The seemingly harmless everyday chemicals that we come across in our daily lives — while eating, cleaning, or shopping — may come together in unexpected ways, causing a multitude of health hazards — and even cancer.
An international study, conducted by 174 scientists across 28 countries, evaluated the link between mixtures of commonly encountered chemicals and the development of cancer. They selected 85 chemicals not considered carcinogenic to humans and found about fifty of them could lead to certain cancerous mechanisms in our body, even at the low exposure levels at which they are found in our daily environment.
Toxicology tests have determined that many of these chemicals, found in cosmetics, food, plastics, paints, and textiles, are benign. While some of the chemicals have not been considered carcinogenic, they hold the potential to trigger cancer-causing mechanisms, especially when a person is exposed to other chemicals that are even mildly carcinogenic.
For instance, a chemical that suppresses the immune system, may not cause cancer on its own, but may contribute to cancer development by dismantling an important layer of the body's defense system, in the presence of other chemicals. Similarly, a chemical that interferes with the capacity of our DNA to repair itself might be benign when tested on its own, but can set the conditions for other chemicals to trigger cancerous mutations.
"Current regulations in many countries (that consider only the cumulative effects of exposures to individual carcinogens…) should be revisited," the researchers said in the paper, published in the journal Carcinogenesis. The study was part of an initiative by the non-profit organization Getting to Know Cancer.
The scientists said conventional toxicology tests — which only take into account single compounds at a time — were inadequate in estimating true cancer risks.
"We urgently need to focus more resources to research the effect of low-dose exposure to mixtures of chemicals in the food we eat, air we breathe, and water we drink," cancer biologist Hemad Yasaei of Brunel University London, who contributed to the study, said in a statement.
Cancer is now one of the leading causes of death worldwide. There were about 14 million new cases and 8.2 million cancer-related deaths in 2012. Both genetic and environmental factors play important roles in an individual's cancer susceptibility, suggesting that effective management of the environmental risks can help to reign in the galloping rates of the global epidemic.
According to estimates from the World Health Organization and the International Agency for Research on Cancer, about 7 to 19 percent of all cancers can be attributed to toxic environmental exposures. While the study suggests that these estimates could be far below the actual risks posed by all the chemicals that we are exposed to, it still provides a fairly decent understanding of a serious health hazard.
"The information gained from this comprehensive review by an international team of experts is significant because it addresses the biologic complexity of cancer, informs future research efforts, and ultimately, might support improved risk assessment," Susan Gapstur, a vice president at the American Cancer Society, told VICE News.
Health risks posed by chemicals used in our everyday lives are not an entirely new issue. Public health advocates have opposed the presence of the chemical bisphenolA (BPA) in plastic containers, water pipes, soda cans, sports gears, and other regularly used items. But even though several studies have associated the chemical with cancer, obesity, neurological damage, and hormonal imbalance, no conclusive links have been found by researchers. The US Food and Drug Administration (FDA), meanwhile, maintains that BPA is safe at current exposure levels in foods and supports its use in food containers and packaging.
The National Toxicology Program, in partnership with the FDA, is carrying out detailed tests to answer questions and uncertainties related to the safety of ingesting low amounts of BPA that can migrate into food from other materials.
"While there has been a considerable body of research on occupational and high-dose exposure to environmental chemicals and cancer risk that has resulted in important regulations to limit these exposures, less is known about low-dose exposures and mixtures of low-dose exposures to the general public," Gapstur told VICE News.
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