MisoI love miso and ironically, I have never had a bowl of miso soup. So what is the problem? Well, if I was on the anti-soy bandwagon created mainly by too many opinions on the internet telling me so, I would not consume miso at all. And this is just another example of how a little misinformation can be spread without much foundation, causing us to lose another beneficial food.

Let’s be clear. I am not talking about miso, made from GMO soy. There is a lot of new research showing that GMO foods are causing health issues and damaging our intestines by interfering with our levels of good bacteria. This is article for another time. So we will leave it out of the conversation. I just want to talk about miso from a plain old soybean, the kind that nature created and that has been consumed for generations. There are many foods created from soybeans, most of them fermented such as tempeh, natto, tamari sauce, soy sauce and of course, miso. And the benefits are numerous.

Research shows that soybeans have the potential to help protect against hypertension, heart disease and cancer especially breast and prostate cancer. They also help the immune system and, strengthen the quality of blood and lymph systems.

Miso, like all soybean products, contains all the essential amino acids, making it a complete protein and it is high in antioxidants. It also is a good plant-based source of B vitamins including B12.

Because it is fermented, miso has three benefits for the gastro intestinal system. It stimulates the secretion of digestive juices in the stomach which help get the digestive process started. It also contains good bacteria to aid the work of the intestines including further helping digestion and the assimilation of nutrients into the body.

Does this sound like a food to be avoided? Some people promote the idea that soy and therefore miso as well, promote estrogen levels in people. Phytoestrogens, which are plentiful in most fruits and vegetables, do not increase estrogen levels. The truth is phytoestrogens have virtually no estrogenic power. Because studies have shown that they help with hot flashes and osteoporosis, there is this assumption that they must increase estrogen levels, even though the causes for these issues are not low estrogen. But that, too, is another article for another time.

Red misoSoy actually contains aromatase inhibitors. Aromatase is an enzyme that promotes the conversion of other hormones to estrogen. Phytoestrogens can also trick the body into thinking estrogen is present by locking onto estrogen receptors sites as in the case of bone building.

Please note that some studies have found that while soy foods show benefits, sometimes the supplements containing isoflavones do not. So we are talking about food here and that is good news. Also interesting is that the isoflavones that anti-soy people tend to focus on are digested by fungus and other organisms that exist in miso as part of the fermentation process. If we are consuming soy that has not been fermented, our gut organism would do the same thing so that we can get the benefit of all the nutrients in soy. So perhaps the caveat should be, unless you are sure about your gut flora and its ability to digest what you need digest, stick with fermented soy like miso and make sure it is non-GMO and preferably organic.

Two great uses for miso this time of year, since soup may not be high on our list of foods to consume during hot weather:

  1. Add it to your vegetable smoothie. It gives the vegetables a nice more rounded flavour and adds beneficial bacteria to the diet
  2. Miso makes a great marinade. Try Chicken in Miso Marinade. Perfect for grilling or sautéing.

References:

  1. Dietary soy and isoflavone intake and risk of colorectal cancer in the Japan public health center-based prospective study. Akhter M, Inoue M, Kurahashi N et al.  Cancer Epidemiol Biomarkers Prev. 2008 Aug;17(8):2128-35. 2008.
  2. Metabolism of the soy isoflavones daidzein and genistein by fungi used in the preparation of various fermented soybean foods. Chang TS, Ding HY, Tai SS et al. Biosci Biotechnol Biochem. 2007 May;71(5):1330-3. Epub 2007 May 7. 2007.
  3. Soy food consumption and risk of prostate cancer: a meta-analysis of observational studies. Hwang YW, Kim SY, Jee SH et al. Nutr Cancer. 2009;61(5):598-606. 2009.
  4. Release of antihypertensive peptides in miso paste during its fermentation, by the addition of casein. J Inoue K, Gotou T, Kitajima H et al. Biosci Bioeng. 2009 Aug;108(2):111-5. 2009.
  5. Association of dietary intake of soy, beans, and isoflavones with risk of cerebral and myocardial infarctions in Japanese populations: the Japan Public Health Center-based (JPHC) study cohort I. Kokubo Y, Iso H, Ishihara J et al.Circulation. 2007 Nov 27;116(22):2553-62. Epub 2007 Nov 19. 2007
  6. Consumption of soy foods and the risk of breast cancer: findings from the Japan Collaborative Cohort (JACC) Study. Nishio K, Niwa Y, Toyoshima H et al. Cancer Causes Control. 2007 Oct;18(8):801-8. Epub 2007 Jul 6. 2007.
  7. Soy processing influences growth of estrogen-dependent breast cancer tumors. Allred CD1, Allred KF, Ju YH, Goeppinger TS, Doerge DR, Helferich WG. Carcinogenesis. 2004 Sep;25(9):1649-57. Epub 2004 May 6.
  8. The effects of dietary phytoestrogens on aromatase activity in human endometrial stromal cells
  9. Katie M. Edmunds et al, Reproductive Biology Division, Department of Obstetrics and Gynecology, McMaster University, Department of Reproductive Medicine, University of California, San Diego, Reprod. Nutr. Dev. 45 (2005) 709–720 709 © INRA, EDP Sciences, 2005
  10. Ipriflavone: an important bone-building isoflavone. Head KA, Altern Med Rev (C2X), 1999 Feb; 4 (1): 10-22