According to a study published in Stroke, soy protein with isoflavones does not help stave off artery-hardening in postmenopausal women but it may help reduce subclinical atherosclerosis in healthy younger women who are at low-risk for cardiovascular disease.
Research in this area has been contradictory but this study, led by Dr Howard Hodis from the Keck School of Medicine at the University of Southern California in Los Angeles (USA), is the largest and longest randomised controlled human study conducted to-date that directly investigates the efficacy of soy protein isolate consumption on the progression of atherosclerosis (lipid deposition in the artery walls).
In this study 350 postmenopausal women 45-92 years of age without diabetes and cardiovascular disease were randomised to two evenly divided daily doses of 25g soy protein containing 91mg aglycon isoflavone equivalents or placebo for 2.7 years.
Both types of protein were delivered in drink powder and food bars and every six months the researchers tested the women for an ultrasound to measure the build-up in their carotid arteries, the arteries which are responsible for carrying blood to the brain.
The researchers found that carotid artery intima-media thickness progression was reduced on average by 16% in the soy protein group relative to the placebo group but that this treatment effect was not statistically significant (P=0.36).
Among a subgroup of women who were randomised within five years of menopause, the participants taking soy protein had on average a 68% lower carotid artery intima-media thickness progression rate than placebo participants, 2.16 (-1.10 to 5.43) vs 6.79 (3.56-10.01) µm/yr (P=0.05).
The study also showed a significant increase in HDL cholesterol in participants consuming soy protein isolate. Compliance was high suggesting that the soy products, which were supplied by Solae, were palatable. It was also noted that no significant adverse effects were found.
The researchers concluded that although soy protein supplementation did not significantly reduce subclinical atherosclerosis progression in postmenopausal women, it may reduce subclinical atherosclerosis in healthy younger women (median age, 53 years) at low risk for cardiovascular disease who were less than 5 years postmenopausal. Further investigation was recommended.
- If you enjoyed this article, you may also like this: New research supports whey protein for weight management
- Soho Coffee moves into leisure centre market
- Mocon creates four business units to support global footprint
- Food manufacturers welcome first stage funding success