Issue 136 the role of eggs in developing countries

COMPETITION WINNER

IN ASSOCIATION WITH BRITISH LION EGGS

Amy Smith Undergraduate Student Amy is a Nutrition and Food Science BSc student, currently on a oneyear placement at Yakult. In her spare time, she enjoys cooking and walking her three dogs.

Judges:

Carrie Ruxton

& Emma Coates

“There was plenty of evidence and demonstration of the author’s knowledge and passion for the subject.” Carrie

“I have not thought about this area of egg nutrition before so was informed and entertained by the topic.” Emma Both judges felt the article was “well researched with a good flow.

THE ROLE OF EGGS IN THE NUTRITIONAL STATUS OF CHILDREN IN DEVELOPING COUNTRIES Eggs are one of the most common singular foods consumed around the world.1 Their popularity comes as no surprise due to their low cost, rich nutrient profile (especially protein) and accessibility. However, over 30% of children younger than five in developing countries are deficient in protein. The use of eggs could go some way to alleviate the risk of protein malnutrition.

We have known for many decades that eggs are rich in nutrients, sometimes considered a ‘powerhouse of nutrition’.1 They are a source of high-quality protein, including a balance of essential amino acids, fatty acids and a variety of vitamins and minerals, including B vitamins and choline2 (see Table 1 for the full nutrient profile of a hen’s egg). In the developed world, eggs and other animal sources of protein are consumed in abundance, with the average UK male consuming 88g per day, 30-40g higher than the RNI (0.75g/ kg body mass),3 yet, the prevalence of protein malnutrition in the developing world is extensive and widespread.4 Protein deficiency in children can lead to many complications, not just in childhood but in later life too, yet it has been estimated that over 30% of children younger than five in developing countries are deficient in protein.4 During childhood, protein deficiency can result in stunted growth and low weight, whilst extreme deficiency can lead to cases of kwashiorkor, a severe form of malnutrition, which can be characterised by a swollen abdomen due to low serum albumin concentrations.5 As a low socio-economic status (SES) is associated with protein malnutrition,4 there is a need for strategies to prevent malnutrition and improve nutritional status in the developing world, particularly in children. The use of hens’

eggs in improving the nutritional status of children of low SES has been studied across the globe, ranging from effects on protein status to neurotransmitters. The most studied areas in children appear to be in stunted growth2,6-9 and specific egg constituents that may influence cognitive development.10,11 The popularity of eggs as one of the most common singular foods1 comes as no surprise due to their low cost, rich nutrient profile, accessibility, sustainability and range of cooking methods. Therefore, the use of eggs in nutrient, protein and micronutrient intervention trials is a common and suitable choice over other animal food sources.

Table 1: Nutrient content of a medium-sized (58g) hen’s egg31 Nutrition Information

Per Medium Size Egg (58g)

Energy kcal (calories)

66

Energy kJ

277

Fat (g)

4.6

Saturates (g)

1.3

Monounsaturates (g)

1.7

Polyunsaturates (g)

0.7

Carbohydrate (g)

trace

Sugars (g)

trace

Protein (g)

6.4

Salt (g)

0.20

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COMPETITION WINNER STUNTED GROWTH

Stunting, as defined by the World Health Organisation (WHO), is ‘the impaired growth and development that children experience from poor nutrition, repeated infection and inadequate psychosocial stimulation.’ In 2016, it was reported by WHO that 154.8 million children around the globe suffer from stunted growth,12 resulting in a plan to reduce stunting in children under the age of five by 40%.

Both early life nutrition and the nutritional status of a mother during pregnancy can impact on stunted growth and consequences include reduced cognitive function and a lower educational performance, as well as increased risk of metabolic disease alongside excessive weight gain.13 Randomised controlled trials, cohort studies and pilot studies involving dietary egg interventions and children, have taken place globally, including in Asia,6,8 South America9 and Africa.2,7 Although the studies differed in their secondary outcomes, the primary outcomes were all focused on height gain. Collectively, they conclude that the addition of eggs into the diet of children of a low SES, aged six months to 13 years, is associated with increased height gain, or a reduction in stunted growth compared to controls. A trial in Ecuador found that after six months of consuming an additional one egg per day, infants were 47% less likely to be stunted compared to control and 74% less likely to be underweight.9 Many of these studies also measured protein status of the participants, all of which increased during the interventions.

Despite being low in energy, at around 66kcal per medium egg, 31 the high content of bioavailable protein is likely to be the key explanation for the additional height gain in children.

SKELETAL DEVELOPMENT AND BONE HEALTH

A final key aspect of the effect of eggs on growth is their vitamin D content, with a medium-sized egg providing 16% of the UK reference nutrient intake (RNI) of 10µg/day.15 Despite vitamin D intake predominantly being a concern in the developed world, there is also data showing low vitamin D and calcium status in populations of developing countries.16 It is known that vitamin D is found somewhat sparsely in the diet and, therefore, any contributor 24

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to boost vitamin D status is beneficial. This micronutrient plays a role in calcium absorption and status for bone synthesis and skeletal development;17 studies have shown an association between vitamin D intake and growth in infants.18 As another contributing factor in children’s growth, this provides further motive for the use of egg interventions in malnourished children.

Furthermore, adequate vitamin D levels in young children have shown to be associated with reduced risk of developing osteoporosis in later life.19 COGNITIVE FUNCTION AND BRAIN DEVELOPMENT

As eggs are also a rich source of some essential nutrients, such as fatty acids, iodine and choline, the role of such nutrients can also be explored and discussed when considering the impact of egg consumption on health.

Here, I provide a short summary of the research that has been conducted, exploring the role of these nutrients and the essential fatty acids on cognitive function and brain development in both children and foetal development.

Choline Eggs are one of our main sources of choline. A medium egg contains around 144mg choline, 36% of the adequate intake (AI) for adults set by the European Food Safety Authority and over 100% of the AI for children aged one to three 20 and, therefore, is likely to make a significant contribution to an individual’s choline intake and status. It is essential for pathways and activities in the body including the formation of phospholipids in cell membranes and the production of neurotransmitters including acetylcholine.21 Due to its involvement with neurotransmitters and cell formation, there is evidence to show that choline is important in foetal brain development.22 This highlights a population group - pregnant women - where there may be a benefit in incorporating eggs into their diets to optimise the health of their infants. A study showed that women with the lowest dietary intake of choline had four times the risk of having a child with a neural tube defect, compared with women with the highest choline intake.23 Choline deficiency has not only been associated with issues in cognitive function,11 but also with stunted growth. A randomised controlled dietary intervention with eggs has

demonstrated an association between increasing choline intake and improving linear growth in children of low SES.9 Iodine Iodine is essential for the production of thyroid hormones, which play a role in brain development and function, yet iodine deficiency is prevalent in many in developing countries.24 This micronutrient is important in the diet of pregnant women, for the healthy development of the foetus and for children’s growth.

The WHO recommends a daily intake of 90120Âľg of iodine for children and as the average egg (50g) contains about 25Âľg iodine, eggs can play a key role in meeting these requirements.25 In Albania, a study found that repletion of iodine into the diet of deficient schoolchildren, improved vision and information processing.26 This highlights that foods containing iodine, such as eggs, could be helpful in maintaining, or improving, iodine status and cognitive function of children in developing countries too.

Essential fatty acids It is widely known that essential fatty acids are required in our diet and that they play a role in brain health and function. Examples of essential fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Eggs are a source of DHA, which is known to play a key role in retina and brain development.27 Dietary interventions have recorded a positive correlation between egg intake and DHA status in children.9 Additional studies have used eggs and DHA-enriched eggs to observe the relationship between the addition of egg yolk in the diet of infants and their DHA status28 and vision development.29 These investigations have begun to depict the beneficial effects of incorporating eggs into the diets of malnourished children on nutritional status, which may subsequently support their mental and cognitive development.

NUTRIENT STABILITY OF EGGS

Storage and preparation of foods can be problematic in terms of nutrient loss and shelf life. Eggs, however, have demonstrated both versatility and stability during processing and

storage. It has been shown that various heating methods, including frying and spray drying, minimally effects the nutritional profile of an egg.30 The benefit of this finding is that in rural areas where eggs may be less available, a freezedried product with a longer shelf life than fresh eggs, may be of equal nutritional value.

MATERNAL HEALTH

In addition to the health benefits discussed in this article, another key point to raise is one of utmost relevance in the developing world: the impact of maternal health and nutritional status of breast milk. Breast milk quality can vary due to the nutritional status of the mother.28 In many developing countries, malnutrition of a breastfeeding mother is common. Therefore, the addition of highly nutritious, but relatively cheap foods such as eggs, into the diet of not only a weaning infant, but also the mother, may support and contribute to both maternal and infant nutritional status and health.

CONCLUSION

Eggs are readily available globally whether they are bought at a relatively cheap cost, or collected fresh in households that raise hens. The nutritional content of eggs is undoubtedly rich and their numerous uses in cooking allow flexibility in presentation too. With all these characteristics appreciated, eggs are now being used in rural and developing countries to boost the nutritional status of children from multiple angles.

As a result of studies that have been conducted, egg interventions are now in place in different settings within the developing world to improve nutritional status and health. For example, in a school in Uganda,2 eggs are given to students regularly as a low cost and simple nutritional strategy to nourish pupils.

Although protein and micronutrient malnutrition is still a worldwide health issue, particularly in developing countries, there are some clear strategies in place to help reduce the magnitude of the matter, in which eggs are playing a key role.

REFERENCES For full article references please CLICK HERE . . .

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