Monday, 18 February 2019

From the ABC : Junk food and life expectancy


Eating ultra-processed foods like chips, sausage rolls and biscuits has been associated with higher risk of obesity, hypertension, and cancer, but up to now studies have not looked at whether you die any earlier.
Turns out you do. Probably.
A study in the Journal of the American Medical Association (JAMA) shows those who ate more junk food had a higher risk of dying earlier than those who ate less.
The risk is about 14 per cent higher for each 10 per cent increase in the proportion of highly processed food a person eats.
The study monitored the diets of tens of thousands of French people between 2009 and 2017 as part of the ongoing NutriNet-Sante study.
After seven years, 602 of the 44,551 adults had died.
The authors of the study have cautioned the results do not mean eating a single packaged meal gives you a higher risk of dying.
"We shouldn't be alarmist," said Mathilde Touvier, director of the nutritional epidemiology research team at Paris 13 University.
"It's another step in our understanding of the link between ultra-processed food and health."
What are ultra-processed foods?
Ultra-processed foods come under group four of the NOVA food classification system recognized by health agencies including the UN Food and Agriculture Organization.
The other three groups are unprocessed foods like fruit and vegetables, or meat and eggs; processed ingredients like oils, butter, sugar and salt; and processed foods like canned fish, fruits in syrup, and certain types of cheeses and bread.
Home delivery isn’t necessarily unhealthy, but it does make it easier to eat badly.
Ultra-processed foods include soft drinks, packaged snacks, reconstituted meat produces, and pre-prepared frozen dishes.
"The main purpose of industrial ultra-processing is to create products that are ready to eat, to drink or to heat, liable to replace both unprocessed or minimally processed foods that are naturally ready to consume, such as fruits and nuts, milk and water, and freshly prepared drinks, dishes, desserts and meals," according to the  Who in 2016.
"Common attributes of ultra-processed products are hyper-palatability, sophisticated and attractive packaging ... health claims, high profitability, and branding and ownership by transnational corporations."
Basically, it's bright shiny junk food. If you know, you know.
Why is junk food unhealthy?
Linking junk food with bad health isn't exactly groundbreaking, and the study itself isn't definitive.
Since it is not possible to conduct an experiment where you cram junk food into people for several years, observational studies are the only option. Since they rely on people accurately reporting what they ate, they are inevitably flawed.
The authors also had to adjust the results to isolate junk food from all the other causes of an earlier death, including the overall quality of the diet, or the amount of exercise - factors that are associated with eating more junk food.
In any case, assuming there is a modest link between junk food and a heightened risk of dying early, the question becomes why is junk food so unhealthy?
The JAMA report offers several hypotheses:
  • High salt content. Consuming more sodium has been associated with heart disease and stomach cancer
  • More sugar. High sugar intake has thas been associated with an increased risk of heart disease
  • Not enough fiber. Dietary fiber has been linked with a substantially decreased risk of dying early
  • Suspected carcinogen-contaminants, such as acrylamide, in foods that have undergone high-temperature processing
  • Food additives such as titanium dioxide have been associated with gut and intestinal inflammation
  • Harmful chemicals present in food packaging may be migrating into food
Whatever the causes, what's not in doubt is that people in lower socioeconomic groups eat more junk.
"These results underline the social inequalities associated with food choices," the authors write in the JAMA report.
"Further prospective studies are needed to confirm these findings and to disentangle the various mechanisms by which ultra-processed foods may affect health."


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