17. Cooking Oils and Cancer - a new study

     Experiments at De Monfort University, recently published by the Daily Telegraph have shown that corn and sunflower oil used in frying can release dangerously high levels of toxic chemicals known as valdehydes, which have been linked to cancer, and heart disease and dementia. Experiment leader Dr Martin Grootveld, a professor of bioanalytical chemistry and chemical pathology at the University has stated that  “a typical meal of fish and chips” fried in these vegetable oils contained up to 200 times more aldehydes than are considered safe. Olive oil, butter, and coconut oil, on the other hand, contained far lower levels of aldehydes.

During his appearance on BBC’s Trust Me, I’m a Doctor, Dr. Grootveld gave volunteers sunflower oil, vegetable oil, corn oil, cold-pressed grapeseed oil, olive oil, butter, goose fat, and lard, and asked the participants to cook foods with them every day. Leftover oil from their cooking was collected and sent to the lab at De Montfort University where they found that sunflower oil and corn oil produced aldehydes at the highest levels, and that it was actually safer to use olive oil, butter, lard, or coconut oil.

     "People have been telling us how healthy polyunsaturates are in corn oil and sunflower oil. But when you start… subjecting them to high amounts of energy in the frying pan or the oven, they undergo a complex series of chemical reactions, which results in the accumulation of large amounts of toxic compounds.” Dr Grootveld commented. 

     “Sunflower and corn oil are fine as long as you don’t subject them to heat, such as frying or cooking,” Grootveld said in a press release. “It’s a simple chemical fact that something which is thought to be healthy for us is converted into something that is very unhealthy at standard frying temperatures.” Olive oil, meanwhile, is much better “because lower levels of these toxic compounds are generated, and secondly, the compounds which are formed are less threatening to the human body.

     For years we have been subjected to official health advice not to use butter or lard for cooking. These  experiments however show that both are very good for frying purposes.  I myself will stick to light olive oil for cooking, and a stronger flavoured virgin olive oil for use in salads.  

The following article in Stuff.co.nz expands on the issues and is well worth reading.  

Stuff.co.nz    Vegetable Oil and Cancer                                                                                                

  

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16. Obesity and Cancer

We all know that smoking is one of the leading causes of cancer - you can't buy cigarettes without being reminded of this on the packet. Within the decade however, obesity will overtake smoking as the lead cause of cancer according to specialists at the recent American Society of Clinical Oncology (ASCO) conference in Chicago. They pointed out that spiralling rates of obesity meanws that cancer, once seen as a disease of old age, is now being diagnosed up to twenty years earlier.                              

We now know that excess weight increases your risk of cancer significantly.  The risk of prostate, colon, womb and all other gynaecological cancers, particularly breast cancer, is elevated, due to the hormone imbalances associated with obesity, which fuel tumour growth.             

The intimate relationship between obesity and cancer does not stop there however, according to Dr. Eric Horwitz, radiation oncology lead researcher at the Fox Chase Cancer Center - American Oncologic Hospital, Philadelphia. His studies have found a correlation between obesity and increased risk for both cancer relapse and spread.  Overweight survivors of prostate cancer treatment were found to have a three percent higher rate of relapse compared to their slimmer counterparts. They also had seven percent higher odds of the cancer spreading.

        Further Reading
        Daily Telegraph   Obesity and Cancer
        American Society of Clinical Oncology (ASCO)  Obesity and its   impact on breast cancer.
        Fox Chase Cancer Center  Ongoing cancer clinical trials.
        Rocketswag  Overweight or obese?

15. Deep Fried Mars Bars and French Fries

Deep Fried Mars Bar by Xian from Lancaster

     Recent nutritional studies by researchers at Tehran and Toronto universities into dietary patterns and breast cancer risk show that healthy eating was associated with eliminating three-quarters of the odds of breast cancer, whereas less healthy eating was associated with up to nearly eight times the odds. Included in the unhealthy eating pattern was the consumption of deep-fried foods, which have previously been linked to breast cancer, pancreatic cancer, lung cancer, oral and throat cancers. Researchers at the Fred Hutchinson Cancer Research Centre in Seattle found that regular intake of deep fried foods, in this instance French fries, chicken, fish, and doughnuts appeared to contribute to the progression of prostate cancer as well.

      The problem lies in the heat of deep fry oil, which can generate potentially carcinogenic compounds, when chicken and fish are cooked at high temperature. Deep-fried plants, on the other hand, can form acrylamide.

     Acrylamide intake has been associated with risk of endometrial cancer, ovarian cancer, lung cancer, kidney cancer, and throat cancer. The level of cancer risk associated with French fries depends on how long and hot they’re fried and to avoid the generation of carcinogenic compounds and acrylamide, cooking temperature and cooking time should be as low and as short as possible.

     Despite promises by the food industry to the European Food Safety Authority of self-regulation and control of fry times there appears to have been little change to date.

     Blanching potatoes before deep frying reduces the formation of acrylamide but potato chip manufacturers and chippies complain that this reduces flavour and leaches away some vitamin C, though if you are relying on potato chips for your daily dose of vitamin C, you probably won't be thinking too seriously about cancer producing compounds.

     As with all dietary advice, moderation is the key word.  An occasional deep fry-up is not going to give you cancer, though a daily dip into deep fries may be shortening the odds – not only on cancer but obesity which is a quick route to a number of cancers – see my blog 14.

     No cancer risk study has yet been published on the consumption of that alleged Scottish delicacy, the Deep fried Mars Bar. I recently saw an online recipe for this, served with French fries….eat that dish too often, and cancer risk will be the least of your worries!

Further Reading

Dietary Patterns and Breast Cancer among Women

Consumption of deep-fried foods and risk of prostate cancer.

Deep Fried Mars Bar