Biologist s and Investigator Perspective. Has Sloppy Communication Slowed Progress??

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1 Biologist s and Investigator Perspective Has Sloppy Communication Slowed Progress?? Thomas B. Clarkson, D.V.M. Comparative Medicine Clinical Research Center Wake Forest University School of Medicine Winston-Salem, North Carolina

2 Things Change in Seven Years 1999 Soy Health Claim Approved By FDA, October 2, grams of soy protein a day, as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease. 26 An American Heart Association Science Advisory (Circulation 26;113: ) the direct cardiovascular health benefit of soy protein or isoflavone supplements is minimal at best. Effect of doses of soy protein up to 5 grams per day reduced LDL cholesterol ~ 3%; no effect on HDL cholesterol, TGs, Lp(a) or blood pressure.

3 Sloppy Titles No Effect of Oral Soy Supplements --- (capsules containing 325 mg of soy extract were given) Effect of Isoflavone on Plasma --- (tablets containing genistein, daidzein and glycetein were given) Comparison Between Phytoestrogen and Estradiol --- (tablets containing 5 mg of an ethanol extract of red clover were given) Phytoestrogens and Coronary --- (conclusions based on plasma genistein concentrations)

4 Sloppy Intervention Descriptions The third group was supplied isoflavones (Dr. Chung s Food Company Limited, Choongbuk, South Korea) added to the diet at a level of.2% - Was Dr. Chung s powder all isoflavones?? Which ones?? Rabbits received isoflavone free rabbit chow plus a 5 mg tablet containing a concentrated ethanolic extract of Trifolium pretense (red clover) Which isoflavones, what proportion of the 5 mg?? Randomly assigned to receive twice a day either a isoflavone tablet that provided 29.8 mg genistein, 7.8 mg daidzein, 2.4 mg glycitein per tablet or placebo tablets with 25 mg starch per tablet Were these aglycone units or glycosides?? Subjects received either 4 soy or 4 placebo capsules daily for 6 months. Each soy capsule contained 325 mg of soy extract with 17.5 mg of isoflavones (the total dose of isoflavones was thus 7 mg/d What constituted the remaining 37.5 mg of each capsule??

5 Confusion About Isoflavone Dose

6 Accurately Describing Isoflavones There is an increasing convention among investigators to express soy phytoestrogen doses as aglycones to reduce confusion* R 1 R 2 O O Aglycone Isoflavone R 3 CH 2 OH O O OH O OH OH R 2 O R 3 Glycoside Isoflavone Isoflavone R 1 R2 R3 ononin Gluc OH OCH3 sissortrin Gluc - OCH3 genistin Gluc OH OH daidzin Gluc - OH biochanin A OH OH OCH3 formononetin OH - OCH3 genistein OH OH OH daidzein OH - OH Aglycones are the bioavailable form. This represents 7% of the content of products containing glycosides, eg., daidzin and genistin from soy. Promensil contains only aglycone isoflavones daidzein, genistein, formononetin and biochanin. 4mg of Promensil (aglycone isoflavones) is the equivalent of 59mg of glycoside isoflavones from a soy product such as Healthy Woman. *Source Clarkson, Menopause, Vol 7, No 2, 2

7 There is an increasing convention among investigators to express soy phytoestrogen (isoflavone) doses as aglycones to reduce confusion* R 1 R 2 O O R 3 Isoflavone R 1 R2 R3 Pills Aglycone Isoflavone CH 2 OH O O OH OH O OH R 2 O R 3 Glycoside Isoflavone genistein OH OH OH daidzein OH - OH genistin Gluc OH OH daidzin Gluc - OH 31 mg/pill 5 mg/pill *Source Clarkson, Menopause, Vol 7, No 2, 2

8 Bioactive Components of Soy Protein Protein Amino Acids Peptides Globulins Saponins Isoflavones Phytic Acid Protease Inhibitors

9 Research Has Been Hampered by Lack of a Suitable Control for Isolated Soy Protein The Soy ( ) Red Herring

10 Diet Compositions Casein Soy ( ) Soy (+) Protein (%of Cal) Carbohydrate (% of Cal) Fat (% of Cal) Cholesterol (mg/cal) SPE (mg/2 Cal) Soy protein isolates provided by Protein Technologies International

11 Effects of Soy Protein and Isoflavones on Plasma Lipoproteins Expressed as % Difference from Casein Control Group % difference p=.15 Soy(-) LDL+VLDLC p=.1 Soy(+) Adapted from: Anthony et al, Am J Clin Nutr 1998 p=.1 Soy(-) HDLC p=.1 Soy(+)

12 Postmenopausal Cynomolgus Monkeys Study Design B A S E L I N E R A N D O M I Z A T I O N n=2 n=2 n=2 Casein/Lactalbumin Cas/Lact + Isoflavones * Soy (+) * 5 months N E C R O P S Y * Isoflavone dose equivalent to a woman's dose of 145 mg/day Adapted from: Greaves et al, J Nutr 1999

13 Effects of Soy Protein and Purified Isoflavones on LDL and HDL Cholesterol mg/dl 12 LDL Cholesterol b b a mg/dl 4 HDL Cholesterol b a a 6 2 C/L C/L+Iso Soy(+) C/L C/L+Iso Soy(+) Adapted from: Greaves et al, J Nutr 1999

14 Design of Crossover Study Primary Outcomes: Lipids = TPC, LDL+VLDLC, HDLC, Tg IF = total plasma isoflavones OVX female cynomolgus monkeys n = 26 C/L diet Baseline measures IF Response Characterization Baseline 2.1 mg IF/g protein 1% protein from soy 14 mg/18 Cal Wk 3 IF Wk 5 IF Wk 7 Lipids Wk 8 IF Wk 9 Lipids Different Isoflavone concentrations in soy protein isolate Low 2.1 mg/g protein ~37% protein from soy 65 mg IF/18 Cal High 4.6 mg/g protein ~37% protein from soy 141 mg IF/18 Cal Sampling Each Phase High 4.6 mg/g protein ~37% protein from soy 141 mg IF/18 Cal Low 2.1 mg/g protein ~37% protein from soy 65 mg IF/18 Cal Wk 7 Wk 8 Wk 9 Wk 1 Wk 12 IF Lipids IF Lipids Lipids

15 mg/dl mg/dl Comparison of Replacing 1% or 37% of the C/L with Soy Total Plasma Cholesterol C/L Soy Soy (1%) (37%) mg/dl Low Density Lipoprotein Cholesterol + Very Low Density Lipoprotein Cholesterol p <.1 equivalent High Density Lipoprotein Cholesterol p <.1 equivalent p < p =.3 equivalent C/L Soy Soy (1%) (37%) Total Plasma Cholesterol:High Density Lipoprotein Cholesterol equivalent C/L Soy Soy C/L Soy Soy (1%) (37%) (1%) (37%)

16 4 nmol/l 3 nmol/l Plasma Isoflavone Concentrations of Monkeys Fed 37% Of Protein as Low or Hi Isoflavone Soy Protein Total Isoflavones Lo Lo p <.1 Daidzein p =.4 Hi Hi nmol/l nmol/l Lo Lo Genistein p =.21 Equol p <.1 Hi Hi

17 mg/dl mg/dl Despite Pronounced Differences in Plasma IF Concentrations There Were No Differences in Plasma Lipids Total Plasma Cholesterol Lo Lo p =.6 Hi mg/dl Low Density Lipoprotein Cholesterol + Very Low Density Lipoprotein Cholesterol p =.13 Hi High Density Lipoprotein Cholesterol Lo Total Plasma Cholesterol:High Density Lipoprotein Cholesterol Lo p =.22 p =.9 Hi Hi

18 Age and Reproductive Life Stage Are Often Not Considered in Studies of Female Animal Models and Women

19 Design and Outcomes of the Soy Utrecht Trial 22 Postmenopausal Women 6-75 years Mean Age 66 yrs Placebo Milk Proteins 25.6 Gms/day Soy Protein 25.6 Gms/day 52 mg genistein 41 mg daidzein 6 mg glycetin 12 months Outcomes Bone Biomarkers not different Bone Density not different Plasma Lipids not different Cognitive Function not different Modified from Kreijkamp-Kaspers et al, JAMA, 24

20 Hypothetical Change in Plasma Estradiol Concentrations at Different Life Stages* Plasma Estradiol Concentrations Breast Health Benefit of Soy Cardiovascular Benefits of Soy *From Eskin and Troen, Menopause Management, 24

21 Experimental Evidence for Estradiol Soy Interactions as Mediators of Beneficial Health Outcomes Premenopausal women given soy supplements have had significant reductions in plasma concentrations of LDL cholesterol but only during mid-follicular and periovulatory portions of the menstrual cycle (Merz Demlow et al, Am J Clin Nutr, 2). There is a significant (p =.2) soy plus estradiol interaction in reducing atherosclerosis extent (Wagner et al, Metabolism, 1997). A soy plus estradiol interaction (p <.5) in enhancing vascular reactivity (Williams et al, Menopause, 21).

22 Effect of Stage of Menstrual Cycle and Plasma Estradiol Concentrations on Changes in Plasma LDL-C Concentrations of Premenopausal Women Administered Soy Containing Either a Low or High Isoflavone Amount (Data are expressed as difference from control) Plasma LDL-C Conc (mg/dl) Plasma E 2 Conc (pmol/l) -8 p<.2 1 Soy (65) Soy (129) p<.2-1 Cycle Stage Early Follicular Midfollicular Periovulatory Midluteal Modified from Merz-Demlow et al, Modified from Duncan et al, Am J Clin Nutr, 2 J Clin Endocrinol Metab, 1999

23 Effect of Casein (Control), Soy, Casein + E 2 and Soy + E 2 on Atherosclerosis Extent of Postmenopausal Monkeys 1.2 Cholesteryl Ester (mg/g) p =.1 for E 2 main effect p =.2 for soy x E 2 interaction Casein Soy Casein + E 2 Soy + E 2 Modified from Wagner et al, Metabolism, 1997

24 Coronary Artery Vascular Reactivity Some Threshold Plasma Concentration of Estradiol Enables and Interacts with Dietary Soy Treatment in Producing Coronary Artery Vasodilation of Postmenopausal Cynomolgus Monkeys Effect of Dietary Casein vs. Dietary Soy on Coronary Artery Vasodilation of Estrogen Depleted or Estrogen Replaced Postmenopausal Cynomolgus Monkeys % Change in Diameter P=.1 P=.45 P=.1 P=.4 Casein Casein Soy Soy + E 2 + E2 From Williams et al, Menopause, 21

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