Dietary Soy Isoflavone Intake Helps Inflammatory Health in Premenopausal Women

by | Jul 10, 2013 | 2013, Menopause, Soy Isoflavones, Women's Health

Written by Greg Arnold, DC, CSCS. In 259 women those with the highest soy isoflavone intake had 50% lower levels of a marker for inflammation.

Soy contains antioxidants called isoflavones that have been found to maintain a number of health benefits (1). This includes, helping maintain healthy levels of inflammation; a risk factor for chronic diseases like: diabetes (2) and its $174 billion annual costs (3), cancer (4) and its $124.5 billion annual costs (5), and cardiovascular disease (6) and its $444 billion annual costs (7).

Many of the health benefits of soy isoflavones, such as skin health (8) to hormonal health (9), have been shown for postmenopausal women. Now a new study (10) suggests soy isoflavones may also benefit inflammatory health in premenopausal women.

The study involved 259 menstruating women between the ages of 18 and 49 participating in the BioCycle study (11). They provided dietary intake information eight times over the course of two menstrual periods via a questionnaire used in previous research to measure soy isoflavone intake (12). At each of the eight visits, patients provided blood samples to measure C-Reactive protein, an inflammatory protein recently emerged as a reliable marker of inflammation and chronic disease risk in young and older women. C-Reactive protein is a validated predictor of blood vessel disease, even among low-risk subgroups of women with no readily apparent markers of disease (13).

By the end of the two menstrual periods, researchers found a significant association between C-reactive protein levels and soy isoflavone intake.  Specifically, those with the highest 25% of isoflavone intake (1.61-78.8 milligrams per day) had 50% lower levels of C-reactive protein (0.6 vs 1.2 milligram/Liter) compared to those in the lowest 25% of isoflavone intake (0.0-0.3 mg/L) (p = 0.009).

When they further divided the groups into those with low (< 1 mg/L), medium (1-3 mg/L), and high (> 3 mg/L) C-reactive protein levels, they found that compared to the 64 patients with the lowest 25% of isoflavone intake, the 65 patients with the highest 25% of isoflavone intake had:

  • 45.7% more women with low C-reactive protein levels (51 vs. 35 subjects)
  • 41% less women with medium C-reactive protein levels (13 vs. 22 subjects
  • 86% less women with high C-reactive protein levels (1 vs. 7 subjects)

For the researchers, “higher isoflavone consumption among young, healthy women was significantly associated with lower concentrations of C-reactive protein” and “the findings from the present study indicate that dietary isoflavones may have the potential to improve health status among young women.” Despite these positive results, the researchers admit the need for larger studies “to confirm these findings and to extend these results to assess the impact of levels of isoflavone intake among larger populations of women.”

Source: Filiberto, Amanda C., et al. “Habitual dietary isoflavone intake is associated with decreased C-reactive protein concentrations among healthy premenopausal women.” The Journal of nutrition 143.6 (2013): 900-906.

© 2013 American Society for Nutrition.

Posted July 10, 2013.

Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY.  You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com

Reference:

  1. Setchell KD, Cassidy A. Dietary isoflavones: biological effects and relevance to human health. J Nutr. 1999;129 Suppl:758S–67S.
  2. Pradhan AD, Manson JE, Rifai N, Buring JE, Ridker PM. C-reactive protein, interleukin 6, and risk of developing type 2 diabetes mellitus. JAMA. 2001;286:327–34.
  3. “2011 Diabetes Fact Sheet” posted on the Centers for Disease Control and Prevention website.
  4. Heikkila¨ K, Harris R, Lowe G, Rumley A, Yarnell J, Gallacher J, Ben- Shlomo Y, Ebrahim S, Lawlor DA. Associations of circulating C-reactive protein and interleukin-6 with cancer risk: findings from two prospective cohorts and a meta-analysis. Cancer Causes Control. 2009;20:15–26.
  5. “The Cost of Cancer” posted on the National Cancer Institute.
  6. Ridker PM, Buring JE, Shih J, Matias M, Hennekens CH. Prospective study of C-reactive protein and the risk of future cardiovascular events among apparently healthy women. Circulation. 1998;98:731–3.
  7. “Heart Disease and Stroke Prevention: Addressing the Nation’s Leading Killers: At A Glance 2011” posted on the Centers for Disease Control and Prevention Website.
  8. Accorsi-Neto A.  Effects of Isoflavones on the Skin of Postmenopausal Women: A Pilot Study.  Clinics (Sao Paulo). 2009 June; 64(6): 505–510. doi:  10.1590/S1807-59322009000600004.
  9. Kurzer MS.  Hormonal effects of soy isoflavones: studies in premenopausal and postmenopausal women. J Nutr 2000; 130(3): 660S-1S.
  10. Filiberto AC.  Habitual Dietary Isoflavone Intake Is Associated with Decreased C-Reactive Protein Concentrations among Healthy Premenopausal Women.  J. Nutr. 2013:143(6): 900-906 doi:10.3945/jn.112.173187.
  11. Wactawski-Wende J, Schisterman EF, HoveyKM, Howards PP, BrowneRW, Hediger M, Liu A, Trevisan M; BioCycle Study Group. BioCycle Study: design of the longitudinal study of the oxidative stress and hormone variation during the menstrual cycle. Paediatr Perinat Epidemiol. 2009;23:171–84.
  12. USDA, Agricultural Research Service. USDA-Iowa State University database on the isoflavone content of selected foods, release 2.0. Washington: Nutrient Data Laboratory; 2008.
  13. Ridker PM, Buring JE, Shih J, Matias M, Hennekens CH. Prospective study of C-reactive protein and the risk of future cardiovascular events among apparently healthy women. Circulation. 1998;98:731–3.