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 Plasmonic biosensors enable development of new easy-to-use health tests
14.12.2017 | Aalto University

nachricht ASU scientists develop new, rapid pipeline for antimicrobials
14.12.2017 | Arizona State University

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: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

Guardians of the Gate

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>