The study by Lollo et al. said that intense physical activity resulted in a substantial volume of stress, leading to a significant probability of immuno-suppression in athletes, with milk proteins being one of the most recommended protein supplements.
Brazilian product (Minas Frescal cheese) containing Lactobacillus acidophilus LA14 and Bifidobacterium longum BL05 was fed for two weeks to adult Wistar rats, which then were brought to exhaustion on a treadmill.
The aim of the study was to assess the effect that consumption of probiotic cheese could produce on the immune system of the rats submitted to a bout of intense, acute physical exercise.
Exercise was effective in reducing lymphocytes counts in the rats fed probiotic cheese reduced 22% compared with 48% fed common cheese.
Monocytes level decrease
The levels of monocytes, which decreased in the exercised animals consuming the conventional cheese, were normal in both the sedentary and exercised rats that consumer the probiotic cheese.
For animals fed the probiotic cheese, the changes in monocyte counts after exhaustion did not differ statistically from those of the non exercised rats, regardless of cheese type.
A significant decrease in the monocyte counts was found in rats fed the common cheese and submitted to exhaustive exercise.
The research team found probiotic cheese caused a 100% increase in high-density lipoprotein (HDL) and exercise decreased triacylglycerols (TAG) by 50%. However, in the rats exercised to exhaustion the lipid profiles did not vary significantly.
The rats were split into four groups, depending on a diet of probiotic or conventional cheese, and whether they were exercised or not.
Neutrophil rate higher
In rats fed probiotic cheese the neutrophil: lymphocyte rate was 2.2-fold higher after exhaustive exercise, where as the common cheese group the ratio was 3.5-fold indicating the inflammatory state occurring after lasting exercise may be lowered due to consumption of probiotics.
The researchers observed an increase in the concentration of neutrophils for rats fed both cheese types but the basal and post exhaustion levels were significantly lower for rats fed probiotic cheese compared with those fed common cheese.
“Therefore, it is possible that part of the immune changes that were seen in this study were actually related to intrinsic changes in the levels of lipids caused by the ingestion of probiotics,” said the authors.
“We conclude that probiotic Minas Frescal cheese may be a viable alternative to enhance the immune system and could be used to prevent infections, particularly those related to the physical overexertion of athletes.”
The researchers said only 14 immunological parameters were analysed but further studies exploring additional parameters such as cytokines and hormone responses to probiotic cheese and exhaustive exercise could improve subject area knowledge.
Further studies should explore the probiotic supplementation of other food matrices such as whey beverages and dairy desserts, they added.
Source: Journal of Dairy Science
Published online ahead of print, doi: 10.3168/jds.2011-5124
“Probiotic cheese attenuates exercise-induced immune suppression in Wistar rats.”
Authors: P. C. B. Lollo, A. G. Cruz, P. N. Morato, C. S. Moura, L. B. Carvalho-Silva, C. A. F. Oliveira, J. A. F. Faria and J. Amaya-Farfan