- Email: [email protected]
Effect of Soy Nuts on Adhesion Molecules and Markers of Inflammation in Hypertensive and Normotensive Postmenopausal Women
Effect of Soy Nuts on Adhesion Molecules and Markers of Inflammation in Hypertensive and Normotensive Postmenopausal Women Melita M. Nasca, PhDa, Jin-Rong Zhou, PhDb, and Francine K. Welty, MD, PhDa,* Recently, it was shown that substituting soy nuts for nonsoy protein in a therapeutic lifestyle change (TLC) diet lowered systolic and diastolic blood pressure by 9.9% and 6.8%, respectively, in postmenopausal women with hypertension and by 5.2% and 2.9%, respectively, in normotensive postmenopausal women. In this study, to examine mechanisms for these reductions, markers of inflammation were measured, including soluble vascular cell adhesion molecule–1, soluble intercellular adhesion molecule–1, C-reactive protein, interleukin-6, and matrix metalloproteinase–9. Sixty healthy postmenopausal women (48 normotensive and 12 with hypertension) were randomized in a crossover design to a TLC diet alone or a TLC diet in which 0.5 cups of soy nuts (25 g soy protein and 101 mg aglycone isoflavones) replaced 25 g of nonsoy protein daily. Each diet was followed for 8 weeks. Compared with the TLC diet alone, levels of soluble vascular cell adhesion molecule–1 were significantly lower on the soy diet in women with hypertension (623.6 ⴞ 153.8 vs 553.8 ⴞ 114.4 ng/ml, respectively, p ⴝ 0.003), whereas no significant differences were observed in normotensive women. Soy nuts were associated with a trend toward reduction in C-reactive protein in normotensive women. No effect on levels of soluble intercellular adhesion molecule–1, interleukin-6, or matrix metalloproteinase–9 was observed. In conclusion, the reduction in soluble vascular cell adhesion molecule–1 with soy nuts in women with hypertension suggests an improvement in endothelial function that may reflect an overall improvement in the underlying inflammatory process underlying atherosclerosis. © 2008 Elsevier Inc. All rights reserved. (Am J Cardiol 2008;102:84 – 86) Recently, we showed that substituting soy nuts for nonsoy protein in a therapeutic lifestyle change diet lowered systolic and diastolic blood pressure (BP) by 9.9% (average reduction 15 mm Hg) and 6.8% (average reduction 6 mm Hg), respectively, in postmenopausal women with hypertension and by 5.2% and 2.9%, respectively, in normotensive postmenopausal women.1 In this study, to examine mechanisms, we measured markers of inflammation, including levels of soluble vascular cell adhesion molecule–1 (sVCAM-1), soluble intercellular adhesion molecule–1 (sICAM-1), C-reactive protein (CRP), interleukin-6 (IL-6), and matrix metalloproteinase–9 (MMP-9). Methods and Results Briefly, 60 healthy postmenopausal women without clinical atherosclerosis or diabetes (48 normotensive and 12 with hypertension) were randomized in a crossover design to a therapeutic lifestyle change diet alone or a therapeutic lifea
Division of Cardiology and bNutrition Metabolism Laboratory, Beth Israel Deaconess Medical Center, Boston, Massachusetts. Manuscript received December 22, 2007; revised manuscript received and accepted February 26, 2008. This study was funded by Harvard Medical School’s Center of Excellence in Women’s Health, Boston, Massachusetts (National Institutes of Health, Bethesda, Maryland); Contract 00T002244 from the Office on Women’s Health, United States Department of Health and Human Services, Washington, District of Columbia; and in part by Grant RR01032 to the Beth Israel Deaconess Medical Center General Clinical Research Center from the National Institutes of Health. *Corresponding author: Tel: 617-632-7659; fax: 617-632-9928. E-mail address: [email protected] (F.K. Welty). 0002-9149/08/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.amjcard.2008.02.100
style change diet in which 0.5 cups of soy nuts (25 g soy protein and 101 mg aglycone isoflavones) replaced 25 g of nonsoy protein daily, as previously described.1 Each diet was followed for 8 weeks. At the end of each 8-week period, the women crossed over to the other diet arm. BP measurements were performed with cycling dynamaps at the end of each diet period, with women seated quietly for ⱖ5 minutes in a chair at 60° to 85° with feet on the floor and right arm supported at heart level. Two readings were taken at the beginning of each visit ⱖ30 seconds apart. If there was a difference of ⱖ5 mm Hg in systolic BP between the 2 readings, a third reading was taken. Hypertension was defined as systolic BP ⱖ140 mm Hg and/or diastolic BP ⱖ90 mm Hg. Study subjects were counseled to adhere to their current exercise regimens (if active exercisers) or to walk 30 minutes daily (if sedentary) and not change their exercise throughout the study to prevent a confounding effect of weight change or exercise on study results. Study subjects recorded the number of minutes of exercise performed daily throughout the study. Serum sVCAM-1, sICAM-1, IL-6, and MMP-9 concentrations were measured using enzyme-linked immunosorbent assays (R&D Systems, Minneapolis, Minnesota), as previously described,2 and CRP concentrations were measured with a validated high-sensitivity immunoturbidimetric assay on a Hitachi 917 analyzer (Roche Diagnostics, Indianapolis, Indiana), using reagents and calibrators from DiaSorin (Stillwater, Minnesota), as previously described in Dr. Nader Rifai’s laboratory.3 Data are expressed as mean ⫾ SD. Continuous variables were compared using 2-tailed paired Student’s t tests (within BP group) and unpaired t tests (normotensive to www.AJConline.org
Systemic Hypertension/Soy Nuts and VCAM-1 in Hypertension
85
Table 1 Levels of soluble adhesion molecules and markers of inflammation at the end of each diet period in women with hypertension and normotensive women Variable
Systolic BP (mm Hg) Diastolic BP (mm Hg) sVCAM-1 (ng/ml) sICAM-1 (ng/ml) CRP (mg/dl) IL-6 (ng/ml) MMP-9 (ng/ml)
Normotensive Women (n ⫽ 48)
p Value‡
Women With Hypertension (n ⫽ 12)
Control Diet
Soy Diet
% Change
p Value*
Control Diet
Soy Diet
% Change
p Value†
116 ⫾ 10 69 ⫾ 8 586 ⫾ 108 290 ⫾ 59 0.22 ⫾ 0.45 2.7 ⫾ 1.7 35.2 ⫾ 13.3
110 ⫾ 11 67 ⫾ 7 577 ⫾ 100 291 ⫾ 54 0.16 ⫾ 0.39 2.8 ⫾ 2.1 32.9 ⫾ 9.6
⫺5.2 ⫺2.9 ⫺1.5 ⫹0.6 ⫺27.3 ⫹3.7 ⫺6.5
⬍0.001 0.02 0.35 0.73 0.07 0.38 0.13
152 ⫾ 12 88 ⫾ 7 624 ⫾ 154 269 ⫾ 63 0.20 ⫾ 0.20 2.1 ⫾ 1.1 32.9 ⫾ 11.1
137 ⫾ 15 82 ⫾ 8 554 ⫾ 114 262 ⫾ 52 0.19 ⫾ 0.19 2.5 ⫾ 1.2 33.2 ⫾ 10.2
⫺9.9 ⫺6.8 ⫺11.2 ⫺2.3 ⫺5.0 ⫹19.0 ⫹0.9
0.003 ⬍0.001 0.003 0.41 0.79 0.18 0.75
⬍0.001 ⬍0.001 0.33 0.28 0.90 0.34 0.58
Data are expressed as mean ⫾ SD. * Soy diet compared with control diet in normotensive women. † Soy diet compared with control diet in women with hypertension. ‡ Baseline values in women with hypertension compared with normotensive women.
hypertensive). A p value ⱕ0.05 was considered statistically significant. At baseline, women with hypertension (n ⫽ 12) were significantly older (58.3 ⫾ 6.5 vs 53.5 ⫾ 5.3 years, p ⫽ 0.01), heavier (body mass index 28.0 ⫾ 4.3 vs 25.4 ⫾ 4.9 kg/m2, p ⫽ 0.008), and had experienced menopause for a longer time (7.4 ⫾ 6.1 vs 4.5 ⫾ 4.3 years, p ⫽ 0.01) than normotensive women (n ⫽ 48).1 Caloric intake and percentage intake of saturated fat, monounsaturated fat, polyunsaturated fat, protein, and carbohydrates in the soy and control arms were shown previously.1 Exercise was not significantly different between normotensive and hypertensive women at baseline (156 ⫾ 118 vs 127 ⫾ 120 min/week, respectively, p ⫽ 0.25). No change in exercise or weight occurred in either group of women during the study. Baseline levels of sVCAM-1, sICAM-1, CRP, IL-6, and MMP-9 were not significantly different between women with hypertension and normotensive women (Table 1). Compared with the therapeutic lifestyle change diet alone, levels of sVCAM-1 were significantly lower on the soy diet in women with hypertension (623.6 ⫾ 153.8 vs 553.8 ⫾ 114.4 ng/ml, respectively, p ⫽ 0.003), whereas no significant differences were observed in normotensive women. Soy nuts were associated with a trend toward reduction in CRP in normotensive women. No effect on levels of sICAM-1, IL-6, or MMP-9 were observed. Discussion In the present study, soy nuts were associated with a significant reduction in levels of sVCAM-1 in hypertensive women compared with the control diet. This reduction in sVCAM-1 may reflect an overall improvement in the underlying inflammatory process that is now known to underlie the atherosclerotic process.4 Diets high in saturated fat or glucose increase inflammation and adhesion molecules and lead to insulin resistance, findings proposed to increase BP.5 Therefore, we hypothesized that a whole soy food may lower BP by improving inflammation and thereby improving endothelial function. Our results provide support for this hypothesis. The sole difference in dietary content in the women with hypertension was higher isoflavone levels with soy nuts,
whereas normotensive women had differences in isoflavones and several additional dietary components when consuming the soy nuts.1 Because the 2 groups of women had reductions in BP, these findings suggest that the isoflavone content may be responsible for BP reductions in the 2 groups. Genistein, the main soy isoflavone, has been shown to facilitate nitric oxide– dependent endothelial vasodilation in humans.6 Although we did not measure plasma nitric oxide levels, soy nuts have been shown to increase levels of nitric oxide in normotensive postmenopausal women who had all 5 components of the metabolic syndrome.7 Therefore, it is reasonable to predict that increased levels of nitric oxide may be responsible for the BP reductions in women with hypertension and normotensive women. The trend toward reduction in CRP, a marker of inflammation, in normotensive women provides support for a beneficial effect on inflammation. Soy had no significant effect on levels of IL-6 in the present study in normotensive women, a finding similar to a previous study of postmenopausal women receiving 36 oz soy milk containing 112 mg isoflavones daily for 16 weeks.8 The lack of effect of soy nuts on levels of sVCAM-1 and sICAM-1 in normotensive postmenopausal women in the present study is consistent with 2 previous studies, the first in normotensive, postmenopausal women with mild hypercholesterolemia who underwent a 6-week dietary intervention with 25 g soy protein/day.9 A second study in healthy, normotensive postmenopausal women after an 8-week diet enriched with 50 mg soy isoflavone/day found no effect in the total group; however, those with the AA genotype of the estrogen receptor , ER AluI polymorphism, had lower sVCAM-1 levels.10 1. Welty FK, Lee KS, Lew NS, Zhou JR. Effect of soy nuts on blood pressure and lipid levels in hypertensive, prehypertensive, and normotensive postmenopausal women. Arch Intern Med 2007;167:1060 –1067. 2. Shai I, Pischon T, Hu FB, Ascherio A, Rifai N, Rimm EB. Soluble intercellular adhesion molecules, soluble vascular cell adhesion molecules, and risk of coronary heart disease. Obesity 2006;14:2099 –2106. 3. Roberts WL, Moulton L, Law TC, Farrow G, Cooper-Anderson M, Savory J, Rifai N. Evaluation of nine automated high-sensitivity Creactive protein methods: implications for clinical and epidemiological applications. Part 2. Clin Chem 2001;47:418 – 425.
86
The American Journal of Cardiology (www.AJConline.org)
4. Ross R. Atherosclerosis—an inflammatory disease. N Engl J Med 1999;340:115–126. 5. Delichatsios HK, Welty FK. Influence of the DASH diet and other low-fat, high-carbohydrate diets on blood pressure. Curr Atheroscler Rep 2005;7:446 – 454. 6. Walker HA, Dean TS, Sanders TAB, Jackson G, Ritter JM, Chowienczyk PJ. The phytoestrogen genistein produces acute nitric oxidedependent dilation of human forearm vasculature with similar potency to 17 -estradiol. Circulation 2001;103:258 –262. 7. Azadbakht L, Kimiagar M, Mehrabi Y, Esmaillzadeh A, Hu FB, Willett WC. Soy consumption, markers of inflammation, and endothelial function: a cross-over study in postmenopausal women with the metabolic syndrome. Diabetes Care 2007;30:967–973.
8. Huang Y, Cao S, Nagamani M, Anderson KE, Grady JJ, Lu LJ. Decreased circulating levels of tumor necrosis factor-alpha in postmenopausal women during consumption of soy-containing isoflavones. J Clin Endocrinol Metab 2005;90:3956 –3962. 9. Blum A, Lang N, Peleg A, Vigder F, Israeli P, Gumanovsky M, Lupovitz S, Elgazi A, Ben-Ami M. Effects of oral soy protein on markers of inflammation in postmenopausal women with mild hypercholesterolemia. Am Heart J 2003;145:N1–N4. 10. Hall WL, Vafeiadou K, Hallund J, Bugel S, Koebnick C, Reimann M, Ferrari M, Branca F, Talbot D, Dadd T, et al. Soy-isoflavone-enriched foods and inflammatory biomarkers of cardiovascular disease risk in postmenopausal women: interactions with genotype and equol production. Am J Clin Nutr 2005;82:1260 –1268.
Division of Cardiology and bNutrition Metabolism Laboratory, Beth Israel Deaconess Medical Center, Boston, Massachusetts. Manuscript received December 22, 2007; revised manuscript received and accepted February 26, 2008. This study was funded by Harvard Medical School’s Center of Excellence in Women’s Health, Boston, Massachusetts (National Institutes of Health, Bethesda, Maryland); Contract 00T002244 from the Office on Women’s Health, United States Department of Health and Human Services, Washington, District of Columbia; and in part by Grant RR01032 to the Beth Israel Deaconess Medical Center General Clinical Research Center from the National Institutes of Health. *Corresponding author: Tel: 617-632-7659; fax: 617-632-9928. E-mail address: [email protected] (F.K. Welty). 0002-9149/08/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.amjcard.2008.02.100
style change diet in which 0.5 cups of soy nuts (25 g soy protein and 101 mg aglycone isoflavones) replaced 25 g of nonsoy protein daily, as previously described.1 Each diet was followed for 8 weeks. At the end of each 8-week period, the women crossed over to the other diet arm. BP measurements were performed with cycling dynamaps at the end of each diet period, with women seated quietly for ⱖ5 minutes in a chair at 60° to 85° with feet on the floor and right arm supported at heart level. Two readings were taken at the beginning of each visit ⱖ30 seconds apart. If there was a difference of ⱖ5 mm Hg in systolic BP between the 2 readings, a third reading was taken. Hypertension was defined as systolic BP ⱖ140 mm Hg and/or diastolic BP ⱖ90 mm Hg. Study subjects were counseled to adhere to their current exercise regimens (if active exercisers) or to walk 30 minutes daily (if sedentary) and not change their exercise throughout the study to prevent a confounding effect of weight change or exercise on study results. Study subjects recorded the number of minutes of exercise performed daily throughout the study. Serum sVCAM-1, sICAM-1, IL-6, and MMP-9 concentrations were measured using enzyme-linked immunosorbent assays (R&D Systems, Minneapolis, Minnesota), as previously described,2 and CRP concentrations were measured with a validated high-sensitivity immunoturbidimetric assay on a Hitachi 917 analyzer (Roche Diagnostics, Indianapolis, Indiana), using reagents and calibrators from DiaSorin (Stillwater, Minnesota), as previously described in Dr. Nader Rifai’s laboratory.3 Data are expressed as mean ⫾ SD. Continuous variables were compared using 2-tailed paired Student’s t tests (within BP group) and unpaired t tests (normotensive to www.AJConline.org
Systemic Hypertension/Soy Nuts and VCAM-1 in Hypertension
85
Table 1 Levels of soluble adhesion molecules and markers of inflammation at the end of each diet period in women with hypertension and normotensive women Variable
Systolic BP (mm Hg) Diastolic BP (mm Hg) sVCAM-1 (ng/ml) sICAM-1 (ng/ml) CRP (mg/dl) IL-6 (ng/ml) MMP-9 (ng/ml)
Normotensive Women (n ⫽ 48)
p Value‡
Women With Hypertension (n ⫽ 12)
Control Diet
Soy Diet
% Change
p Value*
Control Diet
Soy Diet
% Change
p Value†
116 ⫾ 10 69 ⫾ 8 586 ⫾ 108 290 ⫾ 59 0.22 ⫾ 0.45 2.7 ⫾ 1.7 35.2 ⫾ 13.3
110 ⫾ 11 67 ⫾ 7 577 ⫾ 100 291 ⫾ 54 0.16 ⫾ 0.39 2.8 ⫾ 2.1 32.9 ⫾ 9.6
⫺5.2 ⫺2.9 ⫺1.5 ⫹0.6 ⫺27.3 ⫹3.7 ⫺6.5
⬍0.001 0.02 0.35 0.73 0.07 0.38 0.13
152 ⫾ 12 88 ⫾ 7 624 ⫾ 154 269 ⫾ 63 0.20 ⫾ 0.20 2.1 ⫾ 1.1 32.9 ⫾ 11.1
137 ⫾ 15 82 ⫾ 8 554 ⫾ 114 262 ⫾ 52 0.19 ⫾ 0.19 2.5 ⫾ 1.2 33.2 ⫾ 10.2
⫺9.9 ⫺6.8 ⫺11.2 ⫺2.3 ⫺5.0 ⫹19.0 ⫹0.9
0.003 ⬍0.001 0.003 0.41 0.79 0.18 0.75
⬍0.001 ⬍0.001 0.33 0.28 0.90 0.34 0.58
Data are expressed as mean ⫾ SD. * Soy diet compared with control diet in normotensive women. † Soy diet compared with control diet in women with hypertension. ‡ Baseline values in women with hypertension compared with normotensive women.
hypertensive). A p value ⱕ0.05 was considered statistically significant. At baseline, women with hypertension (n ⫽ 12) were significantly older (58.3 ⫾ 6.5 vs 53.5 ⫾ 5.3 years, p ⫽ 0.01), heavier (body mass index 28.0 ⫾ 4.3 vs 25.4 ⫾ 4.9 kg/m2, p ⫽ 0.008), and had experienced menopause for a longer time (7.4 ⫾ 6.1 vs 4.5 ⫾ 4.3 years, p ⫽ 0.01) than normotensive women (n ⫽ 48).1 Caloric intake and percentage intake of saturated fat, monounsaturated fat, polyunsaturated fat, protein, and carbohydrates in the soy and control arms were shown previously.1 Exercise was not significantly different between normotensive and hypertensive women at baseline (156 ⫾ 118 vs 127 ⫾ 120 min/week, respectively, p ⫽ 0.25). No change in exercise or weight occurred in either group of women during the study. Baseline levels of sVCAM-1, sICAM-1, CRP, IL-6, and MMP-9 were not significantly different between women with hypertension and normotensive women (Table 1). Compared with the therapeutic lifestyle change diet alone, levels of sVCAM-1 were significantly lower on the soy diet in women with hypertension (623.6 ⫾ 153.8 vs 553.8 ⫾ 114.4 ng/ml, respectively, p ⫽ 0.003), whereas no significant differences were observed in normotensive women. Soy nuts were associated with a trend toward reduction in CRP in normotensive women. No effect on levels of sICAM-1, IL-6, or MMP-9 were observed. Discussion In the present study, soy nuts were associated with a significant reduction in levels of sVCAM-1 in hypertensive women compared with the control diet. This reduction in sVCAM-1 may reflect an overall improvement in the underlying inflammatory process that is now known to underlie the atherosclerotic process.4 Diets high in saturated fat or glucose increase inflammation and adhesion molecules and lead to insulin resistance, findings proposed to increase BP.5 Therefore, we hypothesized that a whole soy food may lower BP by improving inflammation and thereby improving endothelial function. Our results provide support for this hypothesis. The sole difference in dietary content in the women with hypertension was higher isoflavone levels with soy nuts,
whereas normotensive women had differences in isoflavones and several additional dietary components when consuming the soy nuts.1 Because the 2 groups of women had reductions in BP, these findings suggest that the isoflavone content may be responsible for BP reductions in the 2 groups. Genistein, the main soy isoflavone, has been shown to facilitate nitric oxide– dependent endothelial vasodilation in humans.6 Although we did not measure plasma nitric oxide levels, soy nuts have been shown to increase levels of nitric oxide in normotensive postmenopausal women who had all 5 components of the metabolic syndrome.7 Therefore, it is reasonable to predict that increased levels of nitric oxide may be responsible for the BP reductions in women with hypertension and normotensive women. The trend toward reduction in CRP, a marker of inflammation, in normotensive women provides support for a beneficial effect on inflammation. Soy had no significant effect on levels of IL-6 in the present study in normotensive women, a finding similar to a previous study of postmenopausal women receiving 36 oz soy milk containing 112 mg isoflavones daily for 16 weeks.8 The lack of effect of soy nuts on levels of sVCAM-1 and sICAM-1 in normotensive postmenopausal women in the present study is consistent with 2 previous studies, the first in normotensive, postmenopausal women with mild hypercholesterolemia who underwent a 6-week dietary intervention with 25 g soy protein/day.9 A second study in healthy, normotensive postmenopausal women after an 8-week diet enriched with 50 mg soy isoflavone/day found no effect in the total group; however, those with the AA genotype of the estrogen receptor , ER AluI polymorphism, had lower sVCAM-1 levels.10 1. Welty FK, Lee KS, Lew NS, Zhou JR. Effect of soy nuts on blood pressure and lipid levels in hypertensive, prehypertensive, and normotensive postmenopausal women. Arch Intern Med 2007;167:1060 –1067. 2. Shai I, Pischon T, Hu FB, Ascherio A, Rifai N, Rimm EB. Soluble intercellular adhesion molecules, soluble vascular cell adhesion molecules, and risk of coronary heart disease. Obesity 2006;14:2099 –2106. 3. Roberts WL, Moulton L, Law TC, Farrow G, Cooper-Anderson M, Savory J, Rifai N. Evaluation of nine automated high-sensitivity Creactive protein methods: implications for clinical and epidemiological applications. Part 2. Clin Chem 2001;47:418 – 425.
86
The American Journal of Cardiology (www.AJConline.org)
4. Ross R. Atherosclerosis—an inflammatory disease. N Engl J Med 1999;340:115–126. 5. Delichatsios HK, Welty FK. Influence of the DASH diet and other low-fat, high-carbohydrate diets on blood pressure. Curr Atheroscler Rep 2005;7:446 – 454. 6. Walker HA, Dean TS, Sanders TAB, Jackson G, Ritter JM, Chowienczyk PJ. The phytoestrogen genistein produces acute nitric oxidedependent dilation of human forearm vasculature with similar potency to 17 -estradiol. Circulation 2001;103:258 –262. 7. Azadbakht L, Kimiagar M, Mehrabi Y, Esmaillzadeh A, Hu FB, Willett WC. Soy consumption, markers of inflammation, and endothelial function: a cross-over study in postmenopausal women with the metabolic syndrome. Diabetes Care 2007;30:967–973.
8. Huang Y, Cao S, Nagamani M, Anderson KE, Grady JJ, Lu LJ. Decreased circulating levels of tumor necrosis factor-alpha in postmenopausal women during consumption of soy-containing isoflavones. J Clin Endocrinol Metab 2005;90:3956 –3962. 9. Blum A, Lang N, Peleg A, Vigder F, Israeli P, Gumanovsky M, Lupovitz S, Elgazi A, Ben-Ami M. Effects of oral soy protein on markers of inflammation in postmenopausal women with mild hypercholesterolemia. Am Heart J 2003;145:N1–N4. 10. Hall WL, Vafeiadou K, Hallund J, Bugel S, Koebnick C, Reimann M, Ferrari M, Branca F, Talbot D, Dadd T, et al. Soy-isoflavone-enriched foods and inflammatory biomarkers of cardiovascular disease risk in postmenopausal women: interactions with genotype and equol production. Am J Clin Nutr 2005;82:1260 –1268.