Mercury can exert an estrogenic effect on breast cancer cells by binding to estrogen receptors and causing increased cell growth. Other toxic metals that act in a similar way on breast cancer cells are copper, cobalt, nickel, lead and tin. The heavy metals iron, nickel, chromium, zinc, cadmium, mercury, and lead were found to be higher in human breast cancer tumour samples than in benign breast tissue, suggesting that heavy metals are related to malignancy.
The two most common sources of mercury toxicity are dental fillings and consumption of fish – in fact anyone who consumes fish even only once a month, or has mercury amalgam fillings, will demonstrate a mercury body burden when tested using a chelating substance such as DMPS, followed by a 6 hour urine collection. I routinely test women for toxic metals and commonly find mercury toxicity in women with a breast cancer history. One of the first recommendations I have to patients is to test for and remove heavy metals – for if these are present, how can our tissues be healthy? Heavy metals disrupt cellular repair and energy production, disturb detoxification mechanisms in the liver and kidneys, accumulate in the brain, thyroid and adrenal glands and contribute to cancer susceptibility. Heavy metals increase the likelihood that infectious organisms such as bacteria, fungus and viruses proliferate, and these too are implicated in breast cancer development.