Every cell in our body contains choline. We produce a small amount in the liver but not enough, so we need to absorb it through diet. Australian guidelines suggest adults should have 425mg a day, pregnant women require about 450mg a day, and breast-feeding women need 550mg a day. A single egg contains about 150mg.

One study published in 2011 in The American Journal of Clinical Nutrition found that choline intake during midlife may help to protect our brains, and that people with a higher choline intake tended to have better memories. Meanwhile, 2022 research published in the same journal found that low intake of choline was associated with increased risk of dementia and Alzheimer’s disease, although more research is needed to confirm this relationship.

2. B vitamins

A single egg provides a range of B vitamins and is especially abundant in B12, B9 (folate), B7 (biotin), B5 (pantothenic acid) and B2 (riboflavin). These vitamins are crucial for brain health, Dr Derbyshire explains, and play an important role in a number of processes, including energy synthesis, cellular function and mental performance.

There is a substantial range of observational data that supports the cognitive benefits of B vitamins, says Anne-Marie Minihane, a professor of nutrigenetics and the head of nutrition at Norwich Medical School at the University of East Anglia.

A 2016 review published in Nutrients examined the mechanisms and relationships between B vitamins and the brain, concluding that they are “absolutely essential” for cognitive function. The authors cited a range of studies that uncovered links between severe B9/B12 deficiencies and cognitive decline, mood changes, memory loss and confusion. However, it is important to note that much of the evidence linking B vitamins to brain health is observational, so more research is needed to confirm this relationship, Minihane emphasises.

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Eat For Health Australia recommends we consume 200 micrograms of B9 and 2.4 micrograms of B12 each day. Adding eggs to your diet puts you firmly on the path to reaching these levels, with one medium egg containing roughly 1.4 micrograms of B12, and two containing about 60 micrograms of B9.

3. Protein

“Eating enough protein is crucial for brain health,” Dr Derbyshire says. Two large eggs contain about 14g of protein, a substantial proportion of the often recommended 15-30g per meal.

Eggs are considered a complete protein, meaning they contain all nine essential amino acids that your body needs but cannot produce. These include tryptophan, which the body needs to produce serotonin and melatonin, and phenylalanine, which is involved in the synthesis of dopamine. “These neurotransmitters play important roles in processes related to mood, focus and alertness,” Dr Derbyshire says.

In the recently published Journal of Nutrition, Health & Ageing review, the authors link protein to improved memory and reaction time in healthy young adults, as well as reduced risk of cognitive impairment in older people. They also emphasise the importance of tryptophan and its role in decision-making and memory.

While there isn’t an official recommendation on how much tryptophan we need each day, eggs are one of the richest sources, alongside poultry, oily fish, dairy and soy products. For a typical adult female the recommended amount of protein is 0.75g per kg of body weight per day and 0.84 g per kg males.

4. Antioxidants

Eggs are abundant in antioxidants, particularly lutein and zeaxanthin. “These compounds help protect against inflammation and oxidative stress, and may help brain health, with growing evidence suggesting a role in cognitive function,” Dr Derbyshire says.

In 2021, researchers investigated the impacts of lutein on the cognitive function of healthy older adults in a systematic review. While they examined a relatively small number of studies, they concluded that lutein has a positive impact on brain function and structure, suggesting that daily consumption may help prevent age-related cognitive decline.

In an earlier study published in The Journals of Gerontology, researchers found that higher levels of zeaxanthin in the blood were associated with better processing speed, cognition and memory. However, in both studies the authors emphasised that further investigation is needed to confirm the relationship between these antioxidants and brain health.

A single egg yolk typically contains 100-300 micrograms of lutein and roughly 100-200 micrograms of zeaxanthin, making them one of the richest sources alongside leafy greens and brightly coloured vegetables like sweetcorn and yellow peppers.

5. Omega-3 fatty acids

Omega-3 fatty acids are polyunsaturated fats that perform a range of important functions in the body. Again, our body cannot produce these so it is vital we consume enough from our diets. There are three main types of omega-3 – plant-based ALA (alpha-linolenic acid), marine-based EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). While the body can easily absorb and use DHA and EPA, ALA converts less efficiently.

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According to Minihane, “standard eggs contain minimal amounts of omega-3s (typically 20-30 milligrams per egg). There are now omega-3 enriched eggs available in supermarkets that can provide up to 100 milligrams of DHA per egg.” These come from hens fed a special diet supplemented with an omega-3 source such as flax seeds. Eating two enriched eggs each morning would put you on track to the Australian Heart Foundation’s 250-500 milligram daily target.

A systematic review published in 2022 linked omega-3 consumption to increased learning abilities, memory, cognition and blood flow in the brain. Meanwhile, a study published in Neurology examined 2000 people with an average age of 46 and found that those with higher levels of omega-3s scored higher on a cognitive test and also had a larger hippocampus, an area of the brain that plays an important role in memory. While this suggests an association between omega-3s and brain health, more research is needed to confirm if this is a causal relationship.

Can you reap the benefits from egg whites alone?

Most of the nutrients are contained in the egg yolk, and therefore it is best to eat the entire thing, Minihane says. The main exception is protein, which is also found in egg white.

Are eggs the key to a healthy brain?

“Eggs are a really important brain food,” Dr Derbyshire says. They contain a range of nutrients and vitamins linked to improved cognitive function, mood, focus, memory and neuroprotection. She says that eating three to seven eggs a week (as suggested in the new review) “makes logical sense” to reap their cognitive benefits.

However, Minihane says that the evidence is still “mixed and inconclusive”. She adds: “Further research is merited, and in particular randomised control studies, as based on their nutrient composition, eggs show promise with respect to brain health.” Therefore, eating eggs as “part of a healthy dietary pattern, rich in whole plant foods and oily fish, and limited in high sugar foods and beverages, is likely to contribute to the overall cognitive benefits,” she concludes.

Three brain-boosting ways to eat your eggs

1. Batch-cook for the week ahead

Dr Derbyshire suggests batch-cooking boiled eggs and storing them in the fridge for a few days, to be used in a variety of different meals. “You can use them in wraps or sandwiches with your favourite fillings, or top a salad with them for an easy on-the-go lunch.”

2. Pair them with healthy fats

For breakfast, Dr Derbyshire suggests pairing your scrambled eggs with avocado or seeds. “By pairing eggs with a source of healthy fats and omega-3s, this helps to improve the absorption of many of the nutrients found in the eggs.” Alternatively, keep a pot of flaked smoked salmon in the fridge to sprinkle into an omelette. “This way you’re getting all the brain nutrients from your breakfast, including extra omega-3s and healthy fats from the salmon,” she says.

3. Eat them alongside nuts and berries

Finally, if you’re in need of a filling and brain-boosting snack, Dr Derbyshire recommends a boiled egg with a side of berries and walnuts. “Berries and certain nuts and seeds are brain foods, too, because they contain polyphenols.” These are natural plant compounds that act as powerful antioxidants and help to protect the brain from damage.