The key is in the isoflavones
Soybeans contain isoflavones, which are similar to the female hormone called estrogen and they can act as partial or total antagonists to endogenous estrogens, phytoestrogens and xenoestrogens. They are also considered antioxidants and inhibitors of proteases, tyrosine kinases and angiogenesis.
Besides their antagonist effect, they can also alter steroid metabolism by inhibiting hydroxysteroid dehydrogenase, steroid alpha-reductase and aromatase. (Barrett, 2006)
New research shows that adding soy in your diet will improve the look of your skin and hair but also benefit those who are experiencing hair loss. A paper on the nutrition of postmenopausal women with hair loss problems suggests soy to be not only an isoflavone source but also as a rich iron source, since hair loss is sometimes associated with a deficit of iron. (Goluch-Koniuszy 2016). The study suggests that a mix of proteins, pantothenic acid, iron, calcium and isoflavones, all found in soy and soy products, allow the prevention of hair loss, while keeping hair fibres strong, thick and maintaining natural hair colour and also delaying hair graying for longer periods of time.
Isoflavones as a DHT blocker
The group that consumed high isoflavone soy protein isolate showed a significant decrease in DHT levels
DHT is known to influence the hair growth cycle: the follicles shrink and they no longer produce hair, the hair begins to fall out as the hair follicle cycle survival is shorter, and in the end, hair will stop being produced and microscopic scarring will result from this process. Current treatment for hair loss includes DHT blockers or vasodilators, but they can come with a huge list of side effects and not all people with hair loss can follow the treatment. There are also alternate solutions, from herbal medicine to topical solutions, but even then, the treatment is not 100% safe and successful for everybody. (Barrett, 2006)
A study in 2005 (Dillingham et al.) showed an inverse association between soy and prostate cancer with some serious implications for hair loss as well. 35 men consumed milk protein isolate, low isoflavone soy protein isolate and high isoflavone soy protein isolate for 57 days. The group that consumed high isoflavone soy protein isolate showed a significant decrease in DHT levels. This means that there is a link between DHT production and dietary supplementation of isoflavone and that regardless of isoflavone content in soy protein, it always reduces DHT levels with only minor effects on other hormones.
Isoflavones as an IGF-1 and hair growth stimulator
There is some evidence that soy proteins may play a role in hair growth – a study on mice (Zhao et al., 2011) showed that dietary isoflavone increases insulin-like growth factor-I production and promotes hair growth. The study lasted 3 weeks in which isoflavone was administered to mice; it significantly increased the immunohistochemical expression of IGF-I in hair follicle dermal papilla cells. Hair regrowth, hair pigmentation and enhancements in the hair follicle morphogenesis were also observed suggesting that isoflavone supplementation might promote hair growth.
Evidence suggests a combination of isoflavones and capsaicin produce best hair growth results
Another study (Naoaki, 2007) showed that the administration of capsaicin and isoflavones promotes hair growth both in mice and humans with hair loss. The volunteers with hair loss who followed a capsaicin and isoflavones diet showed significant hair growth after 5 months of administration due to an increase of IGF-I production in the hair follicles. Isoflavone from soy and soy products achieves this by increasing production of calcitonin gene-related peptide (CGRP), which increases the production of Insulin-like growth factor-I (IGF-I), thus, promoting hair growth.
Isoflavones may also be a powerful anti-ageing tool
The increase in blood vessels led to better circulation of the scalp which helps with hair regrowth
It seems that isoflavones also help with various health issues related to skin and hair. A study on 30 postmenopausal women showed significant health benefits when isoflavones were supplemented by 100mg/day. The results showed that isoflavone treatment increased the epidermis thickness by 9.46% in 23 out of the 30 women who participated in the study; the collagen amount in the skin, as well as the number of elastic fibres, increased. Furthermore, the number of dermal blood vessels was increased significantly, which does suggest that isoflavones have a beneficial effect on the skin and the blood vessels. (Accorsi-Neto et al., 2009)
The increase in blood vessels led to better circulation of the scalp which helps with hair regrowth while the increase in the collagen amount gives hair better flexibility and strength, preventing, dry, brittle damaged hair.
A research paper on the lifestyle and environmental factors that contribute to hair loss, showed that patients from Taiwan who had less soy in their diet were more at risk of develop hair loss. The study investigated the blood and urine heavy metals concentrations, environmental factors, dietary intakes, work hours, sleep patterns, genotypes of certain susceptibility genes and personal behaviour of men aged 35 to 75 years of age. (Lai et al., 2013) The research suggested that isoflavones from soy and soy products prevented hair loss by modulating estrogen dependent mechanisms and reducing inflammatory activity.
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Adding more soy in your diet doesn’t just improve your health and prevent certain cancers but it may also help with hair loss. Tofu, soy milk or texturized soy are easy to add to your diet, either as adjuvants to your hair loss treatment or to see whether they can help you stop hair falling and maintain your existing hair by blocking DHT. Although there isn’t any treatment pattern that may include soy or any big trial study that uses soy as a treatment, soy is a natural and safe ingredient that promises to change the way we see hair loss treatments and the fact that we can approach them from a nutritional level.
References and further reading
- Barrett, J. R. (2006). The Science of Soy: What Do We Really Know?Environmental Health Perspectives, 114(6), A352–A358. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1480510/ S
- Harada, Naoaki et al. Administration of capsaicin and isoflavone promotes hair growth by increasing insulin-like growth factor-I production in mice and in humans with alopecia Growth Hormone & IGF Research , Volume 17 , Issue 5 , 408 – 415 https://www.ncbi.nlm.nih.gov/pubmed/17569567
- Zhao, Juan et al. Dietary isoflavone increases insulin-like growth factor-I production, thereby promoting hair growth in mice Journal of Nutritional Biochemistry , Volume 22 , Issue 3 , 227 – 233 http://www.jnutbio.com/article/S0955-2863%2810%2900050-1/abstract
- Dillingham BL, McVeigh BL, Lampe JW, Duncan AM Soy protein isolates of varying isoflavone content exert minor effects on serum reproductive hormones in healthy young men, J Nutr. 2005 Mar ; 135(3): 584-91 http://www.hubmed.org/display.cgi?uids=15735098
- Accorsi-Neto A, Haidar M, Simões R, Simões M, Soares-Jr J, Baracat E. Effects of isoflavones on the skin of postmenopausal women: a pilot study. Clinics. 2009;64(6):505-10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2705153/pdf/cln64_6p505.pdf
- Lai, C.-H., Chu, N.-F., Chang, C.-W., Wang, S.-L., Yang, H.-C., Chu, C.-M., … Liou, S.-H. (2013). Androgenic Alopecia Is Associated with Less Dietary Soy, Higher Blood Vanadium and rs1160312 1 Polymorphism in Taiwanese Communities. PLoS ONE, 8(12), e79789. http://doi.org/10.1371/journal.pone.0079789 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3875420/
- Jin-Rong Zhou, Lunyin Yu, Ying Zhong and George L. Blackburn Soy Phytochemicals and Tea Bioactive Components Synergistically Inhibit Androgen-Sensitive Human Prostate Tumors in MiceJ. Nutr. 2003 133: 2 516-521 http://jn.nutrition.org/content/133/2/516.full
- Goluch-Koniuszy, Z. S. (2016). Nutrition of women with hair loss problem during the period of menopause. Przegla̜d Menopauzalny = Menopause Review,15(1), 56–61. http://doi.org/10.5114/pm.2016.58776 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4828511/