An oyster a day? Cambridge collab “supercharges” shellfish vitamins

20 Jul 2020 --- Vitamin Bullets are microcapsules that could be used to “supercharge” the nutrients of bivalve shellfish, such as oysters, clams and mussels. Developed by the Department of Zoology at the University of Cambridge, UK, and biotechnology company BioBullets, this patented form of seafood fortification results in oysters delivering around 100 times more vitamin A and over 150 times more vitamin D than natural oysters. The Cambridge researchers flag that this avenue is “very affordable,” with the fortification costs involving manufacturing, distribution and implementation costs increasing the oyster retail price by less than 1 percent.

“Food fortification needs to become focused around developing methods to fortify varieties of plant and animal crops that are native to specific global regions. The nutrition industry should see this [research] as a way of providing food that is not only nutritious, but also highly sustainable and affordable to the global population,” David Willer, PhD student at the University of Cambridge and co-author of a study examining Vitamin Bullets, tells NutritionInsight.

Eating bivalves, including ingesting their guts, means that humans digest the nutrients that the animals consumed toward the end of their lives. This makes bivalve shellfish the ideal target for nutritional fortification. The researchers’ idea was to feed 100 Pacific oysters (Crassostrea gigas) vitamin A and D-fortified microcapsules eight hours toward the end of “depuration,” the period in which bivalves are held in cleansing tanks after being harvested.

The Vitamin Bullets dramatically outperformed salmon, commonly known for being a rich source of vitamin D.The research pair found that fortified oysters delivered around 100 times more vitamin A and over 150 times more vitamin D than natural oysters. Even more importantly, they dramatically outperformed salmon, one of the best natural sources of these vitamins. The fortified oysters provided more than 26 times more vitamin A and over four times more vitamin D than salmon. The scientists found that a serving of just two of their supercharged shellfish provided enough vitamin A and D to meet the human Recommended Dietary Allowance (RDA).

Co-author Dr. David Aldridge, Managing Director of BioBullets, further states that he is “very excited” about his company’s potential. “We are now establishing links with some of the world's biggest seafood manufacturers to drive a step change in the sustainability and nutritional value of the seafood that we consume.”

“Major cost advantages”
For this microcapsule fortification technique to be a success, it needs to be affordable for the end-consumer. The study states that the fortification costs involving manufacturing, distribution and implementation costs increase the oyster retail price by 0.9 percent. “[The price increase] corresponds to less than one pence per oyster. Most consumers will not notice the change in price,” Willer predicts.

He also adds that previous research has shown that consumers in developing countries are prepared to pay more for fortified food products, such as fortified milk, as they see the value it can bring to their own health.

The study further points out that the Vitamin Bullets represent a cheaper option than attempting to fortify other terrestrial animals or fish, which need to be fed fortified feeds for a greater period of their lifespan. “Bivalves are also the most sustainable animal food on the planet, with farming having important ecosystem benefits, so there are conservation gains that could be made from bivalve aquaculture expanding in place of other meat production,” the study notes. 

The Vitamin Bullet microcapsules at particle size ~20 µm.Critically, Willer underscores that over-reliance on Western diets of highly processed, energy-rich, but nutrient-poor grains and sugars is trapping farmers in low- and middle-income countries by making them dependent upon big seed companies to grow their crops.

Over-fortification risks are “low”
When asked about the potential risks of over-fortification, Willer states that these are “low,” as the fortification dose can be tailored to need. “In a country where people eat relatively few bivalves, a higher dose may be appropriate, but in a region where bivalves are eaten more regularly, it may be appropriate to lower the treatment dose.”

Regional deficiencies can be especially pronounced, the study highlights. In Ghana, more than 76 percent of children are vitamin A deficient, causing widespread mortality and blindness. Over 40 percent of the US population is vitamin D deficient, rising to 85 percent in India’s citizens, causing cardiovascular diseases, osteoporosis and rickets. 

The Vitamin Bullets are 100 percent food grade and do not affect the taste of the shellfish. Moreover, Willer highlights that he is currently exploring more research that could use the same type of capsule to improve the flavor of shellfish.

Future research is encouraged in the field of identifying which bivalve species, as well as respective dose and formulation of microcapsules and vitamins, would be most appropriate for specific global regions. “Taking these steps can provide stakeholders in aquaculture to make an invaluable contribution toward improving the quality and sustainability of our global food system,” the study concludes.

By Anni Schleicher