Cancer and diet

Originally Published: April 10, 1995 - Last Updated / Reviewed On: December 14, 2012
Share this
Dear Alice,

Are there any health hazards associated with Chinese food? Of course a lot of Chinese foods are high in fat and cholesterol, but what I am worried about is the cooking methods. Generally, they heat the oil to a very high temperature and then throw in the meat or vegetable and make a big sound, sometimes the food even catches fire. As far as I know, I think oil heated to a high temperature, to the point where it begins to emit smoke, may contain cancer-causing substances. Is that true?

I guess I am kind of obsessed about cancer because my grandfather died of stomach cancer two years ago and I was with him for several months before he died. What are the major causes of cancer? How can we avoid them? If we eat some cancer-causing substance, are we more likely to get stomach or intestinal cancer because that's where the food passes through, or are we equally likely to get other cancers? I mean, do a person's digestive organs have a particularly high susceptibility to cancer compared to other parts of the body because they are exposed to the food, which is where almost all the carcinogens come from?

— Worries about cancer and diet

Dear Worries about cancer and diet,

No doubt that losing your grandfather was difficult as we often have a special relationship with our grandparents. Now, while it can be tempting to make generalizations about which cultures have more or less healthy cuisines, it might be more useful to consider how specific ingredients and cooking methods can possibly impact our overall health. Research has shown that many cooking methods, including those you mentioned, can increase the likelihood of depositing carcinogens (cancer causing substances) into the food being prepared. However, there are things you can do to decrease your risk of developing cancer, while still enjoying Chinese food — or any cuisine you would like for that matter.

First, a few words about cancer: Cancer is not one disease, but actually a group of diseases caused by the unrestrained growth of cells in one of the body's organs or tissues. One factor that increases a person's risk of developing cancer is genetic makeup. Environmental triggers (e.g. food choices, sunlight, alcohol, viruses, tar in tobacco smoke, and pollutants in the air) also play a part in cancerous formations.

Research suggests that people with diets high in certain kinds of foods are more likely to develop cancer at some point in their lives. Diets high in fruits, vegetables and fiber have been shown to reduce cancer risk, while diets high in meats, animal products, and fats seem to increase risk. Even within the meat category itself there are distinctions. Red meats like beef, lamb, and pork are considered by experts to carry a greater risk of cancer (especially colorectal cancer) than white meats like chicken, turkey, and other poultry. By contrast, vegetarian diets seem to reduce the incidence of cancer. This appears to be due to the protective effect that fiber (which is found predominantly in fruits and vegetables) has against cancer in the body.

But even within those broad categories, the way your food is prepared can make a difference in the cancer rate associated with its consumption. This gets back to your question about hot cooking oil: Yes, cooking foods at a high temperature as in hot oil can generate carcinogens. Cooking meat at high temperatures is known to form carcinogenic substances inside the meat being cooked. Carcinogens such as heterocyclic amines (HCAs) are found in meats that have been grilled, fried, or broiled. Increased cooking time and temperature has been shown to increase the amount of HCAs in meat. Another family of carcinogens, polycyclic aromatic hydrocarbons (PAHs) are also found in cooked meats. Cooking methods such as direct flame gas grilling and smoking seem to generate the most PAHs in meats, while indirect flame gas grilling, pan-frying, microwave cooking, and steaming appear to produce progressively fewer PAHs. Increasing temperature and cooking time also tends to increase the number of PAHs in food. Another carcinogen, acrylamine is formed when plant based foods high in carbohydrates (such as potatoes, breads, and pastries) are cooked at high temperatures by frying, roasting, or baking. It is also probably not the safest idea to reuse cooking oil when preparing food.

While it appears that eating a vegetarian diet that includes limited frying and grilling in the cooking process is the gold standard in terms of cancer reducing diets, it is not the only way to reduce your risk of developing cancer. In addition to a healthy, varied diet, health experts recommend avoiding major causes of cancer by limiting alcohol consumption, avoiding smoking, maintaining safer sex practices, and avoiding overexposure to UV radiation (like from the sun!). Simply reducing the amount of fried and grilled foods you eat can also make a difference without eliminating them from you diet altogether. Additionally, avoiding unhealthy foods doesn’t mean you have to avoid an entire cuisine. Meals such as Chinese food or other types of cultural cuisines, contain a wide range of ingredients, with several possible ways to prepare or cook. If you want to maintain a healthier diet, you can be selective about the kinds of food you order from restaurants or try cooking them for yourself at home.

If you have questions or concerns about your diet, you may want to speak to your primary care provider or a nutritionist. If you are a Columbia student you might want to call 212-854-2284 or log in to Open Communicator to make an appointment on the Morningside campus or 212-305-3400 for the Medical Center campus. You may also want to consider visiting the Columbia Health website to see information about services and programs available on the Morningside campus or Student Health Services for options at CUMC. If your worries about cancer are negatively affecting you day-to-day life or you just want to talk with someone about your experience with your grandfather, you may want to make an appointment with a counselor or psychologist. Columbia students may want to consider scheduling a visit with Counseling & Psychological Services at Morningside by calling 212-854-2878 or Mental Health Services at CUMC by calling 212-305-3400. Balancing long-term health concerns like cancer with everyday dietary concerns can be challenging, but being informed about the risks and benefits associated with certain foods is a great first step to a long and healthy life.

Alice