Lactobacillus casei is a type of bacteria that's found naturally in the human gut, as well as in fermented foods such as yogurt. While people often think of bacteria as being the cause of health problems, Lactobacillus casei—or L. casei, as it is often abbreviated—is what's known as a "probiotic" bacteria, one that has a positive effect on human health.
Lactobacillus casei is one species of Lactobacillus, a large grouping of micro-organisms, or bacteria, that includes many species. Lactobacillus of various types can be found naturally in the human digestive system and urinary tract. They're also common in fermented foods, such as sauerkraut and pickles, and are used in making yogurt and cheeses. As a probiotic bacteria, L. casei can be beneficial to human health in a number of ways.
Various strains of Lactobacillus casei have been found to be useful in treating gastrointestinal issues, on their own or in conjunction with other probiotics. In a study published in 2003 in the "Canadian Journal of Gastroenterology & Hepatology," patients with chronic constipation saw significant improvement when drinking a daily beverage containing the Lactobacillus casei strain L. casei Shirota. In a 2007 study, published in the journal "BMJ," hospital patients consuming a drink containing L. casei, L. bulgaricus and S. thermophilus bacteria had fewer cases of antibiotic- and infection-associated diarrhea.
Other Health Benefits
The makeup of bacteria in the human gut can influence metabolic factors such as weight and insulin levels. A study published in the "Journal of Applied Microbiology" in 2011 showed that the Lactobacillus casei strain Shirota altered the makeup of gut bacteria in obese mice in a way that led to improved insulin resistance. A 2011 study, published in the "International Journal of Rheumatic Diseases," showed that L. casei supplements could alleviate symptoms of rheumatoid arthritis and lower inflammation markers in women with the disease.
L. Casei In the Diet
One of the most common dietary sources of Lactobacillus casei is yogurt. When yogurt is made in a certain way, it retains live bacteria cultures, such as Lactobacillus casei and Lactobacillus acidophilus. To tell whether a yogurt product contains these cultures, look on the ingredient label for the bacteria names, or look for the National Yogurt Association's "Live and Active Cultures" seal. L. casei can also be found in probiotic supplements.