Research shows that orange peel extract can improve heart health

Orange peels may hold a key to better cardiovascular health, according to new research led by the University of Florida. The findings are published in the Journal of Agricultural and Food Chemistry.

According to the Centers for Disease Control and Prevention, heart disease is the leading cause of death for men, women and people of most racial and ethnic groups.

Recent research has shown that some intestinal bacteria help develop cardiovascular disease. When feeding on certain nutrients during digestion, intestinal bacteria produce trimethylamine N-oxide (TMAO). Levels of TMAO may help predict future cardiovascular disease, according to researchers at the Cleveland Clinic.

Yu Wang and her team investigated the potential of orange peel extracts – rich in beneficial phytochemicals – to reduce the production of TMAO and trimethylamine (TMA). Scientists tested two types of extracts: a polar fraction and a non-polar fraction.

To obtain the polar fractions, scientists used polar and nonpolar solvents to extract the orange peel, Wang said.

“If you imagine your salad dressing, everything in the water or vinegar part is the polar fraction; everything in the oil outside of the water is the nonpolar fraction,” Wang said. “The solvents we used weren’t exactly like water and oil, but they have a similar polarity.”

Results of the study showed that the non-polar orange peel extract effectively inhibited the production of harmful chemicals. Researchers also identified a compound called feruloylputrescine in the polar fraction extract of orange peel, which also significantly inhibits the enzyme responsible for TMA production.

“This is a novel finding that highlights the previously unrecognized health potential of feruloylputrescine in reducing the risk of cardiovascular disease,” said Wang, UF/IFAS associate professor of food sciences and human nutrition.

The discovery of orange peels is significant because 5 million tons of orange peels are produced in orange juice production every year across the country. Nearly 95% of Florida oranges are used for juice. About half of the peels go to animal feed. The rest is lost. But the Food and Drug Administration considers natural orange peel extracts safe for human consumption. Wang hopes to be able to use the peels better.

“These findings suggest that orange peels, which are often discarded as waste in the citrus industry, can be reused into valuable health-promoting ingredients, such as nutritional supplements or food ingredients,” said Wang, a faculty member at the UF/IFAS Citrus Research and Training Center.

“Our research paves the way for the development of functional foods enriched with these bioactive compounds, opening up new therapeutic strategies for heart health.”