Researchers at the Charles Perkins Center at the University of Sydney have conducted the largest study of nutrient interactions by examining the health of mice in 33 different diets containing various combinations of protein to carbohydrates and different sources of carbohydrates.
When carbohydrates were made up mainly of resistant starch, a form of starch resistant to digestion and fermented by bacteria in the intestine, the low protein diet it was the healthiest diet of all. When carbs were a 50:50 fructose to glucose mix, the same makeup as fructose-rich corn syrup (the main sweetener used in the packaged food and beverage industries in the United States) The low-protein diet produced the worst results.
The study, which took three years to complete, is published in Nature’s metabolism today.
“Although the study was conducted in mice, the results appear to explain the disparity between healthy, low-protein, high-carbohydrate diets and the rising levels of obesity and comorbidities associated with modern highly processed diets that also they are proteins. diluted and rich in refined carbohydrates, “said Professor Stephen Simpson, lead author and academic director of the Charles Perkins University Center.
“We have found that the molecular composition of a carbohydrate and how it is digested shape the physiological and behavioral response to reduced levels of dietary protein, affects the way the liver processes nutrients and alters intestinal bacteria.
“These findings could explain why consuming low-protein, high-carbohydrate diets that avoid high-fructose corn syrup, limit easily digestible processed starch, and are abundant in resistant starch (which in a human diet would be whole grains and legumes such as beans and lentils) .associated with good metabolic health “.
The work is based on the team’s innovative 2014 cell metabolism study, which showed diets low in protein and carbohydrates in mice, resulting in longer life and better cardiometabolic health during half and early years of late life.
For the 2014 study, the researchers used easily digestible starch as the main source of carbohydrates, so the next logical step was to examine what happens if the source of carbohydrates is altered. The present study confirms the above findings and expands them to show the importance of the type of dietary carbohydrates, helping to explain why the most living human populations on earth, such as the traditional Japanese of Okinawa, have a low diet. in protein and high in carbohydrates but when protein is diluted in the human food supply by processed refined carbohydrates, the results for health are not so favorable.
Low-protein diets are not all the same
Dr. Jibran Wali, lead author of the new study, said that not all low-protein diets are the same. A low-protein, high-carbohydrate diet is an environment for maximizing the health benefits of carbohydrates accessible to colon bacteria (e.g., resistant starch), but it can also be a means to maximize the adverse effects of highly carbohydrates. processed.
“We found that the 50:50 glucose-fructose mixture created the highest levels of obesity in mice, even when calorie intake was comparable to that of other carbohydrates. This suggests that heat is not a heat when it comes to carbohydrates, not even different sugars and that consumption of glucose and fructose in combination promotes obesity and poor metabolic health, ”said Dr. Wali, Peter Doherty Biomedical Fellow of the NHMRC at the Charles Perkins Center and the School of Life and Environmental Sciences.
Researchers say this finding may come as a surprise to many, as while there is consensus that excess calories in sugar cause weight gain and metabolic diseases, there is an active debate about what form of sugar (sucrose, corn syrup high in fructose, glucose, fructose) is the most harmful.
“The findings could have enormous practical benefits,” said Professor David Raubenheimer, Leonard P. Ullmann Professor of Nutritional Ecology at the Charles Perkins Center and the School of Life and Environmental Sciences and co-author of the study. .
“For many people who want to improve their diet, carbohydrates have become the enemy. Some make extreme efforts, virtually eliminating them from the diet. Our results suggest that this could be a mistake. Reduce certain types of carbohydrates, such as high-fructose corn syrup, but by avoiding the digestive-resistant forms, which are found in many plant foods, you run the risk of losing the benefits of a nutrient. rich in the diets of the healthiest and most living populations on Earth, ”continued Professor Raubenheimer.
“The results of this study help explain why it’s best to stay away from foods like cakes, pizzas and pastries and help fill the plate with whole grains like brown rice, oats and quinoa, legumes like lentils, beans and chickpeas, and opt for many vegetables included sweet potato, pumpkin and beets, “said Dr. Rosilene Ribeiro, a dietitian and researcher at the School of Life and Environmental Sciences and co-author of this study.
As for the study
The preclinical study of male mice explored the impact of 33 diets with different protein-to-carbohydrate ratios and different types and combinations of carbohydrates (fructose, glucose, sucrose, digestible native starch, and resistant starch) with the intake of fixed fats.
Mice were allowed to eat as much as they wanted for 18 to 19 weeks, during which time researchers thoroughly examined their metabolic health and analyzed the intestinal microbiome.
The study used the use of the geometric framework for nutrition developed by professors Stephen Simpson and David Raubenheimer. It allows researchers to consider how nutrient mixtures and their interactions influence health and disease, rather than focusing on any isolated nutrient, which has been the downfall of many previous nutrition studies.
What would diet be like in humans?
Although the current study was conducted in mice, the following is a sample menu for a low-protein, highly resistant starch diet in humans.
Breakfast: porridge and fruit. AM snack: raw vegetables such as carrots, peas, tomatoes. Lunch: Brown rice and quinoa salad made with fresh vegetables and chickpeas. PM snack: wholemeal bread with hummus. Dinner: Lots of vegetables (at least half the plate) like beans and sweet potatoes and a small piece of lean meat or fish. Dessert: fruit.
Nature’s metabolism (2021). DOI: 10.1038 / s42255-021-00393-9
University of Sydney
Citation: The health benefits of low-protein, high-carbohydrate diets depend on the type of carbohydrate (2021, June 7) retrieved June 7, 2021 at https://medicalxpress.com/news/2021-06 -health-benefits-protein-high-carbohydrate-diets .html
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