The most convenient and affordable foods come with a high price tag in the end, according to two new studies: Researchers reporting in The BMJ found that a diet high in ultra-processed foods could increase the risk of all-cause and cardiovascular death.
What are ultra-processed Foods?
A report published in World Nutrition describes the NOVA Classification of foods. Foods are ranked in four groups; ultra-processed foods, Group 4, are described as foods with many ingredients, including sugars, fats, and preservatives; little to no whole, unprocessed foods intact foods; and additives like dyes and color enhancers. Ultra-processed foods and drinks include, but are not limited to:
- Carbonated drinks
- Ice cream, chocolate, and candies
- Mass-produced breads and buns
- Cookies, cakes, and cake mixes
- Breakfast cereals
- Energy bars
- “Health” and “slimming” products
- Ready-to-heat prepackaged foods
“During the past two decades, availability and consumption of ultra-processed foods, characterised by food products with a low nutritional quality and high energy density, has increased markedly in many countries,” reported the authors of the Spain-based study reporting on all-cause mortality. “Between 1990 and 2010 the consumption of ultra-processed foods almost tripled (from 11% to 32% of daily energy intake), parallel with increases in added sugar content.”
The first study included 19,899 participants (12,113 women and 7,786 men) aged between 20 and 91 years (mean age at baseline, 37.6 years). A 136-item questionnaire was administered at baseline to collect information on participants’ eating habits. Food frequency consumption was reported in nine categories ranging from never/almost never to more than six servings daily, and portion sizes were also collected. Participants reported their food and drink intake every two years from December 1999 until February 2014. The primary outcome was the correlation between consumption of ultra-processed foods (consumption stratified into quarters: low, low-medium, medium-high, and high) and all-cause mortality. Median follow-up duration was 10.4 years; a total of 200,432 person years of follow-up were collected, during which time 335 deaths occurred.
The participants who reported the highest consumption of ultra-processed foods (fourth quarter) had a higher body mass index, the researchers observed, and were more likely than members of the first quarter to be smokers and have a family history of cardiovascular disease, cancer, diabetes, hypertension, hypercholesterolemia, prevalent cardiovascular disease, and depression. They were more likely to snack and be sedentary and spent more time on the computer.
Mediterranean Diet Ranked Best Overall Diet
“Adherence to the Mediterranean diet tended to be progressively lower across successive quarters of ultra-processed foods consumption (ie, the higher the consumption of ultra-processed foods, the lower the adherence to the Mediterranean diet), with a correlation coefficient r=−0.39 (95% confidence interval −0.40 to −0.38) between the score for adherence to the Mediterranean diet and consumption of ultra-processed foods,” the researchers observed. (The Mediterranean diet was ranked the best overall diet by experts.) The most commonly consumed ultra-processed foods included processed meats, sugar-sweetened beverages, dairy products, and French fries.
The most common cause of death was cancer (n = 164); mean age at death from cancer was 58 years. And the fourth quarter group was significantly more likely to die from any cause: “Participants in the highest quarter of ultra-processed food consumption had a 62% relatively higher hazard of all cause mortality compared with those in the lowest quarter (multivariable adjusted hazard ratio 1.62, 95% confidence interval 1.13 to 2.33), with a significant dose-response relation (P for trend=0.005).” All-cause mortality relativity increased by 18% with each added serving of ultra-processed food.
“Improving diet based on adherence to minimally processed food—a key aspect of the Mediterranean diet—has been shown to protect against chronic disease and all cause mortality,” the study authors wrote, adding that discouraging ultra-processed food consumption and encouraging people to consume fresh, minimally processed, whole foods could “improve global public health.”
The second study was a population-based cohort study in France that included 105,159 participants (21,912 men, 83,247 women) aged ≥ 18 years (mean age at baseline, 42.7 years). The NOVA Classification was used in this study as well, designating participants’ usual consumption of 3,300 food items. Participants were followed for a median 5.2 years. Researchers collected dietary records for each participant and had a mean 5.7 records for each person over their first two years of follow-up.
Like in the Spain study, members of the fourth quarter had higher BMI and were more likely to be smokers, but they had less family history of cardiovascular disease. During a follow-up of 518,208 person years, 1,409 first incident cardiovascular disease events occurred, including myocardial infarctions (n = 106), angioplasties (n = 485), acute coronary syndromes (n = 74), strokes (n = 155), and transient ischemic events (n = 674). The risk of all cardiovascular diseases increased along with the consumption of ultra-processed foods. Compared to members of the first quarter, participants in the second, third, and fourth quarters had all cardiovascular diseases hazard ratios of 1.06, 1.08, and 1.25, respectively.
“Absolute incidence rates for CVD in the whole population were 253 per 100 000 person years: age and sex corrected absolute rates were 242 per 100 000 person years in the first quarter (low consumers) of the proportion of ultra-processed food intake in the diet, 254 in the second quarter, 252 in the third quarter, and 277 in the fourth quarter (high consumers); with respective rates for coronary heart disease of 109, 116, 125, and 124 per 100 000 person years, and for cerebrovascular diseases of 144, 148, 143, and 163 per 100 000 person years,” the study authors reported.
While the researchers called for further studies to validate their findings, they said that the public should still be informed about these associations, and that action should be taken “to limit the proportion of ultra-processed foods in the diet and promote the consumption of unprocessed or minimally processed foods instead.”
Source: British Medical Journal