« Trends in food intake »
The Global Burden of Disease study showed that dietary factors such as low fruit and vegetable intakes are among the top five risk factors for poor health. Measuring dietary intake across countries, and monitoring changes over time is an important element in our understanding of the relationships between diet and health. In spite of the methodological challenges in accurately assessing intake, the three papers highlighted in this issue illustrate the value of nutrition research to guide policy and practice.
The United Kingdom has a strong track record of monitoring diet, with national surveys dating back over many decades. In addition there are a series of prospective cohorts including dietary data and the paper by Pot et al., that shows changes in intake in the birth cohort born in 1946 that are broadly consistent with the trends across the wider population. By drawing on the lives of this one cohort, it is easier to see the changes in a wider social context. The paper notes how market level changes (e.g. availability of skimmed milk); policy recommendations (e.g. to increase vegetable products and decrease animal products) or even shifts in social standards (e.g. increased wine among women) have affected dietary patterns over time.
Global data presented by Imamura et al., highlights important changes in foods and nutrients relevant for their effects on obesity and non-communicable diseases over the last two decades. High- and middle-income countries have experienced improvements in healthy dietary factors (e.g. fruit, vegetables, fish, fibre, unsaturated fats, etc.) whereas consumption of these healthier foods and nutrients did not improve in the poorest regions. In parallel, consumption of other foods and drinks including sugar-sweetened beverages and meat has increased in most world regions, contributing to the rise in consumption of sugar and saturated fat.
In the context of obesity, dietary energy density is a known risk factor, positively correlated with intake of fat and sugar and negatively correlated with fruit and vegetables. In an Irish population, O’Connor et al., shows that diets with a higher energy density are associated with higher intakes of less healthy food groups (e.g. snacks, confectionery, sugar-sweetened beverages, alcoholic beverages, etc.) but, interestingly, the overall dietary energy density has remained stable from 2001-2010 despite marked increases in the prevalence of obesity. It is clear that more work is needed to identify an integrated measure of the health properties of the whole diet, which shows clear associations with obesity and other health outcomes.
This global perspective on trends in food habits provides a glimmer of hope of some recent improvement, at least among some subgroups in Europe and across the world. But the pace of change is slow and there is a pressing need to identify interventions which help lower- and middle-income countries to maximise the opportunities of the nutrition transition while avoid the damaging consequences of excess consumption of saturated fat and sugar.