The Hidden Power of Melatonin: How Common Foods Can Boost Your Health

The review article examines the presence and health benefits of melatonin in everyday foods, highlighting its varying concentrations and the need for further research on its dietary impact. It emphasizes melatonin's potential in enhancing health through its antioxidant and anti-inflammatory properties.

A study by Ana Munoz-Jurado and Begona M. Escribano from the Department of Cell Biology, Physiology and Immunology, Faculty of Veterinary Medicine, University of Cordoba, and the Maimonides Institute for Research in Biomedicine of Cordoba (IMIBIC) delves into the widespread occurrence and potential health advantages of melatonin found in everyday foods. Melatonin, an indole hormone present in all living organisms, has long been recognized for its role in regulating circadian rhythms, metabolism, immune responses, and sleep. It is an ancient molecule, having appeared around 3000–2500 million years ago, evolving in photosynthetic bacteria to neutralize toxic oxygen derivatives produced during photosynthesis. While initially considered solely an animal neurohormone, melatonin's presence in higher plants was confirmed in 1995. Today, melatonin is known to exist in bacteria, yeast, fungi, animals, and plants, supporting the theory that it is an ancient molecule retained throughout evolution.

Melatonin's Multifaceted Role in Health

Melatonin's functions extend beyond circadian rhythm regulation. It influences metabolism, the immune system, and sleep, and possesses antioxidant, anti-inflammatory, and anti-apoptotic properties. Melatonin also plays a role in immune responses, mitochondrial homeostasis, and cell multiplication, differentiation, and survival in the brain. The use of melatonin supplements has increased in recent years to treat sleep disorders and has demonstrated clinical benefits in conditions like multiple sclerosis. Despite its presence in many daily-consumed foods, the exact concentrations of melatonin in each food and the health effects of consuming melatonin-rich foods remain unclear.

Exploring Dietary Melatonin Sources

The review aims to compile available information on the melatonin content of various foods and evaluate the hormone's effect on different pathologies. The amount of melatonin in foods can vary depending on factors such as variety, origin, heat treatment, processing, and analysis techniques. While dietary interventions with melatonin-rich foods report health benefits, there is no conclusive evidence that melatonin alone is responsible for clinical improvements. Therefore, more research is needed to assess the melatonin content in a broader range of foods and understand the impact of cooking and processing on melatonin levels to estimate total dietary intake and explore its health potential.

Animal-Based Foods: A Source of Melatonin

In foods of animal origin, fish, particularly salmon, contains the highest melatonin concentration. Pork, chicken, beef, lamb, milk, and eggs also contain melatonin, though in varying amounts. For example, pork has 2.5 ng/g, chicken meat 2.3 ng/g, and beef 2.1 ng/g. Cow’s milk contains melatonin levels that fluctuate based on the time of milking, with higher concentrations found during nighttime milking. Seasonal variations also affect melatonin levels in milk, with winter milk containing significantly higher melatonin than summer milk.

Plant-Based Foods: Rich Melatonin Sources

In plant-based foods, melatonin concentrations are generally higher than in animal products. Aromatic and medicinal plants, such as Scutellaria baicalensis, Tanacetum parthenium, and Hypericum perforatum, exhibit significantly high melatonin levels. Coffee beans, particularly in the species Coffea canephora L. and Coffea arabica L., also contain high melatonin concentrations. Various seeds, including white and black mustard, almonds, sunflower seeds, fennel, and green cardamom, are notable sources of melatonin. Additionally, nuts, such as walnuts and pistachios, and fruits, including cherries, goji berries, cranberries, grapes, bananas, pineapples, and oranges, have detectable melatonin levels. Tomatoes and peppers also contain substantial melatonin, with concentrations varying based on species and analysis methods.

Impact of Processing on Melatonin Levels

Processing and heat treatment can alter the melatonin content in foods. For instance, roasted coffee beans exhibit higher melatonin levels compared to green beans, but brewing significantly reduces melatonin concentrations. Fermentation processes, such as those used in wine and beer production, can increase melatonin levels. However, baking bread at high temperatures results in a significant decrease in melatonin content. Raw nuts generally have higher melatonin levels than roasted nuts, with peanuts being an exception where roasting increases melatonin content.

The review highlights the need for more studies to understand the effect of food processing and cooking on melatonin levels. This would enable a more accurate estimation of melatonin intake from a typical diet and its potential impact on health. The article emphasizes that while melatonin supplements have shown clinical benefits, the health effects of consuming melatonin-rich foods require further investigation. More comprehensive research could lead to nutritional interventions that incorporate melatonin to prevent and improve various health conditions.