Eggs and Associated Nutrients: Implications for Brain Development and Function From Conception to Early Adulthood: A Narrative Review

ABSTRACT

Brain development is an ongoing process that occurs throughout the first 1000 days of life (conception until 2 years) and proceeds throughout childhood, adolescence and up until early adulthood. Adequate nutrient intakes are crucial for both neurodevelopment inside the womb and critical life‐stages thereafter when the brain continues to grow and develop. This review critically summarises the current evidence for eggs and nutrients found in eggs in relation to their potential to support brain development and function. Twenty‐one key publications, including a mixture of meta‐analyses, systematic reviews, randomised controlled trials (RCTs), clinical trials and observational studies, were identified, focusing on eggs or nutrients found in eggs that could influence brain development and function. Findings suggest that the consumption of eggs or nutrients found in eggs could have potential benefits for aspects of neurodevelopment, certain markers of motor development and academic performance. Eggs are high in protein, monounsaturated fatty acids, riboflavin, vitamin B12, vitamin D, biotin, iodine, selenium and a source of vitamin A, folate, pantothenic acid and phosphorus. They also provide an array of nutrients and bioactive components, including docosahexaenoic acid, choline, lutein and zeaxanthin that have potential to reinforce brain growth and development. Given the nutrient‐dense profile of eggs, consumption could be encouraged across life‐stages that are physiologically demanding from a brain development, growth and function stance. This includes amongst women of childbearing age, infancy, childhood and adolescence. However, the extent to which egg intake can influence specific markers of brain/cognitive function requires further investigation.

1. Introduction

The role of nutrition across the first 1000 days of life and beyond has been referred to as a ‘golden opportunity’ to optimise brain development which could impact on neurodevelopment and have long‐term consequences with respect to education needs, job potential and mental wellbeing (Cusick and Georgieff 2016). Brain architecture can be moulded by environmental conditions with diet and nutrients being one of these (Cortes‐Albornoz et al. 2021; Fox et al. 2010). The brain is a remarkable organ, and its structural and functional components are formed when there are critical and sensitive developmental periods in life, referred to as ‘windows of opportunity’, or a time of ‘brain plasticity’ (Ismail et al. 2017).

In terms of timings, prenatal nutrition and the first 1000 days of life (from conception to age 2 years) are particularly crucial to brain development, sometimes referred to as neurodevelopment (Schwarzenberg et al. 2018). Neurodevelopment is defined as the brain's development of networks or systems that are responsible for learning, memory, social skills and overarching brain function (Chakraborty et al. 2021). During pregnancy, rapid changes in foetal brain structure occur with the brain transitioning from a smooth, bi‐lobed, non‐complex organ into one more typical of the adult brain, fuelled by rapid rates of neuronal and glial brain cell growth and development (Georgieff et al. 2018). In fact, behaviours such as attention, multi‐tasking and working memory have their neural ontogenies programmed prior to birth (Georgieff et al. 2018). During infancy, three nutrient‐myelin windows have been discovered at ages 6–20 months, 20–30 months and 30–60 months, demonstrating core developmental dynamics between nutrient intakes and brain maturation during this time (Schneider et al. 2023). Over the first 3 years of life, there is rapid development of microstructural white matter (tissue in the central nervous system containing myelinated axons and supporting cells), which appears to be underpinned by increased myelination and axonal packing (Lebel and Deoni 2018). White matter development (myelination and axonal packing) continues to increase in volume until childhood and adolescence (Lebel and Deoni 2018; Lenroot and Giedd 2006). The brain then continues to develop, with white matter accumulating through to 20 years of age (Giedd et al. 1999).

Whilst calories are needed for brain growth, this is not enough for brain development—specific nutrients are essential (Schwarzenberg et al. 2018). Protein, choline, folate, iron, iodine, zinc and vitamins A, D, B₆, B₁₂ and long‐chain polyunsaturated fatty acids have been identified as being central to neurodevelopment (Schwarzenberg et al. 2018). An inadequate dietary supply of certain brain nutrients can have a deleterious impact on human brain development (Cunnane and Crawford 2014). Failure to acquire adequate intakes of key nutrients during critical life‐stages which encompass brain development may lead to life‐long deficits in brain function, even if intakes of nutrients are later replenished (Schwarzenberg et al. 2018). What constitutes a ‘healthy diet’ has transitioned in contemporary times and presently this includes diets higher in plant‐based foods, including fresh fruits and vegetables, whole grains, legumes, seeds and nuts; and lower in fatty and processed meats, with limited amounts of high‐fat, sugar and salt foods and drinks, such as confectionery, biscuits and cakes (Cena and Calder 2020).

Eggs provide an array of nutrients and bioactive components which include amino acids, essential fatty acids, vitamin A, B12, choline, folate, vitamin D, iodine, selenium, lutein, zeaxanthin and others (Table 1). Egg yolk is abundant in fatty acids, including phospholipids, choline, polyunsaturated fatty acids (PUFA) and lipophilic vitamins including carotenoids (Zhang and Mine 2023). In particular, choline, docosahexaenoic acid (DHA), lutein and zeaxanthin have been found to have synergistic associations with foetal neurodevelopment (Christifano et al. 2023). The methyl‐donor nutrients involved in one‐carbon metabolism (choline, vitamin B6, B6 and folate/folic acid) influence DNA and histone methylation which can alter gene expression and influence genes involved in brain development (Bekdash 2024).

TABLE 1.

Nutrients and bioactive compounds found in whole eggs.

Nutrients and bioactive compounds	Content in 100 g of egg
Energy, kcal	143
Water, g	75
Protein, g	14
Carbohydrate, g	Tr
Total fat, g	9.6
Fatty acids, saturated, g	2.7
Fatty acids, total monounsaturated, g	3.69
Fatty acids, total polyunsaturated, g	1.51
Amino acids a
Tryptophan, g	0.166
Threonine, g	0.594
Isoleucine, g	0.616
Leucine. g	1.05
Lysine, g	0.832
Methionine, g	0.418
Phenylalanine, g	0.66
Tyrosine, g	0.512
Valine, g	0.734
Arginine, g	0.787
Histidine, g	0.283
Alanine, g	0.667
Aspartic acid, g	1.27
Glutamic acid, g	1.63
Glycine, g	0.408
Proline, g	0.56
Serine, g	0.919
Hydroxyproline, g	< 0.01
Cysteine, g	0.385
Vitamins
Thiamin (Vitamin B1) μg	0.08
Riboflavin (Vitamin B2) mg	0.47
Niacin, mg	0.1
Pantothenic acid, mg	1.25
Vitamin B6, mg	0.063
Folate, total, μg	30
Choline, total, mg a	335
Choline, free, mg a	0.6
Choline, from phosphocholine, mg a	309
Choline, from phosphatidyl choline, mg a	0.2
Choline, from glycerophosphocholine, mg a	0.2
Choline, from sphingomyelin, mg a	25.1
Biotin, μg a	16.7
Vitamin B6, mg	0.10
Vitamin B12, μg	2.0
Retinol, μg	120
Vitamin D, μg	3.2
Vitamin E, mg	1.63
Minerals
Calcium, mg	55
Iron, mg	1.97
Magnesium, mg	14
Phosphorus, mg	205
Potassium, mg	141
Sodium, mg	150
Zinc, mg	1.3
Copper, mg	0.07
Manganese, mg	0.04
Iodine, μg	52
Selenium, μg	27

^a U.S. Department of Agriculture (USDA) (2024). Data for Eggs, Grade A, Large, egg whole, FDC ID: 748967.

Source: PHE (2021). Eggs, chicken, whole, boiled 12–940.

Micronutrient shortfalls have been associated with alterations in foetal brain development which may feature as childhood behaviour and cognition problems (Freedman et al. 2022). Adequate nutrition is also intricately linked with mental wellbeing which is regarded by the Department of Health and Social Care as a core element of nurturing care (Department of Health and Social Care (DHSC) 2024a). The present review first explains the nutritional properties of eggs, linking these to aspects of brain development and function. The second part of the publication undertakes a review of evidence specifically focusing on egg intake/consumption, related nutrient intakes and markers of brain development and function during the first two decades of life, from pregnancy until young adulthood.

1.1. Egg Nutrients Relevant to Brain Development and Function

Eggs are a high‐quality and highly digestible food protein providing an array of macro‐ and micronutrients. One large egg provides around 6 g protein which is equivalent to approximately 12% of daily protein intake for UK adults (Puglisi and Fernandez 2022; Liao et al. 2018; PHE 2016). Amino acids have recognised roles in neurotransmitter synthesis with tryptophan, tyrosine and phenylalanine being precursors for the neurotransmitters serotonin, dopamine and norepinephrine (Fernstrom 1994). Fatty acids are also important for brain function as they stimulate neuronal activity, gene expression, neurogenesis and synaptogenesis whilst preventing neuroinflammation and apoptosis though a balance between different fatty acid families is needed to prevent deleterious effects (Hussain et al. 2013). Docosahexaenoic acid (DHA) is present in ordinary eggs (about 18 mg DHA/egg) and also in DHA‐enriched eggs (Smuts et al. 2003). There are no specific UK recommendations for DHA but based on cardiovascular risk considerations for European adults 250–500 mg EPA + DHA daily is advised, of which ordinary, standard eggs would be contributing around 4% (EFSA 2012). In a recent review of national and international recommendations, the most frequently recommended intakes for adults were 250 mg/day EPA + DHA and 250 mg/day EPA + DHA plus an additional 100–200 mg/day DHA in pregnancy (Calder et al. 2025).

Regarding micronutrients, eggs provide around 0.47 mg riboflavin and 2.0 μg vitamin B12/100 g (PHE 2021) with respective shortfalls related to brain dysfunction (Thakur et al. 2017) and interference with dendritic formation and myelination (Black 2008). One egg (approximately 60 g) provides 40–86 μg of folate (Czarnowska‐Kujawska et al. 2021) which is involved in neural tube closure, neuronal function, neural stem differentiation and proliferation and thus has potential to affect children's brain and cognitive outcomes (Irvine et al. 2022). This corresponds to 122%, 86%, 57% and 43% of daily folate for ages 1–3 years, 4–6 years, 7–10 years and 11–18 years, respectively (PHE 2016). A further summary of the vitamin and mineral content of eggs and the percentage contribution to Reference Nutrient Intakes in early life, childhood and across the teenage years provided by one medium egg is shown in Table 2. It can be seen that eggs provide an array of important nutrients, contributing to daily vitamin D, folate, vitamin B12, choline, iodine and selenium intakes, in particular.

TABLE 2.

The Percentage of the UK RNIs from early life to young adulthood provided by one medium egg.

Constituent of egg	Amount per medium egg a	1–3 years b (%)	4–10 years b (%)	11–18 years b (%)
Vitamins
Vitamin A μg	70	18	16	11
Vitamin D μg	1.9	19	19	19
Thiamin (Vitamin B1) μg	0.05	14	8	6
Riboflavin (Vitamin B2) mg	0.3	50	33	25
Niacin mg	0.06	1.02	0.6	0.4
Vitamin B6 mg	0.04	6	4	3
Folate μg	17	24	14	9
Vitamin B12 μg	1.2	42	133	89
Choline mg c	194	138	92	88
Minerals
Sodium mg	87	11	5	4
Potassium mg	82	10	5.2	4.7
Calcium mg	32	9	6	3.6
Phosphorous mg	119	44	30	17
Magnesium mg	8	9.4	5	2.7
Iron mg	1.1	16	15	8.4
Zinc mg	0.8	16	12	9.3
Copper mg	0.04	10	6.2	4.4
Iodine μg	30	43	29	22
Selenium μg	16	107	64	29

^a Average weight 58 g, values are for edible contents only (Table 1 values × 0.58).

^b Averaged across age and gender groups.

^c EFSA DRVs for choline averaged across the specified age ranges (EFSA 2016).

Source of RNIs: (PHE 2016).

Today we know that the bioactive metabolite of vitamin A, retinoid acid, is a signalling molecule involved in brain growth, neurogenesis, neuronal survival, synaptic plasticity and the regulation of gene products (Olson and Mello 2010) and eggs provide about 120 μg retinol per 100 g (PHE 2021). Vitamin D is also present in eggs (around 3.2 μg of vitamin D per 100 g) (PHE 2021) and is well recognised for its roles in brain development with neurodevelopmental disorders being linked to vitamin D shortfalls (Eyles 2021). Regarding iodine, eggs contain about 52 μg per 100 g (PHE 2021) with shortfalls associated with impaired mental development and cognitive function (Gunnarsdottir and Brantsaeter 2023). Lipophilic antioxidants such as selenium can be transferred from feed and into egg yolk (Nimalaratne and Wu 2015) with eggs providing around 27 μg selenium per 100 g (PHE 2021). Within neurons of the central nervous system the expression of selenoproteins is widespread and many brain developmental processes depend on the thyroid hormone triiodothyronine, also known as T3 (Schweizer and Fabiano 2022).

Eggs also contain other components and bioactives that may have relevance from a brain development and function stance. They are one of the main dietary sources of choline in European regions, providing around 251–285 mg choline per 100 g (Zeisel 2004; Obeid and Karlsson 2023; Myers and Ruxton 2023). Choline is an important methyl donor, precursor of the neurotransmitter acetylcholine which is involved in memory and learning and membrane phospholipids including phosphatidylcholine (Obeid and Karlsson 2023; Lopez‐Sobaler et al. 2024). Lutein and its isomer, zeaxanthin are concentrated in the nervous system and are associated with cognitive development (Lopez‐Sobaler et al. 2024; Johnson 2014). Lutein is the principal carotenoid in human brain tissue and in paediatric brains the relative contribution of lutein to the total carotenoids is twice that found in adults (Johnson 2014). UK McCance and Widdowson's data shows that whole boiled hens' eggs provide around 97 μg (0.097 mg) lutein per 100 g and boiled/raw egg yolk 550/575 μg (0.55–0.57 mg) lutein per 100 g (PHE 2021). A supplementation study providing 10 mg lutein and 2 mg zeaxanthin to children aged 5–12 years over 191 days observed significant improvements in serum lutein levels at days 90 and 180 (p < 0.05), a 7% improvement in visual processing and significant reduction in eye strain (p < 0.05) (Parekh et al. 2024). Egg protein is also abundant in the amino acid tryptophan, which is a precursor to serotonin, the neurotransmitter involved in mood, and melatonin (Lopez‐Sobaler et al. 2024).

Permittable nutrition claims on the nutritional standard profile of eggs based on European and United Kingdom specifications are shown in Table 3. Overall, eggs are high in protein, monounsaturated fatty acids, riboflavin, vitamin B12, vitamin D, biotin, iodine, selenium and a source of vitamin A, folate, pantothenic acid and phosphorus (European Commission (EC) 2024, Department of Health and Social Care (DHSC) 2024b).

TABLE 3.

Permitted nutrition claims for hens' eggs in the UK and Europe.

Cut offs for ‘source of’ and ‘high in’ claims	Content in 100 g of egg (edible portion)	Permitted nutrition claim for eggs
Protein—Source of = 12% of energy provided by protein; high in = 20% of energy provided by protein	39% of energy provided by protein	High in protein
MUFA—High in = provides > 45% of total fatty acid content and > 20% of energy value	49% of total fatty acid content from MUFA; 24% energy from MUFA	High in MUFA
Vitamin B12 a	108%	High in vitamin B12
Riboflavin a	36%	High in riboflavin
Vitamin D a	64%	High in vitamin D
Selenium a	42%	High in selenium
Biotin a	39%	High in biotin
Iodine a	33%	High in iodine
Vitamin A a	16%	Source of vitamin A
Folate a	24%	Source of folate
Pantothenic acid a	23%	Source of pantothenic acid
Phosphorous a	26%	Source of phosphorous

Abbreviation: MUFA, monounsaturated fatty acids.

^a Source of = 15% of RDA; High in = 30% of RDA.

Source: DHSC (2024b), EC (2024). Adapted from: Myers and Ruxton (2023).

2. Methods

2.1. Inclusion and Exclusion Criteria

Studies were included if they met the following criteria: (1) The outcome(s) of interest needed to focus on markers of brain development or function; (2) focused on conception, pregnancy, childhood or early adulthood. These life stages were selected given that the human brain continues developing and increasing in size until around 20 years (Giedd et al. 1999); (3) English‐language publications; (4) human studies; (5) conducted in the last 10 years; 1st January 2015 until 11th June 2025; and (6) identified publications were meta‐analyses, systematic reviews, randomised controlled trials (RCTs), clinical trials and observational studies. Some studies reporting on eggs and lutein/zeaxanthin intakes were included, but it should be noted that hens' feed varies globally and may influence carotenoid levels (Zaheer 2017; Leeson and Caston 2004). Studies were excluded if they were (1) abstract only/full texts could not be obtained (2) discussion papers, (3) were not undertaken during the specified life stages, (4) did not include a measurable marker of brain development or function, (5) focused on nutrients that were not relevant to brain development or function or (6) were irrelevant for the research question i.e., did not relate to eggs or nutrients found in eggs.

2.2. Sources and Search Strategy

This review was conducted according to the guideline of the Preferred Reporting Items for Systematic Reviews and Meta‐Analysis (PRISMA) statement as shown in Figure 1 (Liberati et al. 2009). PubMed, Science Direct and Google Scholar were searched from 1st January 2015 to 11th June 2025. The search was restricted to English language, human studies and the specified forms of publication. Search terms included ‘egg intake’ or ‘egg consumption’ and ‘brain development’ or ‘neurodevelopment’ or ‘brain function’ or ‘cognit*’ or ‘nutrients’. Reference lists were also searched to identify any additional relevant articles.

FIGURE 1.

Algorithm flow diagram for included publications. Source: Flow of studies through different phases of the systematic review (Liberati et al. 2009).

2.3. Screening Procedure

ED assessed the titles and abstracts of all the identified studies and independently reviewed these to determine which should be included in the publication.

2.4. Data Extraction and Quality Assessment

The following information was extracted from each study: author, year, country, PubMed Identifier, life‐phase/stage, type of study, study methods, level of egg or egg nutrient intake, study outcomes and main findings.

Due to the different types of publication being included in the present review, e.g., both RCTs and observational studies, a ‘potential bias’ column was added to the data extraction table as a measure of determining quality. The major sources of bias were categorised as defined by (Pannucci and Wilkins 2010).

3. Results

3.1. Preconception and Pregnancy

Two studies (a secondary analysis of a RCT undertaken in the USA and a cohort study in the Netherlands) focused on egg consumption, or egg nutrients in relation to aspects of brain function and development (brain maturation indices and cerebellar growth) (Christifano et al. 2023; Parisi et al. 2018) (Table 4). A large (n = 202) well‐designed secondary analysis of data from the Prenatal Autonomic Neurodevelopmental Assessment (PANDA) RCT focusing on foetal neurodevelopment, found that egg intake during pregnancy and intakes of associated nutrients including docosahexaenoic acid and choline were positively associated with fABAS (foetal autonomic brain age score; a brain maturation indices) at 36 weeks, implying synergistic associations with neurodevelopment (Christifano et al. 2023).

TABLE 4.

Key studies—Eggs and markers of brain development and function.

Study (author, year, country)	Life stage	Study design	Methods	Level of egg intake/egg nutrient	Study outcomes	Main findings	Sources of potential bias
Preconception and pregnancy
Christifano et al. (2023) USA	Pregnant women n = 202	Secondary analysis of a RCT	FFQ, foetal biomagnetometry at 32‐ and 36‐week's gestation	Egg intake included eggs used in mix‐dishes or baked goods	Foetal neurodevelopment	Egg intake predicted brain maturation indices (fABAS) at 36 weeks (p = 0.0353). Results indicated that higher egg intake resulted in a more developmentally advanced fABAS score at 36 weeks	Recall bias Transfer bias
Parisi et al. (2018) The Netherlands	Pregnant women n = 126	Periconceptional cohort	FFQ, blood biomarkers & ultrasound scans at set intervals throughout gestation	Diet in analysis was defined as ‘egg‐rich’ derived using principal component analysis	Prenatal cerebellar growth	No significant associations were detected for egg‐rich dietary patterns	Recall bias
Infancy and early life
Bragg et al. (2023) Malawian children	Malawian infants aged 6–15 months n = 200 in egg group n = 200 in control	Observational analysis from the Mazira Project randomised trial	Choline metabolites and developmental assessments at baseline and 6‐months	Intervention group—received weekly batches of eggs, and caregivers were asked to feed the child one egg per day in addition to normal feeding Control group—received no eggs, and caregivers were asked to feed the child as they normally would	Neurodevelopment	3.8% mothers and children consumed eggs. Plasma choline and its metabolites were not related to most measures of development	Compliance Transfer bias
Caswell et al. (2021) Malawi	Malawian infants 6–15 months n = 331 intervention n = 329 control	Part of the Mazira Project, a RCT	Egg intervention or control, 24‐h dietary recall, micronutrient density distributions modelled	Egg group—Caregivers of children in the egg group received a total of 14 eggs per week: 7 eggs for the enrolled child and 7 eggs to share with other household members Control group—no treatment	Nutrient adequacy (extrapolated nutrients relevant to brain development)	The egg group had lower prevalence of inadequacy for selenium, riboflavin, vitamin B12 and choline	Compliance Recall bias Transfer bias
Ernyey et al. (2024) Burkina Faso	n = 244 infants aged 18–33 months n = 78 full intervention group n = 83 in the partial group n = 83 control group	9‐month intervention—The Un Oeuf study	Monthly surveys were used to collect data on egg consumption	Egg consumption was categorised as: 1 = never, 2 = eaten over the last 1–3 months; 3 = eaten over the last 4–6 months and 4 = eaten in all 7 months. Average weekly egg consumption was calculated using 7 months of data	Gross motor and personal social skills	Children with consistent egg consumption (in all months) had a lower odd of falling below the cut‐off scores in gross motor (OR = 0.13, p = 0.02) and personal social skills (OR = 0.34, p = 0.05). And a dose response was established; for each additional egg/week, a 1.9% increase in scores for problem‐solving skills was observed	Recall bias Confounding
Faber et al. (2022) South Africa	Infants 6–9 months n = 70 egg group n = 85 control group	8‐month RCT	Egg intervention or no eggs allocated, 24‐h dietary recall and dietary diversity score calculated	Egg group—received one large‐sized grain‐fed egg (grade 1) per day. Received a dozen eggs per week; seven eggs for the intervention baby, and the rest for consumption by family members Control group—No treatment	Nutrient adequacy (extrapolated nutrients relevant to brain development)	Vitamin D intakes were higher in the egg group by the end of the study 4.6 μg/day (egg group) versus 0.98 μg/day (control group (p = 0.002)) Infants who ate egg on the day of recall had higher intakes of total protein, total fat, monounsaturated fat, polyunsaturated fat, phosphorous, vitamin B12, pantothenic acid, biotin and vitamin D	Compliance Recall bias Transfer bias
Iannotti et al. (2016) USA (undertaken in Haiti)	n = 583, infants 6–11 years	Longitudinal study	Enrolled and followed monthly for 1‐year during which motor developmental milestones were measured	Longitudinal regression models were applied to assess dietary/egg intake associations	Motor and language acquisition	Dietary diversity including egg and oil intake significantly predicted earlier achievement of motor and language development outcomes In DHA‐supplemented infants, visual‐evoked potential acuity was 0.48 logMAR at 6 months and matured to 0.14 logMAR at 12 months (1.5 lines on the eye chart better than controls). Visual maturation of healthy infants is improved by continued supplies of DHA from DHA‐enriched baby foods	Recall bias Confounding
Lutter et al. (2021) Malawi	Malawian infants 6–15 months n = 331 egg group n = 329 control group	Part of the Mazira Project, a RCT	Tablet‐based multipass 24‐h recall	Egg group—One egg per day for the child for 6 months. Eggs were delivered to the household twice weekly, and mothers were encouraged to give the egg to the study child only. To reduce the probability that the egg was shared, intervention households were provided an additional egg per day Control group—No treatment	Dietary diversity in children during a critical period in their development	Infants in the egg group consumed a mean usual energy intake from eggs of 30 kcal/day compared with the control group mean usual intake of 1–2 kcal/day. At midline and endline, more than 80% of children in the egg group consumed a minimally diverse diet compared with 53% at midline and 60% at endline in the control group	Compliance Recall bias Transfer bias
Papanikolaou and Fulgoni 3rd (2023) USA	Infants (birth to 1 year) n = 4770	Cross‐sectional NHANES analysis, 2001–2018	Percentage of infants and children above the Adequate Intake for daily choline intake derived	Identified usual egg intake using dietary recalls and intakes separated into five usual egg intake (oz eq) groups: < 0.25, 0.25–0.50, 0.50–0.75, 0.75–1.0 and ≥ 1.0	Choline adequacy	The percent of infants above the AI when consuming the lowest usual egg intake level (< 0.25 oz. eq) was 33.4 ± 1.3. When comparing 0.25–0.5, 0.5–0.75, 0.75–1.0 and ≥ 1.0 oz. eq to < 0.25 oz. eq of usual egg intake, the percent of infants above the AI for choline was 67.4 ± 1.6, 84.9 ± 2.1, 93.2 ± 1.5 and 98.1 ± 1.3, respectively (all p < 0.0001)	Recall bias Confounding
Papanikolaou and Fulgoni 3rd (2018) USA	Infants 6–24 months n = 561 egg consumers n = 2129 non‐egg consumers	Cross‐sectional NHANES analysis, 2001–2012	Examined egg consumption and associations with nutrient intakes	Egg consumers defined as infants consuming eggs (i.e., with the exclusion of mixed dishes) during a 24‐h dietary recall	Markers of development/nutrient intakes (extrapolated nutrients relevant to brain development)	Infant consumers of eggs also had greater protein (48 ± 0.7 vs. 41 ± 0.4 g/day), monounsaturated fat (17 ± 0.3 vs. 15 ± 0.1 g/day), total choline (281 ± 6 vs. 163 ± 2 mg/day), lutein + zeaxanthin (788 ± 64 vs. 533 ± 23 mcg/day), docosahexaenoic acid (DHA) (0.04 ± 0.02 vs. 0.02 ± 0.001 g/day), vitamin B12 (4.2 ± 0.1 vs. 3.7 ± 0.1 mcg/day), phosphorus (977 ± 15 vs. 903 ± 8 mg/day) and selenium (67 ± 1 vs. 52 ± 0.6 mcg/day; all p‐values < 0.05) vs. non‐consumers of eggs. Egg consumption was associated with greater lutein + zeaxanthin intake per day	Recall bias Confounding
Prado et al. (2020) Malawi	Malawian infants 6–9 months n = 331 egg group n = 329 control group	Part of the Mazira Project, a RCT	Egg or control intervention and developmental tests undertaken	Egg group—1 egg per day for the study child for 6 months Control group—messages about hygiene but did not receive any eggs	Child development	A smaller percentage of children were delayed in fine motor development in the intervention group (10.6%) compared with the control group (16.5%; prevalence ratio: 0.59, 95% CI: 0.38–0.91)	Compliance Transfer bias
Ricci et al. (2023) South Africa	Infants 6–9 months n = 250 intervention n = 250 control	6‐month RCT with a parallel design	Daily egg consumption, head circumference and gross motor milestones measured in a low socioeconomic community.	Egg group—One egg per day Control group—no treatment	Gross motor development	Daily egg intake did not affect linear growth, underweight, wasting, motor milestones development, anaemia and iron status	Compliance Transfer bias
Childhood and adolescence
Barg et al. (2023) Uruguay	n = 270 children aged 6–7 years in first grade	Cross‐sectional study	Two averaged 24‐h dietary recalls	Egg intakes derived from dietary recalls	Cognitive achievement	Higher consumption of nutrient‐dense foods which included eggs (also dark leafy and red‐orange vegetables, beans & peas, potatoes) was associated with better performance in broad reading, with beta coefficient 3.29 (95% CI 0.03, 6.56), p = 0.04. A nutrient‐rich diet may benefit language acquisition at the beginning of schooling	Recall bias Confounding
Liu et al. (2021) USA	Children aged 6 and 12 years n = 835 China Jintan Cohort Study Cross‐sectional study, n = 511	Cohort and cross‐sectional study	Breakfast consumption assessed by self‐assessment, IQ and academic achievement recorded	The foods assessed included fruit/vegetables, grain/rice, meat/egg, dairy products and soy products	Cognitive ability	Egg 6–7 days per week was significantly associated with higher verbal, performance and full‐scale IQs, by 3.56, 3.69 and 4.56 points, respectively (p < 0.05) Egg consumption appeared to facilitate academic achievement (mean difference = 0.232, p = 0.043) Frequent egg consumption during breakfast may be linked with improved cognitive function in youth	Recall bias Confounding
Morales‐Juarez et al. (2024) USA	n = 3633, 14–17 years	Cross‐sectional NHANES analysis, 2007–2018	24‐h recall used to categorise egg diets.	Egg‐rich diet levels were categorised as (1) no eggs, (2) eggs as ingredients in dishes or (3) primarily egg dishes	Nutrient adequacy (extrapolated nutrients relevant to brain development)	Adding 1 egg increased choline and vitamin D usual intakes for some groups and nutrient index scores for all groups (p < 0.0005)	Recall bias Confounding
O'Connor et al. (2022) USA	n = 22 preadolescents (58 females) aged 9–13	9‐month randomised, placebo‐controlled trial	Executive function analysed before and after the 9‐month whole egg powder intervention	Meal or snack replacement products containing powder made from whole eggs	Executive function	Replacement of foods with added whole egg powder did not impact 9‐month changes in preadolescent executive functions	Transfer bias
Papanikolaou and Fulgoni 3rd (2023) USA	n = 6930 young children (2–5 years)	Cross‐sectional NHANES analysis, 2001–2018	Percentage of infants and children above the Adequate Intake for daily choline intake derived	Identified usual egg intake using dietary recalls and intakes separated into 5 usual egg intake (oz eq) groups: < 0.25, 0.25–0.50, 0.50–0.75, 0.75–1.0 and ≥ 1.0	Choline adequacy	The percent of children above the AI when consuming the lowest usual egg intake level (< 0.25 oz. eq) was 22.31. Comparing 0.25–0.5, 0.5–0.75, 0.75–1.0 and ≥ 1.0 oz. eq to < 0.25 oz. eq of usual egg intake demonstrated significant increases in the percent of toddlers above the AI for choline, such that 51.41%, 72.57%, 84.94% and 92.57%, respectively, were above the recommended daily intake for choline (all p < 0.0001)	Recall bias Confounding
Papanikolaou and Fulgoni 3rd (2021a) Canada	n = 9254 children aged 1–18 years n = 159 in the CACFP	Cross‐sectional NHANES analysis, 2011–2014	Dietary recall and a modelling analysis	Model 1: Addition of one egg to breakfast when no eggs were typically consumed at breakfast Model 2: Addition of two eggs at breakfast when no eggs were typically consumed at breakfast Model 3: Addition of one egg at breakfast when breakfast is CACFP compliant Model 4: Addition of two eggs to breakfast when breakfast is CACFP compliant	Nutrient intakes (extrapolated nutrients relevant to brain development)	Intakes of pantothenic acid, riboflavin, selenium and vitamin D increased ≥ 10% (relative to baseline) with the addition of one egg at breakfast. The percentage of children above the adequate intake for total choline increased to 43.6% and 57.8% with one and two eggs, respectively, compared to 22.6% at the baseline	Recall bias Confounding
Papanikolaou and Fulgoni 3rd (2021b) USA	n = 130 infants n = 980 children/adolescents	Cross‐sectional NHANES analysis, 2011–2014	NHANES data analysed for egg consumers and modelling analysis	Modelling analysis conducted to examine choline and lutein + zeaxanthin intake following the removal and addition of eggs to the diet of children	Choline and Lutein + Zeaxanthin Intakes	Removal of eggs from the diet in all age groups examined led to decreases in choline intakes. In children aged 2–8 and 2–18 years old, the addition of 7 eggs per week also showed meaningful increases in choline, lutein + zeaxanthin intakes	Recall bias Confounding
Papanikolaou and Fulgoni 3rd (2019) Canada	n = 3299, egg consumers; n = 17 030, egg non‐consumers, 2–18 years	Cross‐sectional NHANES analysis, 2001–2012	Investigated associations with egg consumption and nutrient intakes	Automated Multiple Pass Method used to collect dietary and egg intake data	Nutrient intakes (extrapolated nutrients relevant to brain development)	Egg consumption was positively related with daily lutein + zeaxanthin and DHA intake (when data considered socioeconomic status)	Recall bias Confounding
Early adulthood
Taguchi et al. (2018)	n = 14 female students 18–22 years	4‐week trial	Provided with a nutritious breakfast including one boiled egg and kept a daily dietary record	One boiled egg as part of a breakfast menu at University. During holidays asked to eat breakfast containing a provided egg at home	Nutrient intakes (extrapolated nutrients relevant to brain development)	Energy percentage from protein and vitamin D and B12 intake were significantly higher during the intervention than baseline values	Compliance Transfer bias

Abbreviations: AI, adequate intake; CACFP, Child and Adult Care Food Programme; CI, confidence interval; DHA, docosahexaenoic acid; fABAS, foetal autonomic brain age score; FFQ, food frequency questionaire; GDM, Gestational Diabetes Mellitus; NHANES, National Health and Nutrition Examination Survey; OR, odds ratio; PANDA, Prenatal Autonomic Neurodevelopmental Assessment; PR, prevalence ratio; RCT, randomised controlled trial; WING, Women and Infants Integrated Interventions for Growth Study.

An observational cohort study using data from the Rotterdam periconceptional cohort (2013–2015) evaluated dietary patterns using a validated food frequency questionnaire (196 food items), blood biomarkers and undertook two and three‐dimensional ultrasound scans and transcerebellar diameter (TCD) measurements at 9, 11, 22, 26 and 32 weeks' gestation. An ‘egg‐rich’ dietary component strand was formed where there were high loadings of eggs (Parisi et al. 2018). However, it should be considered that this component also included nuts, fish sauces and non‐alcoholic drinks. A stronger adherence to the egg‐rich dietary pattern was associated with significantly higher serum and red blood cell folate levels compared to weak adherence (p = 0.02). The dairy‐rich diet was associated with measures of cerebellar growth (p < 0.01), but egg‐rich diets were not (p = 0.99, with data adjustments for energy intake, conception mode, alcohol, smoke, parity, age, BMI, folic acid supplement/multivitamin use and geographical origin). This study was conducted in a tertiary hospital with high levels of education and folic acid supplement use; findings could be different in non‐European and non‐Caucasian populations. As the study was observational in nature, cause and effect relationships cannot be determined. Furthermore, as measures of dietary intake were self‐reported, the reliability of dietary intake data may be questionable.

3.2. Infancy and Early Life

Nutrition in early life has also been found to have lasting effects, with better diet quality being associated with faster cognitive processing speeds at age 17 years (Nyaradi et al. 2015). Ten key studies focused on egg intakes/egg nutrients in relation to markers of brain function or development. Of these, seven were undertaken in Africa, two in the USA and one in Haiti.

An RCT found that egg consumption (1 egg per day) in infants aged 6–9 months has been associated with a smaller percentage of children being delayed in fine motor development (movements that require co‐ordination) (10.6%) compared with 16.5% in the control although at the endline the intervention and control groups did not differ significantly in any developmental score (Prado et al. 2020). Similarly, a longitudinal study with infants aged 6–11 months living in a poor area of Haiti found that diverse diets including eggs significantly predicted earlier achievement of motor and language development outcomes (Iannotti et al. 2016). A 9‐month intervention undertaken in Burkina Faso with infants aged 11–33 months showed that children with a consistent egg consumption had better problem‐solving skills (1.9% increase for each additional egg/week) and lower odds of falling below cut‐off scores in gross motor skills (p = 0.02) (Ernyey et al. 2024). A RCT and egg intervention trial found that daily egg intake, plasma choline and its metabolites did not affect markers of development or growth, with a lack of findings possibly being attributed to poor intervention compliance (Ricci et al. 2023; Bragg et al. 2023). Larger and longer well‐designed RCTs or retrospective cohorts are necessary to investigate whether regular consumption of foods such as eggs could affect specific markers of growth and development, including brain development and validated markers of cognitive function, such as processing speed.

Several RCTs and cross‐sectional studies focused on egg consumption and nutrient intakes in infancy and early life. A 6‐month RCT forming part of the Mazira Project (n = 660 children aged 6–9 months) found that providing one egg daily (resulting in consumption of approximately half an egg per day) was associated with a marginally significant increase in total energy intake of ~30 kcal/day compared to controls (p = 0.087–0.128), with minimal displacement of other complementary foods indicating that the intervention supplemented the children's usual diet rather than replacing nutrient‐dense foods (Lutter et al. 2021). The same study also found 1 egg per day over a week led to infants having a lower prevalence of riboflavin, vitamin B12, selenium and choline inadequacy (Caswell et al. 2021). An 8‐month RCT found that protein, monounsaturated fat, vitamin D, vitamin B12, phosphorous, pantothenic acid and biotin intakes were higher amongst infants eating eggs on the day of the dietary recall (Faber et al. 2022). In the US, two publications using cross‐sectional National Health and Nutrition Examination Survey (NHANES) data found that infant egg consumers had higher intakes of protein, total choline, vitamin B12, selenium, phosphorous, lutein, zeaxanthin and DHA than non‐consumers (Papanikolaou and Fulgoni 3rd 2018) and were more likely to achieve choline adequacy (Papanikolaou and Fulgoni 3rd 2023).

Overall, findings from RCTs and observational cross‐sectional studies suggest that egg consumption during infancy and early life appears to benefit the energy and nutrient density profiles of diets. Eggs could also provide nutrients important for brain development and function, particularly in populations that may have pre‐existing nutritional inadequacies in these nutrients (Papanikolaou and Fulgoni 3rd 2023, 2018; Faber et al. 2022; Caswell et al. 2021). This evidence suggests that eggs and their associated nutrients could benefit markers of motor and language development during infancy and early childhood (Ernyey et al. 2024; Iannotti et al. 2016; Prado et al. 2020). However, some studies have not found associations with markers of brain function or development which may reflect a true lack of effect, short study durations, lack of compliance with egg interventions/intakes or outcome measures that lacked sensitivity (Bragg et al. 2023; Ricci et al. 2023). Adequately powered, long‐term RCTs are needed to replicate findings and collect comparable data on markers of brain function and development across these life stages.

3.3. Childhood and Adolescence

Adequate nutrition during this life stage is important to maintain cognitive development and to take advantage of any opportunities to correct potential deficits (Saavedra and Prentice 2023). By some, adolescence has been regarded as the ‘second window of opportunity’ in brain development due to the brain undergoing continued remodelling and reorganisation (Fuhrmann et al. 2015). Eight studies focused on childhood and adolescence. Of these, seven publications were observational cross‐sectional or cohort studies and one was a randomised placebo‐controlled trial. Of these, five studies were undertaken in the USA, two in Canada and one in Uruguay.

Several publications have identified intakes and patterns of egg consumption in relation to intakes on nutrients that have relevance for brain development and function. Five of these publications were cross‐sectional studies that used data from the large US NHANES survey (Papanikolaou and Fulgoni 3rd 2019, 2023, 2021a, 2021b; Morales‐Juarez et al. 2024). Of these, NHANES cross‐sectional data from 6930 younger children (2–5 years) showed that higher egg intakes (up to 1 oz. eq, or ½ egg) were associated with a greater likelihood of children achieving choline intakes above the Adequate Intake threshold. However, these findings should be interpreted cautiously. Dietary recall data are subject to bias, including the potential over‐ or underreporting of egg consumption and no studies included biological markers of choline status (e.g., plasma or serum choline) or functional outcome data (e.g., cognitive/motor development) (Papanikolaou and Fulgoni 3rd 2023). A modelling analysis also using NHANES data (n = 980 children/teenagers) showed that removing eggs from the diet led to reductions in choline intakes, resulting in fewer young people being above the choline Adequate Intake in the US, with the addition of 7 eggs per week into the diet improving choline and also lutein and zeaxanthin intakes (Papanikolaou and Fulgoni 3rd 2021b). However, once again, it should be considered that improving dietary choline intakes does not necessarily correlate to nutritional adequacy and in further studies it would also be useful to include blood biomarkers. Other research by the same team of scientists focusing on egg consumption specifically at breakfast found that the addition of one egg at breakfast amongst those aged 1–18 years (n = 9254; n = 159 from the Child and Adult Care Food Programme) increased daily intakes of vitamin D, selenium and riboflavin by ≥ 10% and the percentage achieving the adequate intake for choline (Papanikolaou and Fulgoni 3rd 2021a). Another NHANES sub‐analysis with children and teens aged 2–18 years dividing data between egg consumers (n = 3299) and non‐consumers (n = 17 030) found that egg consumption improved daily intakes of protein, DHA, choline, lutein + zeaxanthin, vitamin D, selenium, potassium and phosphorous. Although NHANES data provide valuable insights, caution is warranted when interpreting results due to the limitations inherent in observational research. For example, memory recall bias can occur, despite measures implemented to minimise its impact (Papanikolaou and Fulgoni 3rd 2019). Most recently, an analysis of NHANES data investigating the effects of adding one egg daily into adolescent diets (without and with food insecurity) showed that, irrespective of food security status, 60% of teens risked inadequate intakes of vitamin D, choline and magnesium (Morales‐Juarez et al. 2024). Adding one egg daily in the diet improved choline and vitamin D intake, as well as the overall micronutrient intake patterns indicating that nutrient‐rich foods are particularly important for adolescents (Morales‐Juarez et al. 2024).

Two further observational studies have also been undertaken. In a cross‐sectional study conducted in Uruguay, children aged 6–7 years consuming a ‘nutrient‐dense’ dietary pattern (which included eggs) compared with a ‘processed (high calorie) food’ dietary pattern were associated with better reading performance (Barg et al. 2023). A cohort study with children aged 6–12 years from the China Jintan Cohort Study found that egg consumption on 6 or 7 days of the week was associated with improved cognitive function, which included a stronger verbal performance and improved academic performance, although it should be considered that egg consumption data was also pooled together with meat, and findings could be attributed to characteristics specific to the culture, diet and city educational system (Liu et al. 2021). In the United States, a 9‐month randomised, double‐blinded, placebo‐controlled trial found that food replacement with whole egg powder (also allocated to milk powder and gelatine placebo powder) did not affect executive function, though the sample size was comparatively small (n = 122 preadolescents, 9–13 years) (O'Connor et al. 2022).

While NHANES data indicate positive associations between egg consumption and meeting Adequate Intake for key nutrients, the current evidence on direct functional benefits for cognition in this age group is mixed and largely limited to observational designs. It is also important to consider that meeting Adequate Intake thresholds is a dietary goal and not necessarily indicative of confirmed physiological measures of adequacy or optimal health. Longer and larger, adequately powered RCTs are needed which could be conducted with children or adolescents who have suboptimal diets or are underachieving in relation to validated markers of development/cognitive/learning at baseline.

3.4. Young Adulthood

One small 4‐week pilot trial (n = 14) investigated the effect of an egg intake intervention (breakfast which included one egg) over 4 weeks amongst young Japanese female university students aged 18–22 years (Taguchi et al. 2018). There were some nutritional improvements (higher energy percentage from protein), improved folate status and vitamin B12 and D intakes compared to baseline markers (Taguchi et al. 2018). However, it should be considered that no functional/cognitive markers were collected in this small trial which means that whilst there were some improvements in nutrients that could potentially impact on brain function/performance, such measurements were not recorded and therefore such associations cannot be made. Further research is needed but there is potential scope for universities to incorporate policies to improve student diets that reinforce engagement in cooking and food preparation to help them utilise low‐cost healthier, nutrient‐dense food items (Sprake et al. 2018).

4. Discussion

For humans, the brain is the control centre of the body and central nervous system, and its structure and function are modulated by a range of factors (Zhang and Mine 2023). Nutrients are essential for brain development with nutrient‐sensitive periods accompanying the development of specific brain regions and/or processes (Cusick et al. 2022; Heland et al. 2022). An adequate nutrient intake is important for brain development, neurotransmitter synthesis and function, signalling networks and aspects of memory (Ekstrand et al. 2021). Eggs, when consumed as part of a healthy and balanced diet, may help to supply an array of useful brain nutrients (Rehault‐Godbert et al. 2019), thus potentially helping to reinforce foetal brain maturation indices (Christifano et al. 2023). While mechanistic data and observational associations suggest eggs may help supply key brain nutrients, direct functional evidence from intervention trials remains limited and often context dependent. Specific findings associated with egg intake include fine motor development (Prado et al. 2020), motor and language development (Iannotti et al. 2016), gross motor and social skills (Ernyey et al. 2024), language acquisition (Barg et al. 2023), and higher verbal performance and better academic achievement (Liu et al. 2021).

Unfortunately, in the UK data from a food frequency questionnaire showed that only 54% of infants aged 6–8 months had been offered eggs and average intake was 1–2 times per week which increased with age (Rowan and Brown 2023). Gibson and Gray (2020) also undertook a secondary analysis of Year 9 of the National Diet and Nutrition Survey finding that egg intakes were equivalent to approximately 3.5 eggs per week (Gibson and Gray 2020). Finally, data from the latest UK National Diet and Nutrition Survey analysis (years 2019–2023) show that children and young people aged 4–10 years and 11–18 years are only eating 8 or 9 g of eggs and egg dishes daily (SD 19–29), although it should be considered that there has been a change in the food group reporting structure (Office for Health Improvement and Disparities (OHID) 2025). Several dietary shortfalls of nutrients found in eggs were indicated in the latest survey, for example that 8%, 13% and 45% adults were below the Lower Reference Intake for folate, iodine and selenium respectively. Eighty‐three percent of women of childbearing age also had red blood cell folate levels below the neural tube defect threshold (748 nmol/L) which has raised concerns (Office for Health Improvement and Disparities (OHID) 2025).

Previous advice to restrict egg consumption in pregnancy and weaning were overturned in updated advice on the safety of UK eggs in 2017 and on allergy in 2018, and the NHS now advises that eggs be consumed in pregnancy and introduced early in weaning to help protect infants against future egg allergy (Gulland 2017; SACN 2018; NHS 2022). Nevertheless, reservations about egg consumption by vulnerable groups may continue to act as a barrier to intake (Derbyshire 2024). Animal welfare may also be a concern, although 72% of UK egg production is now free range and/or organic (DEFRA 2025). Eggs tend to be categorised with beef, lamb, poultry and dairy when reporting on the potential environmental impact of food and diets, yet eggs are responsible for less carbon, water and land use than these, particularly beef, and only slightly more than most plant proteins (Mason 2023). It is also recognised that certain barriers such as cultural beliefs, social taboos and education level can potentially act as barriers to egg consumption, although behaviour change interventions can be successful in offsetting some of these (Moore et al. 2022; Schnefke et al. 2019). This demonstrates a need for refreshed communication on the benefits of egg consumption from a brain health perspective. Including eggs within the diet could be a useful way to reinforce brain development and function across key developmental life stages such as pregnancy, infancy, childhood and adolescence.

It is increasingly being recognised that eggs provide an array of nutrients (macronutrients, micronutrients and bioactive compounds) with many having multidimensional impact on brain development and function (Rehault‐Godbert et al. 2019; Georgieff et al. 2018). A growing body of evidence has linked eggs and some of the nutrients they contain such as DHA, lutein, zeaxanthin and choline to markers of brain and cognitive function (Wallace 2018; Christifano et al. 2023). It is, however, important to consider that nutrients do not always work in isolation. In several instances nutrients often work synergistically (e.g., DHA and choline, folate and choline) helping to facilitate neurodevelopment and brain function (Mun et al. 2019; Chen et al. 2023). The choline in whole eggs (a source of phosphatidylcholine; 3 eggs/day) has, for example, been found to be more bioavailable than a choline bitartrate (400 mg choline/day) supplement after 4 weeks of consumption (Lemos et al. 2018). For nutrients such as choline, insufficiencies are common across populations, which include children and young people. However, national nutrition surveys in the UK and many European countries do not currently include choline in routine dietary monitoring or food composition databases, so official prevalence estimates are lacking. Future choline intakes may depend on patterns of egg consumption along with the uptake and scale of plant‐based diets, which typically contain lower levels of choline than animal‐based foods (Zuk et al. 2024). It should also, however, be considered that whilst eggs are a nutritious food the individual nutrients they provide—such as protein, iron, vitamin B12 and choline—are found in other animal products and plant‐based foods (PHE 2021). Ensuring dietary variety is therefore essential, particularly for individuals following vegetarian and vegan diets (Axelsson et al. 2025).

Taken together, including eggs within the diet may help to elevate intakes of nutrients at physiologically demanding life stages given that brain development and growth is occurring (Christifano and Bennett 2023). The importance of nutrition for neurodevelopment and beyond is becoming increasingly apparent (Schwarzenberg et al. 2018; Bragg et al. 2023; Christifano et al. 2023). Nutrition during pregnancy, infancy, childhood and adolescent life stages from a brain health stance warrants more attention. Less nutrient‐dense, highly processed foods such as savoury snacks, ready meals or confectionery could be exchanged for eggs (e.g., swapping a high‐sugar breakfast bar or savoury packet snack for a quick boiled, poached or scrambled egg breakfast or snack meal). Eggs could also be utilised as a cost‐effective means of providing healthy, nutrient‐dense meals for families. In the UK in 2024, 53% of adults reported an increase in their living costs with 90% attributing this to food shopping prices (Francis‐Devine 2024).

Finally, there is scope for healthcare professionals to communicate the potential benefits of including eggs in the diet from a brain health perspective, particularly given their choline profile. For example, in the US both the American Medical Association and American Academy of Paediatrics recognise that failure to provide choline and other key essential nutrients during 1000 days post conception could contribute to lifelong brain function deficits (Wallace et al. 2020). Unfortunately, there are currently no such recommendations in the UK presenting a significant barrier for UK healthcare professionals (E. Derbyshire 2019, 2025). Furthermore, choline is currently not included within the UK National Diet and Nutrition Survey, highlighting that there is a need to raise its presence as a nutrient of concern (E. Derbyshire 2019).

In some countries, it has been proposed that dietary guidance for nutrient‐dense foods like eggs could be reassessed to better ensure meeting energy and protein requirements in children and adolescents (Loria‐Kohen et al. 2022), although we do not have such recommendations in the UK. Egg consumption patterns do appear to be responsive to dietary guidelines and policies indicating a need for refreshed education (Kritz‐Silverstein and Bettencourt 2025).

4.1. Limitations

It should be considered that some limitations exist in the present review process. Firstly, many of the publications evaluated were observational in nature, rather than RCTs. This can hamper the transferability of results, due to the fact that cause and effect relationships cannot be determined as exposure and outcome do not occur at one point in time (Wallace et al. 2022).

Secondly, with regard to methodological limitations not all publications quantify egg intakes or patterns of consumption using aligned methodologies. Some used food frequency questionnaires, others 24‐h recalls, and some were interventions specifying levels of egg consumption. Given this, it is important to consider that dietary recall bias (over‐ and under‐reporting) can exist while compliance issues with egg interventions and transfer bias (participant withdrawal) must be considered when interpreting intervention trials (Pannucci and Wilkins 2010). There is a distinct need for RCTs specifically examining eggs in relation to markers of brain development and function, rather than grouping them as part of a wider ‘protein’ or ‘dairy’ category, which often confounds specific nutrient effects.

Thirdly, much of the data analysed used results from the US NHANES survey which is observational in nature and findings may not necessarily be applicable to the UK or countries that have a high level of nutritional inadequacy. Analysis of data from NHANES has taken place over the last 50 years and its methodologies and data collection goals are now also in need of review to respond to new technologies and mission objectives (Taylor et al. 2023). Similarly, some studies were undertaken in countries that may already have high levels of nutrient inadequacies; thus egg consumption could be of more benefit in countries or regions where diet quality is poorer. As explained, a limited number of studies focused on markers of brain development and/or function and methods used varied between studies which restricts the scope of recommendations that can be made for policy. A greater use of aligned methodologies e.g., evaluating processing speed, working memory, short and/or long‐term memory using validated methodologies would be beneficial. Finally, studies were only included if they were available in English, which might have resulted in some studies being excluded.

5. Conclusions

Eggs are a highly nutrient‐dense food; the combination of nutrients and bioactive compounds found in eggs, many of which work in synergy, is unique as they are designed to support the life of a growing chick (Rehault‐Godbert et al. 2019). They are a natural food that can help to improve the nutrient density of diets by providing amino acids, docosahexaenoic acid, choline, folate, iodine, lutein and zeaxanthin and vitamins A, B12 and D, many of these nutrients having important and collective roles in brain development and function. As much of the evidence reviewed was observational in nature (many studies used U.S. NHANES data), there is a need for more well‐designed RCTs that specifically measure functional cognitive outcomes and more UK‐based research to confirm the applicability of current findings to the UK population. Overall, given the strong associations found in observational data and the demonstrated efficacy in some nutrient‐inadequate populations, integrating eggs within daily diets is an easy and cost‐effective way to help provide a range of important brain nutrients across critical life stages, particularly where baseline nutrient intakes are low.

Author Contributions

Dr. Emma J. Derbyshire is the sole author of the publication and solely undertook the research and writing of this review. No AI software was used to write this publication.

Funding

The author has nothing to report.

Disclosure

Declaration of generative AI and AI‐assisted technologies in the writing process: During the preparation of this work the author(s) did not use any AI and AI‐assisted technologies.

Conflicts of Interest

Dr. Emma J. Derbyshire is an independent advisor to the British Egg Industry Council on scientific issues. This writing of this article reflects the views of the author alone, and the funding source had no role in the research on which the article is based.

Data Availability Statement

The author has nothing to report.