Ultra-processed food? Forever chemicals? Declining birth rates? What’s behind rising cancer in the under-50s? | Science

ILynn Turner, Cancer Research Director around the world, says 2022, was about 16 % of 20 million people with cancer all over the world less than 502. Cancer has always been more than elderly. But between 1990 and 2019, the occurrence of the disease in less than the 1950s increased by 79 %, according to L. research Posted in British Medical Journal In 2023, this short time frame means that height cannot be explained through genetic factors, according to Trisy Woodrov, Director of the University of California, the San Francisco program on reproductive health and the environment.

Many of these “early” cases occur in the richer countries. Marie Beth Terry, a professor of epidemiology at the University of Colombia, says that the rates are noticeable because the younger population is mainly not smoked. She adds that about two -thirds of the cancers in the fifties of the last century occur in women.

In 2019, some of the most common types of cancer in the fifties of the last century were colon, rectum, breast and skin cancer. Early elder cancers that have increased faster Between 1990 and 2019, prostate cancer, nasal pharynx cancer, or wind were. Breast, stomach and intestinal cancers – among other things – were linked to some of the highest death fees.

Colon and straight: processed meat and volatile foods

In 2024, Cancer Research UK and many other organizations funded a research project called probability Consider the global rise in colon and rectum in the 1950s. The trend is particularly concerned in England, where the prices seem to be It rises faster From anywhere else in the world, with the exception of New Zealand, Chile and Puerto Rico. Prospect will investigate a variety of risk factors, including poor diet.

One aspect of the diet that is a source of concern is the high consumption of processed meat, which is a carcinogen “Group 1”, which means that there is sufficient evidence to conclude that it causes disease in humans. The term “processing” of salted, smoked, wizard, or cure to enhance its flavor and longevity – for example, describes pork and bacon. Meat consumption in general I slept To a large extent in the global diet over the past fifty years.

Highly processed meat in compounds is called nitrate and nitrate, which it maintains for a longer period. When these compounds are divided into the body, they can damage cells in the intestine, according to Sofia Louise, the director of higher health information in cancer Research in the United Kingdom. But while there was evidence of this mechanism in mice and mice, it was difficult to show the same thing in large human studies, says Mark Gunter, a chair in cancerous epidemics and prevention of the College of Public Health at the Empire College in London.

Louise says that some ways for some methods of cooking processed meat – such as barbecue at high temperatures – can release chemicals called heterogeneous amids and multi -episode lines, which also lead to cell damage because food studies often depend on self -reporting. “What we think we eat and what we are already eating are very different things,” said Turner in global cancer research.

Another potential food risk factor is foods full Daily energy consumption In some high income countries. They are made with ingredients It is rarely used in home cooking that is then treated by cracking, hydrogenity, or adding flavors and colors. Common upfs includes soft drinks, ready -made meals and sweets.

One Ticket In the United States, I found that men who ranked fifth for UPF consumption had a greater risk of 29 % of colon and rectum from those in the lowest level.

Bradbury says at Auckland University it is not useful to discuss UPFS as one group because the term covers many different foods. Gunter says that the whole bread of the supermarket is classified as UPF because it is industrially produced – however it is rich in fiber and completely. The danger appears to be with specific ingredients present in some UPFS.

One of the ingredients that have been investigated to obtain a cancer link is aspartame. Low -calorie sweetening is 200 times sweeter of sugar and is usually used in nutritional drinks and low sugar milk. There have been some studies on animals that indicate that the aspartame has “pro -cancer properties”, but the conclusion so far is that there is no “final evidence” of cancer in humans, says Gunter.

Gunter says researchers also look at the E -additions that change the flavor, color or texture – but this is a field “there is still a lot of unknown.”

In the American study, diets were linked to sweetened drinks with diabetes, ready -to -eat meat, poultry and seafood, with an increase in the risk of colon and rectal cancer in men. For women, the risk was greater with a high diet in ready -to -eat products.

Breast: reproductive factors and chemicals forever

The rise in breast cancer in less than the 1950s is not a new direction, but the pattern in recent decades is noticeable because it does not seem to be considered the usual risk factors for cancer, such as obesity, according to Terry in Colombia University.

Obesity rates in adults all over the world have more than one Doubling Since 1990, excess fat can increase the levels of growth hormones and inflammation, Louise says. These signals tell cells often divided, which increases the chances of more than ten types of cancer.

Excessive fat can also put some sexual hormones after menopause, which raises the risk of breast cancer. But this does not explain the rise in cases in less than 50 years, says Terry.

One idea is that the rise in early cases can be linked to A global decrease in fertility Because birth of a certain age and breastfeeding is believed to be protection from breast cancer. Hana Modi, director of research and participation in breast cancer in the United Kingdom, says that having children before the age of thirty “is generally accepted as it reduces the risk of developing the disease. The first full period of pregnancy in the full term Changes Women’s breast tissue in a way that makes her less vulnerable to cancer.

Moreover, every 12 months women spend in breastfeeding, reduce the risk of breast cancer by about 4 %, according to Ticket Posted in Cancer medicine. This means that women who have multiple children and all satisfy them can have much lower risk.

It is not believed that the preventive effect of breastfeeding is completely incomprehensible, but it is believed to be associated with a long time associated with sex hormone estrogen, which affects the number of times the cells are divided, says Modi. Breastfeeding may reduce the amount of estrogen traded in the body.

But there is a “very significant increase” in early breast cancers even in countries with high fertility rates, so reproductive factors alone cannot explain this trend, according to Terry.

Another interpretation is exposure to urinary and polyfluoroalkyl (PFAs), also known as “chemicals forever”. This group of thousands of vehicles make products resistant to water, spots and heat, and there are in everything from cosmetics to food packaging and cooking tools.

Moody says that chemicals forever act as an endocrine harassment by increasing estrogen levels in the body or hormone simulation. Ruben Ruben, Director of Science in Breast Cancer Partners, says exposure to these chemicals may lead to a “life effect” in the womb and during early childhood, adolescence or pregnancy – the stages of life when cells are divided quickly.

Moody says most PFAs have never been tested, so its impact on human health is still unknown, but research indicates that a few of them can raise the risk of breast cancer. An analysis of one of eight studies In 2022, it showed a positive connection between breast cancer and two types of PFAs called Perfluoroctanoic acid (PFOA) and sulfonic acid.

PFOA is one of the “original” chemicals forever in the heart of Pfas Water pollution scandal In the United States. Cancer in Group 1 is now valid in the United States and the European Union.

But most people still have quantities of PFOA in their blood due to the longevity of the boat and its use over decades. “The Carbon Florin Box in PFAS is one of the strongest chemistry-for this reason they continue in the environment and our bodies for a long time,” says Robin.

Since the water pollution scandal, chemical manufacturers have turned into making new types of PFAs such as PFHXs, which are now in the environment with higher levels. research It was published in September and found PFHXS associated with an increase in breast density, a risk factor for breast cancer. The compound was effective Prohibited In the UK in 2023, it will take a “period of time to know” any of the most recent PFAs, says Robin.

Skin cancer: UV damage and diagnostic processes

Skin cancer is one of the most common types of cancer in the fifties of the last century, but it is not one of the fastest growth in the world. Data set for certain types of skin cancer is small and countries record different cases, but there was an increase in early cases in the United Kingdom and the United States.

James Larkin, a consultant for a medical oncologist at skin and urinary tract units at Royal Marsen Hospital, says the main risk factor for skin cancer is sunburn.

Sunburns cause a lot of exposure to ultraviolet radiation (UV), which is often driven by a shorter wavelength UVB. UVA rays – which have a longer wavelength and can penetrate deeper into the skin – can also lead to dermatitis and damage.

Larkin explains that UV rays destroy the DNA, which in turn leads to the fact that the genetic mutations that lead to the function of the abnormal protein, the transformation of cancer cells, as explained by Larkin. Crares to educate the public about the risk of UV rays have been present for decades in many high -income countries, and advice to people to search for the shadow when the sun is stronger, applying it, re -applying sunscreen and wearing protective clothes.

“The question is to what extent do people correspond to knowledge? I am not really sure of having high -quality data on whether they take advice seriously or not.”

“There is a lot of information about awareness of the skin, but this does not reach everyone, and some damage has occurred decades ago,” says Turner.

Catherine Olsen, chief research official at the Qimr Berghofer Medical Research Institute, says people between the ages of 15 and 24 are less likely to use sunscreen and sun protection methods, but they also tend to spend more time in Inside. She adds that young women in the northern countries are also likely to use tanning salons.

At the same time, some researchers believe that there Excessive diagnosis From melanomic skin cancer in countries like the United States, with the support of the fact that death rates remain similar despite the high number of cases. The theory is that more skin examination tests, along with low bars to perform biopships and reduced sills to describe the lesion as cancerous, lead to wrong positives.

Marian Bayroik, distinguished professor at the Comprehensive Cancer Center at New Mexico University, says the skin lesions are in the early stages, even well -trained dermatologists, who can find it difficult to know whether something from cancer or not. She adds that the accuracy of the diagnosis also depends on how much the lesion is removed and the extent of its removal is well.

Regardless of the type of cancer, people can reduce their risks by stopping smoking, reducing alcohol, maintaining a healthy weight, eating a balanced diet and staying safe in the sun, says Louise.