Conquering Cancer: What role does your diet play?

Cancer is the number one killer of Canadians and one of the premier public health concerns of our generation. As a public health professional, I take cancer prevention very seriously. It has been nearly a decade since cancer first surpassed heart disease as the leading cause of death in Canada, and the disease is showing no signs of relinquishing that place. In reality, cancer is not a singular disease but rather a set of mostly chronic diseases that can afflict different parts of the human body. Cancer will generally have genetic( family history), environmental and dietary components. Although not every single cancer is necessarily preventable through diet alone, the prevention of many cancers entails an important dietary component. 

The best prevention for most cancers is to live a generally healthy lifestyle, including diet and all other lifestyle considerations such as smoking, drinking, sun exposure and so on. Lung, prostate, breast and colorectal cancer are the most common types of cancer, representing about half of all cases in Canada. The other half of cancer cases are diffusely spread over a variety of other cancers such as pancreas, stomach, brain , liver and so on. As you can imagine, the diversity of forms which cancer can take makes generalizing prevention guidance much more challenging for health educators. Although some causes of cancer are certainly related, different cancers may be primarily caused and prevented by different factors. With this in mind, my aim today will be to provide you with some important nutritional considerations which will contribute to general cancer prevention as well as discussing certain dietary components which are known to be more directly related to specific common cancers. 

Important Nutritional Considerations for Cancer Prevention

Older Age: It is important to understand that cancer is more likely to occur in individuals over the age of 50. Although the guidance I provide here today will be relevant to you regardless of age, if you are indeed over the age 50 know that your risk for cancer is greater and the points that I discuss below are of even greater relevance to you.

The issue of Overweight and Obesity: This is an extraordinarily important public health concern in Canada and across the world. Over half of the Canadian adult population is either overweight or obese, and this is putting our population at a greatly increased risk for all chronic disease, cancer included. I suggest using the following Health Canada toolto determine if you are considered overweight or obese. There is no way to sugar coat the reality that being overweight (or obese) is one the biggest risk factors for cancer. I also appreciate how difficult it can be to lose weight. The good news is that losing between 5-10% of your weight is a great start to reduce your risk for a variety of chronic diseases. For a variety of tips and suggestions to help you start on your weight management journey, please have a look Eat Right Ontario’s Weight Management Resource. I also highly recommend you consider seeking the guidance of a health professional, such as a registered dietitian, especially if you believe the extra support and guidance will benefit you.

Eat more Fruits & Vegetables:  There are many foods out there that have disease fighting components, but none moreso than fruits and vegetables. There is good evidence to suggest that fruits and vegetables ( especially dark green and orange vegetables) are protective against many types of cancer. With that being said,  it is important to eat a great diversity of fruits and vegetables as different types offer different protective nutrients. Garlic, for example, has been shown to have some protective potential against colorectal cancer whereas tomatoes are protective against prostate cancer. Make no mistake, regardless of their specific nutrients, all fruits and vegetables contain common components , such as dietary fibre, that have great value to the wellbeing and longevity of an otherwise healthy individual. The unfortunate reality is that many Canadians do not eat enough fruits and vegetables. Committing to eating one extra piece of fruit and one extra serving ( about a cup) of vegetables a day can be a great start that will do both your long and short-term health a great service.  

Do not rely on supplements: Simply put, vitamin and mineral supplements are not recommended as an acceptable replacement for a balanced diet and adequate fruit and vegetable intake. Fruits and vegetables contain numerous healthy components that cannot be properly replicated by a supplement. If you happen to be aware that you are lacking in a specific nutrient ( as in vitamin B12 in vegans) supplementation may make sense. However, I do not want you to believe that a daily multivitamin will provide you anywhere near the same degree of cancer  or general disease protection as consuming a balanced diet rich in fruits and vegetables. Supplements can also be costly, taking away financial resources that could otherwise be used to purchase healthful whole foods.

Smoking & Beta-Carotene:  You probably know by now that smoking greatly increases your risk of lung cancer. What you may not know is that smoking while taking beta-carotene supplements may further increase that risk. If you are a smoker, I implore you to quit, but while you continue to smoke please ensure you are not taking a daily beta-carotene supplement containing more than 6 mg ( or 6,000 micrograms). If you are, you should consult a health care professional immediately. Dietary beta-carotene ( as found in foods such as carrots & sweet potatoes) intake is much less of a concern at levels of moderate consumption and should be of no concern at all to non-smokers. If you are a smoker who is looking to quit, I highly recommend having a look at Health Canada’s Smoking Cessation Resource.

Physical Activity:  Physical activity provides our bodies several unique health benefits that we cannot always acquire through diet alone. Individuals who are not physically active are missing out on these benefits and are also at greater risk of being overweight. This is an all risk, no reward scenario. Depending on your capabilities, there are a variety of options available to increase your physical activity levels such as walking more, bike riding, joining a recreational level sports team or even viewing instructional physical activity videos online. For even more tips on how to stay physically activity have a look at Health Canada’s Physical Activity Resource.

Red Meat, Processed Meats & Animal Protein: When it comes to colorectal cancer specifically, red and processed meat consumption has consistently been shown to increase your risk. What does this mean for meat lovers? First, it means you should aim to consume no more than 500 grams ( 18oz) of red meat per week. If you are eating multiple 12 oz steaks a week, this could be a problem. Second, it means you should make an honest effort to minimize the amount of processed meats you consume ( ie: hot dogs, bacon. deli meats cured & smoked meats). I recommend consuming processed meats as infrequently as you possibly can as they are generally also high in sodium which Canadian’s already consume far too much of. It is also highly recommended to consume plant protein in place of animal protein whenever possible to help further reduce your risk. This means trying to occasionally incorporate more nuts, seeds, beans, peas, lentils, tofu and soy products in place of milk, eggs, meat, poultry and fish. 

Vitamin D: Vitamin D is currently a topic of great interest in cancer and disease prevention research. I can not say conclusively that Vitamin D plays a definitive role in preventing cancer, but it is certainly  a topic of growing interest and it is very important that you ensure you are getting enough vitamin D (many Canadian’s are not). If you are over the age 50, Health Canada also recommends you take a daily vitamin D supplment containing 400 IU of vitamin D. 

Selenium & Lycopene: Selenium and lycopene are nutrients known to be protective against prostate cancer. The foods richest in lycopene and selenium are as follows:

Lycopene: Guava, watermelon, tomato, papaya and grapefruit, sweet red peppers and asaparagus. 

Selenium: Brazil nuts, oysters, tuna,  sunflower seeds, pork/chicken/beef/lamb and whole wheat bread.

As you can see, lycopene and selenium are found in a very different and diverse group of foods. It is for this reason it is important to always strive for diverse and healthy food selections. If you are eating a balanced and varied diet you are quite likely consuming sufficient selenium, lycopene and a host of other very important disease fighting nutrients.

Alcohol:  Alcohol intake is associated with an increased risk of a variety of cancers. In my personal and professional opinion, it is better not to drink. If you do drink, keep it to 1 drink a day for women and 2 a day for men. What is a drink?

Be with those who support healthy habits:  For many of us, living a healthy lifestyle is much easier if we surround ourselves with likeminded and supportive people. For both your short-term wellbeing and long-term health, I urge you to spend the majority of your time with those people who will positively influence your lifestyle. Alternatively, if you happen to be concerned about the eating habits of someone close to you, be that healthy positive influence for them. Click here or here for links to two of my previous articles which will help teach you how to encourage people you care about to eat and live  healthier. 

I sincerely hope that today’s article has provided you with some important insights into how your diet and lifestyle can play an extremely important role in general and specific cancer prevention. If your own personal family history of cancer concerns you, I hope you have been afforded some piece of mind by today’s content. Cancer is the number one cause of death in Canada and not something to be taken lightly, see a health professional if you are concerned about your own personal risk. Before closing, I would like to take a moment to provide my deepest sympathies and support to any readers who have been affected either directly or indirectly by this horrible disease.

I wish you all the best.


Thank you,
Andy De Santis RD MPH


Today’s article is written in dedication to my late grandmother, Giuseppina Capone, who passed away last year and who I dearly miss. Thanks for everything Nonna.