The post originally appeared on the Feed the Future Innovation Lab for Fish website.

In June-July 2022, Francis Zinenuba Taabia collected hundreds of oyster samples from three estuarine sites in Ghana including the Bortianor area (Densu Estuary, Greater Accra Region), Ekumfi Narkwa (Narkwa Lagoon, Central Region), and New Amanful-Apremdo-Beahu area (Whin Estuary, Western Region). He carefully shucked the oysters, extracted and hand-cleaned the meat, packed, and labelled them individually in polystyrene bags and headed for the laboratory in the Department of Nutrition and Food Science at the University of Ghana. 

Taabia, a 34-year-old PhD candidate in the Department of Nutrition and Food Science at the University of Ghana, assisted in the analysis of a total of 915 oyster samples in the lab over the next few months. Working on an activity led by Brietta Oaks from the University of Rhode Island and Seth Adu-Afarwuah from the University of Ghana, Taabia’s work has helped determine the concentration of essential minerals in these oysters, identifying oysters as a key food that could be used to address micronutrient deficiencies common in Ghana. This analysis has determined that heavy metal contamination is not a concern in the area with levels of mercury, arsenic, cadmium, and lead all below international regulatory limits.

The Feed the Future Innovation Lab for Fish, alongside the University of Ghana and the University of Rhode Island, is conducting this research in Ghana to examine the potential contribution of oysters to the iron and zinc intakes of women shellfishers 15-49 year of age across three estuarine sites in Ghana and to assess whether heavy metal contamination of oysters is a concern at these sites. This Fish Innovation Lab activity is supporting Taabia’s dissertation research with funding for field work, laboratory analysis of the oyster samples, and write-up of results. 

In Ghana, the harvesting and processing of oysters are the mainstay of household subsistence and income for many women (i.e., women shellfishers), living along estuarine sites where oysters are consumed frequently. Despite a substantial reduction during the last few decades, the prevalence of anemia in the country remains high, partly because of low iron intakes from animal-source foods. In 2017, 36% of children 6-59 months of age and 22% women 15-49 years of age were anemic, and 22% of children 6-59 months of age and 14% women 15-49 years of age had iron deficiency. Oysters might provide an easily accessible source of protein and micronutrients to contribute to anemia prevention among women shellfishers in Ghana, but the health risks of their consumption due to heavy metal contamination has not been well-investigated.

"For the oyster samples analyzed, the average concentration per 100 g wet weight was 12.5 mg for iron, 8.2 mg for zinc, and 0.54 g for selenium," Taabia said. "These are relatively high mineral concentrations, which suggest that oysters could provide an accessible and rich source of these micronutrients to address anemia among women and children living along the estuarine sites."