Edited by: Simone Belluco, Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Italy
Reviewed by: Kehinde Ademolu, Federal University of Agriculture, Abeokuta, Nigeria; Ales Tomcala, Academy of Sciences of the Czech Republic (ASCR), Czechia
This article was submitted to Nutrition and Sustainable Diets, a section of the journal Frontiers in Nutrition
†These authors have contributed equally to this work and share first authorship
‡Jacob P. Anankware
Benjamin J. Roberts
Xavier Cheseto
Vincent Savolainen
C. M. Collins
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Two prominent issues facing global development are that of widespread undernutrition and poverty (
Global levels of food insecurity are expected to increase further, a trend already seen since 2014, particularly in the Caribbean and Latin America, adding to already high levels in Africa and South Asia (
Entomophagy, or the consumption of insects by humans, has substantial potential in combatting these issues and is widely practiced globally, particularly within traditional communities (
The benefits of edible insects in achieving sustainable food security are many. They are widely regarded to constitute a highly nutritious foodstuff. Although variable between insect species (
Not only are they nutritious but edible insects also provide a more efficient, cheaper, and less environmentally damaging nutrient source than vertebrate livestock species. As insects are cold-blooded invertebrates, they are highly efficient in converting input feed to edible matter (
The extensive benefits of edible insects and entomophagy cannot all be described here. Briefly, insect farming is also thought to pose far lower risk of agro-zoonosis emergence due to high human-insect taxonomic distance relative to vertebrate species (
Despite these huge benefits in combatting undernutrition and promoting sustainable development, there has been a recent decrease in the prevalence of ento-ethno practices across traditional communities (
Recent strides have been made to nutritionally profile a variety of edible insect species and the number of entomophagy-related publications annually has increased from <10 pre-2012 to 114 in 2020. The general consensus is that edible insects are of high nutritional value and can potentially constitute an effective alternative feedstuff to meat and fish (
Here we analyzed proximate and fatty acid profiles of five species of edible insect of socio-economic importance in West Africa, a region with an emerging profile in ento-ethno research. These species, and the abbreviation used to refer to them in tables and figures, include
Larvae of
Samples were inactivated by putting them in 70% alcohol and dried by freezing in liquid nitrogen before being milled to flour.
The five insect meal flours were analyzed for proximate and fatty acid content at the Chemical Laboratory of the International Center for Insect Physiology and Ecology (
Dried and milled
All proximate measures, other than dry matter, were evaluated on a % dry matter basis; dry matter, organic matter, and ash content were determined in triplicate whilst all other proximate nutrients were in duplicate, except for
Fatty acid profiles were produced for each of the five species of edible insect according to the methods of Cheseto et al. (
Fatty acid profiles for each species were evaluated in triplicate, except for
In order to evaluate interspecific differences in proximate and fatty acid profiles the nutritional literature was rigorously searched and published nutritional profiles were combined with the profiles produced in this study. Although not evaluated originally for each species here, amino acid profiles were also extracted from the literature to assess interspecific differences. The following Google Scholar search string was employed to identify papers, published between 2000 and 2021, concerning the nutritive content of the five species analyzed here:
“
The resultant papers were then briefly read and subjected to the following inclusion criteria to identify relevant publications before being read in detail:
The paper is an original article and has been through a peer review process, rather than being a review/meta-analysis, which uses external data, or a thesis/preprint.
The paper concerns one or more of the relevant species (
The paper specifically measures species nutritive content rather than addressing some other aspect of insect physiology, ecology, or evolution.
Due to the literature search being sorted by relevance to the search string and the high number of returned papers for certain species, with the BSF and HSF searches returning 1,380 and 1,060 papers, respectively, the search was terminated if 50 papers had elapsed since the last relevant one was identified. Relevant papers were then read in detail and subjected to the following further inclusion criteria before the data was extracted:
The paper nutritionally profiles the desired life-stage of each species. For the species analyzed, the desired life-stages were as follows: larvae for
The paper nutritionally profiles the unadulterated insect sample, including no mixing with external ingredients, no cooking, and no defatting.
The paper follows standard methods where possible, with no inappropriate sample preparation.
The paper reports nutritional results in a form consistent with the wider literature and the nutritional analyses presented here. This included units of % dry matter, % total fatty acids, and g/100 g crude protein for proximate, fatty acid, and amino acid profiles, respectively.
For each paper satisfying all of the above criteria, proximate, fatty acid, and amino acid data was extracted for each species analyzed. The number of repeats used by each paper in producing their nutritional profiles was not accounted for during data extraction. Consequently, each paper, including the original profiles produced here, contributed a maximum of one datapoint to the final dataset for each of the proximate, fatty acid, and amino acid analyses conducted for each species analyzed. All papers used are given in
There is high heterogeneity in the nutritional literature in terms of the fatty acids identified and the fatty acid naming system used, with some papers opting for the trivial names whilst others prefer the systematic names or lipid numbers. Therefore, certain steps were taken to increase the comparability of the fatty acid literature.
Firstly, it was ensured that every paper contained the same fatty acids under a consistent naming system; where a paper did not identify a particular fatty acid, it was introduced at a content of 0%. Secondly, papers with a high proportion (>2.5%) of ambiguously named fatty acids, meaning that the specific isomer cannot be discerned, were removed. Where ambiguously named fatty acids accounted for <2.5% of a particular paper's fatty acid profile then the paper was retained but without the ambiguous fatty acid. Where a particular fatty acid was not reported in any form other than the ambiguous form across the utilized literature then the ambiguous name was retained; this was the case for pentadecenoic acid, docosadienoic acid, and decenoic acid. Furthermore, singleton fatty acids, those only identified in a single publication, were removed to reduce the impact of experimental variability and because their inclusion would increase the fatty acid diversity of more represented species. The sum of fatty acid profile in each paper was fixed to 100% by introducing an “Others” category when the profile was below 100%, for instance due to the removal of ambiguous fatty acids. Finally, where a paper reported
This manipulation left a final fatty acid dataset comprised of 16
There is high heterogeneity in the units used to report amino acid profiles in the literature, with amino acid content in g/100 g crude protein, % dry matter, and % total amino acids all being present. Units of g/100 g crude protein were chosen due to being the most prevalent. As a result of
All statistical analyses were conducted in R (v4.1.0) (
Proximate content differences between the five analyzed species were assessed by a series of non-parametric Kruskal-Wallis tests, with
Fatty acid profile structuring between species was assessed by principle component analysis. The PCA output was visualized using the package ggbiplot and interspecific differences in the distributions of the two primary principle components were evaluated using non-parametric Kruskal-Wallis tests, with
There is high variation in the literature in terms of which amino acids are profiled, with some papers reporting only essential amino acids, others reporting all amino acids, whilst others report some other subset of amino acids. Consequently, it was not possible to statistically evaluate how amino acid profiles structure across species. Instead, the mean content of each essential amino acid was determined for each species and these, along with the essential amino acid requirements for adults (
The insect species generally contained high protein levels, ranging from 31% in
Original proximate profiles produced in this study for the four analyzed species of edible insects alongside a beef control, obtained from van Huis et al. (
Dry Matter ( |
92.24 (±0.00) | 88.45 (±0.00) | 39.25 (±0.00) | 87.45 (±0.00) | – |
Organic matter ( |
82.29 (±0.42) | 90.12 (±0.28) | 98.62 (±0.17) | 93.59 (±0.44) | – |
Ash ( |
17.71 (±0.42) | 9.84 (±0.28) | 1.38 (±0.17) | 6.41 (±0.44) | – |
Crude protein ( |
44.82 (±0.40) | 61.00 (±0.66) | 31.05 (±0.55) | 63.64 (±0.22) | 55.00 |
Crude fat ( |
18.03 (±0.13) | 11.49 (±0.46) | 65.35 (±0.14) | 12.18 (±0.09) | 41.00 |
NDF ( |
39.94 (±0.71) | 54.89 (±1.10) | – | 56.22 (±0.00) | – |
ADF ( |
15.57 (±0.37) | 37.15 (±0.54) | – | 32.45 (±0.31) | – |
The black soldier fly,
Fatty acid profiles of the five analyzed species of edible insect.
2-methyl propanoic acid | – | C4:0i | 0.00 | 0.42 | 0.00 | 0.00 | 0.00 |
2-methyl butanoic acid | – | C5:0a | 1.15 | 0.00 | 0.00 | 0.00 | 0.00 |
Hexanoic acid | Caproic acid | C6:0 | 2.61 | 0.00 | 0.00 | 0.64 | 0.00 |
Octanoic acid | Caprylic acid | C8:0 | 0.00 | 0.00 | 0.00 | 1.08 | 0.00 |
Non-anoic acid | Pelargonic acid | C9:0 | 0.52 | 0.00 | 0.00 | 0.00 | 0.00 |
Decanoic acid | Capric acid | C10:0 | 0.62 | 0.00 | 0.00 | 0.00 | 0.00 |
10-methyl undecanoic acid | – | C12:0i | 0.00 | 1.86 | 0.59 | 0.00 | 0.00 |
Dodecanoic acid | Lauric acid | C12:0 | 8.37 | 1.23 | 1.57 | 0.96 | 0.00 |
10-methyl dodecanoic acid | – | C13:0a | 0.00 | 0.53 | 0.00 | 0.00 | 0.00 |
Tridecanoic acid | Tridecylic acid | C13:0 | 0.95 | 2.48 | 0.00 | 0.00 | 0.00 |
Tetradecanoic acid | Myristic acid | C14:0 | 5.01 | 4.80 | 4.66 | 2.89 | 8.98 |
9-methyl tetradecanoic acid | – | – | 1.00 | 1.04 | 0.00 | 0.00 | 0.00 |
12-methyl tetradecanoic acid | – | C15:0a | 1.30 | 0.00 | 0.00 | 0.00 | 0.00 |
13-methyl tetradecanoic acid | – | C15:0i | 3.46 | 2.12 | 0.00 | 0.67 | 0.00 |
Pentadecanoic acid | Pentadecylic acid | C15:0 | 2.31 | 1.93 | 0.81 | 2.67 | 0.00 |
3-methyl pentadecanoic acid | – | – | 0.85 | 0.74 | 0.00 | 0.00 | 0.00 |
Hexadecanoic acid | Palmitic acid | C16:0 | 9.44 | 9.63 | 27.13 | 14.95 | 24.26 |
10-methyl hexadecanoic acid | – | – | 0.00 | 0.75 | 0.00 | 0.00 | 0.00 |
14-methyl hexadecanoic acid | – | C17:0a | 3.20 | 0.00 | 0.70 | 0.00 | 0.00 |
15-methyl hexadecanoic acid | – | C17:0i | 1.02 | 1.92 | 0.93 | 0.00 | 0.00 |
Heptadecanoic acid | Margaric acid | C17:0 | 1.06 | 0.00 | 1.06 | 2.91 | 0.00 |
Octadecanoic acid | Stearic acid | C18:0 | 6.61 | 6.51 | 7.88 | 18.28 | 15.00 |
17-methyl octadecanoic acid | – | C19:0i | 1.21 | 0.00 | 0.89 | 0.00 | 0.00 |
Non-adecanoic acid | Non-adecylic acid | C19:0 | 1.99 | 0.80 | 1.46 | 2.78 | 0.00 |
18-methyl non-adecanoic acid | – | C20:0i | 1.02 | 0.00 | 0.90 | 1.94 | 5.35 |
Icosanoic acid | Arachidic acid | C20:0 | 2.60 | 3.10 | 3.18 | 1.96 | 5.33 |
20-methyl heneicosanoic acid | – | C22:0i | 3.82 | 0.00 | 2.31 | 0.00 | 0.00 |
Docosanoic acid | Behenic acid | C22:0 | 0.00 | 3.03 | 0.00 | 2.76 | 0.00 |
Tetracosanoic acid | Lignoceric acid | C24:0 | 1.27 | 0.00 | 0.00 | 1.41 | 0.00 |
Non-ahexacontanoic acid | – | C69:0 | 0.00 | 1.84 | 0.00 | 0.00 | 0.00 |
5-dodecenoic acid | Lauroleinic acid | C12:1n-7 | 0.00 | 0.00 | 0.00 | 2.42 | 0.00 |
9-tetradecenoic acid | Myristoleic acid | C14:1n-5 | 0.82 | 0.59 | 0.00 | 0.00 | 0.00 |
11-tetradecenoic acid | – | C14:1n-3 | 0.00 | 0.94 | 0.00 | 0.00 | 0.00 |
7-hexadecenoic acid | Hypogeic acid | C16:1n-9 | 0.99 | 0.00 | 0.00 | 0.84 | 0.00 |
9-hexadecenoic acid | Palmitoleic acid | C16:1n-7 | 5.03 | 6.74 | 5.89 | 4.26 | 0.00 |
11-hexadecenoic acid | Lycopodic acid | C16:1n-5 | 0.00 | 2.24 | 0.00 | 0.00 | 0.00 |
8-heptadecenoic acid | Civetic acid | C17:1n-9 | 0.00 | 0.00 | 0.94 | 0.00 | 0.00 |
9-heptadecenoic acid | Margaroleic acid | C17:1n-8 | 0.00 | 0.00 | 0.66 | 1.37 | 0.00 |
10-heptadecenoic acid | – | C17:1n-7 | 1.14 | 0.89 | 0.90 | 2.42 | 0.00 |
6-octadecenoic acid | Petrolselinic acid | C18:1n-12 | 0.00 | 0.00 | 2.02 | 1.12 | 7.97 |
8-octadecenoic acid | – | C18:1n-10 | 0.00 | 3.60 | 0.00 | 0.00 | 0.00 |
9E-octadecenoic acid | Elaidic acid | C18:1n-9 | 7.91 | 5.09 | 0.00 | 0.00 | 12.48 |
9-octadecenoic acid | Oleic acid | C18:1n-9 | 2.59 | 2.24 | 0.00 | 0.00 | 4.41 |
11-octadecenoic acid | Asclepic acid | C18:1n-7 | 4.07 | 4.29 | 29.38 | 0.71 | 0.00 |
13-octadecenoic acid | – | C18:1n-5 | 0.00 | 1.50 | 0.00 | 0.89 | 5.93 |
11-icosenoic acid | Gondoic acid | C20:1n-9 | 0.97 | 1.34 | 0.63 | 0.00 | 0.00 |
13-icosenoic acid | Paullinic acid | C20:1n-7 | 2.56 | 0.00 | 1.36 | 0.00 | 0.00 |
7,10-hexadecadienoic acid | – | C16:2n-6 | 0.79 | 2.52 | 0.00 | 0.00 | 0.00 |
9,12-octadecadienoic acid | Linoleic acid | C18:2n-6 | 6.43 | 8.84 | 2.20 | 5.72 | 8.16 |
6,9,12-octadecatrienoic acid | γ-linolenic acid | C18:3n-6 | 0.94 | 0.81 | 0.00 | 1.41 | 0.00 |
5,8,11,14-icosatetraenoic acid | Arachidonic acid | C20:4n-6 | 0.00 | 1.00 | 0.00 | 0.00 | 0.00 |
9,12,15-octadecatrienoic acid | α-linolenic acid | C18:3n-3 | 0.00 | 0.00 | 0.00 | 17.12 | 0.00 |
11,14,17-icosatrienoic acid | – | C20:3n-3 | 0.00 | 0.00 | 0.00 | 2.93 | 0.00 |
5,8,11,14,17-icosapentaenoic acid | Timnodonic acid | C20:5n-3 | 0.00 | 2.94 | 0.00 | 0.00 | 0.00 |
9Z,11E-octadecadienoic acid | Rumenic acid | C18:2n-7 | 1.02 | 0.00 | 0.00 | 0.00 | 0.00 |
6Z,9Z,11E-octadecatrienoic acid | – | C18:3n-7 | 0.00 | 0.00 | 0.00 | 1.75 | 0.00 |
11,14-octadecadienoic acid | – | C18:2n-4 | 0.00 | 0.00 | 0.59 | 0.00 | 0.00 |
Others | – | – | 3.40 | 9.69 | 1.36 | 1.14 | 2.11 |
ΣSFA | – | – | 61.36 | 44.74 | 54.07 | 55.90 | 58.94 |
ΣMUFA | – | – | 26.06 | 29.46 | 41.78 | 14.02 | 30.80 |
ΣPUFA | – | – | 9.18 | 16.11 | 2.79 | 28.94 | 8.16 |
PUFA (n-3) | 0.00 | 2.94 | 0.00 | 20.06 | 0.00 | ||
PUFA (n-6) | 8.16 | 13.17 | 2.20 | 7.13 | 8.16 |
The palm weevil,
Contrary to mono-unsaturated content, the highest proportion of poly-unsaturated fatty acids was found in the caterpillar,
Species differences in their ash, crude protein, and crude fat contents are shown in
Proximate content, on a % dry matter basis, using both data analyzed in this paper and literature-sourced data. From top to bottom: ash, crude protein, and crude fat content. From left to right:
Highly significant interspecies differences were found in ash, crude protein, and crude fat content (
Statistical output of a series of non-parametric tests: firstly, Kruskal-Wallis output, in the form
Species | 41.49 ( |
30.71 ( |
24.90 ( |
|
BSF - | HSF | n.s. | ** | |
PL | ||||
STC | n.s. | |||
TM | n.s. | n.s. | ||
HSF- | PL | |||
STC | n.s. | n.s. | n.s. | |
TM | ||||
PL - | STC | n.s. | ||
TM | n.s. | n.s. | n.s. | |
STC - | TM | n.s. |
Crude protein was found to be most prevalent in
Crude fat was most prevalent in
The principal component analysis assessing between-species structuring in fatty acid profiles indicates clear, major differences between species in their position relative to PC1 and PC2, particularly in the case of PC2 (
Principal component analysis of the fatty acid profiles of the five analyzed species of edible insect. The relationship between the two primary principal components and individual datapoints, corresponding to a fatty acid profile of an individual species presented either in the literature or analyzed in this study, is shown. Points are colored based on the species to which they belong, as are the ellipses surrounding each species' datapoints. Superimposed onto the plot is the position of the fatty acid profile of beef, obtained from van Huis et al. (
Statistical summary of non-parametric tests assessing how these species of edible insect differ in their fatty acid profiles.
P(Variance) | 49.76 | 22.88 | – | – | – | – | – | |
Species | 14.62 ( |
28.45 |
21.12 ( |
20.29 ( |
10.04 |
5.68 (n.s.) | 9.15 (n.s.) | |
BSF - | HSF | n.s. | n.s. | n.s. | ||||
PL | n.s. | n.s. | n.s. | |||||
STC | n.s. | n.s. | n.s. | |||||
TM | n.s. | n.s. | n.s. | n.s. | ||||
HSF- | PL | n.s. | n.s. | n.s. | n.s. | n.s. | n.s. | |
STC | n.s. | n.s. | n.s. | n.s. | ||||
TM | n.s. | n.s. | n.s. | n.s. | n.s. | n.s. | ||
PL - | STC | n.s. | n.s. | n.s. | n.s. | |||
TM | n.s. | n.s. | n.s. | n.s. | n.s. | n.s. | n.s. | |
STC - | TM | n.s. | n.s. | n.s. | ||||
∑SFA | −0.27 (n.s.) | 0.59 ( |
– | – | – | – | – | – |
∑MUFA | 0.09 (n.s.) | −0.53 ( |
– | – | – | – | – | – |
∑PUFA | 0.16 (n.s.) | −0.16 (n.s.) | – | – | – | – | – | – |
∑PUFAn-6 | −0.07 (n.s.) | −0.07 (n.s.) | – | – | – | – | – | – |
∑PUFAn-3 | 0.33 ( |
−0.16 (n.s.) | – | – | – | – | – | – |
PC2 was shown to share a strong positive correlation with saturated fatty acid content and a strong negative correlation with mono-unsaturated fatty acid content (
Variation in fatty acid profile saturation as a function of insect species. Shown are each species' content, as a % of total fatty acids, of, from top to bottom, saturated fatty acids, mono-unsaturated fatty acids, poly-unsaturated fatty acids, n-6 poly-unsaturated fatty acids, and n-3 poly-unsaturated fatty acids. Shown, from left to right, in each panel:
Poly-unsaturated fatty acid content was highest in
For each species, each essential amino acid is reported as the mean of data reported in the literature and in g/100 g of crude protein. No literature was found reporting the tryptophan content of
The mean content of each essential amino acid, in g/100 g of crude protein, in each species of edible insect, alongside the total sum of essential amino acids. As neither of the two published papers on
For many amino acids, relatively little interspecies variation was detected (
Greater variation was detected in leucine and methionine, with the highest levels of these found in
For all other amino acids, all species exceeded human requirements, as did the total essential amino acid content of all species, demonstrating their nutritive potential.
Here, original nutritional profiles, including proximate and fatty acid data, have been produced for five edible insect species of socio-economic importance in West Africa, a region where entomophagy is highly popular (
These results promote the general suitability and substantial potential of edible insects as a nutrient source. The ash and crude protein content values fit well within the range previously identified for edible insects, with ash previously reported at <1%-25.95% and protein at 4.9–77.13% (
The composition of the crude fat portion, described in part by the fatty acid profile, was also shown here to be generally favorable in the insects. In particular, the insects showed a higher proportion of poly-unsaturated fatty acids than beef, which are recognized as essential for development in children and are often limited in landlocked countries with limited fish access (
These data confirm previous work that edible insects generally represent a viable and thus-far underutilized nutrient source, comparing extremely well to human requirements and traditional meat sources, such as beef (
Much interspecific nutritional variation was found between the five species analyzed here, with implications for their utility in assuring sustainable food security. The protein content and quality of ingredients has been described as the most important consideration in food and feed production (
Furthermore, ash is generally used as an indicator of the mineral content of foods (
Fat is the most energy dense nutrient source, producing 9 kcal per gram (
Furthermore, although not the case for
Therefore, overall these results, although in certain cases with limited sample sizes, suggest that consumption of
In addition to the between-species nutritional variation discussed above, we also identified substantial within-species variation. For example, the crude protein content of
A first source of variation may stem from differences in the experimental procedures used by different studies as some studies may use non-standard methodology or a differing number of repeats. Here, only studies which nutritionally profiled using standard AOAC (
As well as between-study analytical variation, the husbandry and rearing conditions or whether insects were farmed or wild-caught, could inflate nutritional variation. Larval diets can greatly affect the insect's nutritional profile, meaning that different substrates in the studies used here could cause marked within-species nutritional divergence. Nutritional divergence between
Finally, a large contributor to this high within-species variation could be natural or biological variation in individual or population nutrient content. The papers used here isolated insects from a wide range of localities; for example, the original profiles in this paper were produced from individuals from Ghana, whereas Akullo et al. (
Insects can clearly play an important role in future sustainable development and food security, and it is also becoming increasingly clear that this is particularly the case for certain species. Research should continue to characterize the nutrient profiles of as many tractable species as possible to direct interest into promising species in an informed way. For example, here we showed that the shea tree caterpillar,
The original contributions presented in the study are included in the article/
JA designed the research and carried out fieldwork. XC and IO conducted the biochemical analyses. JA and XC analyzed the data. BR conducted the statistical and meta-analyses. JA and BR wrote the initial manuscript, with contributions from VS and CC. All authors contributed to the article and approved the submitted version.
This study received funding contributions from the University of Michigan PARTNER II, AnePaare Farms, Aspire Food Group, the Association of African Universities (AAU), Research England's Global Challenges Research Fund (GCRF), and the Royal Society (UK).
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.
Authors are thankful to the staff of the International Center for Insect Physiology and Ecology (
The Supplementary Material for this article can be found online at: