New research from Taiwan and US researchers lays out many arguments in favor of using natural dietary substances to help prevent breast cancer. The researchers looked specifically at natural phenolic compounds in the diet, a large class of organic molecules made up of a benzene ring with at least one hydroxyl (OH) attached to it. Most foods have some level of phenols in them, and many of these substances have well-understood anticancer properties. The study appeared in the journal Molecular Nutrition & Food Research.
The National Cancer Institute in the United States estimates that in 2015, over 230,000 cases of breast will be diagnosed in US women, and over 40,000 women will die from the disease. It’s the second leading cause of cancer death in women in the US, exceeded only by lung cancer. Around the year 2000, breast cancer incidence rates dropped by approximately 7% after the use hormone in menopausal women was discouraged, but rates have leveled off since then. About 1% of breast cancer cases are in men. As of 2014, almost 3 million women in the US alone have a history of breast cancer, including women in treatment and finished with treatment.
In their paper, the US and Taiwanese researchers note that “recent literature and reviews have demonstrated that dietary natural phenolic compounds can prevent breast tumorigenesis, improve phytochemical bioavailability, and increase drug sensitivity.” They also point to multiple epidemiological studies. Roughly 10-15% of breast cancer cases are believed to involve inherited traits, which means the vast majority of cases involve extrinsic (environmental) factors.
Breast carcinogenesis is complex. Hormonal signaling, genetic predispositions, and epigenetics all may play a role. The researchers believe there are “several lines of support” for the belief that dietary phenols may reverse adverse gene expression and correct some of the epigenetic processes which lead to the development of a tumor. Dietary phenolic compounds, including many common flavonoids and polyphenols, may be effective chemopreventive agents while creating low toxicity. Some flavonoids such as genistein offer hormone regulation as phytoestrogens, while others possess antioxidant, anti-inflammatory, and other anticancer effects.
The researchers note that some of the more well-studied phenolic compounds have extremely low bioavailability, which prevents their constituent molecules from entering the blood stream efficiently after consumption. Epigallocatechin-3-gallate (EGCG, from green tea) and resveratrol (from grapes) bioavailability after oral administration in humans is only about 1%. Curcumin (from tumeric) also has notoriously low bioavailability. To combat this problem, many strategies are used. Some phenols have increased bioavailability when they are eaten with fats (olive oil is a good choice) or foods which inhibit their metabolizing enzymes (e.g. piperine). Still other supplement makers have experimented with unique formulations of phenols. For example, BCM-95 is a patented curcumin formulation which claims to provide almost 7 times the bioavailability of standard curcumin.
The paper highlights a wide variety of phenols and their mechanisms, concluding that “dietary natural phenolic compounds are promising candidates for chemopreventive and chemotherapeutic breast cancer treatment strategies.”