How sugary drinks increase colorectal cancer risk

Colorectal cancer is among the most frequently diagnosed types ranking among the top five common cancers in the country, according to the 2020 Globocan Report released by the International Agency for Research on Cancer (IARC).

The disease is a contributor to the increasing cancer deaths in the country. It affects the colon and rectum, which are parts of the large intestine.

Common symptoms include blood in the stool, a change in bowel movements (diarrhoea, constipation or lump in the abdomen), unexplained weight loss and fatigue.

For decades, the disease was common among older people. But health experts globally are concerned that colorectal cancer cases are increasingly being diagnosed among younger people, below the age of 50.

As such, scientists have been racking their brains in a bid to determine the reason behind the changing colorectal cancer diagnosis landscape worldwide.

A study led by researchers from the US based Washington University School of Medicine offers insights into the matter.

The findings of the study, which have been published in the Gut Journal, indicate that there is a link between drinking sugar-sweetened beverages and an increased risk of developing colorectal cancer in women under the age of 50.

Based on the study, heavy consumption of sugary drinks during adolescence (ages 13 to 18) and adulthood can increase the disease risk.

The researchers therefore note that the evidence generated through the study lends more support for public health efforts that encourage people to reduce the amount of sugar they consume.

Examples of sugary beverages include regular soda, pre-packaged fruit drinks, sports drinks, energy drinks, sweetened waters, as well as coffee and tea beverages with added sugars.

However, the quantities of sugar in these drinks vary. For instance, soft drinks like soda have much higher amounts of sugar compared to the quantities added in coffee or tea.

Based on recommendations from the American Heart Association, men should consume no more than nine tea spoons of added sugar a day. For women, the number is capped at six teaspoons.

But it is worth noting that sugary beverages contribute to the total amount of calories that a person consumes. So, people consuming high amounts of carbohydrates or other solid foods with sugar need to cut back on the amount of sugar in beverages they consume.

"Colorectal cancer in younger adults remains relatively rare. But the fact that the rates have been increasing over the past three decades and we don't understand why, is a major public health concern and a priority in cancer prevention," said Dr Yin Cao, the senior author of the study and associate professor of medicine in the Division of Public Health Sciences at Washington University.

"Due to the increase in colorectal cancer at younger ages, the average age of colorectal cancer diagnosis has gone down. These cancers are more advanced at diagnosis and have different characteristics compared with cancers from older populations.”

The researchers analysed data of nearly 116,500 women that took part in the study. They were requested to answer survey questions about diet; including the types and estimated amounts of beverages they drank.

Of the total study participants, over 41,000 were also asked to recall their beverage habits during their adolescence years.

Over a period of up to 24 years, the researchers found 109 cases of colorectal cancer among the women studied.

The results of the research showed that women who drank two or more sugary drinks per day had an increased risk of developing colorectal cancer compared to those that consumed less than one drink per week.

Specifically, the researchers calculated a 16 per cent increase of developing colorectal cancer before the age of 50, for people who consumed about 230 millilitres of a sugary drink each day.

The risk was found to be higher (at 32 percent) during the adolescence stage (from ages 13 to 18), which is an important time for growth and development in people.

"Despite the small number of cases found among the study participants, there is still a strong signal to suggest that sugar intake, especially in early life, is playing a role, down the road in increasing adulthood colorectal cancer risk before the age of 50," said Dr Cao.

Aside from cancer, the intake of sugar-sweetened drinks has also been linked to non-communicable diseases such as type 2 diabetes and obesity among adults, as well as children.

Yet, the consumption of such drinks has increased over the past 20 years, with the highest consumption level found among adolescents and young adults.

"Given this data, we recommend that people avoid sugar-sweetened beverages and instead choose drinks like milk and coffee without sweeteners," Cao said.

With the increasing rates of colorectal cancer among younger people, the first screening for the disease is now recommended at the age of 45, down from the previously recommended age 50 for people. But those at high risk of getting the disease due to factors such as family history, previous cancer diagnosis, obesity, drinking and smoking are advised to take the test much earlier.

Screening for the disease saves lives by preventing the condition as well as improving treatment outcomes and survival rates.