60% of high-priority research goes unfunded.
Acrylamide is a chemical that appears in certain foods that have been cooked at high temperatures (above 120°C or 250°F). Levels of acrylamide seem to increase the longer the foods are cooked. High levels of acrylamide have been found in French fries, potato chips, cookies, coffee, processed cereals and bread.
Some possible risks to Canadians were identified when acrylamide was reviewed under the federal Chemicals Management Plan. Although research is not yet able to tell us for certain if there is a link between cancer and the levels of acrylamide in food, the federal government is trying to develop ways to reduce the amount of acrylamide we are exposed to. As part of this, Health Canada has started a monitoring program to study the levels of acrylamide in the food we eat. The food industry is also studying ways to reduce the formation of acrylamide during food processing.
If you’re worried about acrylamide, avoid or cut back on fried or deep-fried foods that have been shown to contain it, such as French fries and potato chips.
Aflatoxin and cancer risk
Aflatoxin is produced by a certain fungus that can grow on a wide range of foods including cereals, oilseeds, spices and tree nuts as well as milk, meat and dried fruit. Cereals and nuts such as peanuts, pistachios and brazil nuts are of most concern.
Aflatoxin increases the risk of liver cancer.Aflatoxin contamination is not a concern in Canada. It can be a problem in countries with hot, humid climates and poor storage facilities. The Canadian Food Inspection Agency monitors and tests nuts and nut products as well as some dairy products available in Canada for alflatoxin contamination.
- Store peanuts and natural peanut butter in the refrigerator to stop this fungus from developing.
- Never eat nuts that smell musty, look mouldy or are shrivelled, discoloured or damaged.
Antioxidants are chemical substances in many foods. Antioxidants protect the body's cells and tissues from free radicals, which are made when our bodies use oxygen. Free radicals can damage cells, which may lead to cancer. Antioxidants are thought to help protect cells by removing free radicals before they cause damage.
Certain vitamins and minerals found in many foods, especially vegetables and fruit, act as antioxidants. Vitamin C, vitamin E, beta carotene and selenium are antioxidants. It is best to choose foods with these vitamins and minerals, rather than take vitamin and mineral supplements (pills). Researchers say that it may not be only the vitamins and minerals that help protect against cancer but the special forms of these vitamins or minerals in foods or their combination with other substances in foods.
Sources of common antioxidants
Antioxidants Food source beta carotene*
orange-coloured foods such as sweet potatoes, carrots, squash, pumpkin, peaches and mangoes
some green leafy vegetables like spinach and kale
vitamin A (retinol)
vitamin C many vegetables and citrus fruits such as broccoli, tomatoes, oranges and grapefruit vitamin E
nuts and seeds
many oils such as safflower, corn and soybean
mangoes, Swiss chard and sweet potatoes
green leafy vegetables like collard greens, spinach and kale
tomatoes and tomato products (such as tomato juice and tomato sauce)
rice and grain products such as wheat germ and wheat bran
chicken and fish
*Beta carotene, lutein and lycopene are carotenoids. Carotenoids are compounds that also have antioxidant benefits.
It’s a good idea to eat a variety of foods that contain antioxidants. Make sure to eat a variety of vegetables and fruit daily to get the best mix of antioxidants. (The recommended number of servings per day is different depending on your age, sex and how active you are).
Arsenic and drinking water
Drinking water that is contaminated with a high level of arsenic over a long period of time is known to increase the risk of several types of cancer, including lung, skin, liver and bladder cancers.
Research has shown that drinking water treated with chlorine over a long period of time slightly increases the risk of developing bladder and possibly colorectal cancer.
Genetically modified foods
Genetically modified foods are foods that are changed by altering or adding genes in plants. The purpose is to improve taste and nutrition or to make crops easier to grow and ship. Health Canada inspects new genetically modified foods before they are released on the market. A genetically modified product is only approved for consumption when all of Health Canada’s safety standards are met. Once they are approved for sale in stores, the Canadian Food Inspection Agency monitors them for safety.
Some people are concerned that genetically modified foods cause cancer. However, there is currently no reliable evidence to support this claim. Research to date has not shown a link between genetically modified foods and cancer.
We do know that eating a variety of vegetables and fruit each day is good for your health. About one-third of all cancers can be prevented by eating well, being active and maintaining a healthy body weight.
Irradiation is a process that helps prevent many food-borne diseases that are transmitted through meat, poultry, fresh produce and other packaged foods. It uses ionizing radiation to treat foods, but it does not cause the food to be radioactive. At low doses, irradiation can be used to control insects, stop the growth of moulds, slow down sprouting of vegetables and prolong shelf life. At higher doses, irradiation can be used to control harmful bacteria in fresh meat and poultry. Similar technology is used to sterilize surgical equipment, medical implants and wine corks.
The decision to irradiate foods is regulated by the Food and Drugs Act. Health Canada reviews all requests for use of irradiation on food products to ensure its safety.
Organic foods differ from non-organic foods in the way in which they are grown and processed. Although people may choose organic foods because they believe that they are healthier and safer, there is not enough evidence that this is true.
People often choose organic foods because they are concerned about the use of pesticides and the environment. But pollutants may be found on both organic and non-organic foods, so all vegetables and fruit should be washed thoroughly.
Phytochemicals are natural compounds found in plants. All vegetables and fruit and many grains contain phytochemicals. They give vegetables and fruit their colour. Some phytochemicals act like antioxidants. Some types of phytochemicals are:
- carotenoids (beta carotene, lycopene and lutein)
Phytochemicals may help reduce the risk of cancer, but there is still a lot to learn about the activity of phytochemicals and their protective effects.
The best way to benefit from the different phytochemicals is to eat a variety of vegetables, fruit and grains each day. Dark green and orange vegetables and orange fruit are rich in phytochemicals. Some examples of foods containing high amounts of phytochemicals are:
- vegetables such as broccoli, cabbage and cauliflower
- dark green vegetables such as spinach
- orange and yellow vegetables and fruit
- sweet potatoes, squash and peppers
- cantaloupe, mango and pumpkin
- citrus fruits
- grains such as oats, barley, flax and rye
- soy foods such as tofu, soy milk, soybeans, soy nuts and miso
Soy foods such as tofu, soy milk, soybeans and soy nuts are an excellent source of protein. They are a lower fat, healthy alternative to meat.
Researchers have been studying the role of soy in a number of health conditions. Soy contains estrogen-like phytochemicals, which may help reduce the risk of osteoporosis and heart disease. Studies of the effects of soy on the risk of cancer are not conclusive. The effect that soy may have on cancer risk is very complex. More research is needed to better understand the link between soy and how it impacts cancer risk. Talk to your doctor if you're thinking of adding soy foods to your diet.
Recent studies have shown that there are no harmful effects with soy food intake and breast cancer recurrence in women who have had breast cancer. If you’re being treated for cancer, you may want to talk to your doctor before adding soy to your diet.
Black and green teas are also rich in antioxidants. Some research suggests that tea may help protect against cancer because of these antioxidants, but the research comes mainly from animal studies. The same activity has not been consistently observed in human studies, so more research is needed to study the cancer preventive effects in humans.
Herbal teas are made up of flowers, herbs or spices. Herbal teas do not have the same antioxidant benefits as green or black tea.
A well-planned vegetarian diet tends to be healthy in that it is low in saturated fat, high in fibre and includes a variety of vegetables and fruit. But diets that include lean white meats and fish, and red meats in small amounts can also be healthy.
Vitamin and mineral supplements
The best way to get your full range of vitamins and minerals is to make healthy food choices.
The exception to this may be a need for Canadians to take a vitamin D supplement during the fall and winter months. There is growing evidence that vitamin D may reduce the risk of some types of cancer, particularly colorectal, breast and prostate cancers.