Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Isoflavone dietary supplement improves the functioning of the arteries in stroke patients

24.09.2008
A dietary supplement containing isoflavone – a chemical found in soybeans, chickpeas, legumes and clovers – can improve artery function in stroke patients according to new research published online in Europe’s leading cardiology journal, the European Heart Journal [1] today (Wednesday 24 September).

The study is believed to be the first randomised controlled trial to investigate the effects of isoflavone supplement on the way the brachial artery (the main artery in the arm) dilates in response to an increase in blood flow – a phenomenon known as flow-mediated dilation (FMD) – in patients with established cardiovascular disease. Brachial FMD is an indicator of the functioning of the cells that line the inner surfaces of blood vessels (vascular endothelium), and endothelial dysfunction is implicated in cardiovascular disease.

Professor Hung-Fat Tse, William MW Mong Professor in Cardiology and Academic Chief of the Cardiology Division in the Department of Medicine, Queen Mary Hospital, The University of Hong Kong (Hong Kong, China) and his team found that 12 weeks of isoflavone supplement, at a dose of 80 mg a day, significantly improved brachial FMD and, therefore, vascular endothelial dysfunction in patients who had suffered an ischaemic stroke (a stroke caused by blood clots or other obstructions).

“These findings may have important implications for the use of isoflavone for secondary prevention in patients with cardiovascular disease, on top of conventional treatments,” the authors wrote in their EHJ paper.

The trial was a double-blind, placebo-controlled trial, involving 50 patients taking the isoflavone supplement, and 52 taking a placebo pill. The researchers measured FMD by using ultrasound to record the performance of the brachial artery as the blood flow returned to normal after having a pneumatic tourniquet on the forearm inflated and then released. FMD was defined as the percentage change in the brachial artery diameter between its normal size (baseline) and one minute after the tourniquet’s deflation.

Eighty per cent of the patients had an impaired FMD of less than 3.7% at the start of the study, but after 12 weeks of isoflavone or placebo, there was an improvement of one per cent in the isoflavone-treated patients compared with the controls.

Prof Tse explained: “Although the absolute increase in brachial diameter – one per cent – is small, the relative increase actually amounted to about 50% because the mean average FMD in these stroke patients was about two per cent. In fact, in patients with severe endothelial dysfunction, there might not be dilatation of brachial diameter at all.”

In their paper, the authors wrote: “The treatment effect of isoflavone in our study was comparable with lifestyle changes with endurance training or pharmacological interventions with statin therapy.”

In addition, the prevalence of impaired FMD after 12 weeks became significantly lower in isoflavone-treated patients than in the controls (isoflavone: 58%, control: 79%). There was also a greater effect in patients with more severe endothelial dysfunction.

“The patients who had a lower initial FMD were found, in general, to respond with a larger absolute increase in FMD after receiving 12 weeks of isoflavone intervention, compared to patients who had a better baseline FMD in the first place,” said Prof Tse. “These findings suggest that isoflavone reverses endothelial dysfunction in this group of patients with cardiovascular disease. This has important clinical implications, as the benefit of the treatment is conferred to the group of patients with the highest risks for cardiovascular events, and this effect persists, even at this rather late stage of the cardiovascular continuum.”

No improvement from isoflavone treatment was found in diabetic patients compared with non-diabetic patients, but there was an improvement of one per cent in patients who were current smokers or who had smoked in the past compared with non- or never smokers. “Since smoking is known to be associated with more severe endothelial dysfunction, this observation was coherent with our hypothesis that patients with worse baseline endothelial function are, in general, more responsive to isoflavone treatment,” said Prof Tse.

The researchers also found that 12 weeks of isoflavone treatment resulted in a significant decrease in levels of high-sensitivity C-reactive protein. This protein increases during systemic inflammation and is an independent predictor of cardiovascular-related events. “These findings suggested that isoflavone treatment alleviated vascular inflammatory stress and was an important component that mediated the reversal of endothelial dysfunction in this group of patients,” wrote the authors.

Prof Tse said that the mechanisms by which isoflavone produces these changes in FMD were not completely understood. Other than the anti-inflammatory effect observed in this study, isoflavone is a major class of phytoestrogens – naturally occurring chemicals that mimic the effect of the human hormone oestrogen. Oestrogen is known to protect against heart disease and so this could be a possible mechanism.

He said it was too early to make clinical recommendations about the use of isoflavone supplements for stroke patients. “Our study implied that diets with higher isoflavone contents might be beneficial in reducing cardiovascular risk in ischaemic stroke patients. Since atherosclerosis is a generalised process, it might be reasonable to propose that a similar effect be observed in other kinds of CVD. However, specific response from different CVD-related conditions requires further testing. At this juncture, regular isoflavone supplement might not be advocated since the benefits and side effects of long-term supplementation are still unknown.

“A balanced diet is still the top priority in promoting health. Diets with higher soy content might be beneficial due to the isoflavone contents. These food products also, in general, have higher contents of polyunsaturated fats, fibre, vitamins and less saturated fat.”

Prof Tse and his colleagues are continuing with prospective studies of isoflavone to see what effect it has on clinical outcomes such as overall survival and the incidence of cardiovascular events.

[1] Reduction of C-reactive protein with isoflavone supplement reverses endothelial dysfunction in patients with ischaemic stroke. European Heart Journal. doi:10.1093/eurheartj/ehn409

Emma Mason | alfa
Further information:
http://www.escardio.org

More articles from Health and Medicine:

nachricht 3D images of cancer cells in the body: Medical physicists from Halle present new method
16.05.2018 | Martin-Luther-Universität Halle-Wittenberg

nachricht Better equipped in the fight against lung cancer
16.05.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>