Cutting Sugar Causes Drop in Heart Disease Risk Factors Among Obese Children

Study Shows Sweets, Not Calories, Are Culprits in Cardiovascular Pre-Conditions

By Suzanne Leigh

A teaspoon filled with sugar sits next to a pile of sugarReducing sugar consumption in obese children, rather than cutting calories or starch, or losing weight, leads to a sharp decline in triglycerides and a key protein called ApoC-III – two features that are associated with heart disease in adulthood.

In a study published online July 19, 2016, and in the current issue of the journal Atherosclerosis, researchers from Touro University California and UC San Francisco reported that triglycerides dropped 33 percent and ApoC-III fell by 49 percent in just 10 days of sugar restriction. The work expands on previous research published last year in the journal Obesity that found restricting sugar – without restricting calories or total carbs -- reversed a cluster of metabolic diseases in children, including high cholesterol and blood pressure.

In both studies, 43 children aged between 9 and 18 were recruited from the Weight Assessment for Teen and Child Health (WATCH) clinic at UCSF Benioff Children’s Hospital San Francisco. The participants were obese and had at least one chronic metabolic disorder, such as high blood pressure, high triglycerides, or a marker for fatty liver. Eligibility was limited to Latino and African-American youth, who are at higher risk for metabolic diseases.

Over the course of nine days, the children were provided food and beverages that mirrored the same fat, protein, carbohydrate and caloric levels as their home diets. The difference was that sugary foods like pastries, sweetened yogurts and cake were substituted with starchy ones, such as bagels, pizza and hot dogs. Total dietary sugar was cut from 28 percent to 10 percent, and fructose from 12 percent to 4 percent of total calories.

Other ‘Villain’ to Blame for Cardiovascular Risks

In the current study, researchers compared baseline blood levels with those taken after 10 days and found not only the significant changes in triglycerides and ApoC-III, but also the disappearance of small dense LDL, a type of cholesterol increasingly considered a risk factor for heart disease. 

“LDL is known as the ‘bad’ cholesterol, but it is more complex that that,” said first author Alejandro Gugliucci, MD, PhD, of the department of research at Touro University California College of Osteopathic Medicine in Vallejo. “Many researchers now believe that high LDL is bad only when it is packaged in small containers – so-called small dense LDL. In our study, we found that small dense LDL, which is not normally seen in children, disappeared. We also discovered that the HDL particle got bigger, which is consistent with cardiovascular protection.”

Portrait of Robert Lustig
Robert Lustig, MD, MSL

“While statins are effective in lowering LDL, they only reduce heart disease risk by 50 percent,” Gugliucci noted. “The other villain is blood lipid triglycerides and the associated protein ApoC-III. Drug companies are looking for medicines to specifically block ApoC-III. We found in our study that just reducing sugar consumption did a wonderful job in lowering these two key risk factors by 30 to 50 percent.”

“In order to get this degree of lipid and protein reduction by just eating less, a patient would need to lose more than 20 percent of their BMI, one-fifth of their body weight,” said second author Robert Lustig, MD, MSL, a pediatric endocrinologist at UCSF Benioff Children’s Hospital San Francisco.

“The blood lipid responses of these children is nothing short of astounding, and unrelated to calories or weight change,” he said. “Combined with data from the previous study demonstrating improvement in metabolic health with sugar restriction alone, we have conclusively shown that sugar calories are not like other calories. Sugar is uniquely metabolized to fat in the liver, which leads to fat accumulation in the bloodstream, driving heart disease. As long as we focus on total calories rather than on what those calories are and how they are metabolized, the obesity, diabetes and heart disease epidemics will continue.”

Funding was provided by the National Institutes of Health, UCSF Clinical and Translational Science Institute, and Touro University California. None of the authors report conflicts of interest. 

Senior author is Jean-Marc Schwarz, PhD, of Touro University California. Co-authors are Russell Caccavello of Touro University California and Kathleen Mulligan of Touro University California and UCSF; and Ayca Erkin-Cakmak, MD, MPH; Susan M. Noworolski, PhD; Viva W. Tai, RD, MPH; and Michael J. Wen, MS, all of UCSF.

About the Touro College and University System

Touro University California is a Jewish nonprofit, independent graduate institution of higher learning founded in 1997 on three Judaic values: social justice, the pursuit of knowledge and service to humanity. The university, home to 1,400 students, has professional programs in osteopathic medicine, pharmacy, physician assistant studies, public health, nursing, and education. Faculty, staff and students have a powerful commitment to academic excellence, evidence-based professional practice, inter-professional collaboration, and active engagement with a global community. To learn more, visit or call 707-638-5200.

About UCSF

UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes top-ranked graduate schools of dentistry, medicine, nursing and pharmacy, a graduate division with nationally renowned programs in basic, biomedical, translational and population sciences, as well as a pre-eminent biomedical research enterprise. It also includes UCSF Health, which comprises top-ranked hospitals UCSF Medical Center and UCSF Benioff Children’s Hospitals in San Francisco and Oakland – and other partner and affiliated hospitals and healthcare providers throughout the Bay Area.

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