shows that women with the lowest B12 levels in their bodies have the highest rates of breast cancer.
Vitamin B12 may also be very valuable for women who already have breast cancer. In the laboratory, scientists found that when B12 was applied directly to breast cancer cells, it stopped them from growing.
B12 has several other essential health benefits; for instance, it is necessary for a healthy nervous system and the production of energy.
Vitamin B12 is primarily made by bacteria in animals, so, not surprisingly, the richest sources of vitamin B12 are certain animals—especially specific organs such as the liver, brain, and kidney. Clams, oysters, sardines, and salmon also have significant amounts of B12. But eating meat and fish may actually increase your risk of breast cancer due to the environmental toxins they contain, so getting B12 another way is probably a better idea. For example, B12 is also found in egg yolks and fermented soy products, such as tempeh.
Since B12 is generally found in low amounts in plant foods, it’s not uncommon for vegetarians to be deficient in it. Therefore, if you follow a vegetarian diet—which I recommend because research shows it is the healthiest diet and the one associated with the lowest risk of breast cancer–taking B12 as a supplement is important. About 3–30 micrograms (mcg) a day—about the weight of a tenth of a drop of water—is all you need for B12 to perform its miracles.
To be absorbed into your body, vitamin B12 requires something called “intrinsic factor,” which is secreted by cells in your stomach. As you age, you make less intrinsic factor and, therefore, absorb less B12. So, you must consume more B12 as you age to absorb amounts similar to what you got when you were younger. For this reason, supplemental B12 is a great idea for everyone who is age 50 or older. If you have certain conditions, such as the autoimmune disorder called “pernicious anemia,” or if you have had partial or total surgical removal of your stomach, the amount of intrinsic factor you make will be low. Pancreatic insufficiency, disorders of the small bowel, certain drugs, and a variety of other conditions can also interfere with B12 absorption. In all these situations, it’s very important to take supplemental vitamin B12.
In summery, significantly lowering your risk of breast cancer isn’t difficult. It can be as simple as eating delicious food rich in folic acid, or taking supplemental folic acid and vitamin B12. Both of these vitamins help to protect your DNA from making mistakes that can lead to cancer.



By Christine Horner, M.D.
Christine Horner, M.D. is a board certified and nationally recognized surgeon, author, expert in natural medicine, professional speaker and a relentless champion for women’s health. She is the author of Waking the Warrior Goddess: Dr. Christine Horner’s Program to Protect Against and Fight Breast Cancer, winner of the Independent Book Publishers Award 2006 for Best Book in Health, Medicine, and Nutrition.