Compounds produced by frying, grilling, or pasteurizing may be driving inflammation and ageing, according to a new study from the US.
But reducing intakes of compounds called advanced glycation end products (AGEs) may reduce inflammation and help boost the body’s natural defences, according to results of a dietary intervention published in the Journal of Clinical Endocrinology and Metabolism.
AGEs are toxic substances reportedly produced in abundance in the Western diets, as a result of heating, pasteurisation, drying, smoking, frying or grilling. The compounds are said to promote oxidation and inflammation, which may ultimately increase the risk of chronic diseases, such as diabetes and heart disease.
The study adds to previous studies on that point the finger at the highly processed foods and meats consumed in the Western diet in relation to a range of conditions, from obesity to colorectal cancer.
Researchers from the US National Institute on Aging and Mount Sinai School of Medicine report that a simple dietary intervention that reduces intakes of AGEs may promote weight loss and improve overall health. The improvements occurred without changing caloric or nutrient intake, said the researchers.
“What is noteworthy about our findings is that reduced AGE consumption proved to be effective in all study participants, including healthy persons and persons who have a chronic condition such as kidney disease,” said study author Professor Helen Vlassara from Mount Sinai School of Medicine.
The new study involved 40 healthy people aged between 18 and 45, or older than 60, and another 9 people with kidney disease. The subjects were randomly assigned to one of two diets: One group continued to consume their own regular Western diet, while the second group consumed a diet with the same calorie and nutrient content, but with 50 per cent less AGEs.
Participants in the AGE-less intervention were advised poach, stew, or steam their meals.
After four months of intervention, blood AGE levels, lipid peroxides, inflammatory markers, and biomarkers of blood vessel health declined by as much as 60 per cent in healthy participants, said the researchers. Similar improvements were also observed in the kidney patients on the AGE-less diet, they added.
Worryingly, Vlassara and her co-workers believe that daily AGE intakes in the standard Western diet may be at least three times higher than the safety limit for these oxidants.
“Even though the AGEs pose a more immediate health threat to older adults, they are a similar danger for younger people, including pregnant women and children, and this needs to be addressed,” said Vlassara.
“AGEs are ubiquitous and addictive, since they provide flavour to foods. But they can be controlled through simple methods of cooking, such as keeping the heat down and the water content up in food and by avoiding pre-packaged and fast foods when possible. Doing so reduces AGE levels in the blood and helps the body restore its own defences,” she added.
The Western dietary pattern has also been blamed by some for the obesity epidemic, particularly in children. Indeed, in August 2007 US paediatrician Robert Lustig, MD, from the University of California, San Francisco said that the "toxic environment" of Western diets causes hormonal imbalances that encourage overeating.
Source: Journal of Clinical Endocrinology and Metabolism
Published online ahead of print, doi:10.1210/jc.2009-0089
“Protection against Loss of Innate Defenses in Adulthood by Low Advanced Glycation End Products (AGE) Intake: Role of the Antiinflammatory AGE Receptor-1”
Authors: H. Vlassara, W. Cai, S. Goodman, R. Pyzik, et al.