This month, Buzz’s health-man Jon Sutton looks at the value of whether reducing or increasing intake of certain food types increases risks of cancer. The answer, as ever, is slightly more complex than yes or no.
In 1993, Record Breakers presenter Roy Castle, the very face of British verve and vitality, lost his battle with lung cancer. He’d never even smoked. The nation sat up and took notice: the curse of cancer, and its ability to take down even the most clean-living people, became headline news. What could be done now to fight the human race’s ultimate enemy?
Meanwhile, across the Atlantic, American doctors were starting what would turn out to be the largest study ever carried out into the links between diet and cancer – the results of which are only coming to light today. More specifically, the study, carried out by the Women’s Health Initiative (WHI), targeted the links between cancer and the consumption of fat.
In the early 90s, fat was still considered to be a major cause of mortality, but more recently it has become apparent that much of the blame for mortality had simply been shifted onto fat by scientists working for the sugar industry, as a New York Times article suggested. Surely, then, the results of the WHI study would reflect this modern way of thinking about fat – that removing it from our diet would have no effect on cancer cells?
Yet strangely – at least for followers of the ketogenic movement, which now states that consumption of fat is healthy – the study did actually prove that the risk of death in women with breast cancer could be mitigated by a reduction of fat intake. In its words, “Adoption of a low-fat dietary pattern associated with increased vegetable, fruit, and grain intake … significantly reduced the risk of death from breast cancer.”
Once again, it looked like fat could be blamed for adding to all-cause mortality. Until, that was, experts looked a little closer into the results and the words “increased vegetable, fruit and grain intake”. Was it the reduction of fat which appeared to save lives – or the inclusion of vegetables in place of fat?
Dr Rhonda Patrick PhD, in a recent edition of her FoundMyFitness podcast, laid down the case that all evidence points to the cancer-crushing qualities of green ‘cruciferous’ vegetables. In one recent study, according to Dr Patrick, people were ranked by the amount of cruciferous vegetables they ate, with the top 20% of people eating the most showing a 22% reduction in all-cause mortality.
Another study showed a 40% decrease in prostate cancer risk in men eating three to five servings of cruciferous veg per week; another indicated that men who ate two servings of broccoli per week reduced their chance of developing bladder cancer by 44%. In two other studies, smokers who consumed four and a half servings of cruciferous vegetables per month showed a 55% reduction in lung cancer risk and, for women, a breast cancer risk reduction of between 17% and 50%. (The results were thought to vary because of preparation methods; many of the nutrients can lose effect when overcooked.) Even people who already had bladder cancer saw a 57% reduction in mortality when consuming four servings per month.
Delving deeper into the links between cancer and diet, Dr Patrick goes on to talk about the potential risk of developing cancer by overeating meat – the amino acids in meat help muscles to grow, but can also do the same for cancer cells. In 2016, the largest study to date on the topic found that meat did indeed lead to a higher death rate. “It’s a legitimate concern,” says Dr Patrick. “But the studies only held up when there was another risk factor involved.” Examples of these would be sedentary lifestyle, obesity or drinking/smoking too much.
But whilst the jury is still out on both meat and fat, Dr Patrick refuses to sit on the fence when it comes to refined sugar. “Refined sugar intake is a big problem … Scientists estimated that consumption of sugar-sweetened beverages in 2010 may have contributed to 6,450 deaths from cancer.” In one particularly damning study, men who regularly drank sugary drinks tripled their chance of prostate cancer due to sugar’s inflammatory nature.
But that doesn’t mean cutting sugar out wholly: for those who crave it in their diets, fruit is still on the table. The fibre found in fruit helps to break down the sugar faster, whilst also giving a healthy boost of vitamins.
When it comes to staying healthy and combatting cancer, most things are OK in moderation. Refined sugar, it seems, doesn’t want to stick to those rules.