What is miso soup

Miso soup (misoshiru) is a traditional Japanese soup consisting of a stock called “dashi” into which softened miso paste (fermented soy bean paste) is mixed. Many ingredients are added depending on regional and seasonal recipes, and personal preference ¹. Miso is fermented from a mixture of soybeans with rice, wheat or oats and contains vitamins, microorganisms, salts, minerals, plant proteins, carbohydrates, and fat ². Saponin inhibiting lipid peroxides, trypsin inhibitor, isoflavones, lecithin, colin, prostaglandin E and others are additional substances ¹. The most common dashi soup stocks for miso soup are made of niboshi (dried baby sardines), kombu (dried kelp), katsuobushi (thin shavings of dried and smoked bonito, aka skipjack tuna), or hoshi-shiitake (dried shiitake). The kombu can also be used in combination with katsuobushi or hoshi-shiitake. The kelp and/or shiitake dashi serve as a vegetarian soup stock.

No traditional Japanese meal is complete without miso. Miso is used on a daily basis as a flavor in soup and solid food in Japan and other parts of Asia and is an essential ingredient for Japanese cuisine. The miso paste is used as a seasoning for soups and a host of traditional dishes and has been a key ingredient Japanese diets for centuries. Miso originated in China, before finding its way into Japan in the 7th century where it was gradually transformed into intrinsically Japanese seasoning ¹. In Japan, miso soup and white rice make up the central dishes of the traditional Japanese breakfast.

Types of Miso ¹

• Kome miso (Rice-malt miso): made from soybeans, malted rice and salt
• Mugi miso (Barley-malt miso): made from soybeans, malted barley and salt
• Mame miso (Soybean-malt miso): made from soybeans, malted soybeans and salt

Figure 1. How miso is made

[Source ¹]

Outside Japan, American or European style miso soup is sometimes made by dissolving miso in a Western vegetable stock. The stock might include ingredients such as negi, carrot, potato and daikon radish. In some versions of the dish chicken stock, Western-style fish stock, and other non-dashi bases can even be used, but there is some debate over whether or not miso soups made using these non-traditional bases count as true misoshiru.

Miso is considered to exert health-promoting benefits, relieving fatigue, regulating intestinal functions, aiding digestion, protecting against gastric ulcer, decreasing cholesterol and blood pressure, and preventing diseases associated with the lifestyles, like cancers ².

Table 1. Miso soup (packet) nutrition facts

Nutrient	Unit	PACKET 10 g	Value per 100 g
Approximates
Energy	kcal	35	350
Protein	g	3	30
Total lipid (fat)	g	1	10
Carbohydrate, by difference	g	4	40
Fiber, total dietary	g	0	0
Sugars, total	g	0	0
Minerals
Calcium, Ca	mg	0	0
Iron, Fe	mg	8.82	88.2
Sodium, Na	mg	820	8200
Vitamins
Vitamin C, total ascorbic acid	mg	0	0
Vitamin A, IU	IU	0	0
Lipids
Fatty acids, total saturated	g	0	0
Fatty acids, total trans	g	0	0
Cholesterol	mg	0	0

Ingredients: POWDERED WHITE MISO (ORGANIC SOYBEANS, RICE, SALT), POWDERED RED MISO (ORGANIC SOYBEANS, RICE, SALT), POWDERED SHIITAKE, DEHYDRATED SEAWEED, DEHYDRATED TOFU (SOYBEANS, MAGNESIUM CHLORIDE), YEAST EXTRACT, DEHYDRATED GREEN ONION, POWDERED KONBU

[Source ³]

Table 2. Miso soup (packet), instant vegetarian nutrition facts

Nutrient	Unit	GRM 7.5 g	Value per 100 g
Approximates
Energy	kcal	25	333
Protein	g	2	26.67
Total lipid (fat)	g	1	13.33
Fiber, total dietary	g	1	13.3
Sugars, total	g	3	40
Minerals
Calcium, Ca	mg	0	0
Iron, Fe	mg	0	0
Sodium, Na	mg	380	5067
Vitamins
Vitamin C, total ascorbic acid	mg	0	0
Vitamin A, IU	IU	0	0
Lipids
Fatty acids, total saturated	g	0	0
Fatty acids, total trans	g	0	0
Cholesterol	mg	0	0

Ingredients: DRIED FERMENTED SOYBEAM PASTE (SOYBEAN PASTE (SOYBEANS,RICE,SALT), DRIED GREEN ONION, DRIED TOFU(SOYBEANS ,CALCIUM SULFATE, CORN STARCH , TREHALOSE), YEAST EXTRACT, DRIED SEAWEED,CORN STARCH.

[Source ³]

Is miso soup gluten free?

Gluten is the name given to the protein found in some, but not all, grains:

• Grains containing gluten – wheat (including wheat varieties like spelt, kamut, farro and durum, plus products like bulgar and semolina), barley, rye, triticale.
• Gluten-free grains – corn, millet, rice, oats (uncontaminated), sorghum.
• Gluten-free pseudo-cereals – amaranth, buckwheat, quinoa.

Types of Miso ¹

• Kome miso (Rice-malt miso): made from soybeans, malted rice and salt
• Mugi miso (Barley-malt miso): made from soybeans, malted barley and salt
• Mame miso (Soybean-malt miso): made from soybeans, malted soybeans and salt

So the answer to the question is it depends what type of miso is being used in the making of miso soup.

• Miso soup is gluten free if it’s made from Kome or Mame miso.
• Miso soup is not gluten free if it’s made using Mugi miso (Barley-malt miso).

Miso soup ingredients

According to Japanese custom, the solid ingredients are chosen to reflect the seasons and to provide contrasts of color, texture, and flavor. Thus negi (spring onion) and tofu, a strongly flavored ingredient mixed with a delicately flavored ingredient, are often combined. Ingredients that float, such as wakame seaweed, and ingredients that sink, such as potatoes, are also combined. Ingredients may include mushrooms, potatoes, seaweed, onion, shrimp, fish, clams, and sliced daikon. Nearly any Japanese ingredient is added to some type of misoshiru. However, misoshiru does not typically contain many ingredients beyond the stock and miso.

If pork is added to miso soup, it is called tonjiru, meaning “pork soup”.

Miso soup can be prepared in several ways, depending on the chef and the style of soup. Japanese recipes usually call for most vegetables and meats to be cooked in the simmering dashi, particularly mushrooms, daikon, carrots, potatoes, tofu, and fish. The miso is suspended separately in some dashi stock removed from the simmering mix, to keep the miso paste from cooking, which alters the flavour, kills beneficial bacteria, and reduces the health benefits of biologically active miso paste. When the vegetables are cooked, the stock is removed from heat, the miso suspension is added and mixed into the soup, any uncooked ingredients are added, and the dish is served.

Miso soup health benefits

Generally, 1 bowl of miso soup contains 1 gram of salt and an increase in dietary salt intake is well known to contribute to the elevation of blood pressure ⁴. Reducing the consumption of miso soup and Japanese pickles may be an effective approach for decreasing the level of dietary salt intake in the general Japanese population ⁵. These results suggest the possibility that the habitual consumption of miso soup can lead to increased blood pressure. Furthermore, Anderson et al. ⁶ reported dietary sources of sodium in China, Japan, the United Kingdom, and the United States from the INTERMAP study and that the sodium intakes per day (systolic blood pressure mm) in these countries were 3,990 mg, 4,651 mg, 3,406 mg and 3,660 mg, respectively. In general, excessive sodium intake is a key factor in the epidemic of perhypertension/hypertension and is linked to increased risk of cardiovascular diseases. The American Heart Association recommends no more than 2,300 milligrams (mgs) a day and an ideal limit of no more than 1,500 mg per day for most adults ⁷. Average Americans eat more than 3,400 milligrams of sodium each day. More than 75 percent of the sodium Americans eat comes from some processed, prepackaged and restaurant foods – not from the salt shaker. Because the average American’s sodium intake is so excessive, even cutting back to no more than 2,400 milligrams a day will significantly improve blood pressure and heart health. The guideline to reduce to 1,500 mg doesn’t apply to people who lose big amounts of sodium in sweat, like competitive athletes, and workers exposed to major heat stress, such as foundry workers and fire fighters, or to those directed otherwise by their healthcare provider. If you have a medical conditions or other special dietary needs or restrictions, you should follow the advice of a qualified healthcare professional.

Here are the approximate amounts of sodium in a given amount of table salt:

• 1/4 teaspoon salt = 575 mg sodium
• 1/2 teaspoon salt = 1,150 mg sodium
• 3/4 teaspoon salt = 1,725 mg sodium
• 1 teaspoon salt = 2,300 mg sodium

However, in contrast to the above, this study ⁸ involving 527 Japanese participants with mean age of 60.4 years, results indicate that miso soup consumption might decrease the heart rate, but not have a significant effect on the blood pressure. The subjects who reported a high frequency of miso soup consumption had a lower heart rate ⁸. In addition, the researchers found that the participants who reported a high frequency of miso soup consumption had a lower heart rate, and that the high frequency of miso soup consumption was independently associated with a lower (below the average) relative heart rate. Another Japanese study, Fujita reported ⁹ that taking miso soup together with protein and potassium-rich vegetable as spinach, “wakame”, or seaweed, calcium rich food such as dried sardine and dried bonito; or magnesium such as seaweeds and soybean, prevented increases in blood pressure even in salt-sensitive individual.

In another study on miso soup consumption and breast cancer ¹⁰, in January 1990, 21 852 Japanese female residents (aged 40-59 years) from four public health center areas completed a self-administered questionnaire, which included items about the frequency of soy consumption. Through December 1999 and 209 354 person-years of follow-up, 179 women were diagnosed with breast cancer. Consumption of miso soup and isoflavones, but not of soyfoods, was associated with a reduced risk of breast cancer ¹⁰. What is unusual about this result is that isoflavones also known as phytoestrogens (daidzein, genistein, and glycitein) are active substances that have chemical structures similar to mammalian estrogens ¹¹ are present in soy beans which is the main ingredients of miso or miso soup. Why is consuming miso soup isoflavones be any different to soy foods isoflavones? Other studies have shown soy ¹², ¹³ may protect against chronic diseases. Convincing evidence indicates that the antiestrogenic, anticarcinogenic, anti-inflammatory, and antioxidative properties of isoflavones favorably influence the risk of several cancers in Asian countries as opposed to Western countries, where soy foods are typically not consumed in large amounts ¹⁴, ¹⁵. Given the low breast and prostate cancer mortality rates in soy food–consuming countries like Japan, investigations have understandably focused on these two hormone-dependent malignancies ¹⁶. The similar chemical structure of soybean and soy food isoflavones to that of the mammalian hormone estrogen gives these compounds an antiestrogenic effect and possibly, in turn, an anticarcinogenic effect ¹⁷. Several experimental studies have shown that genistein has a direct inhibitory effect on large-bowel cancer cell growth via its activation of estrogen receptor-β as well as blocking of tyrosine protein kinases and DNA topoisomerases. Other anticancer activities included a decrease in abnormal cellular proliferation and the induction of apoptosis and inhibition angiogenesis ¹⁸.

In cohort study involving intake of isoflavones, miso soup, and soy food in Japan ¹⁹, found the risk of proximal colon cancer in men decreased with increasing consumption of isoflavones, miso soup, and soy food. In contrast, they found no association for distal colon or rectal cancer in men or women. These findings suggest that the intake of isoflavones, miso soup, and soy food may not be associated with the risk of colorectal cancer in Japanese men and women ¹⁹. These epidemiologic findings for dietary soy and isoflavone intake and colorectal cancer risk are partially consistent with the results of a previous cohort study ²⁰ in women, four case-control studies in men and women combined ²¹, ²², ²³, ²⁴, and one case-control study ²⁵ in men and women separately. In the Takayama prospective study ²⁶, soy products showed a dose-dependent inverse association with colon cancer risk. Witte et al. ²¹ reported that higher consumption of tofu was inversely associated with colorectal adenomatous polyps. The Ontario Familial Colorectal Cancer Registry found that isoflavones were associated with a decrease in colorectal cancer risk ²². A case-control study ²³ found that soybean products, except miso soup, reduced colon and rectal cancer separately. Jingfu et al. ²⁴ reported that decreased consumption of bean products was associated with an increase in risk for cancer of the rectum. The results from another case-control study ²⁵ suggested an inverse association between colorectal cancer and soy consumption.

With regard to the possible estrogen-like effect of isoflavones in women, several observational studies investigating the relation between hormone replacement therapy and colorectal cancer have reported a protective effect on colorectal cancer in women ²⁷, ²⁸. The Women’s Health Initiative trial, which included healthy women who received a combined oral estrogen-progestin regimen, confirmed a reduced incidence of colorectal cancer ²⁹. These studies provide evidence that colorectal cancer is a hormone-sensitive malignancy and that phytoestrogens may play an important role in preventing colorectal cancer ³⁰. However, this study ¹⁹ showed no such decrease in colorectal cancer risk by plant estrogen (isoflavones) in either premenopausal or postmenopausal women as well as in women overall.

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