Study links consumption of ultraprocessed foods to mortality
11th February 2019
A study published in the Journal of the American Medical Association today links consumption of so-called ‘ultraprocessed foods’ to early death.
This was a prospective cohort study that followed a population of French adults, 45 years and over for a period of about 7 years. 44,551 people (about 70% female) were included in this study and the association between their consumption of ‘ultraprocessed foods’ (using the NOVA definition) and mortality assessed.
The study found that higher consumption (as a proportion by weight) of ultraprocessed foods was associated with significantly higher risk of mortality from any cause – a 10% increase in consumption of ultraprocessed foods was associated with a 14% increased risk in all-cause mortality (Hazard Ratio 1.14, 95% CI 1.04-1.27, P=0.008).
This study follows a number of others using the NOVA definition of processed foods, linking consumption of ultraprocessed foods to negative health outcomes including cancer and obesity.
However, it is important to note that this type of study can only look at associations and not causes and to consider the complex factors that could affect an association between different aspects of diet and health.
When looking at the backgrounds of the people involved in the study, the researchers found that those who ate more ultraprocessed foods tended to have lower incomes and levels of education, were more likely to live alone, had higher BMIs, lower levels of physical activity and were more likely to smoke. This suggests that those consuming more ultraprocessed foods also had less healthy lifestyles and a lower socioeconomic status.
The study also looked at other aspects of the diet in relation to ultraprocessed food consumption. Diets that were higher in ultraprocessed foods also tended to be higher in saturated fat and sugars, lower in fibre and were less likely to meet French nutrition recommendations overall.
The authors adjusted for many of these factors in the analysis and still found that their results were significant, and so they concluded that other factors related to food processing such as additives, process contaminants or compounds formed at high temperatures could be causing the association with mortality.
However, it is almost impossible in this type of study to rule out all confounding and so it is difficult to be clear on whether the effects seen in this study are genuinely due to consumption of ultraprocessed foods or down to generally poorer diet and lifestyle.
The ‘ultraprocessed foods category’ includes a wide range of different types of food. Many are those that we are already advised to cut down on such as confectionary, fried snacks, processed meats, cakes and biscuits. However, this definition of ultraprocessed foods also includes foods like wholegrain breads and wholegrain, lower sugar cereals which can be part of a healthy diet. Categorising foods purely on their level of processing does not take account of their nutrient content and does not allow us to select more healthy types of processed foods such as wholemeal rather than white bread or a vegetable-based pasta sauce rather than one based on cream and cheese. In the UK, we have food-based dietary guidance in the form of the Eatwell Guide which shows how foods in the diet can provide us with the balance of nutrients needed for good health based on their nutritional composition. This is likely to be more a meaningful guide to choosing healthy foods than considering level of processing alone.