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Meta-study | Healthier diet after cancer increases chances of survival
If people who have survived cancer eat healthier, they reduce their risk of death in general. In this group, however, a healthier diet does not reduce the risk of dying specifically from cancer, a Spanish meta-study concludes.
Ultimately, the researchers found 35 epidemiological studies that compared the dietary patterns of large groups of people with and without cancer, and 14 trials that assessed the effect of lifestyle changes on people with cancer.
Epidemiological studies are not always reliable, and that certainly applies to the cohort studies used by the Spaniards. These studies are based on completed questionnaires, so they are only as good as the memory and honesty of the study participants.
Incidentally, the definition of 'healthy food' was that of governments and large organisations: lots of fruit and vegetables, lots of fibre, few sugars... You know the drill.
The trials in this case were also a bit problematic. In many trials, the study participants not only started eating healthier, but also exercised a little more. The researchers were unable to separate the effects of the two.
The first figure below shows that women who ate a healthy diet were 23 percent less likely to die than women who ate an unhealthy diet.
The second figure does not relate to the risk of death in general, but only to the risk of death as a result of breast cancer. There is a trend that healthy eating reduces the risk of dying from the disease, but it is inconclusive.
The researchers also looked at people with colon cancer and prostate cancer, and found the same phenomenon in those groups. The healthier the cancer survivors ate, the less likely they were to die. However, the researchers did not find any significant effects on the risk of death as a result of the disease.