Last night I heated some extra virgin olive oil and fried chopped potatoes, onion and asparagus. After a few moments I tossed in some spinach leaves and chopped tomato, then poured over beaten eggs. A sprinkle of cheese and a light grill to brown the top and voila – yummy frittata for an easy Sunday evening meal. The big question is have I increased my risk of getting cancer by frying in olive oil?

“Exposure to second-hand cigarette smoke or going outside without sun-block is much more likely to cause cancer than burning your cooking oil,” writes fats and oils expert, Laurence Eyres, in the October/November issue of Food New Zealand – the official journal of the NZ Institute of Food Science and Technology. But what about all those cancer causing chemicals – polycyclic aromatic hydrocarbons – that are formed when we burn cooking oil? It’s true that when oil is repeatedly heated to its smoking point it will begin to accumulate cancer causing substances and lose its natural antioxidants. But who uses the same oil over and over again, especially when we’ve burnt it? We usually just heat and eat.

When researchers feed ‘severely heat-abused frying fats’ (more than we would ever do at home) to some poor experimental animals there are ‘very few deleterious effects’. In fact olive oil is especially stable because it is monounsaturated. Extra virgin olive oil is even better than a lower quality olive oil because it has more natural antioxidants to soak up nasty free radicals. And good news for those of us who love New Zealand extra virgin olive oil. Compared to overseas olive oils it has more antioxidants and a higher smoking point, so you can heat it hotter before it starts to burn.

Bowel cancer is one of the most common cancers in New Zealand and on a world ranking we’re way up there. Around 2500 New Zealanders develop bowel cancer each year and about 1000 die.

Considering there are just over 4 million of us, it’s pretty high. Bowel cancer is not so common in Maori people but those who do develop it are less likely to be diagnosed and therefore more likely to die.

Bowel cancers begin as polyps. As you can see in the picture, taken at virtual colonoscopy, these are small growths that can enlarge within your bowel on a stalk. As they grow bigger, the more chance there is of one of these turning into a killer -  a malignant cancer.

Bowel cancer is more common as you age but it’s never too early to get into healthy habits to cut your risk. Here’s the top 4 ways…

1. Physical activity
2. Fibre especially from wholegrains and fruit
3. Garlic
4. Calcium – have some low fat milk and yoghurt each day

From a diet perspective, here are the top 4 ways to increase your risk of bowel cancer?

1. Obesity, especially around the stomach
2. Processed meat such as sausages and salami
3. Red meat – it’s great for iron and zinc but keep it to less than 500 grams a week
4. Alcohol

Mesothelioma is a horrible cancer caused by exposure to asbestos. Asbestos was used widely in New Zealand in the 1960’s and 70’s – the home I grew up in had a lovely asbestos ceiling! Between 1992 – 2005 there were 164 cases of mesothelioma in New Zealand, and the number of cases is increasing. A large number of the people who contracted this disease were tradesmen such as builders, plumbers and electricians.

Although the main cause of mesothelioma is asbestos, not poor diet, it always helps to eat healthy food. Here’s a story from the US Mesothelioma Centre, that they have asked me to post, on how healthy eating can help people with mesothelioma:

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The main cause of mesothelioma cancer is exposure to a naturally occurring mineral called asbestos. The cancer develops in the mesothelial cells that make up the lining of the lungs, heart and abdomen. Like many types of cancer, it is most treatable when caught early. The symptoms of mesothelioma can take anywhere from 20 to 50 years to become obvious and by the time the cancer is diagnosed, it is typically in advanced stages making it more difficult to treat.

It has been confirmed by the National Cancer Institute that at least 35 percent of all cancer cases are linked to poor nutrition. And while malignant mesothelioma is not a cancer that is related to poor nutrition, improving nutritional intake can help strengthen mesothelioma cancer patients’ bodies to fight the progressive disease.

Eating a balanced and healthy diet is vital to help fight cancer. A more balanced and healthy diet can not only improve chances of survival, but also alleviate painful symptoms and unwanted treatment side effects.

Garlic can be helpful for mesothelioma patients as it produces a chemical called allicin. Garlic seems to have the greatest affect on stomach cancer and prostate cancer in men, but affects have been noted in all types of cancer and on different carcinogens. Animal trials have been completed with positive effects. In one such study, a number of mice with cancer were injected with allicin. The control group (those not injected with the compound) lived an average of two months, while those receiving the injection lived an average of six months or longer.

Fruit is also a definite must. There are many delicious types of berries you can incorporate into your diet to benefit from the cancer-fighting nutrients they contain, including blueberries, blackberries, raspberries, strawberries, loganberries, cranberries. Berries contain a number of cancer-fighting phytonutrients like anthocyanins, ellagic acid, pterostilbene and resveratrol. In one study, extracts of six types of berries were tested for their ability to prevent the growth and spread of different types of cancer cells. Amazingly, each different type of berry was found to have an entirely unique combination of phytonutrients, and all six varieties of berry extract were able to kill cancer cells in the laboratory.

One of the most common side effects of mesothelioma treatment is nausea. There are a number of dietary changes you can make to help this problem. Dry grain products like crackers and toast can help calm an upset stomach. Bland foods will also help with nausea, as well as acid reflux problems.

Low white blood cell count is another common trait found in cancer patients, which raises the risk of contracting an infection. To avoid this side effect, a number of changes can be made in the foods you eat. It is most important to avoid “bad” bacteria, which is common in foods that are spoiled or not prepared well. Avoid buffets when eating out, wash your hands before preparing meals, avoid raw meats and fish (like sushi), and throw away any foods that are bruised or damaged.

Cancer is a complex medical condition, with many factors playing various roles in development and treatment. However, most patients will undoubtedly benefit from good nutrition in a number of ways.

Maybe it’s just my age (40-something) but it seems that just about everyone around me knows someone who has cancer. One of my very close friends doesn’t have cancer any more – they chopped it out. But now she is going through the gruelling process of chemotherapy. Fifteen weeks into her treatment and she is still the most positive, happy person I know! Her doctors are amazed at her attitude and progress.

A few weeks ago I dropped off some food to her – and a brochure about healthy eating when your immune system is low. She rang me the next day. “I didn’t know sushi could be dangerous for me!” she exclaimed. “I’ve been eating it every day. I thought it was healthy.”

Sushi is a healthy food but because it is often made a few hours before you eat it, even if it’s refrigerated, it can still harbour listeria.  You would think that if you kept a food in the fridge it would be safe to eat but unlike most bacteria listeria enjoys cold temperatures. For most of us it’s not a deadly bug and we may hardly notice if we’ve eaten some. But listeria can kill an unborn baby and certainly won’t make someone on chemotherapy feel too good.

So if you are on chemotherapy or have any long term illness that seriously whacks your immune system, stick to this food safety rule: ‘Fresh or Hot’. Apart from sushi, steer clear of these ‘high risk’ for listeria foods:

• pate
• cold pre-cooked chicken, ham, salami etc
• stored and takeaway salads
• unpasteurised milk and cheese
• brie and camembert cheese (all other cheese is fine)
• any food that has been in the fridge for more than 2 days

But don’t despair if you really want that left-over pizza from the other night. Heat it until it’s steaming (over 70C) and any lurking listeria will be well and truly dead.