The discovery of conjugated linoleic acid (CLA) caused a scientific sensation some years ago. This fatty acid found in red meat and cheese showed strong anti-cancer properties. In fact, scientists found CLA to be more strongly anti-carcinogenic than other fatty acids. What made CLA especially unique is that even low concentrations significantly inhibited cancer cell growth. CLA was particularly effective in inhibiting breast and prostate tumors, as well as colorectal, stomach, and skin cancer, including melanoma.
CLA helps prevent the initiation, promotion and metastasis of breast cancer.
A group of Cornell researchers conducted one particularly interesting study in which they induced experimental mammary cancer in rats. The animals were fed either high CLA butter fat or a free fatty acid mixture of CLA isomers (typical of that found in supplemental CLA) during the time of pubescent mammary gland development.
Only 53% of the animals given CLA, both in the form of butter and free fatty acids, developed mammary tumors compared to 93% of controls! The researchers concluded that this laboratory animal model suggests that CLA could be beneficial in reducing the risk of breast cancer. According to Dale Bauman, one of the lead authors of the Cornell study, Most dietary substances exhibiting anti-carcinogenic activity are of plant origin and are only present at trace levels. However, CLA is found almost exclusively in animal products and is among the most potent of all naturally-occurring anti-carcinogens. In another study, it was found that, besides inhibiting tumor growth, CLA totally prevented the metastasis of breast cancer to the lungs and bone marrow.
CLA inhibits the growth of prostate cancer while linoleic acid promotes it.
In one study using immunodeficient mice, animals were fed either a standard diet or diets supplemented with 1% linoleic acid or 1% conjugated linoleic acid by researchers. The researchers then inoculated the mice with human prostate cancer cells and continued to treat the animals with the two fatty acids. Mice fed the CLA-supplemented diet displayed not only smaller tumors than the other groups, but also a significant reduction in lung metastases, indicating that CLA was inhibiting the spread of the cancer.
CLA has been shown to inhibit ACF, a biomarker of colon cancer, in rats.
Colon cancer is a leading cause of cancer-related deaths. One of the earliest changes in the colons of animals treated with carcinogens (such as the heterocyclic amines found in cooked meat) is the appearance of aberrant crypt focus (ACF), a biomarker for colon cancer. Conjugated linoleic acid has been shown to inhibit ACF in rats.