Genomic adaptations to a rice-based diet mitigate the risk of obesity and diabetes

September 21, 2020

The traditional rice-based diet of some east-Asian population has brought to a number of genomic adaptations that may contribute to mitigating the spread of diabetes and obesity. An international study led by the University of Bologna and published in the journal Evolutionary Applications has recently suggested this interesting hypothesis. Researchers analysed and compared the genomes of more than 2,000 subjects from 124 south-east-Asian populations.

"We suggest that it may be possible that some east-Asian populations, whose ancestors started eating rice on a daily basis at least 10,000 years ago, have evolved genomic adaptations that mitigate the harmful effects of high-glycaemic diets on metabolism", confirms Marco Sazzini, study coordinator and professor at the Department of Biology, Geology and Environmental Sciences of the University of Bologna. "Furthermore, these adaptations plausibly continue to play a pivotal role in protecting them from the negative effects that derive from major dietary alterations brought about by the globalisation and westernization of their lifestyles. These alterations dramatically increased their consumption of food rich in processed sugar and with a high glycaemic index".

RICE AND GLYCAEMIC INDEX

Among the so-called domesticated cereals, rice presents a high glycaemic index and is rich in carbohydrates. This means that once ingested and digested, it causes sugar in the blood to increase. If eaten regularly and in large quantities, rice may represent a potential risk factor for developing insulin resistance and related metabolic diseases such as type 2 diabetes.

However, if we compare east-Asian people having used rice as a staple food for over 10,000 years with those in the Indian sub-continent, we soon find out that the latter show higher rates of diabetes and obesity than east-Asians. Why are these two groups different?

A 10,000-YEAR-OLD DIET

Archaeology may provide a hint to answering that question. Archaeobotanical findings in some eastern regions of Asia show that wild rice had been part of the inhabitants' diets in the past starting 12,000 years ago. After rice domestication and the introduction of rice farming techniques, between 7,000 and 6,000 years ago, rice spread rapidly across Korea and Japan. In northern regions of the Indian sub-continent, an independent domestication process had started 4,000 years ago and brought to the selection of rice varieties presenting a lower glycaemic index if compared to east-Asian rice.

"Different rice varieties and a head start of millennia may have put populations in China, Korea, and Japan under a more pressing metabolic stress than that experienced by south Asian populations", explains Arianna Landini, first author of this study and a PhD student at the University of Edinburgh. "This might have allowed them to evolve genomic adaptations that mitigate the risk of becoming ill with metabolic diseases linked with a high-sugar diet".

RICE AND GENOMIC ADAPTATIONS

To test such a hypothesis, researchers analysed the genome of more than 2,000 subjects from 124 east-Asian and south-Asian populations. Then, they compared the adaptive evolution observed in Chinese Han and Tujia ethnic groups, as well as in people of Korean and Japanese ancestry (with a long-standing tradition of rice-based diets) with that of people from regions of Pakistan, Bangladesh, Myanmar, Vietnam, and south-east Asia. Southeast Asian subjects were used as control groups because their adoption of cereal-based diets occurred many thousand years later.

"The genomic adaptations observed in control groups differ greatly from those of east Asian populations and are not related to metabolic stress due to a specific diet", says Claudia Ojeda-Granados, one of the authors and a research fellow at the University of Bologna. "Chinese Han and Tujia ethnic groups, as well as people of Korean and Japanese ancestry show instead similar metabolic genomic adaptations".

Some of the genetic modifications the researchers identified are associated with a lower BMI and a weaker risk of cardiovascular diseases thanks to a reduced conversion of carbohydrates into cholesterol and fatty acids. Some other adaptations favour a reduced insulin resistance as they negatively modulate the glucogenesis in the liver. Finally, some others stimulate the production of retinoic acid, which is a metabolite of vitamin A. Deficiency in this nutritional organic compound often causes health-issues in people eating a rice-based diet.

"Our results demonstrate once again how studying evolutionary history may successfully inform biomedical research, eventually leading to the identification of the mechanisms underlying the different susceptibility of human populations to different diseases", concludes Sazzini.
-end-
THE AUTHORS OF THE STUDY

The title of this study is "Genomic adaptations to cereal-based diets contribute to mitigating metabolic risk in some human populations of East Asian ancestry" and was published in the journal Evolutionary Applications. The research coordinator is Marco Sazzini, professor at the Molecular Anthropology Lab and Genomic Biology Center of the Department of Biology, Geology and Environmental Sciences of the University of Bologna and of the Alma Mater Research Institute on Global Challenges and Climate Change.

Other researchers of the University Bologna participating in the study are Shaobo Yu, Paolo Abondio, Claudia Ojeda?Granados, Stefania Sarno, Sara De Fanti e Davide Pettener (Department of Biology, Geology and Environmental Sciences), together with Eugenio Bortolini and Donata Luiselli (Department of Cultural Heritage), Giovanni Romeo (Unit of Medical Genetics of the Policlinico Sant'Orsola) and Cecilia Prata (Department of Pharmacy and Biotechnology).

Adriana Landini (Centre for Global Health Research at the University of Edinburgh, UK) also took part in the study and was its the first authors alongside Shaobo Yu. Finally, other participants were Guido Alberto Gnecchi Ruscone (Max Planck Institute for the Science of Human History in Jena, Germany), Davide Gentilini and Anna Maria Di Blasio (Istituto Auxologico Italiano) and researchers from universities in South Korea and Vietnam.

Università di Bologna

Related Diabetes Articles from Brightsurf:

New diabetes medication reduced heart event risk in those with diabetes and kidney disease
Sotagliflozin - a type of medication known as an SGLT2 inhibitor primarily prescribed for Type 2 diabetes - reduces the risk of adverse cardiovascular events for patients with diabetes and kidney disease.

Diabetes drug boosts survival in patients with type 2 diabetes and COVID-19 pneumonia
Sitagliptin, a drug to lower blood sugar in type 2 diabetes, also improves survival in diabetic patients hospitalized with COVID-19, suggests a multicenter observational study in Italy.

Making sense of diabetes
Throughout her 38-year nursing career, Laurel Despins has progressed from a bedside nurse to a clinical nurse specialist and has worked in medical, surgical and cardiac intensive care units.

Helping teens with type 1 diabetes improve diabetes control with MyDiaText
Adolescence is a difficult period of development, made more complex for those with Type 1 diabetes mellitus (T1DM).

Diabetes-in-a-dish model uncovers new insights into the cause of type 2 diabetes
Researchers have developed a novel 'disease-in-a-dish' model to study the basic molecular factors that lead to the development of type 2 diabetes, uncovering the potential existence of major signaling defects both inside and outside of the classical insulin signaling cascade, and providing new perspectives on the mechanisms behind insulin resistance in type 2 diabetes and possibly opportunities for the development of novel therapeutics for the disease.

Tele-diabetes to manage new-onset diabetes during COVID-19 pandemic
Two new case studies highlight the use of tele-diabetes to manage new-onset type 1 diabetes in an adult and an infant during the COVID-19 pandemic.

Genetic profile may predict type 2 diabetes risk among women with gestational diabetes
Women who go on to develop type 2 diabetes after having gestational, or pregnancy-related, diabetes are more likely to have particular genetic profiles, suggests an analysis by researchers at the National Institutes of Health and other institutions.

Maternal gestational diabetes linked to diabetes in children
Children and youth of mothers who had gestational diabetes during pregnancy are at increased risk of diabetes themselves, according to new research published in CMAJ (Canadian Medical Association Journal).

Two diabetes medications don't slow progression of type 2 diabetes in youth
In youth with impaired glucose tolerance or recent-onset type 2 diabetes, neither initial treatment with long-acting insulin followed by the drug metformin, nor metformin alone preserved the body's ability to make insulin, according to results published online June 25 in Diabetes Care.

People with diabetes visit the dentist less frequently despite link between diabetes, oral health
Adults with diabetes are less likely to visit the dentist than people with prediabetes or without diabetes, finds a new study led by researchers at NYU Rory Meyers College of Nursing and East Carolina University's Brody School of Medicine.

Read More: Diabetes News and Diabetes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.