Colorectal cancer prevention

Balanced diet

Preventing colorectal cancer is simple. Minor changes in your daily life and diet, and following a healthy lifestyle can prevent or reduce the risk of developing colorectal cancer.

1. Eat more food rich in fibre, such as whole-grains, beans, fruits and vegetables
   • There is strong and consistent evidence showing that diets rich in fruits and vegetables can reduce the risk of many cancers, for example, colorectal cancer, gastric cancer, oesophageal cancer, oral cancer, probably lung cancer and breast cancer.
   • Frequent consumption of pickled or salted vegetables is associated with a higher risk of cancer.
   • Eat more fruits and vegetables.
     • Consume at least 2 servings of fruits and 3 servings of vegetables a day. (One serving is about 80g. At least 400g of a variety of fruits and vegetables should be consumed every day.)

       

       

     • One serving of fruits is approximately defined as one of the following:
       [Note: 1 cup = 240ml; 1 bowl = 250-300ml]
       • 2 pieces of small-sized fruits (e.g. plums and kiwifruits)
       • 1 piece of medium-sized fruit (e.g. oranges and apples)

         

         

       • 1/2 piece of large-sized fruit (e.g. bananas, grapefruits and starfruits)

         

       • 1/2 cut of cut-up fruits (e.g. watermelons and honeydew melons)

         

       • 1/2 bowl of berry-sized fruit (e.g. grapes, lychees, cherries and strawberries)
       • 1/4 bowl of dried fruit without added sugar or salt (e.g. raisins and prunes)
       • 3/4 cup of fresh fruit juice without added sugar (e.g. fresh orange juice with pulp)
     • One serving of vegetables is approximately defined as one of the following:
       [Note: 1 cup = 240ml; 1 bowl = 250-300ml]
       • 1 bowl of raw leafy vegetables (e.g. lettuce and purple cabbage)

         

       • 1/2 bowl of cooked vegetables, sprouts, gourds or mushrooms (e.g. Chinese flowering cabbage, Chinese kale, spinach, white cabbage, bean sprout, eggplant and carrot)

         

       • 3/4 cup of fresh vegetable juice without added sugar (e.g. fresh tomato juice with pulp)
       • 1/2 bowl of cooked beans (e.g. snow pea, red kidney bean)
2. Decrease consumption of red meat and processed meat
   • Red meat consumption is associated with increased risk of colorectal cancer and breast cancer. For colorectal cancer, stronger association is found for the consumption of processed meat.

     

   • Decrease consumption of red meat and processed meat
     • Decrease consumption of red meat (e.g. beef, lamb and pork)
     • Eat less meat with high salt content (e.g. ham, sausages and bacon)

       

     • Avoid processed meat (e.g. luncheon meat and sausages)

       

Regular exercise

1. Exercise improves the cardiorespiratory endurance, muscular fitness and bone health, and reduces the risk of cancer.
2. Physical activity refers to any bodily movement produced by skeletal muscles that increases energy expenditure above a basic level.
3. You may spend at least 150 minutes every week on aerobic physical activity of moderate intensity or at least 75 minutes every week on an aerobic physical activity of vigorous intensity.
4. Aerobic physical activities of moderate intensity include brisk walking, biking on level ground or a slight slope, sports involving catch and throw (e.g. table tennis and volleyball), ballroom dancing and line dancing.
5. Aerobic physical activities of vigorous intensity include jogging or running, jumping rope, aerobics, vigorous dancing and sports that often involve running (e.g. basketball and football).

   

6. Each session of physical activities should last for at least 10 minutes.
7. You may flexibly combine physical activities of moderate intensity with those of vigorous intensity.
8. You can gradually increase the time that you spend on physical activities.  The more time you spend on them, the more benefits you can get from them.  
9. Besides aerobic physical activities you should spend at least two (non-consecutive) days each week on activities that strengthen your muscles, including weight lifting, band exercises, push-ups and sit-ups.
10. It is safe for most people to increase their amount of exercise.  People suffering from chronic diseases and the elderly may need a medical check-up before they start exercising.  If you have any questions, consult your doctor.
11. Elderly people who cannot fulfil the recommended amount of exercise should do as much as their health and fitness allows.

    

12. We should take safety precautions to reduce the risk of injury caused by physical activities:
1. Wear comfortable clothes and suitably padded shoes to protect your ankles and foot arches.
2. Use suitable gears, for example, a helmet and kneepads when cycling.
3. Remember to warm up before exercise and to cool down afterwards, in order to reduce the risk of pulling a muscle and twisting a joint.

   

   

4. Have suitable breaks during your exercise.
5. Do not exercise with an empty stomach or just after a big meal.  Have snacks before exercise, for example a piece of toast or some skimmed milk, to supply you with energy.
6. Be sure to drink enough water before, during and after exercise, especially for prolonged exercises like hiking.
7. Pay attention to the weather and the environment.  Do not exercise outdoors in extreme weather conditions.
8. Pay attention to your physical condition.  If you feel unwell, do not exercise.  If you experience dizziness, shortness of breath, chest pain, nausea or severe pain in your muscles or joints, stop exercising and seek medical advice as soon as possible.

Maintain healthy body weight and waist circumference

1. Maintain a healthy body weight and waist circumference. Aim for a body mass index (BMI) between 18.5 and 22.9, and a waist circumference of less than 90 cm (about 36 inches) for men and less than 80 cm (about 32 inches) for women.

2. Body Mass Index
   BMI is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. 　It is defined as a person's weight in kilograms divided by the square of his/her height in metres (kg/ m²).
   BMI = weight (kg) / (height (m) x height (m))
   

   	BMI
   Obese	25 or above
   Overweight	23 – 24.9
   Normal	18.5 – 22.9
   Underweight	Below 18.5

   
   [Note: The West Pacific Regional Office of the World Health Organization published the above ranges of the index for the reference of Asian adults. They are not applicable to children under 18 years old or pregnant women.]
   

   

3. Central obesity
   While BMI is commonly used as a measure of obesity, it does not distinguish between weight associated with muscle or fat in an individual, thus the relationship between BMI and body fat content varies according to body build. In fact, central fat accumulation would be a more sensitive indicator of cardiovascular and chronic disease risk.

   For Asian adults, if you have a waist circumference of over the following limits, you have an increased risk of developing cardiovascular diseases and other chronic diseases:
   

   
   

   Sex	Waist circumference (cm)	Waist circumference (inches)
   Male	90 or above	Around 36 or above
   Female	80 or above	Around 32 or above

   Measuring your waist circumference:
   

   1. Measure directly against your skin. Remove things such as your wallet or mobile phone that you may carry near your waist.
   2. Breathe out naturally.
   3. Make sure the tape is snug, without compressing the skin.
   4. Measure halfway between your lowest rib and the top of your hipbone, roughly in line with your belly button.

      

4. Tips for maintaining a healthy body weight
   
   1. Have a balanced diet
      1. To build a healthy eating habit, start by paying attention to the food you buy, how you cook it, when you eat and what you eat in each meal. For example,
         1. Buy a variety of food to get balanced nutrition.
         2. Avoid food with high fat content by replacing, for example, whole milk with low-fat milk or skimmed milk, fatty meat with lean meat and by skinning poultry meat before you cook it.
         3. Avoid food and drinks with high sugar content.
         4. Steam, boil, bake or stir fry food to avoid using a lot of oil in cooking.
         5. Eat three meals at regular times. The size of each meal should be reasonable. The major portion of each meal should consist of grains, followed by vegetables. Meat should consist the least portion in each meal. You may eat healthy snacks such as fruits between the two main meals.

            

            

   2. Regular physical activities
   1. To stay healthy, an adult should have a total of 150 minutes of aerobic physical activities of moderate intensity per week. People who have never exercised regularly should consult a doctor before starting. Remember, to control your weight effectively you have to exercise regularly and maintain a healthy diet.

      

   Abstain from alcohol drinking

   

   1. Alcohol has been classified by the International Agency for Research on Cancer, which forms part of the World Health Organization, as a Group I Carcinogen, another example of which is tobacco. Alcohol can cause various cancers, including colorectal cancer, breast cancer and liver cancer, which are common in Hong Kong.
   2. There is no "safe" level of alcohol drinking as far as cancer risk is concerned. So the wisest choice is not to drink at all. The more you drink, the higher the risk of developing cancer.
   3. Drinking a lot of alcohol in a short period of time can cause acute alcohol intoxication, which harms the body to various degrees, including damage to functions of the brain (impairing judgment, slowing reaction time, reducing physical coordination or affecting articulation), hypothermia, coma and sudden death.
   4. Alcohol affects the digestive system. It may cause oesophagitis and gastritis. It damages the liver, causing hepatitis, cirrhosis of the liver and liver cancer. It also leads to erectile dysfunction, high blood pressure and affects functions of the heart. In the long run, every mouthful of alcohol you drink gradually affects your health.
   5. Strategies for abstaining from alcohol:
      
      1. Record the time, place and reason for drinking and the quantity you have drunk in a diary or on your mobile phone, in order to discover what triggers you to drink. Avoid occasions in which you need to drink or which might trigger you to drink.
      2. Change your lifestyle. Try to keep your distance from alcohol and reduce your desire for alcohol by, for example,
         1. setting a realistic goal for abstaining from alcohol;

            

         2. drinking plenty of water, not having any alcohol at home, and replacing alcohol by non-alcoholic drinks such as fruit juice, vegetable juice, soda water or green tea;
         3. diverting your attention from alcohol by engaging in other activities such as taking a shower or hobbies such as listening to music;
         4. exercising regularly, learning relaxation techniques and meditating or practicing yoga to replace drinking and to relieve stress;
         5. seeking support from family members, friends and colleagues, letting them know that you have decided to stop drinking and remind them not to provide you with alcohol, nor to drink in your presence;

            

         6. developing techniques for refusing alcohol, for instance, saying "No, thank you, I am trying to drink less”, or “No, thank you, I have stopped drinking."
         7. reminding yourself by various means, including labels, posters, automatic text messages or emails, the reasons to drink less or not to drink; and
         8. seeking professional help, by joining a support group for alcohol problems run by the Hospital Authority or by using the alcohol abstinence service of voluntary organisations instead of facing your drinking problem alone.

   Abstain from smoking

   1. Besides causing lung cancer, smoking has been proven to cause a lot of cancers, such as mouth cancer, throat cancer, tongue cancer, oesophageal cancer, stomach cancer, bladder cancer and kidney cancer.
   2. The nicotine in tobacco affects the circulatory system, reducing blood flow to a man's penis and his ability to maintain an erection.  Smoking increases the chance of women having fertility problems and may disrupt their menstrual cycle.  
   3. Smoking speeds up ageing of the skin.  Smokers look older than their actual age.
   4. Second-hand smoke contains smoke that a smoker inhales and exhales (mainstream smoke) and the smoke released from tobacco between puffs (side-stream smoke).  Research show that second-hand smoke contains 7,000 odd chemical substances found in first-hand smoke, at least 69 of which are carcinogens.
   5. Besides causing coughing, sore-throat and headache, second-hand smoke leads to conditions such as heart disease and stroke, which may be fatal.  It increases the chance of premature birth and miscarriage.  It causes acute lower respiratory infection and asthma in children, eventually causing chronic respiratory diseases.
   6. Some smokers think that low-tar or low-nicotine tobacco products have fewer harmful effects.  In fact, all tobacco products may be fatal.   Smokers may believe these products are safer and, in turn, smoke more. Consequently, doing more harm to their health.
   7. Research studies have shown that even if smokers  above 60 years old give up smoking, they can on average live three years longer.  If a smoker stops smoking for even only one week, their cardiorespiratory function will improve significantly, as well as their quality of life.  Therefore it is worthwhile for smokers of all ages to give up smoking, the earlier the better.  
   8. Strategies for stopping smoking:
      1. Set a quit date in the future in which you wish to stop smoking.  Share with family members and friends the good news that you are going to stop smoking and try to obtain their support and help.

         

      2. Assess the obstacles that you may encounter and make plans for dealing with them.  For example, you may change your habits, or you may write down the reasons to stop smoking, in order to encourage and remind yourself.
      3. Throw away all tobacco products, ashtrays and cigarette lighters.
      4. Try to stay away from places where people smoke.

         

      5. Firmly refuse tobacco products offered to you.
      6. Have plenty of exercise, rest and a balanced diet.  Develop new hobbies.

         

      7. Call the Smoking Cessation Hotline of the Department of Health to obtain information on smoking cessation and to use counselling services for smoking cessation.

         

         Integrated Smoking Cessation Hotline of Department of Health 1833 183