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Nana Gletsu-Miller, NUTR, HHS Researchers Spotlight

Professor Explores Nutritional Complications of Bariatric Surgery

Nana Gletsu-Miller

Nana A. Gletsu-Miller, PhD

Assistant Professor, Department of
Nutrition Science


PhD, University of Alberta, Edmonton, Canada, 1998 Nutrition and Metabolism

BSc, University of Saskatchewan, Saskatoon, Canada, 1990 Biochemistry, Honors


Assistant Professor of Nutrition Science, Purdue, 2011-present

Assistant Professor of Surgery and Assistant Professor of Hubert Department of Global Health, Emory University, Atlanta, 2006-11

Research Instructor of Surgery, Emory University, 2001-06

Postdoctoral Fellow of Pathology, Emory University, 1998-2001


NIH/Research Supplements for Under Represented Minorities Fellowship, 1998-2001

Graduate Student Research Award from American Society for Nutritional Sciences, 1998


The Obesity Society, 2003-present

American Society of Nutritional Sciences,

Canadian Nutrition Society, 1996-present

American Diabetes Association, 2008-present

Bariatric surgery has become a popular weight-loss option with more than 200,000 surgeries performed in the U.S. in 2011.

"There are not many other proven programs for people who have 100 or more pounds to lose," stated Nana Gletsu-Miller, assistant professor of nutrition science. "And the surgery works. In a month people lose about 10 percent of their body weight and 25 percent over six months. It takes one to two years to realize normal body weight."

With bariatric surgery, the procedure makes the stomach smaller and allows food to bypass part of the small intestine and to go directly to the lower intestine. The operation fools the patient into feeling full with less food than before the surgery when the stomach was its original size. Although patients are absorbing less fat and losing weight, thus reducing serious health risks, such as heart disease, diabetes and stroke, there are drawbacks to the surgery. Nutrients are not absorbed as well in the lower intestine, and because patients are eating less, fewer essential nutrients and vitamins are available in the body.

Research Focus

Gletsu-Miller's research studies the impact of weight-loss surgery on overall health, and she wondered, "Are these patients trading one set of problems for another?"

"With the weight loss, patients often feel so good after surgery they stop going to their doctors for follow-up and monitoring. Over time we see nutritional deficiencies," she explained. "Patients lack iron, Vitamin D, some B vitamins, zinc, and copper resulting in a range of issues including fatigue, anemia, hair loss or neurological problems."

Surgery itself only helps with weight loss for a year or two. Outcomes of Gletsu-Miller's work include helping post-surgical patients maintain weight loss over the long term while encouraging better nutritional health. "It is fascinating to study. We know obesity leads to cancer and heart disease, but why? What are the molecular reasons? The best way to study these things is to study people who lose weight."

Part of the work, she added, is to share data with Purdue collaborators Kolapo Ajuwon, assistant professor of animal sciences, and Kee Hong-Kim, assistant professor of nutrition science. Both researchers study the mechanisms that link excess body fat and diseases such as diabetes, heart disease, cancer and metabolic syndrome. "We supply biological samples, and they look at the molecular basis. This population allows us to make observations from human samples we analyze in the laboratory, as opposed to taking information from the lab to humans. We can use our understanding of what is going on to help others.

"These patients develop nutritional problems we haven't seen in this country in decades," she continued. "We do see them in underdeveloped or developing countries. So, what we find using research with bariatric surgery patients, especially related to iron, copper and zinc deficiencies, can be applied to other populations who are at risk."

Gletsu-Miller was drawn to this research "randomly" 13 years ago while at Emory University. She was studying obesity using mouse models when a physician friend mentioned that surgeons were beginning to acknowledge nutritional issues after bariatric surgery. That piqued her interest, and she began to study post-surgery patients as part of her research. "The best surgery clinics have teams to work with the patients. As a nutritionist, I became part of that team."

What's Next?

The author of dozens of scholarly articles acknowledged there are more important questions to answer. What is the connection between obesity and disease? Why does diabetes basically disappear overnight after surgery? Is that because of changes to diet, or changes to the anatomy after surgery?

Ongoing research will include studying protein and fatty acids. "Some fats are essential, but some post-surgery patients are avoiding fats altogether," she said. "They don't realize they are missing out on some essential fats, which can be a problem."

Educating post-surgery patients on the nutritional risks remains a key to optimal health, said Gletsu-Miller. "Patients should get routine nutritional check-ups after surgery, and always continue to take vitamins and minerals. It is important to be aware of symptoms and to not ignore them."