Anti-cancer diets and ‘miracle' foods are the dish du jour for global media who look to draw readers or viewers in with often sensationalised reports that do not consider the full weight of scientific evidence.
However, the public requires more information about the effects of diet as a whole on cancer risk, as well as the importance of achieving and maintaining an ideal body weight, regular physical activity, and avoiding a sedentary lifestyle – say experts led by Maki Inoue-Choi from the University of Minnesota, USA.
The expert commentary, published in Nutrition and Cancer, questions whether we really have sufficient evidence to make claims of ‘anticancer foods’ or ‘super foods,’ which have the power to magically prevent or ‘cure’ cancer to an eager public.
“Media coverage of these so-called miracle foods is often just a marketing tool,” write Inoue-Choi and her colleagues. “Stories of miracle foods sell magazines and advertising space; food industries often sponsor research to show that their foods or products are superior, and supplement industries look to boost sales.”
“In real life, however, we do not live on one single food item,” they note. “We eat meals that consist of a considerable variety of foods, several times each day.”
The ‘Oz’ effect
Inoue-Choi and her team provide examples of scientific studies that theorise a decreased risk of ovarian cancer – the first due to flavonoids in red onions and another due to omega-3 in sea bass.
They note that both of these studies were reported as fact on the popular US television talk show The Dr. Oz Show, which claimed these two foods, in addition to endive, “can decrease the risk of ovarian cancer by up to 75%.”
However, the authors assert that with further research, five other studies would have been found that called the findings of these single studies in to question.
“A reduced risk of ovarian cancer related to higher onion intake, which was assessed after cancer diagnosis, was reported by one case-control study,” they note. “Conversely, three large prospective studies … reported no association between onion intake and ovarian cancer risk.”
“Yet, again, the evidence of an association between fish intake and ovarian cancer risk is not convincing,” they add.
Total diet
The team warn that “although perhaps not as ‘sexy’ as Dr. Oz would like”, the public needs better quality information about the effects of diet as a whole on cancer risk.
“When evaluating potential cancer prevention benefits from the foods we eat, we need to consider diet in its totality, as well as other lifestyle factors such as physical activity, and the potential influences of genetic and epigenetic factors.”
Indeed, Inoue-Choi and her colleagues note that certain foods and food components consumed together may have synergistic or antagonistic effects on health outcomes, while genetic differences may lead to differences in the health benefits of certain dietary interventions.
Source: Nutrition and Cancer
Volume 65, Issue 2, Pages 165-168, 2013, doi: 10.1080/01635581.2013.748921
“Reality Check: There is No Such Thing as a Miracle Food”
Authors: Maki Inoue-Choi, Sarah J. Oppeneer, Kim Robien