Type of study: A single blind partially randomized controlled cross-over design

Problem: Zinc deficiency is estimated to attribute to over 800,000 child deaths per year. Zinc deficiency especially affects children in developing countries where the diet is mainly cereal based. The high prevalence of deficiencies in this group can be related to increased needs during growth and development and a low dietary intake. Strategies to increase the intake of zinc include increasing dietary diversity and home fortification amongst others. Increasing dietary diversity can be achieved by adding locally available and culturally acceptable foods to the diet. Insects are of high nutritional value and a sustainable source of minerals, and therefore an ideal candidate for enriching the diet of these young children. This study will be the first to determine zinc absorption from insects in humans.

Objectives: The main objective is to assess the total absorbed zinc (TAZ) from freeze-dried house crickets added to non-refined maize porridge in comparison with a plain porridge in young children (24-36 months). Secondary objectives consist of: the comparison of the TAZ from freeze-dried house crickets added to non-refined maize porridge to the TAZ from protein powder extracted from crickets and added to non-refined maize porridge. In addition, the TAZ from freeze-dried house crickets added to non-refined maize porridge is compared to the TAZ from ZnSO₄ (the best available form) added to non-refined maize porridge.

Methodology: Research subjects (young children, 24-36 months old) will be exposed to four different test meals, two per test day. The four test meals all contain maize porridge, mixed with crickets, protein powder extracted from crickets, ZnSO4, or no additions. The test meals will be labelled with different stable zinc isotopes. Every test day one intravenous dose of labelled zinc will be given. Using the Zn isotope ratios in the urine, collected on day three and four after consumption of the test meal, the total absorbed zinc can be calculated from each meal. 

Expected findings: The main study endpoint is the TAZ from house crickets in a non-refined maize porridge compared to the TAZ of the usual porridge. This is assessed through isotope analysis of zinc present in spot urine samples. The secondary study endpoint is the TAZ from protein powder extracted from crickets and added to a non-refined maize porridge and from a porridge where ZnSO4 is added (the best bioavailable form of Zn). This is assessed through isotope analysis of zinc present in spot urine samples. We expect the protein powder to have a higher TAZ compared to the house cricket porridge, since the zinc will be better bioavailable.

Dissemination plan: Within the field, all participants will receive their laboratory results. After final study analyses, we will share the final report and any published paper or published study findings with all interested parties listed in the protocol.

Type of study: A single blind partially randomized controlled cross-over design

Problem: Zinc deficiency is estimated to attribute to over 800,000 child deaths per year. Zinc deficiency especially affects children in developing countries where the diet is mainly cereal based. The high prevalence of deficiencies in this group can be related to increased needs during growth and development and a low dietary intake. Increasing dietary diversity and home fortification are two of the main strategies used to increase the intake of zinc. Increasing dietary diversity can be achieved by adding locally available and culturally acceptable foods to the diet. Insects are of high nutritional value and a sustainable source of minerals, and therefore an ideal candidate for enriching the diet of these young children. Evidence of house crickets as a viable source of absorbable dietary zinc is lacking therefore this study will be the first to determine zinc absorption from insects in humans.

Objectives: The main objective is to assess the total absorbed zinc (TAZ) from freeze-dried house crickets added to non-refined maize porridge in comparison with a plain porridge in young children (24-36 months). Secondary objectives are to: compare the TAZ from freeze-dried house crickets added to non-refined maize porridge to the TAZ from protein powder extracted from crickets, added to non-refined maize porridge; and to compare the TAZ from freeze-dried house crickets added to non-refined maize porridge to the TAZ from ZnSO₄ (the best available form) added to non-refined maize porridge.

Methodology: Thirty-two eligible young children, 24-36 months old recruited from the Ober Kamoth subdistrict hospital under 5s clinic will be exposed to four different test meals, two per test day comprising maize porridge, mixed with: crickets (test meal (TM 1), ZnSO4 (TM 2), protein powder extracted from crickets (TM 3), or with no additions (TM 4). The test meals will be labelled with different stable zinc isotopes: either  ⁶⁸Zn (TM 1 and 3) or ⁶⁷Zn (TM 2 and 4). A baseline venous blood sample and a urine sample will be collected on each test day, and spot urine samples collected on two consecutive days after the test day. Every test day one intravenous dose of labelled zinc  (⁷⁰Zn) will be given. There will be a one-month washout period between test days giving a study duration of 36 days. Serum Zn, CRP, AGP, ferritin and soluble transferrin receptor will be assessed in the blood sample. Zn isotope ratios determined by the dual isotope tracer ratio (DITR) technique in the spot urine samples, will be used to calculate the TAZ from each meal.  The main study endpoint is the TAZ from house crickets in a non-refined maize porridge relative to the TAZ of the usual porridge. The secondary study endpoint is the TAZ from protein powder extracted from crickets and added to a non-refined maize porridge and from porridge where ZnSO4 is added.

Expected findings: We expect the protein powder to have a higher TAZ compared to the house cricket porridge, since the zinc will be better bioavailable.

Dissemination plan: All participants will receive their laboratory results. After final study analyses, we will share the final report and any published paper or published study findings with all interested parties listed in the protocol.