Pearls of local oysters make the detox grade

University of Hong Kong researchers have revealed that the powder of a pearl from a local oyster species could be used for heavy metal detoxification in people, which can help local fishermen increase their income by pearl breeding.

The accumulation of heavy metals in the human body could pose health threats to human beings, said HKU chair professor of endocrinology Billy Chow Kwok-chong.

Heavy metals could possibly lead to diseases in the nervous system, kidney and blood vessels.

Chow said that as it is inevitable for humans to take in heavy metals from the food chain, supplements that have the property of detoxification would be critical.

Pearl powder has been used in Chinese medicine for centuries. Rich in protein, amino acids, calcium, magnesium and other minerals, the powder has various benefits to one's physical health, such as improving skin health and reducing inflammation. But little research has been done on the detoxification properties of pearls.

The HKU research team led by Chow first fed pearl powder of different concentration levels to four groups of mice. The team then compared the concentration of heavy metal in mice urine, feces and serum.

A locally bred pearl oyster species, Pinctada fucata, was used in the research, Chow said yesterday.

The results have proven that the powder made from Pinctada fucata pearls could reduce the concentration level of heavy metals, regardless of the amount of powder.

Chow said the team got the patent for the use of pearl powder in the preparation of detoxification drugs.

The chairman of the Hong Kong Fishermen Consortium, Cheung Siu-keung, said the discovery is helpful for the fishermen, as it offers an alternative means to earn a living.

A former president of the Conservancy Association, Yan Wah-tat, said the project started in 2016 when the fishermen were being taught how to produce pearls by breeding mussels.

The fishermen will be offering 10,000 pearls, which is part of their harvest, to Ocean Park next month, he said.

He said that the best places to rear pearls would be near Sai Kung.

"Sai Kung has long been a popular breeding ground for pearls for Chinese people, according to ancient Chinese records," he said, adding that the rising temperature and acidity of seawater posed a challenge.

Although they could tackle the problem of rising seawater temperatures by placing the mussels in deeper water, he said that rising acidity could hinder the formation of pearls.

He added that the presence of microplastics in the sea has also affected breeding.

"Microplastics might be absorbed when they are forming the pearls. And the absorption of microplastics would harm the mussels."