The incidence of colorectal cancer affecting young adults increases alarmingly before the age of 50. Thus, it is estimated that a person aged 20 to 30 (born in the 1990s) currently has twice the risk of being affected by early colon cancer and four times the risk of rectal cancer than was a person of the same age born in 1950 .
Lifestyle and food hygiene in question
These early cancers are very surprising. Since colorectal cancer generally takes 10 to 35 years to develop and reach an advanced, clinically detectable stage. To be diagnosed in people under the age of 50 (and sometimes even younger), this cancer must therefore have appeared abnormally early in the life of these people or have developed extremely rapidly following the appearance of the first precancerous lesion (polyp).
The vast majority (75%) of colorectal cancers are directly related to lifestyle habits. While the contribution of genetic factors, transmitted by heredity, is less than 10%. The only way to explain the sudden increase in the incidence of early colorectal cancers is therefore that changes in lifestyle that have taken place over the past decades have created favorable conditions for the appearance and/or progression of cancer cells. at the level of the colon.
500% increase in sugar consumption since 1950
One of the major changes that occurred after 1950 was the sharp rise (500%) in the consumption of sugary drinks (soft drinks, sports drinks, energy drinks). Compared to previous generations, people born after 1950 started consuming these beverages at a younger age and in larger quantities. For example, the caloric contribution of sugar-sweetened beverages to the diet of young people increased considerably between 1977 and 2001, rising from 5 to 12% among 19-39 year olds and from 5 to 10% among 2-18 year olds. This high intake of simple sugars is harmful to health. Indeed, it promotes the development of metabolic disorders (obesity, insulin resistance and type 2 diabetes) which increase the risk of several diseases, including cancer.
Sugary drinks: main factor among young people
It also seems that the excessive consumption of sugary drinks could contribute to the increase in the incidence of early colorectal cancer observed in recent years. By analyzing the eating habits of 95,464 nurses aged 25 to 42 who participated in the Nurse Health Study II, the researchers observed that women who drank 2 or more sugary drinks a day as adults had a risk of developing early colorectal cancer twice as high as those who drank only rarely, less than once a week.
This increased risk is even worse if the habit of consuming sugary drinks was already present in adolescence (13-18 years), with a 3-fold increase in the risk of cancer observed in women who drank more than 2 drinks sugar per day during this period.
Prevent colorectal cancer
To prevent colorectal cancer, it is therefore necessary to drastically reduce the consumption of sugary drinks, but also that of ultra-processed industrial foods in general. With their high fat, sugar and salt content, these products throw the metabolism out of whack and create conditions of chronic inflammation that greatly increase the risk of colorectal cancer.
Eating more plants and less red meat (especially less cold cuts), staying slim and doing regular physical activity at least 150 minutes a week, remain the pillars for preventing colorectal cancer, in young adults too.
Siegel RL et al. Colorectal cancer incidence patterns in the United States, 1974-2013. J. Natl Cancer Institute
Hur J et al. Sugar-sweetened beverage intake in adulthood and adolescence and risk of early-onset colorectal cancer among women. gut
Tabung FK et al. Association of dietary inflammatory potential with colorectal cancer risk in men and women. JAMA Oncol.
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