At World Cancer Research Fund International, we have examined how eating wholegrains, vegetables and fruit affect a person’s risk of developing cancer.
There is strong evidence that:
There are more details on these findings in our 2018 Diet and Cancer Report. Download the chapter on wholegrains, vegetables and fruit.
While the evidence for links between individual cancers and non-starchy vegetables or fruit is limited, the pattern of association is consistent and in the same direction and overall, greater consumption of non-starchy vegetables or fruit protects against a number of aerodigestive cancers.
For wholegrains and foods containing dietary fibre the evidence shows that, in general, the more people consume, the lower the risk of some cancers.
– This is the opinion of our panel of experts in 2018
Grains, or cereals, are the seeds and energy stores of cultivated grasses and the main types are wheat, rice, maize (corn), millet, sorghum, barley, oats and rye.
Wholegrains are grains and grain products made from the entire grain seed, which consists of the bran, germ and endosperm. They contain starch and protein as well as variable amounts of fibre, B vitamins and other micronutrients that are most concentrated in the germ and outer layers of the grain. The refining of wholegrains usually removes the germ and outer layers of the grain, thereby reducing the presence of fibre and micronutrients. Consumption of grains in refined forms, such as white rice, bread or pasta, is generally more common than consumption in wholegrain form.
Pulses (legumes) such as beans, lentils, peas and peanuts (groundnuts) as well as minimally processed grains are particularly concentrated sources of dietary fibre. However, vegetables, fruit, nuts and seeds also contain significant amounts of dietary fibre.
Vegetables can be separated into groups according to their individual starch content.
Starchy vegetables such as potatoes, sweet potatoes (yams), cassava (manioc), sago yams and taro contain higher levels of carbohydrate than non-starchy vegetables. Levels of other nutrients also vary between the two groups.
Examples of non-starchy vegetables include:
Grains and pulses (legumes) may be contaminated with mycotoxins such as aflatoxins, which are produced by certain moulds growing on agricultural crops.
People can be exposed to aflatoxins by eating contaminated foods. Although moulds that contaminate foods are usually destroyed by cooking, any toxins they produce may remain.
All naturally-occurring aflatoxins are classified as human carcinogens by the International Agency for Research on Cancer.
Aflatoxins are most problematic in regions with hot, damp climates and poor storage facilities; levels of aflatoxin contamination tend to be highest in sub-Saharan Africa and South-East Asia, as well as China, and rates of liver cancer are high in these countries.
Aflatoxin-contaminated foods are generally consumed in the countries where they are produced, but they may also be exported to neighbouring countries and intercontinentally.
In 2018, we produced the Diet and Cancer Report, the third in our series of major reports looking at the many ways in which our diets, and how active we are, affect our cancer risk. You can find out much more about wholegrains, fruit and vegetables and the risk of cancer by downloading a pdf of the relevant chapter in the 2018 report. Please note, however, that this webpage may have been updated since the report was published.