Top 10 health benefits of miso

Benefits of miso include:

• Source of protective antioxidants
• May support gut health
• May promote vitamin levels
• May help in the fight against cancer
• May support immune function
• May support brain health
• May help alleviate menopausal symptoms
• May support cholesterol balance
• May support heart health
• May support bone health

Discover our full range of health benefit guides including the health benefits of soya, tofu and tempeh. Get inspired with our collection of miso recipes, from our miso aubergine to our delicious alternative to cheese on toast, miso & spinach toast.

Different varieties of miso

The most common type of miso is made only from soybeans but the variety and ratio of the raw ingredients can vary. Some miso pastes are made from cultured wheat or millet, or combinations of different grains and beans. The colour is a fairly good indicator of the strength of flavour and the texture may vary also, with miso made from wholegrains typically saltier than that made from a hulled grain.

White miso (shiro)

Made from soybeans and rice and fermented for no longer than two months. Shiro ('white' in Japanese) is light in colour and sweet to mildly salty. Shiro is a great ‘gateway’ miso – it's very versatile, providing a bit of oomph to salad dressings or fried vegetables.

Yellow miso (shinsu)

Another mild version that is fermented for slightly longer than white miso. Yellow miso is adaptable in a wide range of recipes.

Red miso (aka)

If a recipe calls for dark miso, you’ll want to use an aka or red miso. Russet in colour, this type is made from a higher proportion of soybeans, fermented for up to three years and has a saltier and deeper flavour. It is best used in hearty dishes like stews and tomato sauces. Use with caution because its flavour can overpower other ingredients.

Barley miso (mugi)

Made from barley and soybeans, mugi miso usually has a longer fermentation process than most white miso. It has a strong barley aroma, but is mild and slightly sweet in flavour.

Nutritional profile of miso

1 tbsp (15g) of miso provides:

• 30kcal / 128kj
• 2.0g protein
• 0.9g fat
• 3.5g carbohydrate
• 0.63mg iron
• 0.49mg zinc
• 5mcg folate
• 1.37g salt

When buying miso, choose the unpasteurised, live, enzyme-rich product that will need to be stored in the fridge – this version is loaded with beneficial microorganisms. After opening, the texture, colour and flavour may change, however, some can be kept for quite a long time without any concerns or variations to quality.

Top 10 health benefits of miso

1. Source of protective antioxidants

Soya beans, from which miso is made, contain natural compounds called isoflavones. These are categorised as a type of antioxidant and as such help minimise the damage known as oxidative stress, which is caused by free radicals. It’s this oxidative stress which is involved in both aging and the onset of chronic disease.

2. May support gut health

The fermentation process, necessary to produce miso, promotes levels of beneficial bacteria. These bacteria are thought to help a range of health issues, including digestion and gut health.

By incorporating a variety of fermented foods in your diet, you may help promote levels of good bacteria and enzymes in your gut, which may in turn improve the balance of microbes as well as the function of your digestive system. When buying miso, choose the unpasteurised, live, enzyme-rich product that will need to be stored in the fridge.

3. May promote vitamin levels

Studies in 1997 and 2013 have confirmed that good bacteria in the gut manufacture vitamins (primarily vitamins K and B12) as a by-product of their metabolism. This means that by improving the balance of your gut microbes you’ll also benefit from a better nutritional status.

The process of fermentation also reduces toxins and anti-nutrients, such as phytic acid in miso, which means we can absorb and use more of the nutrients available to us.

4. May help in the fight against certain cancers

Regular miso consumption is thought to potentially reduce the risk of certain cancers, including breast cancer, especially in post-menopausal women. This is thought to be thanks to the paste’s isoflavone content. Miso is also a rich source of other antioxidants which may further support its protective role in this area. However, more studies are needed to clarify and confirm these benefits.

5. May support immune function

Being a rich source of beneficial bacteria, miso may support immune function and help fight infections. Regularly consuming a variety of fermented foods, like miso, may minimise your need for antibiotic therapy when fighting infection. That said, many of these studies used probiotic supplements rather than fermented foods and more research is needed to assess the benefits of specific strains of bacteria, including those most commonly present in miso.

6. May support brain health

Recent advances in our knowledge and understanding of gut-brain connectivity supports a role for diet and in particular the consumption of fermented foods in cognitive health, including anxiety and depression. Although much has been learned, there is still more to discover before we can definitively define the bacterial strains that may be of most value.

7. May alleviate menopausal symptoms

Soya isoflavones (daidzein and genistein) have attracted a great deal of attention because they are phyto-oestrogens, plant compounds that mimic a weak form of the hormone oestrogen. Some women find including these in their diet helps with peri-menopausal symptoms, including poor mood and hot flushes. However, genetics, your gut microbiota and environmental factors all play a part in how your body reacts to certain foods, so as yet, we can’t say whether a diet rich in phyto-estrogenic foods is beneficial for all women or not.

8. May support cholesterol balance

Soya beans contain phytosterols, these plant compounds are structurally similar to cholesterol and work in the body by inhibiting cholesterol absorption. This explains why regularly eating foods made from soya has been associated with reduced cholesterol levels. Studies also suggest this includes a reduction in low-density lipoprotein (LDL), the type often referred to as ‘bad’ cholesterol, as well as total cholesterol.

9. May support heart health

Regular consumption of legumes, and products made from them, has also been linked to a lower risk of heart disease; this is thought to be because they are a rich source of phytochemicals as well as fibre.

10. May support bone health

Soya foods may be a beneficial inclusion for mid-life women, this is because lower levels of oestrogen after the menopause may lead to a greater reduction in calcium levels in the bone. Some studies suggest that including 40-110mg of soy isoflavones each day may reduce this bone loss and improve bone mineral density. From a practical perspective, this would be the equivalent to eating 35-100g of cooked soya beans or 3-4 tbsp of miso each day, in reality this is best achieved by eating a variety of soy foods daily, given miso’s high salt content.

Is miso safe for everyone?

Miso is generally recognised as safe for most people, unless you follow a low-salt (sodium) diet, then you may wish to limit your intake because miso has high levels. There are some other considerations relevant for certain people, these include:

• Some people may have an allergy to soy protein and will therefore need to avoid miso and other soy-based foods.
• Soybeans are considered to be goitrogenic. This means if you have a thyroid issue you may be advised to minimise your intake. This is because these foods may interfere with the absorption of iodine, which is needed for the production of thyroid hormones. However, it’s worth bearing in mind that you would need to eat a reasonable amount, and on a consistent basis, for this to be an issue.
• Those with coeliac disease must check labels to ensure the miso product is appropriate for them, including having been made in a suitably gluten-free environment.
• If you are on blood-thinning medication such as warfarin, your GP or dietitian may suggest you monitor vitamin K-rich foods like miso in your diet to ensure you eat similar amounts consistently. If in doubt, consult your GP before making any significant changes to what and how much you eat.

Overall, is miso healthy?

Being made from soya beans, miso offers an array of vitamins, minerals and plant compounds, including isoflavones. The fermentation process used to produce miso may be especially helpful as it helps support digestion and may enhance immunity. However, those following a low salt diet, are on prescribed blood thinners or who have a thyroid condition may choose to limit their intake.

Miso recipes to try

Miso soup can provide a tasty base to add other ingredients:
Miso chicken & rice soup
Salmon with miso vegetables

Miso makes a delicious marinade:
Miso-marinated salmon
Miso-glazed tofu steaks with beansprout salad & egg strands

It can also be used to add depth and distinctive flavour to vegetable dishes:
Miso aubergines
Saucy miso mushrooms with udon noodles

Enjoyed this? Read more…

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This article was reviewed on 28 March 2024 by Kerry Torrens.

Jo Williams is a registered nutritionist (RNutr) with the Association for Nutrition with a specialism in public health.

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