Grains are a staple food around the world with rice, wheat and corn making up a large part of many diets.
Grains are sometimes linked to bad health outcomes and blamed for increasing rates of overweight and obesity and the associated risk of chronic diseases. The grains referred to in this context, however,
are refined and processed sources of grain that make up many unhealthy foods like cookies, cake and snack foods. Many foods high in refined and processed grains also contain large quantities of sugar and salt.
When a grain is refined it loses much of its fibre and nutrient content. In contrast to this, the grains that are often featured in dietary guidelines are wholegrains, which include the outer bran, germ and endosperm (the part that contains some nutrients and most of the carbohydrate). Consumption of wholegrains has been linked to positive health outcomes including lower risk of type-2 diabetes,
heart disease and some cancers.
A large meta-analysis investigated the health outcomes associated with the consumption of wholegrains. Fourteen studies involving close to 800,000 people were included and looked at the association
between wholegrain intake and death from heart disease and cancer. The studies showed that as the amount of wholegrain consumption increased, the death rate (particularly from heart disease) decreased.
Eating three servings of wholegrains a day equated to around 25% lower risk of dying prematurely from heart disease and stroke, compared to eating less than three serves a day. The results of this study also showed a reduction in risk of death from cancer.
This research was observational so a cause-and-effect association cannot be confirmed. The researchers did, however, highlight a plausible explanation as to why wholegrain foods could be beneficial for
health: that the fibre in wholegrains can regulate blood sugar and improve blood cholesterol levels; that it is a good substrate for gut bacteria; and that wholegrains are also a good source of important nutrients
and plant bioactive compounds.
The case for a diet high in wholegrains and low in refined grains is supported by this research. Choosing wholegrain bread, rice and pasta over the ‘white’ versions of these products is a good start, as is
checking food labels and opting for foods with wholegrain or wholemeal as one of the top three ingredients.
Zong, G et al. Wholegrain intake and
mortality from all causes, cardiovascular disease,
and cancer: a meta-analysis of prospective cohort
studies. Circulation Epub online June 13, 2016. Doi: