Source: Radio New Zealand (world)
Researchers have analysed the biomarker differences in a small group of older Australians after putting them on a four-week diet. Older Australians who reduce either dietary fat or animal-based protein show signs of reduced biological age, according to a new small Australian study.
University of Sydney nutritional ecologist Alastair Senior, who supervised the study, told Sunday Morning biological age is about putting a number of years to how well you’re functioning, rather than how long you’ve lived, using biomarker profiles.
For this research, 104 Australian participants between 65 and 75 years old (none were smokers, vegetarians or had serious health complications) were randomly assigned to one of four diets. Four-week diet could wind back the aging clock The study was “very well controlled”, with all of their food delivered.
Drinking alcohol was also not allowed and processed food intake was reduced compared to the typical Australian diet, Senior says.
“So, that let us really focus in on the specific nutrients we’re trying to manipulate, rather than types of foods, for example.” Each of the four diets had 14 percent energy from protein, with the source and carb/fat ratio differing.
For the omnivorous, half of the protein came from animal sources and the rest from plants, while the semi-vegetarian had 70 percent of protein coming from plant sources. So the diets were: omnivorous high-fat, omnivorous high-carb, semi-vegetarian high fat, and semi-vegetarian high carb.
When the groups’ biomarkers were reassessed, the omnivorous high-fat group showed no meaningful change. Senior believes this could be because the diet closely resembled what most participants were already eating. The other three diets showed some reductions, but it was the omnivorous high-carbohydrate diet that showed the largest reductions, Senior says.
“Now, in some ways, we’re splitting hairs a little bit to contrast the semi-vegetarian and the omnivorous high-carb diets, because they all did very well.” Some of the food options for such a diet could include muesli and yogurt for breakfast, brown rice or quinoa salad for lunch, followed by fruit or a nut bar.
A heavier lunch or an evening meal might include a chicken tikka masala or a casserole, he says. Animal studies had already shown substituting protein for carbohydrates or cutting specific amino acids in the diet can lead to increased lifespan, he says.
“We think that happens by switching off pro-growth pathways in cells, and putting cells into maintenance mode.
So we think perhaps the omnivorous high-carb diets and the pro-vegetarian diets start to do this over the course of about four weeks.” While diets have become central to our biology because of the way we’ve evolved, lead researcher Caitlin Andrews noted it’s too soon to say definitively that specific changes to diet will extend your life.
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