6 things we found out were linked to cancer in 2022, from junk food to hair products

• Cancer is a leading cause of death in the US, with an estimated 1.9 million new cases this year.
• Scientists linked several food ingredients and personal care products to cancer risk in 2022.
• Many factors contribute to cancer risk, so more research is needed to learn how lifestyle factors play a role.

Researchers have identified several cancer-causing ingredients in the foods we eat, tools we use to cook, and products we apply to our bodies every day.

That list grew longer in 2022, as scientists confirmed certain chemicals are linked to abnormal cell growth and identified new risk factors for future research.

Cancer-causing chemicals can show up in all kinds of products due to industrial contamination, so even personal care products approved by regulators have been subject to scrutiny from independent investigators. Researchers have continued to look to manufacturing of food, home, and beauty products for potentially toxic ingredients.

While it's tricky to pinpoint what causes individual cases of cancer, research so far has led scientists to conclude that genetics, environment, lifestyle, and occupation all play a role in personal risk.

Chemicals used to make nonstick cookware are linked to liver cancer risk

A landmark study confirmed a link between "forever chemicals," also known as PFAS, used in household products and an elevated risk of liver cancer.

Certain chemicals under the PFAS (per- and polyfluoroalkyl substances) umbrella have been loosely linked to liver damage in the past, but most evidence has come from animal studies. 

Researchers at USC's Keck School of Medicine had access to blood and tissue samples from more than 200,000 people living in Los Angeles and Hawaii, which gave them a unique opportunity to study the impact of PFAS on the human liver. Their findings were published in JHEP Reports in August.

They found that people with the highest levels of exposure to PFOS — a "forever chemical" that was once used to make nonstick pans — had a 4 ½ times higher risk of developing liver cancer. 

According to an analysis of tissue samples, that increased risk may be explained by changes to metabolism in the liver, but more research is needed to understand how PFAS exposure may disrupt normal liver function.

Men who eat a lot of ultra-processed foods may have an increased risk of colon cancer

Recently, researchers have zeroed in on the health risks of ultra-processed foods like hot dogs, potato chips, and frozen pizza. Most of the food we eat is processed to some extent, but ultra-processed foods are made of more artificial ingredients than whole foods.

In August, a study published in the British Medical Journal found that American men who eat a lot of ultra-processed food have a 29% higher risk of developing colorectal cancer compared to their peers who consumed the least processed food.

Researchers sorted the men into five groups according to their diets, and then compared the top consumers of ultra-processed foods to the group with the lowest intake.

Past studies have linked ultra-processed meats like cold cuts and beef jerky to higher odds of developing bowel cancer, which may account for some of the men's dietary risk.

Artificial sweeteners may be linked to increased cancer risk

Artificial sweeteners such as aspartame are commonly used to replace sugar in diet sodas and low-calorie snacks. However, past research has linked these replacements to some of the same health risks as regular sugar, including heart disease.

Some artificial sweeteners may come with an additional risk of breast cancer and obesity-related cancers, according to a French study published in PLOS Medicine in March.

Based on data from more than 100,000 French adults, researchers found that those who consumed the most artificial sweeteners had a 13% higher risk of developing cancer compared with those who didn't consume artificial sweeteners. Although the study found a correlation between sweeteners like aspartame and a small increase in cancer risk, more research needs to be done to find out if consuming artificial sweeteners really causes cancer.

Hair products marketed to Black women may cause cancer growth

Hair care and beauty products geared towards Black women commonly contain parabens, a class of chemicals known to mimic the hormone estrogen.

Past studies have shown that parabens, like estrogen, can lead to the abnormal growth of breast cells that precedes breast cancer. New research presented at the Endocrine Society's annual meeting in June found that the effect was stronger in Black women compared to white women.

Researchers found that parabens increased the growth of Black breast-cancer cell lines more significantly compared to white breast-cancer cell lines exposed to the same dose. The chemicals also increased the expression of genes linked to breast cancer in cells from both Black and white women.

More dry shampoos have been found to contain benzene

In 2021, spray deodorants and sunscreens were subject to recalls after an independent lab tested them for benzene, a chemical known to cause cancer.

The lab, Valisure, has continued to test beauty and personal care products for the carcinogen in 2022. It most recently found that 11 brands of dry shampoo contained more than 2 ppm of benzene, exceeding the FDA's recommended limit.

One brand, Not Your Mother's, sold dry shampoos containing over 10 times the recommended amount of benzene.

Benzene has been known to increase cancer risk since 1977, when a study found workers who were exposed to it were nine times more likely to develop leukemia. 

Breast implants are linked to some cancers

In September, the Food and Drug Administration issued a warning about cancers that may be linked to breast implants.

The FDA said fewer than 20 cases of squamous cell carcinoma, a cancer that normally affects the skin, have been found in the scar tissue surrounding the breast implant. They also identified fewer than 30 cases of other lymphomas not previously linked to implants.

The agency has connected some cases of anaplastic large cell lymphoma (ALCL) to breast implants in the past, specifically implants with textured surfaces.

These cancers are rare, and not all breast implants lead to cancer, but people with implants should be especially careful to keep an eye out for symptoms.