Melatonin, magnesium and selenium have all been linked with getting a better night’s sleep – and nuts contain all three!

Melatonin: Nuts are a top source

A review paper, which looked at the melatonin content of a large number of foods, found nuts have amongst the highest melatonin content of plant foods (1). And pistachios, in particular, contain high levels of melatonin.

Melatonin is a hormone produced by the brain, mostly at night (2).

Studies consistently show that it helps people sleep longer and fall asleep more quickly (3). Melatonin has also been linked with improving sleeping disorders like insomnia, which affects one in three people (2,4).

The body’s melatonin levels increase after eating foods that contain melatonin.

What other foods contain melatonin?

Plants have higher concentrations of melatonin than animals (14).

Among plant sources, in addition to nuts, medicinal plants and some cereals, legumes and seeds are also rich in melatonin. And salmon and eggs contain high amounts of melatonin amongst animal sources (1).

The amount of melatonin in foods may vary depending on factors like their place of origin, the variety or species, environmental factors (such as sunlight exposure), processing techniques, and even the detection or analysis techniques used to determine melatonin content, among other factors (14).

This means the reported melatonin content of foods can vary quite a bit (1,14).

Pistachios and melatonin

Researchers from Louisiana State University, in partnership with American Pistachio Growers, analysed the melatonin content of pistachios. They found that pistachios have around 660 nanograms (ng) of melatonin per gram (5). And roasting pistachios didn’t impact their melatonin content.

Other research has reported pistachios (Pistacia vera) at 233ng/g, so there is some variation.

However, these figures for pistachios are much higher than most fruits, vegetables, cereals, legumes and seeds (1). For example, the melatonin content of oats has been reported at around 90ng/g, sunflower seeds at 29ng/g and tomatoes at up to 24ng/g, depending on the type.

Did you know? A recent study, involving 80 healthy young adults, found that a daily serving of 40g of walnuts increased melatonin, and improved sleep quality and reduced daytime sleepiness (13).  

Minerals for sleep

Nuts are among the best food sources of selenium and magnesium. Researchers have begun exploring links between these minerals and a good night’s sleep (6-8).

A large observational study found people who only slept 5 – 6 hours a day (termed ‘short sleepers’) had lower intakes of selenium, compared with people who slept 7-8 hours a day (normal sleepers) (6).

Brazil nuts are one of the highest natural sources of selenium. Just three Brazil nuts a day provides 100% of the recommended dietary intake selenium.

Magnesium has been shown to help improve insomnia in clinical trials, especially among older people (nearly 50% of older people suffer from insomnia) (7-8). Magnesium is found in a variety of foods, but the best sources include nuts and seeds, and green leafy vegetables.

Adherence to overall plant-based diets, especially healthy plant-based diets, has been linked with optimal sleep quality (12).

Sleep quality and the Mediterranean diet

Often considered one of the healthiest dietary patterns in the world, the popular Mediterranean diet has been shown to reduce the risk of chronic disease and overall mortality.

But it may come as a surprise to learn that it’s also been linked with better sleep quality (9,10)!

Plant foods (like nuts, seeds, legumes, whole grains, fruit, vegetables, herbs and olive oil) take centre stage in the Mediterranean eating pattern. The healthy unsaturated fats and phytochemicals these foods offer have a beneficial effect on inflammation, which may negatively impact sleep duration and quality.

Did you know? A study involving almost 8,000 older Australian women found better adherence to dietary guidelines was linked with fewer sleep problem symptoms, including taking a long time to fall sleep or waking up early (11).

The bottom line: Healthy diet, healthy sleep

Many factors (some of which are really complex!) affect the quality of our sleep.

Is there one best food for a good night’s sleep? Probably not. Instead, a healthy, balanced diet will offer the range of nutrients needed to support sleep.

Enjoying a healthy handful (30g) of nuts each day can boost your intake of melatonin and a host of nutrients, including selenium and magnesium – which could just up your odds of getting a better night’s sleep!

Did you know? A 2022 review of 20 studies found that, in general, diets rich in fibre, fruits, vegetables, and anti-inflammatory nutrients and lower in saturated fat were associated with better sleep quality (10).