Women’s Health Update

by Tori Hudson, ND

Research Update in Cardiovascular Disease

Calcium Not Associated with Coronary Artery Calcification

This paper was a retrospective analysis of data from 2710 men and 1143 women that included 626 postmenopausal women and overall, an average age of 30 or older in Seoul, South Korea. None of the study subjects were taking a calcium supplement and a 24 hour dietary recall was used to assess calcium intake.

Women with the highest calcium intake had lower total cholesterol levels and LDL cholesterol levels compared to those with the lowest calcium intake. With the coronary artery calcium scores (CACS) that were greater than 100 including different calcium intakes, dietary calcium intake was not significantly associated with CACS in either men or women. In addition, there were no negative effects of calcium on fasting glucose, insulin and platelet aggregation relative to all groups of dietary calcium intake. Higher phosphate levels did increase the risk for coronary artery calcification in men.

Commentary:

There has been a longstanding advocacy for adequate dietary and/or supplemental calcium for the prevention and/or treatment of osteoporosis. There is also some evidence that calcium may be able to offer some vascular disease prevention by lowering cholesterol and blood pressure. Observational studies have even shown that women with higher calcium intake had a lower risk for death from cardiovascular disease and ischemic strokes (strokes due to lack of blood flow) when compared to women with lower calcium intake.

The lack of any detrimental effects of calcium on fasting glucose, insulin, and platelet aggregation is reassuring as these are considered mechanisms by which calcium could have a negative impact on cardiovascular disease. Another mechanism by which dietary calcium intake might adversely affect cardiovascular disease is through vascular calcification.

The Women’s Health Initiative demonstrated that <1000 mg calcium supplementation per day did not raise CACS. In the Auckland Calcium Study, calcifications of the aorta were decreased in the group with the highest dietary calcium intake.

However, there have been some recent studies which have demonstrated that there may be a positive relationship between higher blood levels of calcium and the increased risk for cardiovascular disease (myocardial infarction) and stroke, and others which show that calcium supplements might increase the risk of cardiovascular events while dietary calcium does not. Another observation is that the risk for cardiovascular events may be associated with the total of dietary and supplemental calcium intake. In a meta-analysis of 15 randomized blinded placebo-controlled trials, researchers evaluated 12,000 patients who were taking at least 500 mg of calcium supplementation per day (in addition to their dietary intake) and were older than 40. Calcium supplement intake was linked to a 30% increased risk for myocardial infarction. While this is considered only a modest increase, this would translate to about 36 more extra heart attaches of the course of two to five years in 12,000 women. In the midst of this controversy comes this retrospective study that I have reported on today. We may have to rethink and reassess the role of calcium supplements in the prevention and treatment of osteoporosis and perhaps lower the recommendations from a total (diet and supplement) of 1200 mg/day to somewhere around 800 to 900 mg per day to find that sweet spot for bone and heart health without harm to either. Stay tuned for more news to come.

Hee Kim J, Won Yoon J, Won Kim K, et al. Increased dietary calcium intake is not associated with coronary artery calcification. Int J Cardiology. 2012 Jun 14;157(3):429–431.

Cocoa and Chocolate and Cardiovascular Risk Factors: Review and Meta-Analysis

This systematic analysis of randomized clinical trials to assess the effects of cocoa, chocolate or cocoa flavan-3-ols on classic cardiovascular biomarkers included a total of 42 trials and 1297 subjects with relevant outcomes examined cocoa, chocolate, or flavan-3-ols. Twenty-one trials used cocoa drinks, 15 dark or milk chocolate, 3 trials of cocoa supplements, 2 trials of solid chocolate plus cocoa drinks and 1 trial of a diet that included cocoa powder and chocolate.

Biomarkers of cardiovascular disease such as systolic and diastolic blood pressure, lipid profiles, fasting glucose, insulin, triglycerides, hemoglobin A1c (HbA1c), C-reactive protein (CRP), and flow-mediated dilation (FMD) were included. The review was consistent with Cochrane methodology and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. MEDLINE, EMBASE, and the Cochrane Library data bases were used to retrieve controlled parallel or crossover trials.

In this meta-analysis, FMD improved within 2 hours after ingestion of chocolate/cocoa in 11 studies and after chronic intake in 11 studies. There was also a reduction in fasting insulin and serum insulin after a glucose challenge in 2 trials after chocolate or cocoa interventions. There appeared to be no effect on fasting glucose, HbA1c and triglycerides.

Reductions of diastolic blood pressure occurred in 22 trials after chronic intake. There was only a small effect on lowering LDL (−0.07 mmol/L) in 21 studies and HDL (0.03 mmol/L) in 21 studies. No significant effects were seen on CRP, total cholesterol, or systolic BP after acute or chronic intake. There was insufficient information or too few trials to determine effect on body weight, body mass index, and waist circumference.

Comment:

It’s always comforting news when a beloved food shows health benefits. This appears to be true for chocolate, cocoa, black tea, and yes, even coffee, at least up to a point. There are obviously many studies on cocoa and chocolate and individual cardiovascular parameters, but this is the first systematic review and meta-analysis assessing randomized clinical trials on cocoa and chocolate in terms of vital cardiovascular risk factors. In terms of lowering insulin resistance and reduction in insulin secretion, both cocoa and chocolate show benefit. The impact on FMD appears to be clinically significant. The effect on diastolic blood pressure, and marginal effects on LDL and HDL have some small potential for clinical utility. Other than caloric impact of a specific chocolate/cocoa product, this systematic review confirms the value of the judicious use of these dietary and supplemental food items.

Hooper L, Kay C, Abdelhamid A, et al. Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: a systematic review and meta-analysis of randomized trials. Am J Clin Nutr. 2012;95(3):740–751.

Soy Improves Lipid Profiles in Elderly Women with Metabolic Syndrome

This randomized, controlled trial was conducted for 12 weeks. A total of 75 Iranian women, aged 60 to 70 years old who met the criteria of metabolic syndrome with 3 or more of the following: a waist circumference >80 cm, serum high-density lipoprotein cholesterol (HDL-C) <50 mg/dL, triglycerides ≥150 mg/dL, fasting blood glucose ≥100 mg/dL, systolic blood pressure ≥130 mmHg, and diastolic blood pressure ≥85 mmHg. Women were excluded from the study if they were current or previous users of estrogen therapy; were using soy products or supplements, aspirin or antibiotics; had a history of cardiovascular disease, hyperthyroid, hypothyroid, cancer, kidney or liver disease; smoked; or were vegetarians.

Patients were divided and put in one of 3 groups: group A (n = 25) received 35 g/day of soy nuts; group B (n = 25) received 35 g/day of textured soy protein; group C (control; n = 25) received no treatment. Patients were instructed not to change their diet or level of physical activity. They were monitored every 2 weeks for compliance and health status. Blood pressure, dietary intake and physical activity were monitored once per month. Blood tests were taken at baseline and at the end of 12 weeks.

The primary outcome was to evaluate the effects of soy nuts and textured soy protein (TSP) on lipid profiles, apolipoproteins, C-reactive protein, fibrinogen, and blood pressure in elderly women who have metabolic syndrome.

At the end of 12 weeks, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein cholesterol (VLDL-C), and apolipoprotein B100 (Apo B100) were significantly lower in the soy nut group compared with the control group. Textured soy protein resulted in a significant reduction in total cholesterol and LDL-C when compared with the control group.

Soy nuts

TSP

TC mean reduction 20.54 ± 5.9 mg/dL 15.6 ± 6 mg/dL

LDL-C mean reduction 22.27 ± 4.2 mg/dL 19.32 ± 4.2 mg/dL

VLDL-C mean reduction 6.7 ± 1.46 mg/dL 4.65 ± 1.47 mg/dL

Apo B100 mean reduction 0.37 ± 0.05 g/L 0.35 ± 0.05 g/L

The mean change for both TG and HDL-C was not significant in either the soy nut group or the TSP group, although they both did show a reduction greater than the control group, the treatment groups showed more of a reduction than the control group. There were no significant differences in the mean changes in CRP, fibrinogen, or blood pressure in any of the groups.

Comment:

Older women with metabolic syndrome are at significantly higher risk for cardiovascular disease. Soybeans and soy nuts contain isoflavones that have lipid-improving properties and can be one tool and a simple dietary ingredient in improving the lipid profiles of these women. The results of this study are consistent with at least 3 other studies with similar amounts of isoflavones from soy nuts and TSP and cardiovascular health.^1–3

Bakhtiary A, Yassin Z, Hanachi P, Rahmat A, Ahmad Z, Jalali F. Effects of soy on metabolic biomarkers of cardiovascular disease in elderly women with the metabolic syndrome. J Fam Reprod Health. September 2010;4(3):95–104.

Notes

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(10):1060–1067.

2. Matthan NR, Jalbert SM, Ausman LM, Kuvin JT, Karas RH, Lichtenstein AH. Effect of soy protein from differently processed products on cardiovascular disease risk factors and vascular endothelial function in hypercholesterolemic subjects. Am J Clin Nutr. 2007;85(4):960–966.

3. Chen ST, Chen JR, Yang CS, Peng SJ, Ferng SH. Effect of soya protein on serum lipid profile and lipoprotein concentrations in patients undergoing hypercholesterolaemic haemodialysis. Br J Nutr. 2006;95(2):366–371.

Dr. Tori Hudson graduated from the National College of Naturopathic Medicine (NCNM) in 1984 and has served the college in many capacities over the last 28 years. She is currently a clinical professor at NCNM and Bastyr University; has been in practice for over 28 years; and is the medical director of the clinic A Woman’s Time in Portland, OR, and director of research and development for Vitanica, a supplement company for women. She is also a nationally recognized author, speaker, educator, researcher, and clinician.