Can Pistachios Help You Sleep?

With about 20% of the U.S. population suffering from sleep disorders, it’s no surprise there’s a wide range of sleep aids – from prescription to over-the-counter to homeopathic. But did you know that eating a small number of pistachios before you go to bed at night might help you sleep?

First, some background.

Our brains produce the hormone melatonin in response to darkness. Melatonin helps regulate our circadian rhythms (the body’s 24-hour internal clock) and produces signals that it’s time to sleep. Furthermore, melatonin can help keep our eyes healthy, calm stomach ulcers and heartburn, and even regulate our immune function.

However, watching TV at night or being on devices can limit many of these benefits. Exposure to light can block melatonin production and alter the circadian rhythm. Since lack of sleep can negatively impact health, some people attempt to increase their melatonin through food or supplements.

This is where pistachios come in.

A 2014 study estimated that a 3.5-ounce (100-gram) serving of shelled pistachios contains about 23 mg of melatonin. This is significantly higher than the 1 mg recommended dosage (older adults should potentially have a lower dosage). Interestingly, other researchers questioned the accuracy of the methodology in this study.

A 2018 Louisiana State University study reported that American-grown pistachios contain significant amounts of melatonin, much higher than most fruits, vegetables, cereals, and seeds. Using two different methods, the researchers found that pistachios contained 0.0034-0.066 mg of melatonin per 3.5 ounces. According to the researchers, pistachios contain phenolics which reduce the breakdown of tryptophan to toxic compounds so that it is instead converted to melatonin. Yes, the same tryptophan in your Thanksgiving turkey.

This all sounds very promising. Except, the study was funded by the American Pistachio Growers. That feels like a potential conflict of interest.

So, can pistachios help you sleep or not?

To me, the jury is still out. There are clearly health benefits to eating pistachios which are loaded with protein, vitamin B6, and magnesium – all of which are associated with better sleep. My advice would be to limit yourself to a 1-ounce portion late in the day; otherwise, the extra calories could have the opposite affect and keep you awake.