Across two studies, researchers at the University of California Davis (UC Davis) tested the performance of Lactobacillus casei, a probiotic frequently used in yogurt and other dairy products, in the intestine.
In the first, Lactobacillus casei low-temperature, dairy-associated proteome promotes persistence in the mammalian digestive tract, UC Davis researchers compared the effectiveness of milk, milk enriched with Lactobacillus casei, and a non-nutritive medium (supplement) containing the same probiotic strain in preventing symptoms of inflammatory bowel disease (IBD) in mice.
Those mice fed milk enriched with Lactobacillus casei exhibited fewer symptoms of IBD, they found.
"L. case BL23 protected against the development of colitis when ingested in milk but not in a nutrient-free buffer simulating consumption as a nutritional supplement," the study, published in the Journal of Proteome Research, concluded.
"Consuming (acidified) milk alone also provided some protection against weight loss and intestinal inflammation but was not as effective as L. casei and milk in combination."
Maria Marco, an associate professor in the Department of Food Science and Technology at UC Davis, attributed the result to the carbohydrate content of dairy, which supports probiotic growth, and the the potential of such products to protect probiotics from exposure to acidic conditions in the stomach.
"Increased its survival"
In the second study, Attenuation of colitis by Lactobacillus casei BL23 is dependent on the dairy delivery matrix, published in Applied and Environmental Microbiology, UC Davis researchers sought to determine if the low temperature at which dairy products are typically stored better prepares Lactobacillus casei for survival and functionality in the intestine.
The persistence of Lactobacillus casein incubated in refrigerated (4C) and non-refrigerated (37C) milk was compared.
Incubation of Lactobacillus casein in milk at 4C "increased its survival in the mammalian digestive tract," they found.
"These results show that the food matrix can have a profound influence on dietary (probiotic) bacteria and their functional significance in the mammalian gut," the study concluded.
Concluding, Marco added: "Taken together, our findings indicate that the manner in which a probiotic is delivered - whether in food or supplement form - could influence how effective that probiotic is in delivering the desired health benefits."
Source: Journal of Proteome Research DOI: 10.1021/acs.jproteome.5b00387
Title: Lactobacillus casei low-temperature, dairy-associated proteome promotes persistence in the mammalian digestive tract
Authors: B Lee, S Tachon, R Eigenheer, B Phinney, M Marco
Source: Applied and Environmental Microbiology DOI: 10.1128/AEM.01360-15
Title: Attenuation of colitis by Lactobacillus casei BL23 is dependent on the dairy delivery matrix
Authors: B Lee, X Yin, S Griffey, M Marco