EATING too many ultra-processed foods has been linked to a higher risk of early death, a study 30-year study has found.
Scientists from Harvard University tracked over 114,000 healthy US adults over the course of three decades to gauge the long-term consequences of their diets.
Processed meats were associated with 13 per cent higher risk of death
BMJPrevious research has linked UPFs to 32 illnesses[/caption]
They found that diets heavy in ultra-processed foods (UPF) were linked to a slightly higher risk of death, with processed meats and fizzy drinks posing the greatest danger to health.
UPFs are foods that have been heavily altered from their original state in a way that you wouldn’t be able to recreate in your kitchen.
They typically contain added sugar, salt and fat, as well as chemical additives like sweeteners, emulsifiers and colours, but tend to be low in vitamins and fibre.
Mounting evidence has linked these foods to a higher risk of obesity, heart disease, diabetes and bowel cancer, with junk food linked to 32 illnesses in recent research.
But few studies have followed participants for such as long time, or focused specifically on risk of death.
The Harvard study – published in the BMJ – also differed from previous research in zeroing in on specific foods.
It found that processed meat, poultry, and seafood based products, sugary drinks, dairy-based desserts, and highly processed breakfast foods showed the strongest link to early death.
People who regularly ate processed meats such as sausages and bacon had a 13 per cent higher risk of dying.
Those who guzzled sugary or artificially sweetened drinks had a 9 per cent increased risk.
Meanwhile, dairy deserts and breakfast cereals were linked to 6 and 4 per cent elevated risk of dying.
Commenting on the research, Prof Christine Williams, Emeritus Professor Human Nutrition at the University of Reading, said: “These categories of foods have long been advised to be eaten in modest quantities due to potentially adverse effects on body weight, cholesterol levels, and in the case of processed meats, colorectal cancers.”
Researchers tracked the long-term health of 74,563 female registered nurses and 39,501 male health professionals, who had no history of cancer, cardiovascular diseases, or diabetes before enrolling in the study.
They provided information on their health and lifestyle habits every two years and completed a detailed food questionnaire every four.
Participants with the highest UPF intake – an average of seven servings daily – had a 4 per cent higher risk of early death compared to people who consumed an average of three servings daily.
Over 34 years, researchers identified 48,193 deaths, including more than 13,000 due to cancer and just over 11,000 attributed to cardiovascular diseases.
But no specific relationship between total UPF consumption and cancer or heart disease deaths was observed.
Instead, the elevated risk – amounting to an extra 64 deaths per every 100,000 person-years – was only seen for deaths from all causes.
The link was less pronounced after overall dietary quality was taken into account, suggesting that dietary quality had a stronger influence on long term health than UPF consumption, the authors noted.
The study was observational study, meaning no firm conclusions on cause and effect could be drawn.
While they didn’t call for all UPFs to be restricted, researchers argued that their findings “provide support for limiting consumption of certain types of ultra-processed food for long term health”.
They said future studies are needed to confirm their findings in other populations.
Experts criticised the research, with Sir David Spiegelhalter, emeritus professor of statistics at the University of Cambridge, saying: “This study shows weak associations of ultra-processed foods with overall mortality.”
Dietitian Dr Duane Mellor, spokesperson for the British Dietetic Association, said: “It is also noticeable that those who consumed most ultra-processed foods tended to eat few vegetables, fruit, legumes and wholegrain.
“It might not be as simple as that those who ate more ultra-processed foods are more likely to die earlier — it is quite possible that these foods might displace healthier foods from the diet.’
He added: “Not all groups of UPFs are associated with the same health risks, with sugar and artificially sweetened drinks and processed meats being most clearly associated with risk of an early death.”
Professor Gunter Kuhnle, an expert in nutrition and food science at the University of Reading, said it was “impossible to know how reliable the results are”, urged for the results to be “treated with a lot of caution”.
“I don’t think this study provides evidence suggesting limiting certain foods just because of their level of processing,” he added.
How ultra processed is YOUR kitchen?
Ultra processed foods (UPFs) were defined by Brazilian researchers who made the NOVA classification system. It breaks foods into groups depending on how processed they are. The most natural foods are in group 1, while the most processed are in group 4.
The groups do not entirely indicate how healthy a food is. However, it does indicate how processed it is – and studies have linked UPFs to a number of diseases.
How does your kitchen compare to the following groups?
Unprocessed or minimally processed foods (group 1)
vegetables and fruits (fresh or frozen)
dried fruits with no added sugar, honey, or oil
grains and legumes (chickpeas, lentils)
meat, poultry, fish, seafood, eggs
milk without added sugar
plain yogurt with no added sugar
nuts and seeds
spices and herbs
tea, coffee, water
Processed culinary ingredients (group 2)
iodized salt
salted butter
sugar and molasses from cane or beet
honey extracted from combs
syrup from maple trees
vegetable oils crushed from olives or seeds
butter and lard from milk and pork
starches extracted from corn and other plants
vegetable oils with added anti-oxidants
vinegar with added preservatives
Processed foods (group 3)
canned vegetables, fruits, and legumes
fruits in syrup
salted or sugared nuts and seeds
salted cured or smoked meats
canned fish
artisanal breads and cheese
Ultra-processed foods (group 4)
pop and fruit drinks
sweetened yogurt
sweet or savoury packaged snacks (e.g., cookies)
candies and cake mixes
mass-produced packaged breads and buns
margarines and spreads
breakfast cereals
cereal and energy bars
energy drinks
instant soups, sauces, and noodles
poultry and fish nuggets, hot dogs
many ready-to-heat products: pre-prepared pies, pasta, and pizza dishes