PLANT SOURCES OF MELATONIN
Since its initial identification in plants in the mid-1990s, there have been subsequent references to melatonin (“phytomelatonin”) levels in various edible foods and medicinal herbs. However, its concentration is wide-ranging and inconsistent, dependent upon many factors such as cultivars, growing conditions, germination, harvesting, and processing (e.g., roasting, drying) (1–3). There may also be methodological issues that result in variability in outcomes (4).
Melatonin has been documented in major plant-derived foods and beverages (5), including vegetables, fruits, nuts, seeds, grains, wine, and beers (see Table 1). Although it can be found throughout most plant parts, melatonin is typically higher in the plant’s reproductive organs, especially the seeds (2), most likely to help ensure the plant’s survival and protection against environmental stressors. Notably, one of the many roles of melatonin within plants is to stimulate the production of health-promoting phytonutrients like glucosinolates and polyphenols (6). Along similar lines, Italian researchers have suggested that dietary phytomelatonin, rich in grains, tomatoes, grapes, and wine, may be one of the relevant phytochemicals that work in synergy with other plant-based components in the Mediterranean diet, which is currently the most well-researched healthful dietary pattern (7).
Table 1: Select plant food sources of melatonin.
Vegetables
Several types: Asparagus, beetroot, cabbage, carrot, corn, ginger root, purslane, spinach, taro (3,5,18–23)
Fruits
Several types: Apple, banana, cherries (sweet, tart), cucumber, grapes, kiwifruit, peppers, pineapple, pomegranate, strawberries, tomatoes(18–20,23–29)
Nuts
Almonds, pistachios, walnuts (14,17,22–24,30)
Seeds
Anise, celery, coriander, fennel, fenugreek, flax, green cardamom, mustard (black, white), poppy, sunflower; Raw and germinated seeds of alfalfa, broccoli, lentil, mung bean, onion, red cabbage, and radish (3,23,31,32)
Grains
Barley, oat, rice, wheat (19,20,22,23)
Beans & Legumes
Kidney beans (sprouts), soybeans (33,34)
Herbs & Spices
Black pepper, feverfew, sage, St. John’s wort, select Chinese medicinal herbs (35–38)
Oils
Argan oil, extra virgin olive oil, grapeseed oil, linseed oil, primrose oil, sesame oil, soybean oil, sunflower oil, walnut oil, wheat germ oil (39)
Beverages
Beer, coffee, grape juice, orange juice, wine (24,29,40–42)
While it is true that several foods naturally contain trace amounts of melatonin, science demonstrates an individual would need to consume enormous quantities of these foods to get the natural physiological dose of melatonin that an average middle-aged adult naturally produces from the pineal gland each day, which is 0.3 mg (35).
Melatonin in Select Foods (Table 2)
Tart Cherries
Tart cherries have been touted for their melatonin content. In one study, Montmorency cherries were found to contain 13.46 ± 1.1 ng of melatonin per gram cherries (36). Thus, aiming for a physiological dose of 0.3 mg melatonin would imply that roughly 50 pounds of cherries (approximately 2,718 cherries) would need to be consumed daily (37), which is an unlikely dietary goal, that would result in consuming about 14,000 kcal and nearly 3 kilograms of sugar. Even though the amount of melatonin may be nominal, tart cherries have been suggested to promote healthy sleep in insomnia, perhaps due to the minimal melatonin content, antioxidant levels, or even ability to modify tryptophan availability (37–40). Of course, foods are complex mixtures of nutrients, so it is difficult to confirm that a physiological effect is the sole result of one compound. A recent study (41) in healthy adults found that Montmorency tart cherries as either juice (2 × 240 mL per day) or as a supplement (two capsules containing 500 mg freeze-dried tart cherry powder) for thirty days did not affect serum melatonin (although it was measured in the morning when levels tend to be low), or sleep time or quality compared with placebo. This finding may have been different in those with insomnia.
Pistachios and Walnuts
It is worth noting that there is some debate about the melatonin level of pistachios. A research paper (20) by scientists at the University of Kerman in Iran reported melatonin levels in the kernels of four different varieties of pistachio. Therein, it is claimed that one of the varieties of pistachio displayed unusually high levels of melatonin. Five years after this publication, there was a published erratum in the same journal(42) stating that the editors were informed by the German Federal Institute for Consumer Protection and Food Safety that they could not replicate these results in the same pistachios. Similarly, the American Pistachio Growers, in conjunction with researchers in the School of Nutrition and Food Sciences at Louisiana State University, reported a lower amount of melatonin in pistachios (43) when using the spectrofluorometric method used in the Oladi et al. publication (20). While there may be some discrepancy in melatonin in plant foods due to growing and harvesting conditions, there remains some debate about whether pistachios supply a therapeutic amount of melatonin. Using the American Pistachio Growers data (660 mg/g raw pistachios) would equate to consuming 1,567 pistachios for 0.3 mg of melatonin (43). Despite these inconsistencies, pistachios still feature prominently on the list of melatonin-containing foods and may have chronobiotic potential (22).
Walnuts are sources of several nutrients that can be helpful for sleep and brain health, like omega-3 fatty acids and tryptophan. The melatonin content is less than pistachios or tart cherries at approximately 3.5 nanograms per gram. This would translate to consuming about 857 cups of shelled walnuts (over 500,000 kcal) to get 0.3 milligrams of melatonin (1).
Strawberries
Strawberries provide multiple antioxidant nutrients, like polyphenols and vitamin C, which can support healthy immune function. However, over 2000 fresh medium strawberries would need to be consumed to achieve the daily needs of melatonin (44). Individuals with a histamine intolerance may need to avoid consumption of strawberries.
Apples
One study tracked the melatonin content of Fuji apples across several months (45). The researchers found that the levels fluctuated greatly. The highest level of melatonin was documented in mid-July at 134.3 nanograms per gram of apple. Even though that is a relatively modest amount of melatonin compared with other foods, the amount of Fuji apples at the right time of year to give you the 0.3 milligrams would equate to a little more than 11 medium-sized Fuji apples.
Grapes
Much like the other plant foods, grapes can be a variable source of melatonin depending on the type of grape and how they are prepared. Wine contains melatonin, but in much lower amounts than the grape itself. A research study analyzed grape seeds, flesh, and skin (46). One would have to eat the flesh of about 15,000 grapes to get 0.3 milligrams of melatonin. While the seeds are much higher in melatonin, finding and safely eating seeds is difficult. Grapes are not a significant dietary source of melatonin, although they are beneficial to eat in season for their nutrient profile.
Tomatoes
Researchers have studied several varieties of tomatoes for their melatonin content. Like all other foods, the amounts significantly differ depending on the variety. Based on the tomato with the highest level of melatonin documented in an analytical study (44), the daily consumption would be about 20 whole, medium-sized tomatoes to get 0.3 milligrams of melatonin.
Mushrooms
As noted with other foods, the amount of melatonin found in mushrooms varies based on the type of mushroom. One study (47) measured melatonin in the white button mushroom, a common variety at grocery stores. About 60 fresh mushrooms would need to be eaten to get 0.3 milligrams of melatonin.
Bananas
Bananas are well-known to be an excellent source of potassium and fiber that can assist with gut, heart, and kidney health. However, this food source would not be an ideal choice as a source of melatonin as it would take 3,852 bananas to get 0.3 milligrams of melatonin(1).
Table 2: Summary of the top suggested foods for their melatonin content, their nutrition, and potential health benefits.
Tart Cherries
2,718 fresh cherries
Antioxidants, vitamin C, polyphenols
Healthy anti-inflammatory response, antioxidant
Pistachios
1,567 pistachios
Antioxidants, fiber, protein, lutein, vitamin B6
Antioxidant, brain health, eye health, gut health
Walnuts
~857 cups (shelled walnuts)
Omega-3 fatty acids, protein, polyphenols
Gut health, antioxidant
Strawberries
~2000 fresh medium strawberries
Vitamin C, fiber, polyphenols
Antioxidant, immune health, healthy anti-inflammatory response
Apples
A little more than 11 medium-sized Fuji apples
Fiber, quercetin (polyphenol), vitamin C
Antioxidant, immune health
Grapes
~ 15,000 grapes
Resveratrol, polyphenols
Antioxidant, brain health, cellular health, gut health
Tomatoes
~ 20 whole tomatoes
Lycopene, vitamin C
Antioxidant, cardiovascular health, prostate health, skin health
Mushrooms
60 fresh mushrooms
Protein, fiber, minerals
Immune health
Bananas
3,852 bananas
Potassium, fiber
Gut health, heart health, kidney health, antioxidant
Authors: Deanna Minich, Ph.D., Melanie Henning, ND, Catherine Darley, ND, Mona Fahoum, ND, Corey B. Schuler, DC, James Frame
Reviewer: Peer-review in Nutrients Journal
Last updated: August 22, 2023
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