The practice of eating insects is called entomophagy. According to a 2013 Food and Agricultural Organisation (FAO) of the United Nations’ Forestry paper, it is estimated that insect eating is practised regularly by at least two billion people worldwide. The most commonly eaten insect groups are beetles, caterpillars, bees, wasps, ants, grasshoppers, locusts, crickets, cicadas, leaf and plant-hoppers, scale insects and true bugs, termites, dragonflies and flies.

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The fact that insects are typically eaten whole – exoskeleton, organs and all, even when ground into flour – makes them especially nutritious.

“In countries where cereal proteins are key dietary staples, people are often lacking in essential amino acids such as tryptophan and threonine,” says Claudia Correia, a dietitian at Raffles Hospital in Singapore.

“These edible insects complement their diets. Insects are highly nutritious, but just like other foods, their nutritional value can vary depending on their metamorphic stage and the cooking methods used.”

Overall, Correia says insects are good sources of energy and protein, and are rich in fibre, monounsaturated fats and polyunsaturated fats. The unsaturated omega-3 fatty acid content in some insects is comparable with fish.

Insects are also rich in minerals such as copper, iron, magnesium, manganese, phosphorous, selenium and zinc, and in vitamins such as riboflavin, pantothenic acid, biotin and folic acid.

 “One example of the importance of insects in humans’ health is evident in Uganda and Zambia, where queen termites are fed to undernourished children,” Correia says.

“Interestingly, in Mali in Western Africa, it was common for children to collect grasshoppers in the cotton fields and eat them as a snack. Then the agricultural practice of developed countries of using pesticides to kill insects from cotton crops was incorporated into Africa, and now children are discouraged [from collecting] and [eating] grasshoppers. As a result, 23 per cent of children in Mali are at risk of protein deficiency.

“This is a good example of how insects have supplied significant amounts of protein and prevented children from becoming malnourished.”

 At present there is a huge global demand for livestock products; this is expected to double over the next 50 years. With so much pressure on already limited land and energy resources, edible insects are being touted as an environmentally friendly alternative to meat.

“Livestock production already accounts for 70 per cent of agricultural land, whereas in many cases, insects can be grown on organic waste,” Correia explains. “The livestock sector is also a big contributor to greenhouse gas emissions, such as carbon monoxide, methane and nitrous oxide, and uses up to eight per cent of drinkable water in the world.”

These problems are not associated with insect rearing. According to the FAO paper, edible insects also have high feed-conversion efficiency – this is an animal’s capacity to convert feed mass into increased body mass, represented as kilogram of feed per kilogram of weight gain. Crickets, for example, require only 2kg of feed for every kilo of body weight gain, while for cattle, that number is 10kg.

Furthermore, unlike livestock, insects pose a low risk of transmitting infections.

Rearing insects is important to reduce the negative environmental impact from overharvesting. Some insects are being farmed in countries such as Thailand, Laos, Vietnam and China.

The harvesting or rearing of insects requires no agricultural land, low technology and low capital investment. Therefore, it has the potential to benefit the poorer sections of some societies, such as women and non-land owners.

“For all these reasons, the FAO has, since 2003, been developing several programmes to create awareness of the consumption of insects,” says Correia.

 It is important to note that some insects are toxic when eaten. Tessaratomids, for instance, which resemble large stink bugs, can cause severe body pain and even temporary blindness.

“There are limited reports of adverse reactions caused by insect consumption,” Correia points out. “Some insects may contain excessive cadmium and lead, and the pesticides found on locusts and grasshoppers may pose some health risks. In these cases, regulated insect rearing is beneficial, since all chemical and pesticide exposures are controlled.”

Like most foods that contain protein, insects may also induce immunoglobulin-mediated reactions in sensitive humans, she adds. These allergens may cause eczema, dermatitis, rhinitis, conjunctivitis, congestion, angioedema and bronchial asthma.

Long-term exposure may also lead to allergic sensitivity. However, this is more problematic in people who have frequent contact with insects, especially those who are involved in the rearing of insects.

Honeybee larvae contain pollen and as such are not recommended for individuals with pollen allergies.

 “Generally, for the majority of people, ingestion and exposure to insects do not pose a significant risk of causing allergenic reactions, especially if the individual has no history of arthropod or insect allergen sensitivity,” Correia says.

Sheena Smith, a naturopath and clinical nutritionist from the Integrated Medicine Institute in Hong Kong’s Central district, adds that insects are also susceptible to microbial contamination, such as from bacteria, fungi and mycotoxins, as their nutrient content makes them a good host for pathogens under certain conditions. This may affect people who eat them raw.

“Insects also have the ability to ... concentrate substances from their environment or feed, as do other animals that we consume,” Smith adds.

“Because of this ... these substances could potentially be passed on to the consumer. There is some evidence that insects can have concentrations of chemicals that exceed levels that are typically acceptable for food consumption. Also, some insects produce their own poisons as defence mechanisms, which may be toxic in large quantities.”

Whole insects are available fresh, frozen, dried, canned or grilled. As for what they taste like, descriptions have ranged from “nutty shrimp” and “nutty mushrooms” to “soft shell crab”, “raw bacon” and “peanut butter”.

Can’t stomach the idea of ingesting whole bugs? Some health food stores sell more palatable versions of the stuff – think insect flour, insect paste, extracted insect proteins, insect trail mix, insect granola bars, insect protein powder, and even chocolate-coated insects.

So if creepy crawlies are set to be the wonder food of the next generation, it might be time to stop fearing them and start adding them to the menu. Bee-LT sandwich, anyone?