The Phytonutrient Daidzein Has a Lot of Health Benefits
Daidzein (pronounced daed-zeen or daed-zine) belongs to a group of phytonutrients called isoflavones or phytoestrogens. Phytoestrogens have been shown to have many protective effects in hormone-related conditions like menopause, osteoporosis, and heart disease. Daidzein has both oestrogenic and anti-oestrogenic effects, as well as antioxidant properties. Oestrogen, or estrogen, is a steroid hormone released by the ovaries and placenta that induces oestrus, stimulates changes in the female reproductive organs during the oestrous cycle, and promotes development of female secondary sexual characteristics.  Daidzein also has anticarcinogenic, antiatherogenic, and anti-osteoporotic activity. In terms of plant foods, it is most abundant in soy, soy flour, tofu, and miso, among others. 
First things first, we need to talk about how to get the benefits of daidzein. Nutrients—including vitamins, minerals, and phytochemicals—can often be isolated or synthetic. These don’t even come close to natural nutrients in their whole food state; they are not the same. We believe in the synergistic effect of all phytonutrients. Read our helpful resource about how they are different and why natural nutrients, as opposed to isolated or synthetic, are safer and much more beneficial.
One study found that daidzein increased protein content, alkaline phosphatase activity, and DNA content in certain cells. Though, this can be prevented by certain protein synthesis inhibitors. Alkaline phosphatase is an enzyme located in the liver with many functions. For one, it accelerates the hydrolysis (chemical breakdown due to water) of organic phosphate esters (synthetic compounds that are neurotoxic in humans).  Overall, this tells us that daidzein has anabolic effects on cells. Anabolic effects promote muscle building.
Plus, daidzein affects health because it's associated with intestinal bacteria, which are associated with health differences and disease susceptibility. According to Sage Journals, daidzein is metabolized by intestinal bacteria into equol (an estrogen) and O-desmethylangolensin (a phytoestrogen). Production of these two bacterial metabolites has been linked to a reduced risk of certain diseases such as breast and prostate cancers.
In addition, soy has been shown to inhibit tumor numbers in animal models of breast cancer due to its isoflavones. Daidzein, specifically, can inhibit breast cancer and prostate cancer growth in people.
The Journal of Agricultural and Food Chemistry provides that soy consumption has been able to change hormonal characteristics of healthy, premenopausal women in a way that reduces risk factors of breast cancer. In fact, whole soybean consumption by postmenopausal women could be associated with other health benefits, too, like prevention of atherosclerosis progression (build-up of fatty deposits in arteries), lower cancer risks, positive effects on hot flashes, vaginal symptoms, cognitive function or dementia, and bone preservation.
Daidzein prevented bone loss in ovariectomized rats, a model for postmenopausal osteporosis in one study, without any adverse affects on the uterus. It was concluded that isoflavones (including daidzein) have promise in maintaining and improving bone health, particularly bone mass, in humans when consumed at favorable doses.
Daidzein’s potential effect on breast cancer growth is a bit of a slippery slope. Some studies show it may stimulate existing breast tumor growth, and some have since proven that eating normal amounts of soy products is safe as well as beneficial (if one is not allergic).
While it’s been shown that daidzein has weak estrogen-like effects, soy intake has been shown to improve prognosis and recurrence of breast cancer. Moreover, Frontiers in Pharmacology claims that the content of daidzein in soy food is relatively low, and an increased risk of breast cancer only comes after continuous consumption of high-dose isoflavone supplements.
Here at Balance of Nature, we know that consuming plant foods in their whole form is safe, whereas extracts are another story. When we extract chemicals, we get side effects.
Dr . Douglas Howard, founder and formulator of Balance of Nature, said that soy is the most perfect protein that will give us all the essential amino acids (an essential amino acid is something our bodies can’t make, so we have to consume it).
“Soy has the most perfect balance of amino acids for our body. It’s not meat. Egg whites are a perfect protein also,” but “soy is still a better source,” he says. There are countries with billions more people than us with far less breast cancer than us who eat soy every single day.
For example, in Asian countries, soybeans have been eaten for at least a thousand years. This intake is believed to have played an important role in preventing various chronic diseases, certain cancers, osteoporosis, and symptoms of menopause.
Take edamame, for instance. “ ... Edamame isn't processed; it’s just the whole soybean,” says Dr. Howard. “Do not use soy isolates; get whole soy. Soy isolates are hormone precursors, and they can increase some things as isolates.”
Cereals often contain added protein from soy isolates. Ashley Koff, registered dietitian, nutrition expert, and coauthor of Mom Energy: A Simple Plan to Live Fully Charged, explains that, “to create it, the processor takes whole soybean (which is typically a genetically modified organism, or GMO) and removes the essential fatty acids, fiber and other nutrients from the soybean, leaving just the ‘isolate’ soy protein.” So, read your labels and try to choose products that use whole food sources.
In female rats, Toxicological Sciences reported that a diet high in daidzein reduced progesterone but not estrogen levels. A low daidzein-containing diet didn’t. Both daidzein doses resulted in slight decreases in ovarian and uterine weights as well as mammary gland size.
Epigenetic Cancer Therapy says that daidzein is one phytochemical continually undergoing trials for chemotherapeutic and chemopreventive purposes in several cancer subtypes. It is also a modulator of oxidative stress, angiogenesis, cell growth, and apoptosis. Angiogenesis is the formation of new blood vessels. Apoptosis is a regulated process a cell undergoes when dying. Oxidative stress occurs when free radicals damage cells.
According to Stephen Daniells, PhD and editor-in-chief of “NutraIngredients-USA” and “FoodNavigator-USA”, increased levels of daidzein have been linked to improved cholesterol levels and better heart health.
One study revealed that people with favorable lipoprotein profiles also had high blood levels of daidzein. In women, increased levels of daidzein also came with lower levels of triglycerides and higher levels of HDL-cholesterol (the “good” cholesterol).
The Last Bite
The isoflavone daidzein may be involved in a lot of different aspects of health—bone, heart, and hormonal.
Soy foods are a major source of daidzein. Soy consumption in particular has lowered LDL (“bad”) cholesterol levels and prevents buildup in the arteries. We assure that whole soy is good (not soy extracts; there’s a difference)!
Daidzein is also a phytoestrogen and antioxidant used to treat conditions affected by estrogen levels in the body, for instance, by inhibiting the growth of cancerous cells by replacing estrogen. Tofu, raw soy milk, soy flour, miso, and soybeans are also good sources of this phytochemical. Increase your intake of daidzein by adopting more soy foods into your diet.
Go enjoy some soy to reap all the benefits of daidzein!
 Graham S. Smith, Gail L. Walter, and Robin M. Walker, “Practice of Toxicologic Pathology,” Alkaline Phosphatase - an overview | ScienceDirect Topics (Academic Press, 2013), https://www.sciencedirect.com/topics/neuroscience/alkaline-phosphatase.
 Michelle Guignet and Pamela J. Lein, “Role of Inflammation in Environmental Neurotoxicity,” Organophosphate - an overview | ScienceDirect Topics (Advances in Neurotoxicology, 2019), https://www.sciencedirect.com/topics/medicine-and-dentistry/organophosphate.
 Emi Sugimoto and Masayoshi Yamaguchi, “Stimulatory Effect of Daidzein in Osteoblastic MC3T3-E1 Cells,” Biochemical Pharmacology (Elsevier, January 17, 2000), https://www.sciencedirect.com/science/article/abs/pii/S0006295299003512.
 “Performance-Enhancing Drugs: Know the Risks,” Mayo Clinic (Mayo Foundation for Medical Education and Research, May 18, 2019), https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/performance-enhancing-drugs/art-20046134.
 Cara L. Frakenfeld, Charlotte Atkinson, and Johanna W. Lampe, “Gut Bacterial Metabolism of the Soy Isoflavone Daidzein: Exploring the Relevance to Human Health - Charlotte Atkinson, Cara L. Frankenfeld, Johanna W. Lampe, 2005,” SAGE Journals (Experimental Biology and Medicine, March 1, 2005), https://journals.sagepub.com/doi/abs/10.1177/153537020523000302.
 Lori Coward et al., “Genistein, Daidzein, and Their .Beta.-Glycoside Conjugates: Antitumor Isoflavones in Soybean Foods from American and Asian Diets,” ACS Publications (J. Agric. Food Chem., November 1, 1993), https://pubs.acs.org/doi/pdf/10.1021/jf00035a027.
 Lalita Khaodhiar et al., “Daidzein-Rich Isoflavone Aglycones Are Potentially Effective in Reducing Hot Flashes in Menopausal Women,” NCBI (Menopause, 2008), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3207039/.
 Christel Picherit et al., “Daidzein Is More Efficient than Genistein in Preventing Ovariectomy-Induced Bone Loss in Rats,” Oxford Academic (The Journal of Nutrition, July 1, 2000), https://academic.oup.com/jn/article/130/7/1675/4686187.
 Mário L de Lemos, “Effects of Soy Phytoestrogens Genistein and Daidzein on Breast Cancer Growth - Mário L De Lemos, 2001,” SAGE Journals (Annals of Pharmacotherapy, September 1, 2001), https://journals.sagepub.com/doi/abs/10.1345/aph.10257.
 Stefan Poschner et al., “The Impacts of Genistein and Daidzein on Estrogen Conjugations in Human Breast Cancer Cells: A Targeted Metabolomics Approach,” frontiers in Pharmacology (Frontiers in Pharmacology, September 19, 2017), https://www.frontiersin.org/articles/10.3389/fphar.2017.00699/full.
 Weijun Pan et al., “Genistein, Daidzein and Glycitein Inhibit Growth and DNA Synthesis of Aortic Smooth Muscle Cells from Stroke-Prone Spontaneously Hypertensive Rats,” Oxford Academic (The Journal of Nutrition, April 1, 2001), https://academic.oup.com/jn/article/131/4/1154/4686931.
 Ashley Koff, “Why Does My Cereal Have Protein?,” Prevention (Prevention, June 12, 2019), https://www.prevention.com/food-nutrition/healthy-eating/a20446940/nutritional-information-protein-in-cereal/.
 Coral A. Lamartiniere et al., “Daidzein: Bioavailability, Potential for Reproductive Toxicity, and Breast Cancer Chemoprevention in Female Rats,” Oxford Academic (Toxicological Sciences, February 1, 2002), https://academic.oup.com/toxsci/article/65/2/228/1634706.
 Michael Schnekenburger and Marc Diederich, “Nutritional Epigenetic Regulators in the Field of Cancer,” ScienceDirect (Epigenetic Cancer Therapy, 2015), https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/daidzein.
 Stephen Daniells, “Daidzein from Soy Linked to Heart Health Benefits,” NutraIngredients.com (William Reed Business Media Ltd, June 22, 2006), https://www.nutraingredients.com/Article/2006/06/23/Daidzein-from-soy-linked-to-heart-health-benefits.