UTHSC Researcher Expands National Discussion of Cardiovascular Health

Yangbo Sun, PhD, assistant professor in the Department of Preventive Medicine in the UTHSC College of Medicine, is helping to expand the national discussion of cardiovascular health and healthy lifestyles.

With a research focus on chronic diseases such as cardiovascular diseases, and breast cancer, Dr. Sun conducts research in areas of modifiable lifestyle risk factors, such as nutrition and physical activity.

An observational study published last year in the Journal of the Academy of Nutrition and Dietetics by a team of researchers led by Dr. Sun, found eating one meal a day was associated with a higher risk of all-cause and cardiovascular disease mortality in adults aged 40 or older in the United States. In addition, skipping breakfast was associated with a higher risk of cardiovascular disease death, while skipping lunch or dinner was associated with a higher risk of dying from all causes.

After participating in prior research with another colleague about the association of skipping breakfast and the risk of mortality, Dr. Sun wanted to expand the literature on risks associated with skipping meals.

“In that study, we actually found that skipping breakfast was associated with increased risk of mortality from cardiovascular disease. Then, I was thinking, what about skipping lunch or dinner?” Dr. Sun said. “We looked into the literature and could not find answers, and there was no previous study looking into skipping lunch or dinner with mortality, so we decided to return to conduct the study to find answers to those questions.”

The research resulted in stories in the U.S. News & World Report, Independent, and other media outlets earlier this year.

“It is very exciting and I feel honored that our study has been picked up by various media outlets. More people have realized that it is important for health to maintain a healthy diet and a healthy lifestyle,” Dr. Sun said.

The team analyzed a National Health and Nutrition Examination Survey between 1999 and 2014 with participation from a total of 24,011 adults aged 40 or older. The participants’ eating behaviors were assessed, and the death and causes of death data were obtained from death records through December 31, 2015.

The study is also the first to show that participants eating three meals a day in a shorter time interval of 4.5 hours or less between them was associated with a higher risk of dying of all causes, due to impacting metabolism.

“A shorter waiting time between meals also means a larger energy load in that given period of time,” Dr. Sun said. “A larger energy load will aggravate the burden of glucose metabolism regulation, causing metabolic deterioration.”

“Our study is an observational study, so we cannot imply causality. We can’t say that skipping meals causes something without saying skipping meals is associated with something,” she said. “Based on what we observed, I would suggest, in terms of cardiovascular health and mortality, try to eat at least two to three meals per day, if possible and spread them out throughout the day with an average interval between meals of more than 4.5 hours.”

Dr. Sun said her study differs from intermittent fasting research. While skipping meals focuses on skipping breakfast, lunch, or dinner, intermittent fasting involves the consumption of all food and beverages during a specific segment of time.

“Intermittent fasting and skipping meals are two different concepts. The three most widely studied intermittent fasting include alternate day fasting, 5:2 intermittent fasting, and time-restricted feeding. Time-restricted feeding involves limiting the intake of all foods and the calories contained in beverages to a segment of time, for example, eight hours per day. Or, if an individual does 16:8 intermittent fasting, meaning you consume all your calories in eight hours and refrain from consuming any calories for the remaining 16 hours of the day, that is intermittent fasting,” she said. “For skipping meals, we focus on meals that are skipped, not considering other things that aren’t meals such as eating snacks or consuming energy drinks. That is the main difference between our study and intermittent fasting studies.”

For this study, Dr. Sun collaborated with Yang Du, MS; Yuxiao Wu, MS; Qian Xiao, PhD; Linda Snetselaar, PhD; Robert Wallace, MD; and Wei Bao, MD, PhD, at the University of Iowa. Other investigators were: Shuang Rong, PhD, at Wuhan University of Science and Technology in Wuhan, China; and Liangkai Chen, PhD, in the Tongji Medical College at Huazhong University of Science and Technology in Wuhan, China.

In addition to her research in cardiovascular health, Dr. Sun is currently conducting a study focusing on identifying modifiable lifestyle risk factors for breast cancer survival.

She is also a co-author in a recent study on the association of weight changes and longevity in women, featured in Science Magazine, Neuroscience News, SciTech Daily, and other media outlets. The multi-institutional study found that women who maintained their body weight after age 60 are more likely to reach the ages of 90, 95, or 100.

Dr. Sun joined the College of Medicine in April 2020. She earned her bachelor’s degree in economics and her Bachelor of Medicine, Bachelor of Surgery degree (MBBS) in Preventive Medicine from Peking University in Beijing, China. She received a PhD in chronic disease epidemiology and biobank from the University of Hong Kong.