Plant Protein Might Be Your New Bedtime Snack Hero, According to a New Study

Diet, physical activity, and sleep are three lifestyle factors that impact everything to do with our health and wellbeing, including mood, relationships, productivity, avoiding illness and disease, and generally feeling good and enjoying life. Getting high-quality sleep may be the most crucial factor in supporting the rest. As a necessity for both physical and mental health, a restful night’s sleep is vital for daily functioning and long-term health.

Despite this, consistently obtaining the recommended 7-8 hours of quality sleep is a lofty goal for many people — plenty of ongoing research into lifestyle factors that influence sleep, with dietary choices being a popular topic. Recently, a study has shown a link to the potential impact of protein choices on sleep quality.

While protein intake, ideal diet types, and food choices are clearly influential on sleep, this study looks specifically at how dietary protein sources can impact sleep quality. Published in The European Journal of Clinical Nutrition, the research suggests that a higher intake of plant-based proteins may improve it. (1)

The Study at a Glance

The research explored the dietary determinants of sleep quality, aiming to uncover the relationship between protein intake and sleep patterns. This investigation pooled data from three prospective cohort studies: the Nurses’ Health Study (NHS), Nurses’ Health Study II (NHS2), and the Health Professionals Follow-up Study (HPFS).

Researchers assessed the participants’ dietary habits using a food frequency questionnaire, which provided data for a detailed analysis of the types and quantities of protein the study participants consumed over time.

The researchers used the Pittsburgh Sleep Quality Index (PSQI), a well-established measure of sleep quality among the participants, to determine a relationship between diet and sleep. This data gave insight into the specifics of how different types of protein intake might influence sleep patterns.

The study’s key findings revealed a nuanced picture — while total protein intake did not directly correlate with sleep quality, a significant positive association was observed with plant protein intake. This suggests that the source of protein — rather than the quantity — may be the most important factor in influencing sleep quality and hints at the potential benefits of plant-based proteins in promoting better sleep.

Plant vs. Animal Protein and Sleep Quality

The research points to a significant difference in how plant and animal proteins each uniquely affect sleep quality.

Plant proteins, found in foods like legumes, nuts, and whole grains, are linked to better sleep outcomes, so opting for plant-based protein sources could be beneficial if you’re struggling with sleep quality. On the other hand, animal proteins — particularly processed red meats and poultry — show a connection to poorer sleep. Interestingly, the study notes that dairy and fish do not exhibit the same adverse effects on sleep as other animal proteins.

While interesting, the actual benefits might not be as tied to protein as they appear on the surface. Underlying differences may be due to the other nutrients found in these proteins. For instance, plant proteins are rich in tryptophan. This amino acid plays a crucial role in the production of sleep-regulating hormones like serotonin and melatonin, which might explain some of the positive impact of plant proteins on sleep quality.

The study indicates a complex relationship between protein sources and sleep and the potential benefits of choosing more plant-based proteins. While total protein intake doesn’t directly correlate with sleep quality, the type of protein — plant vs. animal — appears to make a significant difference.

Enhancing Sleep Quality with Plant Proteins

The specific nutrient profiles of plant proteins can enhance sleep quality. Foods like legumes, nuts, and whole grains are rich in tryptophan and contain a wealth of phytonutrients and other sleep-promoting compounds.

Unlike animal proteins, plant proteins come with a host of other nutrients that collectively contribute to better sleep outcomes. For instance, the fiber in plant-based foods can influence the release of tryptophan into the bloodstream, making it more available to the brain for serotonin and melatonin production.

Tryptophan is an essential amino acid and a major player in sleep regulation. It serves as a precursor to the calming neurotransmitter serotonin and converts into melatonin. Tryptophan is found abundantly in both plant and animal proteins, but plant proteins typically have a slightly better ability to cross the blood-brain barrier. This ability boosts the production of serotonin and melatonin, promoting better sleep quality.

Often called the “sleep hormone,” melatonin is directly involved in the body’s sleep-wake cycle. Its production is influenced by the circadian rhythm, with levels peaking at night to facilitate sleep. Dietary sources of melatonin can bolster the body’s natural production, potentially aiding in the onset and quality of sleep.

Plant-based foods are abundant in phytonutrients, including antioxidants and flavonoids. These compounds may support sleep by taming inflammation and oxidative stress, which can otherwise impair sleep.

Practical Tips for Improving Sleep with Diet

Improving sleep quality through dietary changes is effective, but it doesn’t necessarily require giving up your favorite meats. Other nutritional patterns have solid scientific backing for improving sleep, such as the Mediterranean diet, which is also high in phytonutrients, plant proteins, healthy fats, and fiber. If you are active, eating enough, especially overall protein and vitamin content, is important for healthy sleep patterns and recovery. And being sure to eat all of your big meals during daylight hours and avoiding heavy, greasy foods before bed will also support sleep quality.

You can make a difference by incorporating more plant proteins into your meals while avoiding processed meats and junk foods, which are the ones that harm sleep the most. Here are some practical tips to help you enhance your sleep through diet.

Incorporating More Plant Proteins

Start small: If you’re new to plant-based eating, introduce plant proteins into one meal a day. Consider swapping out your go-to animal proteins for plant-based alternatives such as lentils, chickpeas, or tofu.
Get creative and experiment: Experiment with plant-based recipes that appeal to your taste buds. Try making a hearty lentil stew, a chickpea salad, or a tofu stir-fry, or just exchange some of these ingredients for a portion of animal-based ones.
Snack smart: Opt for something light yet rich in plant proteins for bedtime snacks. A small bowl of almond yogurt with cherries, whole-grain toast with almond butter, or a few pieces of dark chocolate with nuts can satisfy late-night hunger without disrupting sleep.

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1. Wirth, J., Lin, K., Brennan, L. et al. Protein intake and its association with sleep quality: results from 3 prospective cohort studies. Eur J Clin Nutr (2024). https://doi.org/10.1038/s41430-024-01414-y