Carried out by researchers in the Nutritional Epidemiology Research Team (EREN) of the French National Institute of Health and Medical Research (Inserm), University of Paris 13, the new study evaluated four different diets and their effect on the risk of cancer.
The diets included the WCRF/AICR score (based on recommendations by the World Cancer Research Fund and American Institute for Cancer Research), which encourages plenty of whole grains, fruit, vegetables, and beans with limited fast food, red and processed meat, alcohol, and sugary drinks; the Alternate Healthy Eating Index, which is a diet based on foods and nutrients that could reduce the risk of certain chronic diseases; and the French Nutrition and Health Program-Guidelines Score, which advises at least five portions of fruit and vegetables per day, foods rich in calcium such as dairy, starchy foods such as whole grains and potatoes, meat or fish one to two times a day, and limited saturated fat, sugar, and alcohol.
A more recent index was also included, the MEDI-LITE score, which measures adherence to a Mediterranean diet.
The researchers gathered data from 41,543 French adults aged 40 or older, who were asked to report on their diet every six months, detailing all the foods and beverages they consumed during a 24-hour period.
The results showed that all four diets were associated with a reduction in the risk of cancer, but the WCRF/AICR diet, which was developed specifically with cancer prevention in mind, had the strongest association.
More specifically, a one-point increase in the WCRF/AICR score was associated with a 12% decrease in overall cancer risk, a 14% decrease in breast cancer risk, and a 12% decrease in prostate cancer risk.
The researchers believe that the WCRF/AICR recommendation to avoid alcohol is the part of the diet that most likely contributed to the reduced cancer risk, with recent research also suggesting that alcohol is a risk factor in many cancers including oropharyngeal, oesophagus, liver, colorectal, stomach, and breast cancers.
However, the team added that the “synergistic contribution” of a healthy diet was more important than just a single dietary recommendation.
“The World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) estimated that in developed countries, around 35% of breast cancers and 45% of colorectal cancers could be avoided by better adherence to nutritional recommendations,” commented one of the study’s authors, Bernard Srour.
“This emphasizes the role of an overall healthy lifestyle — nutrition and physical activity and alcohol avoidance — in cancer prevention. It is, therefore, important to keep in mind that every lifestyle factor counts and it is never too late to adopt a healthy lifestyle,” he added.
The results can be found published online in Cancer Research, a journal of the American Association for Cancer Research.