Blanco-Rojo R, Sandoval-Insausti H, López-Garcia E, et al. Consumption of ultra-processed foods and mortality: a national prospective cohort in Spain. Mayo Clin Proc. 2019;94(11):2178-2188.
To assess the prospective association between ultra-processed food consumption and all-cause mortality and the effect of isocaloric unprocessed food substitution
A prospective study of adult Spaniards’ food intake
11,898 Spanish adults aged 18 years or more, 50.5% of whom were female
Noninstitutionalized adult Spaniards, representative sample from ENRICA (Nutrition and Cardiovascular Risk in Spain) Study
Institutionalized adult Spaniards
Study Parameters Assessed
Study measurements involved the NOVA classification of foods. This includes:
- Unprocessed or minimally processed foods—plant and animal food consumed shortly after harvesting, gathering, slaughtering, or husbanding without alteration by the addition of other substances (eg, eggs, meat, fish, poultry, grains, coffee, plain fermented dairy);
- Processed culinary ingredients—extracted and refined from elements of foods (such as plant oils, animal fats, starches, sugars, and salts) not normally consumed by themselves (eg, salt, sugar, honey, olive oil, butter);
- Processed foods—made by adding salt, sugar, vinegar, or oil to preserve or enhance the foods’ palatability (eg, cheese, condensed milk, naturally cured ham, bread, beer, wine);
- Ultra-processed foods—formulated with little or no whole-food content and whose ingredients and additives imitate sensorial qualities of unprocessed or minimally processed foods (eg, custard, ice cream, processed meat/cold cuts, pizza, flavored yogurt and flavored fermented dairy, candy, carbonated drinks and juices, instant soup, whiskey, gin, rum, mayonnaise).
Measurements also involved the DH-ENRICA (validated computer-based dietary history), which included 880 foods that could be cooked in 29 separate ways and 184 recipes commonly eaten across the various regions of Spain.
Researchers also collected data on age, sex, education level, marital status, physical activity, smoking status, alcohol consumption, daily medication, and presence of chronic conditions diagnosed by a physician. They collected these data during a telephone interview and at least 2 home visits.
24-hour food intake recall as detailed above.
All-cause mortality from 2008 to December 31, 2016, via Spanish National Death Index.
The researchers built Cox models with adjustment for (1) age and sex, (2) education and marital status, (3) lifestyle factors, and (4) clinical factors. They performed secondary analysis of the energy and nutrient intake by the 4 NOVA food categories. They performed the analyses with Stata for Windows Version 14 with significance set at P<0.05.
The cohort included 11,898 adults with a mean age of 46.9 years; 50.5% were female. Their average ultra-processed food consumption was 385 g/day, or 24.4% of total daily energy intake. The first quartile of ultra-processed food consumption consumed 8.7% of total energy intake (156 g/day) compared to 42.8% (641 g/day) in the highest quartile. At the end of 7.7 years and 93,599 person-years of follow-up, 440 deaths occurred. The researchers found that those who consumed more ultra-processed foods consumed more energy from food per day; were younger, more frequent current smokers, and more educated; had a higher activity index; watched fewer hours of television but devoted more time to other sedentary activities; took less medication; and had less stroke, heart disease, osteoarthritis, and cancer but had more depression.
The highest quartile also had a higher intake of carbohydrates, simple sugars, total fat, saturated fat, polyunsaturated fat, trans fat, and sodium. Their most common ultra-processed foods were meat and meat products (17.1%), cakes and pastries (13.6%), cookies (9.2%), flavored yogurt and fermented milk (8.8%), jam and confectionery (7.4%), and precooked dishes (7.1%). Only trans fatty acid intake was significant for the highest versus lowest quartile, HR=1.39, P=0.05. Among food groups, ultra-processed yogurt and fermented milk (such as flavored ones) contributed the most to increased mortality, HR=1.37.
Those in the highest quartile of ultra-processed food intake had a higher mortality risk than those in the lowest quartile; HR=1.44, P=0.03. When ultra-processed food contributed more than 33% of total energy intake, there was a 44% higher all-cause mortality risk compared to when it contributed up to 14% of total energy intake.
The current study under review is not the first one of its kind to indicate that ultra-processed food is associated with poor health outcomes.
A similar Spanish study, the Seguimiento Universidad de Navarra (or SUN) study, looked at 19,899 university graduates aged 20 to 91 years from 1999-2018 and followed every 2 years from December 1999 to February 2014. The SUN study used the same NOVA classification and evaluated intake of 136 foods.1 From 1990-2010 consumption of ultra-processed foods nearly tripled from 11% to 32% of daily energy intake.2 The primary outcome of the SUN study was all-cause mortality. There were 7,786 men and 12,113 women in the SUN study. The highest quartile of ultra-processed-food consumers had a higher average BMI, consuming primarily processed meats, sugar-sweetened beverages, flavored dairy products, and French fries. The main cause of death was cancer at a mean age of 58.0 years. This quartile had HR=1.62, P=0.005 versus the lowest quartile of intake. The researchers also found that each additional serving of ultra-processed food increased mortality by 18%. Five or more servings per day of ultra-processed food was the mean in the highest quartile of intake.
When ultra-processed food contributed more than 33% of total energy intake, there was a 44% higher all-cause mortality risk compared to when it contributed up to 14% of total energy intake.
A French study examined consumption of ultra-processed food among adults aged 45 years or more from the French NutriNet-Santé Study.3 The researchers collected data from May 2009 to December 2017; mean of 7.1 years. Of the 44,551 participants, 73.1% were women (n=32,549), and the average overall age was 56.7 years. The 3,000 foods in the NutriNet-Santé Study followed the NOVA classification and included a minimum of at least 24-hour dietary recall. Ultra-processed foods were an average of 29.1% of total daily energy intake, with a 10% intake increase associated with a 14% increase in all-cause-mortality, P=0.008. Ultra-processed food consumption was associated with younger age (45-64 years), lower income (<1,200 Euros/month), lower education (no diploma), living alone, higher BMI (>30), and lower physical activity. This quartile had higher saturated fat and sugar intake and lower fiber intake as well.
A fourth ultra-processed food study was conducted in Canada.4 This study included 19,363 adults aged 18 years or more from the 2004 Canadian Community Health Survey, Cycle 2.2, involving a 24-hour recall and the NOVA classification system. Ultra-processed foods represented 45% of calories consumed by Canadian adults. Fruits and vegetables were consumed an average of 4.21 times per day, with total calories being 2,047.36/day of which 939.65 calories were from ultra-processed foods. For every 10% increase in ultra-processed-food consumption, the likelihood of obesity was 1.03. Intake of fruits and vegetables did not significantly change the obesity risk. Ultra-processed foods were more likely in men, young adults, those with less formal education, smokers, physically inactive individuals, and those born in Canada. Immigrants consumed significantly less ultra-processed foods. The current level of obesity in Canada is 25% of adults—nearly double the prevalence in 1978.5
A United States study published in 2018 assessed intake of ultra-processed food across socioeconomic groups and time (2007-2008, 2009-2010, and 2011-2012).6 This study used the NOVA classification based on food items in the National Health and Nutrition Examination Survey (NHANES) and queried individuals aged 2 years or more using 24-hour diet recall. The population was 23,847 individuals who were visited at home for physical measurements and laboratory studies and who then reported to a mobile examination center for detailed study. As with the Canadian study, pregnant and lactating women were excluded. The average US daily energy intake from 2007-2012 was 2,042.5 kcal with 59.5% from ultra-processed foods. The most common ultra-processed foods were bread (9.9%), frozen or shelf-stable meals (8.6%), confectionery (6.1%), fruit and milk drinks (5.8%), cake, cookies, pies (5.7%), soft drinks (4.6%), salty snacks (4.1%), and breakfast cereals (3.0%). The increase in ultra-processed foods was slightly over 1% per 2-year cycle, P=0.05. Ultra-processed-food consumption was least among college-educated individuals and most among adolescents, American blacks and whites, younger age, and those with lower income.
In other countries consumption of ultra-processed food represents a quarter or more of total daily calories. In the United Kingdom from 2008-2009 it made up 53% of total calories,7 in Canada in 2004 it made up 47.7%,8 in Chile in 2010 it was 28.6%,9 in France from 2009-2014 it was 35.9%,10 and in Mexico in 2012 it was 29.8%.11 This change in dietary habits is associated with a higher incidence of dyslipidemia, hypertension, and cancer.12-14 The incidence of breast cancer in France was found to increase 12% with a 10% increase in the consumption of ultra-processed foods.14
The NOVA food classifications grew out of the various guidelines used in multiple countries and the rise of fast foods in the diet.15 The EPIC (European Prospective Investigation into Cancer and Nutrition), the NOVA from the University of São Paulo, Brazil, and 3 other systems were reviewed and combined into the current NOVA food classification system. Six classes of food were melded into the current 4, and NOVA became the most common system used by food scientists and epidemiologists.15 Ultra-processed foods have been associated with obesity, cardiovascular health, cancer, depression, asthma and wheezing, gastrointestinal disorders, frailty syndrome, and all-cause cardiovascular and cancer mortality.15 Significant mortality associations have been shown with high or excessive amounts of sugar, saturated fat, trans fat, sodium, high dietary nutrient density, and low or insufficient content of protein, fiber, and potassium in the diet. The United States National Institutes of Health (NIH), US National Cancer Institute, and the World Cancer Research Fund/American Cancer Research Fund have noted that in order to protect against cancer, one needs to maintain a healthy weight and eliminate or at least reduce ultra-processed foods in the diet in favor of unprocessed, nutrient-dense foods.16 They have proposed health initiatives adopted in some Latin American countries, support for health-food preparation in schools, market incentives to value fresh, minimally processed foods that are affordable and stable in price, and statutory regulations to control consumption of carbonated soft drinks, sweet and savory snacks, cookies, confectionery, cakes, pastries, and desserts.17 Unfortunately they are up against a powerful industry with capable lobbies.
The study reviewed here was generally well-conducted and easy to read. When compared to the French, Canadian, American, Brazilian, and Mexican studies, there were many similarities; the NOVA classification was used with variances made for the culinary differences of each country. It was not stated whether only 1 person per household was examined or whether pregnant or lactating women were excluded. A comparison of who eats ultra-processed foods varied to some degree by country, but internationally it is a pervasive issue not limited to a narrow subset of the populations. As with the other studies, the Spanish authors noted that consumption of ultra-processed foods is a major challenge for governments and an opportunity for major disease prevention if the dietary habits of citizens can be significantly changed.
A role for naturopathic doctors is patient education from a very early age to counter the seductive advertisements. Another role is helping patients make sense of confusing labels and nutritional claims, as well as promoting local and organic growers and the family vegetable garden. It is sobering to note that despite the Canadian study finding that Canadian adults were eating 4.21 servings of fruits and vegetables per day, that did not decrease obesity rates when ultra-processed foods were consumed in large quantities. Clearly consuming less ultra-processed foods is the best choice.
This national Spanish study found that increased consumption of ultra-processed foods was associated with a significant increase in mortality. The theoretical isocaloric substitution of ultra-processed foods with unprocessed or minimally processed foods should reduce mortality risks.