Reduce consumption of high glycaemic index foods.

According to the researchers, people on a diet containing sugara starchy diet, may be increasing your risk of cancer lung cancer, even if they do not smoke

The glycaemic index is a term that is familiar to people with diabetes. It tells us which foods raise blood sugar and stimulate insulin production, such as doughnuts, white rice and some fruits like melon and pineapple.

This is not the first study to link glycaemic index to cancer risk, but it is rare to link it to lung cancer.. That could be because lung cancer is overwhelmingly caused by smoking.

The team at MD Anderson Cancer Center in Houston studied 1,905 people who had been diagnosed with lung cancer and compared them to 2,415 people without cancer. They were questioned about their eating habits, smoking, diet and other factors.

People who ate the most foods with a high glycaemic index were 50 percent more likely to be in the lung cancer group. than people who reported eating less high-glycaemic foods, the team reported in the journal Cancer Epidemiology and Biomarkers.

The link was strongest among people who had never smoked; non-smokers were more than twice as likely to get lung cancer if they ate a high glycaemic index diet.

"The results of this study suggest that, in addition to maintaining healthy lifestyles, reducing consumption of high glycaemic index foods and beverages may serve as a means to reduce the risk of lung cancer," said Dr Xifeng Wu, who led the study.

How sugar fuels cancer growth

Doctors are unsure, but there is a theory that  high glycaemic index foods stimulate the body to produce insulin, which in turn affects cell growth through compounds called growth factors insulin-like or IGF. Cancer is the uncontrolled proliferation of cells, so it could be that high-glycaemic foods are fuelling the growth of small tumours.

"It has been shown that IGFs play a critical role in the regulation of cell proliferation and differentiation in the cancer and there is evidence to suggest that IGFs are elevated in lung cancer patients," Wu's team wrote.

Sugar is a suspect for several types of cancer.

"Previous studies have investigated the association between glycaemic index and related measured glycaemic load and a variety of cancers including colon, stomach, pancreatic, endometrial, ovarian, prostate and thyroid cancers.but these studies are limited and the results have been inconclusive," the researchers wrote.

This study is not conclusive, either. For one thing, the researchers asked volunteers to remember what they ate. For another, it's an association. People who eat high-glycemic foods may also do something else that raises cancer risk. And this particular study focused only on non-Hispanic whites.

Marji McCullough, a nutritional epidemiology expert at the American Cancer Society, says it will be important to look at people who don't have cancer now and see what they eat for years or decades, and see who develops cancer.

Cancer experts go nuts over dietary guidelines

Lung cancer is the most deadly cancer. By the time most people are diagnosed, the cancer has already spread and is then much more likely to be fatal.

Experts know that diet and lifestyle can affect cancer. Obesity, lack of exercise, eating red meat and high-fat dairy portions, and eating too little fruit and vegetables can increase a person's chances of developing cancer.

This study adds to a growing body of evidence that people can reduce their risk of cancer not only by staying away from tobacco and exercising more, but by choosing a healthy diet.

"Aside from not smoking, it is important to follow the cancer prevention guidelines of maintaining a healthy body weight, physical activity and eating an overall healthy diet rich in vegetables and plant-based foods and less red and processed meat. Choose foods that help maintain healthy body weight," McCullough said.

According to the American Diabetes Association, low glycaemic index foods include:

• 100 percent wheat plant or wholemeal rye bread
• Oatmeal (or rolled steel cut oatmeal), oat bran, muesli
• Pasta, converted rice, barley, bulgur (wheat-derived)
• Sweet potato, maize, yam, yam, Lima / beans, peas, lentils and pulses
• Most fruits, non-starchy vegetables, and carrots

Foods with a medium glycaemic index are:

• wheat, rye and pita bread
• Quick Oats
• Brown or basmati rice, couscous

Foods with a high glycaemic index include:

• White bread, including bread rolls
• cornflakes, puffed rice, bran flakes, instant oatmeal
• short-grain white rice, rice pasta, macaroni, and some cheeses
• Red potatoes, pumpkin
• Pretzels, rice crackers, popcorn, pretzels, crackers
• Melon and pineapple