“Our environment is extremely toxic, from the air we breathe to the products we put on our bodies and the food we put in them,” wrote a reader with the online name Time17. “It’s no wonder people are getting sick at younger ages than ever before. I’m no scientist, but I can see the connection.”
While such a link may seem obvious, it is extremely difficult to prove that even those who raise the alarm about environmental toxins acknowledge it.
Cancer takes years to develop, and it’s nearly impossible to track which chemicals and how much people have been exposed to over decades. Determining causal relationships with cancer in people under 50 is particularly difficult. That’s because, although the incidence of cancer is rising, the number is still relatively small.
Dr. Beate Ritz, professor and associate chair of the Department of Epidemiology at the University of California, Los Angeles, School of Public Health, said: “We need to follow a very large number of people for a long time before we can do a full study.” . Such research has begun but will take decades to complete.
However, there is no question that we are exposed to chemicals in our air, water, and food, many of which are known carcinogens. These substances can be harmful to our health, but it is not clear how much exposure is required to cause cancer.
“There is limited data on the proportion of cancers that can be explained by these chemicals,” said Timothy Rebeck, professor of cancer prevention and epidemiology at Harvard’s T.H. Chan School of Public Health. “That doesn’t mean there aren’t risks. Our ability to measure and understand risks is very poor.”
Leveque points out that despite the increase in the number of people under 50, overall cancer rates have declined over the past 50 years.
“If these chemicals collectively had a huge impact, would cancer rates be as low as they have been?” he said.
Here we take a look at some of the substances that our readers are concerned about.
endocrine disruptor
these are chemicals anything that mimics, blocks, or interferes with hormones; and they are everywhere — Food, air, water, clothing, furniture, etc.
These include bisphenol A, best known as BPA, which is used in the manufacture of plastics. Per- and polyfluoroalkyl substances (PFAS), the so-called “forever chemicals”, are used in firefighting foams, nonstick pans, and textile coatings. Phthalates are liquid plasticizers found in hundreds of products, including some food packaging, cosmetics, and children’s toys.
These chemicals disrupt hormonal pathways and can be particularly harmful during pregnancy, childhood, and adolescence.
But do they cause cancer? Associated with PFAS Kidney and testicular cancer occurs in people who are highly exposed, such as at work or in the military. What this means for people exposed to trace amounts and the risk of other cancers remains unclear.a 2020 review Previous studies concluded that “overall, evidence for an association between cancer and PFAS remains weak.”
However, the lack of evidence does not mean there is no risk, and these chemicals are ubiquitous in our lives.
Julia Brody, executive director of the Silent Spring Institute, an organization that studies the link between everyday chemicals and women’s health, said years of research has shown a link between environmental toxins and breast cancer. Ta. Such data is certainly relevant to early-onset breast cancer, she said.
The institute identified 300 chemicals in the environment that increase estradiol and progesterone, hormones that can promote breast cancer. “I’m not saying they cause breast cancer because we don’t know that yet. But they’re definitely a good place to look,” said Ruthann Rudel, the institute’s director of research.
The institute also lists chemicals that cause mammary tumors in animals, “because that’s also a very good predictor,” she said.
Women born in the 1950s were the first generation to be exposed to chemicals such as PFAS and phthalates, and their children, now in their 30s and 40s, were exposed in the womb. As a result, they face a greater cancer risk, said Carmen Messerlian, an assistant professor at the university. Environmental Reproductive, Perinatal, and Pediatric Epidemiology at Harvard University Chan.
“Our environment is becoming increasingly hostile to our health,” she said. “This generation is very exposed. It’s not at all surprising to me that we have a high percentage of people under 50.”
Air pollution
It’s clear that air pollution is bad for your health, but does it play a role in early cancer development? “We don’t know the answer,” said Joel Schwartz, a professor of environmental epidemiology at Harvard University. “It may be contributing to early cancer development. But we don’t know if it plays a role in increasing the rate.”
Mr. Schwartz recently took command. the study Research showing that exposure to nitrogen dioxide and particulates in air pollution is associated with increased colorectal and prostate cancer among Medicare beneficiaries, people age 65 and older.
It is unclear whether air pollution has the same impact on people under 50. But air quality has improved in recent decades, so people under 50 likely have less exposure to these harmful particles, Schwartz said. (However, wildfires are starting to reverse that trend.)
Still, the mechanisms by which air pollution promotes cancer are clear.
“Air pollution enters your lungs, but it doesn’t necessarily stay there. Some particles are so small that they can pass through your lungs and into your capillaries,” Schwartz said. . “Increased exposure to particulate air pollution is often associated with significant increases in systemic inflammatory markers.”
Inflammation, along with other changes, causes cells to mutate, which can advance cancer progression and “to some extent thwart the immune system’s attempts to kill cancer cells,” Schwartz said.
Ozone, heavy metals and particulates can cause oxidative stress, essentially “rusting” proteins and lipids, said Litz, the UCLA researcher. Even worse, chemicals known as polycyclic aromatic hydrocarbons, or PAHs, can destroy DNA within cells.
Rudel, of the Silent Spring Institute, pointed to research showing that every increase in particulates leads to 3,000 new breast cancer cases.
Pesticides and herbicides
Most studies on exposure to pesticides have focused on people, primarily men, who are exposed to high concentrations through chemical spraying, and these studies have found an association with increased cancer rates. ing.
but, UCLA research A paper published last year looked at more routine exposures. They found that the incidence of thyroid cancer was higher among people who lived within 500 meters of where any of the 10 pesticides had been used. Lead author Dr. Avital Harari said it was most likely that nearby residents inhaled the chemicals, but it was also possible that the chemicals got on food or were filtered and deposited on surfaces.
The chemicals most definitely linked to cancer are: paraquat, a powerful herbicide that can only be used commercially. However, we also found the following associations: glyphosatethe herbicide contained in Roundup.
Cancer risk was highest in people over 65, but younger people were also affected. In fact, Harari, an endocrine surgeon at UCLA Health, began this research because when he moved to California, he noticed a much more advanced case of thyroid cancer and suspicions of farming. “I started treating a 20-year-old woman with metastatic thyroid cancer,” she said, not a typical age for such a serious disease.
When asked if he thought pesticides were playing a role in the rise in early cancer cases, Harari replied, “I think they do.” She said many factors are involved, including possible obesity and other environmental exposures, but “pesticides are at least one piece of the puzzle.”
What you can do
Although you can’t completely avoid environmental toxins, there are steps you can take to reduce your exposure to them. Messerians avoid plastic. She packs her food in foil or glass containers and never uses nonstick pans. When her son orders her take-out pizza, she immediately removes it from the coated box.
If you’re concerned about air pollution, buy an air purifier that filters particles, advises Schwartz, who has two at home.
Online resources offer other suggestions as well. Silent Spring Institute offers an app called. detox me, guide you to safer choices.environmental working group healthy life With 120,000 food and personal care products rated on the app, the organization offers a wide variety of products. consumer guide.
But at the end of the day, we can’t escape all toxins in the environment, and it’s not clear that efforts to avoid them will make a difference.
Even Messerlian says “the best thing you can do” is to change your lifestyle: eat more fresh fruits and vegetables, exercise, sleep better, and reduce your consumption of processed foods.
“We have to tip the balance away from the bad,” she said.
Litz, of the University of California, Los Angeles, points out that vegetables and other greens contain antioxidants. “So even if you are exposed to air pollution that causes oxidative stress, antioxidants can counteract it.”
Felice J. Freyer can be reached at [email protected] her @felicejfreyer.
