Insects contain iron, and if you breed them on an iron-rich substrate, the concentration of this nutrient, of which a quarter of the global population has a deficiency, can even be increased threefold. This is revealed in a new study conducted by PhD student Tomer First (Food Quality and Design).
‘We wanted to know whether we could increase the iron content in insects without genetically modifying the insects. In this case, we manipulated the iron concentration in insects simply by adjusting their diet’, First states. He investigated how different levels of iron in feed affect two types of insects: the yellow mealworm (Tenebrio molitor) and the black soldier fly (Hermetia illucens). First: ‘The yellow mealworm is one of the most popular insects in human consumption, and the black soldier fly is used in animal feed.’
Initially, the researcher wanted to know how an iron-rich diet impacts the two insect species’ survival. To this end, he added different amounts of iron to the breeding boxes of both species. The yellow mealworm appeared vulnerable to iron toxicity, and part of the population perished. On the contrary, the black soldier fly was extremely strong. ‘The black soldier fly was unaffected by the high concentration of iron in its diet and grew as it normally would. Even when we increased their iron intake twenty-fold, their chances of survival were not at all impacted.’
Iron and protein bomb
First went on to analyse different characteristics of the grown larvae, such as macronutrients and how much of these were usable in animal feed or human food, and how much iron they contained. ‘Yellow mealworms showed a slight increase in iron when put on an iron-rich diet. However, we do not consider this path viable as the insects appear to be very vulnerable. Particularly when compared to the black soldier fly.’
‘The black soldier fly is a very strong species and has a high survival rate. Moreover, its iron content increased by some 300 per cent. Its calcium content simultaneously increased by twenty per cent, rendering the fly a veritable protein bomb. I believe this insect is essential to the protein transition.’
Absorption
The fact that the insects seem to absorb the iron so well is a great first step, the scientist states. ‘Further research is needed to prove that the insect-iron can be absorbed by the human and farm animal intestinal system. After all, if that is not the case, this knowledge becomes less relevant.’ ‘Black soldier flies excel at absorbing heavy metals, which are generally toxic. Iron is also a heavy metal, but is essential to our health. We are now investigating how soluble the iron contained in these iron-rich insects is. Humans require highly soluble substances for our intestines to process them. Still, it would be really cool to eat an insect for breakfast rather than an iron supplement.’