Using data from a study called involving over 120,000 subjects from Denmark, Sweden and Norway, researchers found that a high intake of wholegrains lowered mortality rates caused by cancer, coronary heart disease, stroke and diabetes.
Mortality rate ratios were reduced by 1 - 17% across the board for men and women and the effect was not linked to one specific type of wholegrain or wholegrain product.
“In this large Scandinavian population, intake of wholegrain products was associated with lower all-cause mortality. In particular, (…) intake of breakfast cereals and non-white bread was associated with lower mortality.”
Around 80% of breakfast cereals consumed in Scandinavia are wholegrain, such as muesli, porridge and oatmeal.
“The size of the estimates may seem small but considering the fact that wholegrain is just one single dietary component, and diet is just one of a range of lifestyle factors predicting mortality, it is still a valuable and achievable goal for the Scandinavian populations,” wrote the researchers, led by Nina Johnsen from the Danish Cancer Society Research Centre.
The researchers said this is the first study to investigate the intake of different types of wholegrain in relation to specific causes of death, as well as the overall mortality rate.
The researchers noted national differences in dietary sources of wholegrain – but this did not affect the lower mortality rate. In Denmark rye bread made up two thirds of wholegrain intake whilst in Norway and Sweden the largest contributor was mixed-grain bread.
Median intake of breakfast cereals in Sweden was around 30 g per day but was close to zero in Denmark and Norway. Similarly, crispbread intake in Sweden was high – between 34 and 57 g per day – but was very low for the other countries.
A total of 120,010 participants aged between 30-62 years participated in the HELGA cohort from 1992 to 1998, completing detailed food frequency questionnaires. Johnsen et al. analysed this data to estimate wholegrain intake in each country. Information on the wholegrain content of products consumed was gleaned from recipes, ingredient lists and data from manufacturers and national surveys.
Mortality rate ratio for the highest and lowest quartiles of total wholegrain intake was 0·68 for women and 0·75 for men.
“The results were consistent and highly statistically significant,” wrote the researchers, although they did note the possibility of misclassification of wholegrain products from the self-reported data, and the fact that people who eat lots of wholegrain may have a better diet and healthier lifestyle in general.
In Scandinavian countries, the official recommended daily intake of wholegrains has been set at 75 g per day but it is estimated that only around 16% of Danish men and 35% of Norwegian women hit this target.
“Although the intake of wholegrains is part of the traditional diet in the Scandinavian countries, effort has to be made to increase and keep the intake high.”
Source: British Journal of Nutrition
First published online July 2015, doi:10.1017/S0007114515001701
“Whole-grain products and whole-grain types are associated with lower all-cause and cause-specific mortality in the Scandinavian HELGA cohort”
Authors: Nina Johnsen, Kirsten Frederiksen, Jane Christensen et al.