Tag: diabetes

How sucrose, the ‘real’ sugar commonly found in sodas, can disrupt your appetite

Sugar-sweetened drinks interfere with the hunger-suppressing hormones that signal a sense of feeling full, a new USC study finds.

(photo/Pexels)

Sugary drinks interfere with hormones that tell the body “I feel full,” potentially contributing to obesity and undermining weight loss efforts, a new USC study shows.

The findings, which appear Thursday in the Journal of Clinical Endocrinology and Metabolism, strengthen the case against sugar-sweetened beverages, a significant driver of obesity. Sugary drinks are the single largest source of calories from added sugar for American adults.

“Our study found that when young adults consumed drinks containing sucrose, they produced lower levels of appetite-regulating hormones than when they consumed drinks containing glucose — the main type of sugar that circulates in the bloodstream,” said Kathleen Page, an associate professor of medicine specializing in diabetes and childhood obesity at the Keck School of Medicine of USC.

The impact on hormone signaling was even greater among women who were already obese, as well as men, regardless of whether they were obese or not.

Sugar-sweetened foods, beverages can lead to lower amounts of appetite-regulating hormones

The study included 69 young adults ages 18 to 35 who participated in two study visits where they consumed drinks containing either sucrose or glucose. Sucrose, a combination of glucose and fructose, comes from sugar cane or sugar beets. Glucose is found in honey, grapes, figs and plums.

Participants gave blood samples at 10, 35 and 120 minutes after drinking the drinks. Researchers found that when the participants consumed drinks containing sucrose, they produced lower amounts of hormones that suppress hunger compared to when they consumed drinks containing an equal dose of glucose.

They also found that individual characteristics, including body weight and sex, affected the hormone responses to the different sugars. For example, people with obesity and those with lower insulin sensitivity had a smaller rise in hunger-suppressing hormones after consuming drinks sweetened with sucrose compared to glucose.

Page, who leads the Diabetes & Obesity Research Institute at USC, said the takeaway for the general public isn’t to switch from one sweet drink to another but to try to reduce added sugar altogether.

“The majority of sucrose that people consume in the American diet comes from sugar-sweetened foods and beverages, whereas glucose is found naturally in most carbohydrate-containing foods, including fruits and whole-grain breads,” she said. “I would advise reducing the consumption of sugar-sweetened foods and beverages and instead trying to eat more whole foods, like fruits.”

— Leigh Hopper


Other authors of the study include Alexandra G. Yunker, Sabrina Jones, Brendan Angelo, Alexis DeFendis, Trevor A. Pickering, Shan Luo, Hilary M. Dorton and Jasmin M. Alves, all of the Keck School of Medicine; and John R. Monterosso, of the USC Dornsife College of Letters, Arts and Sciences.

The study was supported by grants from the National Institute of Diabetes and Digestive and Kidney Diseases, part of the National Institutes of Health (R01DK102794), and the Southern California Clinical and Translational Science Institute (NIH UL1TR001855).

USC, Mexico make strides in public health research

Jonathan Samet has partnered with many Mexican agencies on studies involving public health issues.

For more than 20 years, Jonathan Samet has developed strategies to prevent smoking in Mexico, with help from scientists and leaders at the country’s National Institute of Public Health (INSP).

The USC Distinguished Professor teams with several of Mexico’s 12 institutes of health, which aim to improve public health through research, policy and care. The INSP’s research centers and school of public health examine tobacco, obesity and other issues that contribute to health problems.

Samet assisted in the development of the institute’s Center for Tobacco Control Research and co-founded the Summer Program in Public Health, one of the largest of its kind in Latin America, with INSP Director Mauricio Hernández-Ávila. Samet has taught in the program every year since it began 22 years ago and has arranged for Trojans to teach there as well.

Building momentum

Since 2008, the year of Samet’s arrival at USC, the Department of Preventive Medicine has gained momentum in its research and scholarly exchanges with Mexico. Samet’s ties to INSP have enabled USC researchers to collaborate on various public health projects in the country and among Mexican and immigrant populations.

“The U.S. and Mexico share more than a border,” said Samet, holder of the Flora L. Thornton Chair in the Department of Preventive Medicine at the Keck School of Medicine of USC. “We share health challenges but also the expertise to combat them.”

In 2015, preventive medicine professors Lourdes Baezconde-Garbanati and Mary Ann Pentz founded the Center for Health Equity in the Americas to advance health equity in the region through research, training and partnerships. Using findings from an international summit in October, the group is working with INSP on a cervical cancer prevention report to be published in INSP’s journal, Salud Pública de Mexico, later this year.

Other centers in the department, including the Institute for Global Health, the Program on Global Health & Human Rights and the Immigrant Health Initiative, have hosted Mexican researchers and collaborators for talks, seminars and training on subjects, including sexually transmitted infectionsobesity, H1N1premature mortality and cervical cancer prevention.

Institute for Global Health Associate Director Heather Wipfli collaborated with INSP in 2016 to survey Mexican corporations about how health and wellness are integrated into their workplaces. The project is helping to inform the global cancer prevention programs begun by the American Cancer Society.

Another recent project, led by USC neurologist John Ringman and Mellissa Withers, assistant professor of clinical in the Department of Preventive Medicine, examined knowledge and attitudes regarding Alzheimer’s disease, genetics and participation in research among populations at-risk for a rare form of early onset familial Alzheimer’s disease in Mexico.

Fair exchange

In 2015, the Department of Preventive Medicine welcomed INSP postdoctoral fellow Katia Gallegos as part of an initiative with Mexico’s National Council of Science and Technology, in which USC provides scholars from Mexico with residencies in fields related to science, technology and innovation.

Gallegos is working with large binational data sets to determine the impact of acculturation in patterns of physical activity and sedentary behavior, as well as its association with body mass index observed in Mexicans, Mexican immigrants and Mexican-Americans. In addition, she is teaming with U.S. tobacco-use databases to study young people with mental illness who use multiple tobacco products.

Department researchers have also examined Mexico’s indoor smoking bancigarette sales tax, drug reform and teenagers’ smoking habits, as well as mental health risks and lower colorectal cancer susceptibility among Mexicans who migrated to the United States.

Along with Mexican and other U.S. scientists, USC researchers in 2013 discovered a genetic link associated with higher Type 2 diabetes risk among Mexican populations. Most recently, a study found that Latino children living in areas with higher levels of air pollution have a greater risk of developing Type 2 diabetes.

Career dedicated to public health

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Jonathan Samet accepts an honorary degree awarded by Mexico’s National Institute of Public Health. (Photo/Heather Wipfli)

Now celebrating its 30th anniversary, the INSP gave Samet an honorary doctorate recognizing his contributions to public health on Jan. 27.

At that event, Hernández-Ávila cited Samet’s scientific and professional achievements, among them his 27 books, 127 chapters and more than 350 scientific articles. “This Honoris Causa is awarded to recognize Dr. Samet’s work for global public health — for the health of all people,” he said.

A graduate of the University of Rochester School of Medicine and Dentistry, Samet has participated since the 1980s in the reports of the U.S. surgeon general on smoking and health, and he served as senior scientific editor for the 50-year anniversary edition in 2014. Most recently, he contributed to the 2016 surgeon general report on e-cigarettes and youth, the first of its kind.

His work has contributed to national legislation to control tobacco use, air pollution and radiation both in the United States and Mexico.

“I’m honored to be a part of this celebration to mark INSP’s decades-long commitment to public health in Mexico and to receive this very high recognition,” Samet said. “I look forward to continuing our partnership for many years to come.

Air pollution linked to heightened diabetes risk

High levels of pollution may make insulin-creating cells become less efficient, increasing the risk for Type 2 diabetes, USC researchers say

Latino children who live in areas with higher levels of air pollution have a heightened risk of developing Type 2 diabetes, according to a new USC-led study. Scientists tracked children’s health and respective levels of residential air pollution for about 3.5 years before associating chronic unhealthy air exposure to a breakdown in beta cells, special pancreatic cells that secrete insulin and maintain the appropriate sugar level in the bloodstream. By the time the children turned 18, their insulin-creating pancreatic cells were 13 percent less efficient than normal, making these individuals more prone to eventually developing Type 2 diabetes, researchers said. “Exposure to heightened air pollution during childhood increases the risk for Hispanic children to become obese and, independent of that, to also develop Type 2 diabetes,” said Michael Goran, co-director of the Diabetes and Obesity Research Institute at the Keck School of Medicine of USC and corresponding author of the study. “Poor air quality appears to be a catalyst for obesity and diabetes in children, but the conditions probably are forged via different pathways.” Published in the journal Diabetes on Jan. 30, the study, researchers said, is the first to follow children for years to find a connection between air pollution and diabetes risk in children. These children lived in neighborhoods that, according to the U.S. Environmental Protection Agency, had excess nitrogen dioxide and tiny air pollution particles that are generated by automobiles and power plants, formally called particulate matter 2.5 (PM2.5). Researchers found that the beta cells that were still functional were overworking to compensate for the damaged cells, leading to burn out. As the cells failed to secrete insulin efficiently, regulation of sugar in the bloodstream overwhelmed the system, heightening the risk of Type 2 diabetes. Diabetes has quadrupled in the past four decades, according to the Centers for Disease Control and Prevention. If the trend continues, 1 in 3 Americans will have diabetes by 2050. Serious complications include blindness, kidney failure, limb amputation or early death. “Diabetes is occurring in epidemic proportion in the U.S. and the developed world,” said Frank Gilliland, senior author and a professor of preventive medicine at the Keck School of Medicine. “It has been the conventional wisdom that this increase in diabetes is the result of an uptick in obesity due to sedentary lifespans and calorie-dense diets. Our study shows air pollution also contributes to Type 2 diabetes risk.” 

Latino children living in polluted areas are at higher risk

 Researchers examined the data of 314 overweight and obese Latino children who were between 8 and 15 years old when they enrolled in the National Institutes of Health-funded Study of Latino Adolescents at Risk of Type 2 Diabetes (SOLAR) study, a 12-year undertaking. Scientists tracked the Los Angeles County children for an average of 3.5 years. None of them had Type 2 diabetes when they enrolled, but some may have been on the road to the disease toward the study’s end. Each year the participants fasted and then came to the Childhood Obesity Research Center at USC for a physical exam and to have their glucose and insulin levels measured over a span of two hours. When they turned 18, the participants had nearly 27 percent higher blood insulin after having fasted for 12 hours. During their two-hour glucose test, they had about 36 percent more insulin than normal, indicating that the body was becoming less responsive to insulin. This observation illustrated that increased exposure to air pollution was associated with increased risk factors for Type 2 diabetes. The researchers adjusted for body fat and socioeconomic status. In some instances, at age 18, the effect of long-term exposure to higher air pollution was larger than the effect of gaining 5 percent body weight, meaning air pollution is definitely a risk factor for diabetes, said Tanya Alderete, lead author of the study and a postdoctoral research scholar at the Keck School of Medicine. 

Steps people can take to reduce their risk

 The findings suggest that the negative effects of elevated and chronic exposure to nitrogen dioxide and tiny dirty air particles begin in early life. If other risk factors such as having an unhealthy diet persist, then risk for Type 2 diabetes is compounded, researchers said. “Air pollution is ubiquitous, especially in Los Angeles,” Alderete said. “It’s important to consider the factors that you can control — for example, being aware that morning and evening commute times might not be the best time to go for a run. Change up your schedule so that you’re not engaging in strenuous activity near sources of pollutants or during peak hours.” None of the children developed Type 2 diabetes during the study, but many showed signs that they may eventually develop it and were characterized as pre-diabetes. Some 8.1 million people in the United States have diabetes but haven’t been diagnosed, according to the CDC. That means some 28 percent of people with diabetes do not even know they have diabetes. Undiagnosed diabetes raises the risk of afflictions such as stroke, kidney damage and Alzheimer’s disease. Future studies will also include participants who are not overweight or obese and should collect data on diet and physical activity, researchers said. Findings from this study may be generalized only to overweight and obese Latino children, mostly of a lower socioeconomic status, according to the study. The research was supported by the National Institutes of Health, the National Institute on Minority Health and Health Disparities, the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institute of Environmental Health Sciences, the Southern California Children’s Environmental Health Center and the U.S. Environmental Protection Agency.

— By Zen Vuong