Gastrointestinal cancers are common in Hong Kong. Today is World Digestive Health Day, so there’s no better time to find out how to minimise your risk of developing the disease and maintain a healthy gut. According to the most recent data from the Hong Kong Cancer Registry, for the year 2016, three out of the 10 most frequently diagnosed cancers in the city were related to the digestive system: colorectal cancer (ranked first with 5,437 new diagnoses), liver cancer (ranked fifth with 1,810 new diagnoses), and stomach cancer (ranked sixth). Moreover, five of the 10 cancers responsible for the most deaths in Hong Kong were related to the digestive system: colorectal cancer (ranked second, responsible for 2,089 deaths), liver cancer (ranked third, 1,540 deaths), stomach cancer (ranked fourth), pancreatic cancer (ranked sixth), and oesophageal cancer (ranked ninth). The risk of developing colorectal cancer increases noticeably after the age of 50, which is why most international guidelines recommend that average-risk individuals start colorectal cancer screening at this age. Lately, however, there has been a rise in the number of colorectal cancer cases in people younger than 50, particularly in the United States, and in parts of Europe and Asia, including Hong Kong. “The risk factors for developing colorectal cancer can be separated into non-modifiable and modifiable factors,” says Dr John Wong, a gastroenterologist at OT&P Healthcare, Central Specialist Clinic in Hong Kong. “Besides advancing age, another non-modifiable factor is a family history of the disease. If you have a family history of colorectal cancer or advanced polyps, speak to your doctor about the best time to start screening.” Risk factors largely relate to lifestyle, such as diet, level of physical activity, weight, whether someone smokes, and alcohol consumption. Wong says eating a lot of red and processed meats can increase the risk of developing colorectal cancer, as can not eating enough whole grains, fruit, vegetables, legumes and dietary fibre. To lower your risk of developing colorectal cancer, Wong recommends consuming at least 30g of fibre per day from a variety of sources, and no more than 510g of red meat per week. It is also important to maintain a healthy body mass index (BMI), of between 18.5 and 24.9kg/m 2 for Caucasians, and 18.5 to 23kg/m 2 for Asians. (BMI can be calculated by dividing your weight in kilograms by your height in metres squared.) Symptoms of problems in the lower digestive tract may include a change in bowel habits, rectal bleeding, abdominal pain, and unintentional weight loss. “Benign and malignant digestive diseases can have overlapping symptoms,” Wong says. “For example, don’t assume that rectal bleeding is always due to haemorrhoids, as inflammation of the colon and colorectal cancer may also cause this symptom.” Besides maintaining a healthy lifestyle through balanced eating, adequate exercise and staying at an acceptable weight, screening may reduce your risk of developing and dying from certain gastrointestinal cancers. Even if you don’t have symptoms, Wong says screening can help identify precancerous growths so that they can be removed before they become cancerous; it can also identify early-stage cancers to improve your chances of survival. “This is particularly relevant for colorectal cancer in Hong Kong, as more than 50 per cent of the colorectal cancers being diagnosed are late-stage – either stage III (cancers that have spread to the lymph nodes) or stage IV (cancers that have spread to other organs,” Wong explains. Two common gut conditions in Hong Kong 1. Irritable bowel syndrome (IBS): According to Violet Man, a dietitian at OT&P Healthcare in Hong Kong who works at its clinics in Central, Repulse Bay and Clear Water Bay, IBS is a disorder that involves abdominal pain and bloating, changes in bowel movements, constipation, diarrhoea, or both constipation and diarrhoea. The causes of IBS are unknown, Man says, although the symptoms may be due to increased sensitivity to the function of the bowel, leading to discomfort and abnormal bowel contractions. 2. Inflammatory bowel disease (IBD): The causes are unknown, says Man. The disease often develops between the ages of 15 and 30, although it can start at any age, and it is more common in women than men. How do we maintain a healthy gut? A balanced diet, specifically one that contains prebiotics and probiotics, is key to maintaining a healthy gut, says Man. Our gut contains trillions of friendly and harmful bacteria – the more good bacteria there are the healthier the gut. Good intestinal bacteria help the body digest certain foods, assist in the production of some vitamins, like B and K, protect us from harmful organisms, and boost our mood and energy. Prebiotics, sometimes called fermentable fibre, contain non-digestible food particles that support the growth of friendly bacteria already living in the gut. The best sources of prebiotics include bananas, berries, onions, garlic, leeks, asparagus, legumes, and whole grain foods. Probiotics, on the other hand, are live microorganisms. They provide a range of health benefits for the host, including maintaining digestive comfort, regulating the immune system, reducing the problems associated with IBS and IBD, helping with the digestion of dairy products, and reducing symptoms of diarrhoea associated with antibiotic usage or acute illness. Probiotics are found in fermented foods such as yogurt, aged cheese, kefir, sauerkraut, miso, kimchi, tempeh, soy beverages and dietary supplements.