Preventing Cancer — Part 1

What’s the big deal?

• Overweight and obesity increase your risk of a number of cancers, such as colorectum, oesophagus, breast, kidney and pancreas cancers, as well as the risk of other chronic conditions like hypertension, stroke and diabetes.

What can you do?

• Keep your Body Mass Index (BMI) within the normal range. The healthy range is between 18.5 and 25, but may vary between countries due to differences in body fat percentage and distribution across populations.

  For example in Singapore, the recommended BMI range for Asians is between 18.5 and 22.9, and the cut-off points for overweight and obesity are also lower. So you should take the BMI range that is tailored for your ethnic group.

  To find out your BMI, enter your height and weight in the BMI calculator below, and then click on the ‘Calculate’ button.

  BMI Calculator

  Height (in metres):
  

  Weight (in kilograms):
  

  Your Body Mass index is:
  

  Note: BMI as a tool to classify body fatness has its flaws. For instance, if you are a muscular person with low body fat, or someone who is less than 1.52 m tall, the BMI result you get will not be indicative of your actual weight condition.

• Avoid weight gain and increases in waist circumference throughout your adulthood. If you have gained weight, even if it is within the normal range, you should aim to return to your original weight. Because weight gain during adulthood is usually associated to an accumulation of fat rather than lean mass, increasing your risk of cancers related to weight gain, overweight and obesity.

• Waist circumference is another simple way to find out whether your weight is healthy or not. It correlates closely with BMI and it gives you a rough estimate of your intra-abdominal fat mass and total body fat.

  You should aim to maintain a waist circumference of not more than 94 cm (37 inches) if you are a man, or not more than 80 cm (31.5 inches) for women. Waist circumferences beyond 102 cm (40.2 inches) in men and 88 cm (34.6 inches) in women increase the risk of cancers and other diseases.

  For Asian populations, lower waist circumference cut-offs of 90 cm (35.4 inches) for men and 80 cm (31.5 inches) for women have been proposed.

• If you have young children, ensure that their body weight stay within the lower end of the normal BMI range. In another word, prevent your kids from excess weight gain, or becoming overweight or obese. Research has shown that children who are overweight during childhood are more likely to be overweight and obese when they grow up, thereby increasing their cancer risks.

What’s the big deal?

• Energy-dense foods and sugary drinks promote weight gain, especially when consumed frequently and in large portions.

• Correspondingly, low energy-dense foods like vegetables and fruits, protect you against weight gain, overweight, obesity and some cancers.

What can you do?

• Replace energy-dense foods with low energy foods like non-starchy vegetables, fruits, and relatively unprocessed grains and legumes.

  Energy-dense foods, especially processed foods like fried foods, pastries, desserts and snacks, tend to contain large amounts of fat or sugar than those that include high amounts of fresh foods. As a result, they are likely to lead to overweight and obesity.

• Substitute sugary drinks with unsweetened drinks like water, coffee or tea without sugar. Although sweet soft drinks are less energy-dense than foods, they do not induce satiety and often lead to over-consumption of energy and weight gain. Even fruit juices with no added sugar, are likely to have the same effect and therefore, should not be drunk in large quantities.

• Consume ‘fast foods’, such as burgers, fried chicken pieces, French fries and fatty or sugary drinks, sparingly, if at all. These readily available convenience foods tend to be energy-dense and consumed frequently and in large portions.

What’s the big deal?

• Red meat, especially processed meat is a cause of colorectal cancer. The evidence on processed meat is even more clear-cut than that on red meat. Diets with high levels of animal fats are also usually high in energy, increasing the risk of weight gain.

• A favorite dish in some parts of Asia — Cantonese-style salted fish — has been linked to nasopharyngeal cancer, though fish prepared or salted by other means have not been found to have the same disastrous effect.

• Diets high in calcium (about 1.5 g per day or more) are a probable cause of prostate cancer.

• Milk from cows may offer some protection against colorectal cancer.

What can you do?

• Evidence shows that people who adopt vegetarian diets are at low risk of some diseases including cancers. But, it is not easy to distinguish whether these people derive the benefits from their diets alone, or from their lifestyle as they also tend not to smoke and drink little, if any, alcohol.

• If you eat flesh foods, limit your consumption to less than 500 g (18 oz) a week and choose only lean cuts. Foods of animal origin can be nourishing and healthy if they are consumed in modest amounts as they provide valuable nutrients such as protein, iron, zinc, and vitamin B12.

• Substitute red meat with poultry and fish (except Cantonese-style salted fish of course). Poultry contains a lower proportion of saturated fats than red meat and a higher proportion of polyunsaturated fats. Fish contains an even lower amount of saturated fats and it also contain fatty acids which are essential to the development and function of the brain and retina, among other benefits.

• Avoid processed meat as much as you can. A safe level of processed meat consumption cannot be determined yet, as they not only contain high levels of salt, they also contain carcinogens which are generated during the preservation process. So it is best to avoid processed meat completely.

  Processed meat includes ham, bacon, pastrami, and salami. Sausages, frankfurters, and hot dogs, to which nitrates/nitrites or other preservatives are added, are also processed meats. Minced meats and ‘hamburgers’ also fall under this category if they are preserved chemically.

Note: It is not necessary for you to eat a lot of red meat in order to get adequate amounts of protein and iron.

All flesh foods are naturally high in protein, and for people who consume varied diets without any flesh foods, more than adequate protein can be derived from a mixed diet of legumes and grains. Iron can also be found in many plant foods, as well as meat.