Thought bowel cancer was all about processed meat? Think again, and beware of SUGAR.
There may be a link between the consumption of sugary, fatty foods and bowel cancer, a Scottish research study has found. Yet another reason to ditch the biscuits and fizzy drinks...
Anyone with even a passing interest in a healthy diet has most probably heard about the link between bowel cancer and the consumption of processed meat products such as bacon, sausages and black pudding. A new Scottish study, published in the European Journal of Cancer Prevention, suggests that processed meat products aren't the only dietary risk factor for bowel cancer: Sweet foods might be another culprit. It's yet another piece of evidence that strengthens the case for limiting our sugar consumption.
The Edinburgh study
Scientists from the University of Edinburgh looked at data from the Scottish Colorectal Cancer Study, carried out in 2012. This is a large-scale study that included 2062 people with bowel cancer and 2776 healthy volunteers. Participants filled in a detailed questionnaire about their dietary habits, general lifestyle and family history. The study replicated well-established links between an increased risk of bowel cancer and a family history of cancer, smoking, and lack of exercise. It also uncovered a new association between the consumption of sugary, fatty foods and bowel cancer.
Over 170 different foods were included in the analysis of people's diets, including fruit, vegetables, fish and meat, as well as a range of high-energy snack foods such as chocolate, desserts, biscuits, crisps, nuts and sugary drinks. Two broad eating patterns were identified, one high in fruit and vegetables and the other high in meat, fat and sugar. The latter was associated with an increased risk of bowel cancer. Those people who consumed the most high-energy snacks were 18% more likely to develop bowel cancer than those who ate the leat, even once other cancer risk factors such as obesity and lack of exercise were taken into account.
Like any other piece of research, this study is not without its shortcomings. It relies on data obtained from questionnaires, so it's open to biases in people's self reports, for starters. Then there's the old problem that you cannot prove causation with association – there was a link between diet and cancer risk, but that in itself does not prove that once caused the other. Even so, this study is being taken seriously in scientific and medical circles and should make us think about our consumption of sugary snacks.
Sugar + trans fats: A (well-known) deadly combination
Let's think for a moment about the foods that were found to be associated with an increased risk of bowel cancer. Chocolate, crisps, sugary drinks, biscuits and puddings. Most of these foods are high in both sugar and trans-fats (unsaturated fats that have been chemically manipulated by the addition of hydrogen molecules to stay solid at room temperature, so that food containing them tastes rich without feeling greasy). It's not exactly news that eating them isn't great for our health, so is the Edinburgh study really anything more than just another piece of research that confirms what we already know?
But it goes further...
Well, yes. Buried among a wilderness of complex statistical analysis was the finding that the consumption of fruit and vegetable juice was associated with an increased risk of bowel cancer. No, that isn't a typo: People who drank more fruit and vegetable juices were more likely to develop bowel cancer.
But surely we're always being encouraged to eat more fruit and vegetables?! Yes, more fruit and vegetables. Not juice. It turns out that the juice isn't nearly as healthy as the whole fruit or vegetable, and the main reason seems to be sugar. When it comes to blood sugar levels, your body doesn't particularly care whether you're eating a jam donut or drinking orange juice. Blood sugar levels are important because they influence on insulin production, and abnormal insulin regulation has been identified in some quarters as one of the mechanisms involved in increasing our risk of developing all sorts of illnesses, including (but not limited to) cancer.
This principle also holds for foods that might not actually be sweet, but cause the same spikes in blood sugar levels as actual sugar. Crisps. Anything involving white flour – biscuits, cakes and so on. A lot of these foods also contain high levels of fat, and it's generally been assumed that this is the biggest health culprit. But perhaps we should be worrying more about sugar, and the refined starchy carbohydrates that are basically processed by the body in exactly the same way as sugar is.
Jumping to conclusions?
Let's be clear: The Edinburgh study has found some associations between the consumption of high-energy, sugary foods and an increased risk of bowel cancer. That's all. Anything else is speculation, even if it is well-founded speculation. But there's no denying that overall trends in nutrition research are pointing more and more towards the dangers of sugar in all of its forms. It's time to get serious about the health risk posed by the contents of most of our supermarket aisles.