Walnuts are a source of melatonin, shows study

By Jess Halliday

- Last updated on GMT

Related tags: Melatonin

The health-conferring benefits of walnuts have been widely studied,
but new research has shown that they are a source of the
antioxidant hormone melatonin. It indicates that consumption of
walnuts can boost blood levels of melatonin and antioxidants in
rats.

Melatonin is a hormone that is naturally produced in humans by the pineal gland. It is most commonly associated with inducing and regulating sleep, since it is produced during the hours of darkness. In the US, melatonin supplements are commonly used by people whose sleep patterns are irregular, and those doing shift work or suffering from jet lag.

The new research was carried out at the University of Texas Health Science Center and published in the September issue of Nutrition​.

The researchers set out to investigate whether melatonin is present in walnuts, and whether eating walnuts has an effect on levels of melatonin and antioxidants in the blood.

First, they extracted melatonin from walnuts and quantified it using HPLC (high-performance liquid chromatography). The amount of melatonin in the nuts was found to be between 2.5 and 4.5 nanograms per gram.

The researchers then fed either walnuts or regular chow to rats, after having restricted their diet prior to the study. Their serum melatonin levels and 'total antioxidant power' were measured.

The walnuts were seen to increase blood melatonin concentrations threefold in the rats that ate them, compared with those on the regular chow. Serum antioxidant power also increased.

Lead researcher Russel Reiter said: "Our studies demonstrate that walnuts contain melatonin, that it is absorbed when it is eaten, and that it improves our ability to resist oxidative stress caused by toxic molecules called free radicals."

Although it is not clear how many walnuts humans would need to eat in order to benefit, in theory they might be expected to reduce the incidence of cancer, delay or make less severe neurodegenerative diseases of aging, including Parkinsonism, Alzheimer's disease and reduce the severity of cardiovascular disease, said Reiter.

Melatonin produced by the human body decreases with age. The study raises the question as to whether there may be a link between declining melatonin and the development of free-radical-related diseases in later life.

The omega-3 content of walnuts has already been shown to help reduce the risk of heart disease. Reiter maintains that the synergistic effect of omega-3, melatonin and other nutrients give walnuts the edge over a supplement containing just one element.

"I think the value of the walnut is the composite of what it contains,"​ he said. He is planning further research on the interplay between melatonin and omega-3.

Reiter's research was supported by a grant from the California Walnut Industry.

Related topics: Research, Botanicals

Related news

Show more

Related products

show more

Total Solutions for Cognitive Health by Lubrizol

Total Solutions for Cognitive Health by Lubrizol

Lipofoods, a Lubrizol Company | 05-May-2022 | Technical / White Paper

Globally, health and wellbeing have shifted from a focus on physical health and nutrition to also include cognitive and mental wellness, therefore consumers...

Mediterranean Nutraceutical products

Mediterranean Nutraceutical products

Esserre Pharma | 19-Apr-2022 | Product Brochure

From the best Mediterranean ingredients to effective and safe finished products, Esserre Pharma researches and develops unique formulations.

Trending solutions for immunity beverages

Trending solutions for immunity beverages

Prinova Europe Limited | 12-Apr-2022 | Technical / White Paper

One of the effects of COVID-19 has been to increase consumer interest in beverages with functional benefits, particularly for immune health.

Related suppliers

Follow us

Products

View more

Webinars