Hot Nutrition Topics - Prevent CRC

A Healthy Diet and Lifestyle Helps Prevent Colorectal Cancer
Written by Candy S.M. Wong, Accredited Practising Dietitian (Australia) 

Colorectal cancer is becoming increasingly common
In recent years, increasing Hong Kong people are diagnosed with colorectal cancers. According to Hong Kong Cancer Registry1, there were about 5,400 cases of colorectal cancer among the about 31,000 new cancer cases registered in 2016. Colorectal cancer ranks as the most common cancer and the number two cancer killer in Hong Kong, causing a total of about 2,100 deaths in 2016.

Are there magic bullets for cancer?
Have you ever spent money on rare functional food or dietary supplements to prevent cancer? Did you know that these “cancer-prevention” claims may not be based on scientific evidence? There are, in fact, some evidences showing that high dosage of certain supplements might increase cancer risk. For instance, beta-carotene supplements were shown to increase lung cancer risk2. Therefore, these unproven “cancer-prevention” supplements may not value for money, and more importantly they could be harmful to your health!

Dietitians recommend you to have a balanced emphasizing on a variety of food to obtain natural nutrients. Certain populations, like pregnant women, strict vegetarian or frail elderly, may require supplements to meet their nutritional requirements. You are therefore advised to seek professional advice from your doctors or dietitians before taking any supplements.

Good news: cancer can be prevented by living a healthy lifestyle
Many people think cancer is down to fate, while in most of the time it is not the case. Only 5-10% of the cancer cases are inherited. Among the top 10 common cancers, 8 of them are closely linked to our diet, lifestyle and smoking. By living a healthy lifestyle, you can greatly reduce your cancer risk. According to WCRF/AICR Expert Report (2007), Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective2, convincing scientific evidence shows that about one-third of cancer could be prevented by maintaining a healthy weight, eating healthily and staying physically active. In addition, deciding not to smoke or quitting smoking can offer you extra protection against cancer. All these are simple, inexpensive yet effective ways to lower your cancer risk.

Among all cancers, colorectal cancer has the most number of risk factors that you can modify to reduce your risk. That’s why it is often called the most preventable cancer. USA Centers for Disease Control and Prevention organized “Colorectal Cancer Awareness Month”3 in March every year. Why not act now to follow a healthy lifestyle? It is never too early or too late to start your cancer prevention plan. Remember that colorectal cancer is largely preventable, and you can always modify your diet and lifestyle to lower your cancer risk. 

Top 3 way to reducing your risk of colorectal cancer

(1)    Maintain a healthy weight
Research shows that being overweight or obese and carrying excess weight around your waist increases the risk of colorectal cancer2. Yet a survey conducted in April 2009 by the Behavioral Risk Factor Surveillance System of the Department of Health4 revealed that about 40% of the Hong Kong population was classified as overweight and obese. Choosing a healthy diet and being physically active can help you manage your weight.

To check whether your weight is healthy, you can obtain your Body Mass Index (BMI) by dividing your weight (in kg) by your height (in m) squared. Asian adults should aim for a healthy BMI of 18.5 – 22.9. To check whether you have excess weight around your waistline, you can measure your waist circumference, which is the narrowest point between the bottom of your ribs and the top of your hipbone. 

Asian male should aim for a waist circumference of less than 35.5 inches (90cm) while Asian female should aim for less than 31.5 inches (80cm).

Research shows that for every one-inch increase in waist circumference, colorectal cancer risk will increase by 5%2. In fact, by achieving a healthy weight, you could prevent not only cancer, but also other chronic diseases such as diabetes, high blood pressure and heart disease.

(2)    Be physically active
Research shows that being physically active reduces your colorectal cancer risk2, by helping you control weight and moving food through your intestine more quickly. Many international health organizations, such as American Heart Association5 and World Cancer Research Fund2, recommend at least 30 minutes of moderate physical activity every day for optimum health.
Physical activity has more benefits, such as:
-    Improve cardiovascular fitness
-    Lower blood pressure
-    Improve blood sugar control
-    Increase insulin sensitivity
-    Increase “good” HDL-cholesterol
-    Increase bone density
-    Improve mood

The easiest and most achievable physical activity is walking. Every step you take counts. Just grasp every opportunity to walk, such as walking the stairs instead of taking escalators, getting off the bus earlier and walk to your destinations, or going for a after-dinner walk with your family. If you have a pedometer, why not set small goals to keep you motivated? Start with 5000 steps a day, and then increase by 1000 steps each time, until an ultimate goal of 10000 steps is reached. When you get used to moving more, you can then try a variety of exercises to keep you interested.

(3)    A healthy diet
Increasing your dietary fibre intake helps you prevent colorectal cancer2, as well as other gut problems such as constipation. It is suggested to consume 25-30g of fibre per day. Simple changes to diet can help you “fibre-up”, such as bringing a piece of fruit to work, changing white bread to whole meal bread, or mixing brown rice with white rice. Don’t forget to have 5 serves of fruit and vegetable daily to help you achieve the fibre intake goal. And choose fruit and vegetables of different colors give you a range of antioxidants such as lycopene, anthocyanin or vitamin C to protect your cells against oxidative damage, subsequently reducing the risk of colorectal cancers. 

Research shows that red meat (beef, pork, lamb) and processed meat (ham, sausage, luncheon meat) greatly increase colorectal cancer risk2. Let’s opt for other healthy protein source, such as fish, legume, poultry, tofu. Remember always to remove animal skin and fat for your heart health.

Drinking alcohol is shown to be linked to colorectal cancer too2. In fact, excess alcohol can put you on weight, increase your blood pressure, and overload your kidney and liver. If you drink, it is recommended to have no more than 2 standard drinks daily for men, while no more than 1 standard drink daily for women. 1 standard drink is equivalent to 1 can of beer, 1 glass of wine (100ml) or 1 shot of spirit (30ml). If you never drink at all, don’t start drinking. 

Hope these tips help! Start now to lead a healthy lifestyle for cancer prevention! If you have any questions regarding how to manage your weight, how to be more physically active or how to eat healthily, you can always seek professional advice from a registered dietitian. 

References:
1.    Hospital Authority: Hong Kong Cancer Registry web site. 
       http://www3.ha.org.hk/cancereg/topten.html (accessed January 2019)
2.    World Cancer Research Fund/ American Institute for Cancer Research. Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective. 2007 (www.dietandcancerreport.org) 
3.    Centers for Disease Control and Prevention. www.cdc.gov/Features/ColorectalAwareness/
(accessed March 2010)
4.    Department of Health:Behavioural Risk Factor Surveillance System web site. www.chp.gov.hk/en/behavioural/10/280.html (assessed March 2010)
5.    Physical Activity and Public Health: Updated Recommendation for Adults From the American College of Sports Medicine and the American Heart Association. Circulation 2007;116;1081-1093