UVB exposed mealworms: The next go-to source of vitamin D?
24 Jul 2018 --- Insects have come into the spotlight over the past years as being a good source of healthy protein and several other nutrients, as well as more environmentally friendly in their production than many other animal-derived proteins. The one gallon of water it takes to produce one pound of insect protein pales in comparison to the almost two thousand gallons of water poured into every pound of beef destined for human consumption. Scientists at Wageningen University & Research (WUR) have now uncovered another reason to consume insects by proving that certain insects can be a rich source of vitamin D following exposure to ultraviolet radiation. The researchers have presented their results in the journal Scientific Reports.
“The whole idea for this research started quite some years ago when I was working on a project that showed that UVB exposure was a lot more efficient than providing vitamin D via the diet in vertebrates. While doing my Ph.D., I started to wonder if there was anything known about vitamin D in insects. I found out that although some analysis had been done, no research had been conducted on UVB and vitamin D formation in insects,” Dennis Oonincx, lead researcher, tells NutritionInsight.
The WUR research team exposed four insect species to ultraviolet radiation and subsequently determined their vitamin D concentrations. Several of the investigated species had strongly increased vitamin D levels compared to their unexposed counterparts, with UVB exposed yellow mealworms showing vitamin D concentrations of up to 60 times higher than unexposed specimens.
According to the researchers, these UV exposed yellow mealworms contained similar amounts of vitamin D as salmon, tuna and mackerel, making them one of the few good dietary sources of vitamin D.
So would mealworms be a better source than, for example, salmon?
“There are a lot of ways to answer that,” Oonincx says. “If you look at environmental factors, the impact of mealworms is very limited. However, my interest was: if people were to eat insects, how do we make them more nutritious? Using this UVB light will cause them to produce a lot of vitamin D but that does not mean they would be better than salmon, especially not in terms of vitamin D levels as these are quite similar.”
The researchers expect insect producers to implement the results of this study in the short term, thereby further increasing the nutritional value of insect-based products.
Vitamin D is known to be essential for bone metabolism and low levels of the vitamin increase the risk of rickets, osteomalacia and osteopenia. Vitamin D may also improve plasma lipid levels and have a beneficial impact on other risk factors for cardiovascular diseases.
A special characteristic of vitamin D – also known as the sunshine vitamin – is that it can be obtained via the diet, but can also be synthesized in the skin. However, this synthesis is only possible when sufficient solar energy (ultraviolet radiation) reaches the skin, the researchers note.
This is not the case during winter, and synthesis is severely impaired when the skin is covered by cloths or sunscreen, or in pigmented skin. This causes vitamin D deficiency to be widespread, especially amongst people that live in countries at longer latitudes.
Research into the vitamin D potential of insects will continue, with Oonincx telling NutritionInsight that he intends to look into more species and what determines their capacity to produce vitamin D. Furthermore, he will look into the function of vitamin D in insects which could provide further insight into the function of vitamin D in higher species, such as humans.
By Lucy Gunn
