South Australian University highlights diet as key factor in surge of digestive cancer

Science Alert has published an article highlighting the rising incidence of bowel cancer in people under 50 which is becoming an alarming trend.

The number of individuals under 50 diagnosed with bowel cancer has risen sharply in recent decades. According to two new studies from Flinders University, this alarming increase may be linked to shifts in dietary habits.

"We've identified numerous direct links between poor dietary choices and digestive cancers," says nutrition epidemiologist Yohannes Melaku.

"Unhealthy eating patterns, characterized by high consumption of red and processed meats, fast food, refined grains, alcohol, and sugary drinks, are strongly associated with an increased risk of gastrointestinal cancers."

Gastrointestinal (GI) cancers, which are responsible for one-third of cancer-related deaths globally, can develop anywhere in the digestive system, from the throat to the stomach, pancreas, intestines, rectum, and anus.

Epidemiologist Zegeye Abebe and colleagues reviewed studies on dietary patterns and GI cancers, analyzing 28 relevant studies. While some studies presented conflicting findings, the overall data indicated that healthy eating habits tend to reduce cancer risk.

Additionally, a separate analysis by some of the same researchers, which examined data from 97,561 individuals, found that diets rich in fiber and unsaturated fats were associated with a lower likelihood of developing colorectal cancer—a disease expected to cause 1.6 million deaths by 2040.

"Given the rising number of digestive cancers, such as bowel cancer, especially in people under 50, it's crucial to take action to safeguard digestive health," Melaku emphasizes.

"Our studies show that nutrition education and the promotion of healthy eating habits could play a crucial role in reducing the risk of GI cancers and enhancing patient outcomes,"

As a systematic review of observational studies, the analysis cannot establish causality, but based on previous research, the team believes that the mechanisms connecting diet and cancer likely involve inflammatory processes and interactions within our microbiome.

Foods rich in antioxidants, such as berries, leafy greens, fruits, vegetables, almonds, walnuts, flax seeds, turmeric, ginger, garlic, citrus, fatty fish, and colorful vegetables, have anti-inflammatory properties. In contrast, red meat, sugary drinks, and refined carbohydrates, like those found in white bread, promote inflammation and can increase insulin resistance.

"Insulin resistance increases the risk of cancer through activation of insulin-like growth factor 1," Abebe and his team explain.

Their findings align with global dietary guidelines and support previous research showing that diets high in junk food and red meat negatively impact health. In contrast, diets rich in fresh fruits and vegetables are consistently linked to better health outcomes.

"While our results are promising, further research is needed, especially with a greater focus on nutrition in clinical settings and the use of nutritional biomarkers to better understand the relationship between diet and GI cancer," says epidemiologist Amy Reynolds.

"We need to understand how various dietary patterns may affect the risk of developing digestive cancers. Additionally, increasing education around healthy eating could lead to better health outcomes for individuals at risk for GI cancers."

By Naila Huseynova