Cancer is a chronic disease that most of us will be impacted by at some point in our lives. It may be a friend or family member fighting the disease or it could be you. In fact, the most current incidence rates show that 40% of Canadian women and 45% of men will develop cancer during their lifetimes. Indeed, one out of every four Canadians will die from cancer (Canadian Cancer Society, 2009).

In addition to inactive lifestyles and obesity, diet-related factors are thought to account for about 30% of cancers in developed countries. The link between diet and cancer began to gain more attention in the 1970’s when it was noted that many people in western countries, such as Canada, consumed diets high in animal products, fat, and sugar. People in western countries also had high rates of certain types of cancer (i.e., colorectal, breast, prostate, endometrial, and lung). In contrast, people in developing countries that consumed diets that were low in animal products, fat, and sugar, had low rates of these types of cancer.

The short-term benefits of eating a healthy diet high in vegetables, fruit, and fibre are well-known and include weight control, increased energy levels, and regularity. As more research is completed, the long-term benefits of healthy eating, such as cancer prevention, have become more evident. In fact, there are now scientifically grounded dietary recommendations that we can follow that are likely to reduce our risk of cancer.

WHY

Why is diet important for cancer prevention?

Although cancer survival rates are increasing, the number of Canadians diagnosed with cancer is also increasing. On the bright side, research suggests that approximately half of all new cancer cases and cancer deaths worldwide are preventable. In developed countries such as Canada, the greatest risk factors are tobacco smoking (30%) and poor diet, obesity, and low levels of physical activity combined (30%). It’s important to be informed of all the steps you can take to prevent cancer. A healthy lifestyle and specifically, making changes to your diet, can reduce your risk of getting certain types of cancer.

WHAT

What parts of my diet can I change to lower my cancer risk?

Making wise choices when it comes to what you eat and drink can reduce your risk for cancer. In 2007, a global report titled Food, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective, was produced by a group of experts from around the world. The table to the right shows the link between diet and the risk for certain types of cancer.

HOW

How can I eat better to reduce my risk of cancer?

There are a number of things you can change in your diet and lifestyle in order to reduce your risk of cancer. Remember, small changes go a long way to improving your overall health and well-being. Choose the areas of your diet, activity levels, and lifestyle that you want to focus on first. Then make a plan and stick with it.

Reach and keep a healthy body weight.

Keeping a healthy body weight throughout life is one of the most important things you can do to prevent cancer. A Body Mass Index (BMI) of 18.5-24.9 places you at the lowest risk for developing many types of cancer. Evidence shows that increased body fat raises the risk of esophageal, pancreatic, colorectal, postmenopausal breast, endometrial, and kidney cancer. Having a waist circumference of ≥102 cm (40’’) in men and ≥88 cm (35’’) in women has also been linked to a higher risk of cancer. In fact, abdominal fat specifically increases the risk of colorectal cancer. Cut down on eating calorie dense foods, such as sugary drinks (e.g., soft drinks) and high-fat food (e.g., fried foods like chips and french fries). Eating healthy and being active everyday can help you reach and keep a healthy body weight.

Limit your intake of red meat and certain higher-fat, processed meats.

Research shows clearly that eating red meat and processed meat increases the risk of colorectal cancer, the second leading cause of cancer death in Canada. If you eat red meat regularly, try to limit it to less than 500 g (18 oz) per week. Also, really limit your intake of processed red meat, including ham, bacon, pastrami, salami, sausages, frankfurters, and hot dogs. They can be higher in calories, contain high levels of sodium, and may contain chemical preservatives such as nitrites/nitrates that are linked with cancer. There is probable evidence that salt, salty foods, and salt-preserved foods increase the risk of stomach cancer.

Eat more vegetables, fruit, and whole grain products.

You can cut down on your intake of calorie dense foods by replacing them with foods lower in calories and higher in nutrients. Focus on high fibre and non-starchy vegetables, fruit, legumes, and whole grain products. Try to eat at least five servings of non-starchy vegetables and fruit each day. Eating non-starchy vegetables, such as cabbage, broccoli, cauliflower, kale, and brussels sprouts is linked to a reduced risk of cancer of the stomach, esophagus, mouth, pharynx, and larynx.

Limit the amount of alcohol that you drink.

There is growing evidence that all types of alcoholic drinks are linked to a number of cancers, including mouth, esophagus, larynx, colorectal, pre- and post-menopausal breast, and liver. The Canadian Cancer Society reports that drinking more than 3.5 drinks a day can double or even triple your risk of developing most of these types of cancer. Just over one drink a day on average almost doubles the risk of breast cancer. Limit yourself to no more than one standard drink per day for women or no more than two drinks per day for men. Occasional heavy drinking is even more likely to lead to poor health outcomes.

• 5 oz/142 mL of wine (12% alcohol)

• 1.5 oz/43 mL of spirits (40% alcohol)

• 12 oz/341 mL of regular strength beer (5% alcohol)

Remember to be physically active.

Limit time where you are inactive, such as watching T.V. or using computers and aim to get at least 30 minutes of moderate activity (e.g., brisk walking) every day. Try increasing your daily physical activity up to 60 minutes of moderate activity or 30 minutes of vigorous activity (e.g., running or swimming) daily. Regular physical activity decreases the risk of colon cancer. It also helps you reach and keep a healthy weight, which is associated with many types of cancer already listed. Remember that physical activity doesn’t have to mean playing a sport or going to the gym. It can be as simple as going for a bike ride, doing household chores, gardening, or walking the dog.

Key References:

Canadian Cancer Society. (2009).Cancer statistics. Retrieved June 1, 2009 from

http://www.cancer.ca/canadawide/about%20cancer/cancer%20statistics/powerpoint%20slides.aspx?sc_lang=en

Centre for Addiction and Mental Health. (2008). Low-risk drinking guidelines. Retrieved June 23, 2009 from http://www.camh.ne /About_Addiction_Mental_Health/Drug_and_Addiction_Information/low_risk_drinking_guidelines.html

Marrett, L.D., De, P., Airia, P., & Dryer, D. (2008). Cancer in Canada in 2008. Canadian Medical Association Journal, 179, 11, 1163-1170.

National Cancer Institute. (2009). Red wine and cancer prevention: Fact sheet. Retrieved June 23, 2009 from http://www.cancer.gov/

World Cancer Research Fund & American Institute for Cancer Research, (2007). Summary: Food, nutrition, physical activity, and the prevention of cancer: A global perspective. Retrieved on June 2, 2009 from http://www.dietandcancerreport.org/