University of Florida researchers study the nutrients in orange peels. Photo courtesy of University of Florida Citrus Research and Education Center
ORLANDO, Fla., Oct. 24 (UPI) -- Nutrients found in orange rind and orange pith are getting a closer look from researchers in Texas and Florida as mouse studies show benefits for heart disease and cancer.
New uses for oranges, especially underused parts like the rind, could help revive Florida's signature agricultural crop. Crops in recent years have been one-quarter of the record highs set in the 1990s due to disease and storms, but overall impact with jobs and suppliers is still estimated at over $10 billion.
Mice who were fed an extract from orange peels at University of Florida's research station for citrus didn't get overweight and avoided heart disease compared to other mice. University scientist Yu Wang has received a $500,000 grant from the U.S. Department of Agriculture to study the impact on humans.
"Orange peel has been used in Asia for many years for medicinal uses," Wang said. "We know that if we treat mice with orange peel extract, it can control weight and reduce fat accumulation."
Some alternative medicine advocates in the United States have touted extracts or nutrients found in orange peel or orange pith -- the white spongy layer under the orange surface. But it has been used mostly for flavorings or livestock feed, Wang said.
Citrus was first grown in Asia thousands of years ago and brought to Florida by early Spanish colonialists, according to research published in the journal Nature. But native diseases and pests that evolved with citrus in Asia also arrived in Florida, particularly citrus canker and citrus greening. Both diseases are widespread and considered endemic in Florida now.
Wang's research showed that vitamins and other compounds from orange peels prevent a damaging substance called trimethylamine, or TMA, from forming in the digestive tract. TMA contributes to hardening of the arteries and heart disease. With a healthier gut, there's less likelihood of heart disease, scientist say.
Testing orange peels on humans doesn't require special equipment or permissions, Wang said.
"It's from the orange, so it's safe for human consumption. We plan to put it in smoothies and track the impact over time," she said. "We want to know what exactly in the orange peel functions that way."
Oncologist Sanjay Awasthi has been studying the effects of orange peel and rind nutrients on cancer for years. He's now at Texas Tech University's Health Sciences Center in Lubbock.
Specifically, he's been looking for the best ways to extract the nutrients. He said he's found positive results from a skin cream with orange extract in controlling melanoma.
"Many antioxidants come from rare substances. But orange peel and husk pulp have beneficial components and they are very common," Awasthi said. "Millions of pounds of orange peel are basically discarded, composted or fed to livestock every year."
Awasthi received a grant for more than $1 million from the Department of Defense for his research into the prevention of breast cancer.
He'll test a chemical that is derived from oranges to activate other medical compounds and possibly address other health issues such as heart disease.
He's also familiar with historic Asian medicine from India, in the Ayurvedic tradition, where orange peel is used in many treatments.
Nutrients found in the pith and peel are similar to those found in the orange fruit and juice, but occur in different concentrations and with various possible compounds.
Florida's agriculture department has long promoted oranges and orange juice as healthy. It was the state's marketing effort that once provided orange juice to travelers driving into the state and led to orange juice becoming a staple of breakfast.
The state's Department of Citrus more recently has battled perceptions that orange juice is too full of sugar to be healthy.
The department's website quotes a study in the European Journal of Clinical Nutrition that found "no negative effects on body mass index, waist circumference, body composition or weight with consumption of 100 percent orange juice" and even found evidence that people who drink orange juice are less likely to be obese.
After Wang's research grant was announced to the citrus industry in Florida, she said she received many calls and emails from growers who wanted to know what kind of oranges carried the most beneficial nutrients to combat heart disease.
"They are looking forward to growing the best kind," she said. "We're still working on it."