Scientists from Chiang Mai University report that daily consumption of synbiotic fermented milk containing Lactobacillus paracasei and inulin for two weeks was associated with a “beverage significantly enhanced oral bioavailability of isoflavones”.
The study’s findings, published in the International Journal of Food Sciences and Nutrition, add to previous data supporting the potential of probiotics to influence the bioavailability of isoflavones, which could have implications for a number of health conditions, including heart health and the maintenance of bone health in post-menopausal women.
Isoflavones are well known phytoestrogens - active substances derived from plants that have a weak estrogen-like action. They have also been studied for their potential role in reducing the risk of certain cancers and slowing down the aging process in peri-menopausal women, and have proved to be a popular alternative to hormone replacement therapy for those wishing to control menopause symptoms without resorting to drugs.
The Thailand-based scientists recruited 12 healthy post-menopausal women to participate in their one-group study. At the start of the study, the women consumed a single 375 mL dose of a soy beverage, and blood samples were collected to measure the bioavailability of the isoflavones. The women then consumed 180 mL of the synbiotic fermented milk after breakfast and dinner for 14 days and then, on day 15, consumed the same quantity of the soy beverage.
Results showed that “continuous consumption of synbiotic fermented milk followed by a single oral administration of soy beverage significantly enhanced oral bioavailability of isoflavones compared with a single oral dose of soy beverage alone”, wrote the researchers.
Gut microbiota modifications and bioavailability
Numerous studies have reported the potential effects of modification of the gut microbiota to alter the absorption and bioavailability of specific nutrients or dietary ingredients. Prebiotics are known to selectively promote the growth of beneficial bacteria in the gut, which in turn produce short chain fatty acids. These fatty acids decrease the pH within the intestine, and improve the solubility of the minerals present. Calcium and magnesium have both been reported to be boosted by prebiotics.
Probiotics, for their part, have recently been reported to improve protein utilization resulting in strength and lean body increases. A study performed with Ganeden BC30 was found to boost leucine uptake into the blood by 23%.
Leucine is the most important amino acid to increase post-workout effects on muscle protein synthesis. A combination of probiotics with protein has been touted as a way to allow athletes to use lower amounts of whey protein without losing the physiological benefit or allow those with lactose allergies or those who are cautious about cholesterol to use protein sources with naturally lower leucine concentration such as soy and rice.
Source: International Journal of Food Sciences and Nutrition
September 2014, Volume 65, Number 6, Pages 761-767, doi: 10.3109/09637486.2014.908169
“Effect of synbiotic fermented milk on oral bioavailability of isoflavones in postmenopausal women”
Authors: P. Timan, N. Rojanasthien, M. Manorot, C. Sangdee, S. Teekachunhatean