Is Miso Soup Healthy Before Bed? The Science Behind the Sleep Benefits

November 14, 2025 •

4 min read

Studies have shown that consuming fermented foods like miso may promote better sleep quality due to their probiotic content and positive effect on the gut microbiome. However, many wonder: Is miso soup healthy before bed, especially given its high sodium levels?

Quick Summary

This article explores the health implications of consuming miso soup in the evening, detailing how its ingredients can affect sleep, digestion, and hydration.

Key Points

Tryptophan Content: Miso contains the amino acid tryptophan, which the body uses to produce sleep-regulating hormones serotonin and melatonin.
Probiotic Benefits: As a fermented food, miso provides probiotics that support a healthy gut microbiome, which is linked to better sleep quality via the gut-brain axis.
High Sodium Warning: Miso can be very high in sodium, a potential issue that could lead to water retention and disrupt sleep for some individuals.
Histamine Intolerance: Due to its fermentation, miso is high in histamines and should be avoided by those with histamine intolerance, as it can cause sleep-disrupting side effects.
Optimize Your Preparation: To maximize benefits, use low-sodium miso paste, consume it a couple of hours before bed, and ensure proper hydration.
Easily Digestible: The fermentation process makes the protein in miso easier for the body to digest and absorb, which is ideal for a late-night snack.

Miso soup, a staple of Japanese cuisine, has long been revered for its umami flavor and nutritional profile. Made from a fermented soybean paste, it is rich in probiotics, vitamins, and minerals. While its overall health benefits are well-documented, the question of whether it is a good choice before bed requires a closer look at its specific components and their effects on the body's nighttime processes.

How Miso Soup Promotes Better Sleep

The Role of Tryptophan and Melatonin

One of the most compelling reasons to consider miso soup as a bedtime beverage is its amino acid content, specifically tryptophan. Tryptophan is an essential amino acid that the body uses to produce serotonin, a neurotransmitter that regulates mood, and melatonin, the hormone that controls sleep-wake cycles. A warm bowl of miso soup can provide a natural dose of this sleep-inducing amino acid, potentially helping to regulate your body's internal clock and prepare you for rest.

Probiotics and the Gut-Brain Connection

Emerging research continues to highlight the profound connection between gut health and overall well-being, including sleep. The fermentation process used to create miso paste produces beneficial bacteria, known as probiotics, that can support a healthier gut microbiome. A balanced gut can influence the production of neurotransmitters and reduce inflammation, both of which are crucial for regulating sleep. By nourishing your gut with probiotics from miso soup, you may be helping to create a more favorable internal environment for a restful night.

Potential Downsides of Miso Soup Before Bed

The Sodium Content Consideration

While the fermented aspect of miso is beneficial, its high sodium content is a significant drawback, particularly for evening consumption. A single cup of miso soup can contain a considerable amount of salt, which can lead to increased thirst, water retention, and, for some, frequent nighttime urination. This can disrupt sleep patterns and counteract the soothing effects of the warm broth and tryptophan. Individuals with hypertension or those advised to monitor their sodium intake should be especially mindful of this factor.

Histamine Intolerance Concerns

As a fermented product, miso is also high in histamines. For individuals with histamine intolerance, consuming high-histamine foods can trigger a range of symptoms, including headaches, congestion, and digestive issues. These symptoms could easily interfere with sleep, making miso soup a poor choice for those with a sensitivity. If you suspect a histamine intolerance, it's wise to limit or avoid late-night consumption of miso and other fermented products.

Optimizing Your Miso Soup for Evening Consumption

For those who wish to enjoy miso soup before bed, a few adjustments can maximize the benefits while minimizing the downsides:

Choose Low-Sodium Paste: Opt for miso varieties that are explicitly labeled as low-sodium to control your salt intake. Some traditional miso recipes can contain a high level of salt.
Stay Hydrated: Compensate for the sodium by drinking plenty of water throughout the evening, not just after your soup.
Time Your Meal: Consume your miso soup at least an hour or two before going to bed. This allows time for digestion and for your body to process the sodium without interrupting your sleep cycle.
Add Calming Ingredients: Enhance the soup's sleep-promoting properties by adding ingredients known for their calming effects. Examples include mild root vegetables, bok choy, or small pieces of silken tofu.

A Quick Comparison: Miso Soup vs. Other Late-Night Snacks


Feature	Miso Soup	Herbal Tea (e.g., Chamomile)	Bananas	Dairy (e.g., Milk)
Tryptophan Content	High	None	High	High
Probiotic Benefit	Yes, from fermentation	No	No	Some, in yogurt/kefir
Sodium Content	High, can be an issue	Low	Low	Moderate
Digestion	Easy to digest, especially fermented paste	Very easy	Easy	Varies by individual
Melatonin Content	Indirectly boosts via tryptophan	No	Yes	Indirectly boosts via tryptophan
Warmth & Comfort	High	High	Low	High

Conclusion: The Final Verdict on Miso Soup Before Bed

Ultimately, whether miso soup is a healthy choice before bed depends on your individual health profile and how you prepare it. For most healthy individuals, a small, warm bowl of miso soup can be a soothing and nutritious snack that aids digestion and provides sleep-supportive nutrients like tryptophan. However, due to the high sodium content, those with salt-sensitive hypertension or other cardiovascular concerns should approach with caution and opt for low-sodium versions. Pay attention to your body's response, especially concerning potential histamine sensitivity, and consider optimizing your preparation to enjoy the benefits without the drawbacks. The gut-brain axis is a key factor, and a well-prepared, low-sodium miso soup can be a beneficial part of a restful nighttime routine.

For more information on the health benefits of miso and other fermented foods, explore the extensive resources available on the National Institutes of Health website.

Frequently Asked Questions

For many, miso soup can be a good late-night snack due to its tryptophan and probiotic content, which may aid sleep. However, its high sodium can be a drawback, so it is best to use a low-sodium version and consume it an hour or two before bed.

No, miso soup does not contain melatonin directly, but it is rich in the amino acid tryptophan. The body uses tryptophan as a precursor to produce its own serotonin and melatonin, the hormones that regulate sleep.

Yes, the high sodium content in some miso pastes can lead to water retention and increase the need for nighttime urination, which can disrupt a peaceful sleep.

Probiotics in fermented foods like miso support the gut microbiome. A healthy gut is linked to the production of neurotransmitters that influence the brain and sleep-wake cycles, improving overall sleep quality.

Yes, fermented foods, including miso soup, are typically high in histamines. Individuals with histamine intolerance should be cautious, as it can trigger symptoms that disrupt sleep.

The fermentation process breaks down soy proteins, making them easier for the body to digest compared to unfermented soy products. This makes miso soup a relatively easy-to-digest option for a late-night meal.

It is best to consume miso soup at least one to two hours before going to bed. This allows time for digestion and for your body to process the sodium without interrupting your sleep.

To make miso soup healthier for nighttime, use a low-sodium miso paste, add hydrating vegetables, and avoid consuming it right before lying down to minimize the effects of sodium.