Social needs are increasing due to the increase of degenerative brain diseases because of the aging society. The most common type of degenerative brain diseases is Alzheimer's disease and Parkinson's disease, which makes most of cases. New scientific challenges indicate that gut microbiota are directly associated with the progress of degenerative brain diseases through triggering metabolic diseases, modulating immune response, and changing diversity of microbial community. A high-valuable strategy is proposed for the management of these disorders and as an adjuvant for psychiatric treatment of degenerative brain diseases and other related metabolic diseases through modulation of the gut microbiota including probiotics.

We isolated 105 strains of lactic acid bacteria (LAB) from home-made kimchi and breast milk-fed Korean infant feces on the basis of morphological analysis. This study aimed to compare the probiotic characteristics of selected strains of LAB including bile and acid tolerances, cholesterol assimilation and adhesion activity. Among the isolates of LAB, 54 isolates were identified as Lactobacillus plantarum (14 strains), L. brevis (12 strains), L. sakei (9 strains), L. acidophilus (3 strains), L. casei (1 strain), and L. fermentum (1 strain). Acid tolerances under artificial gastric juice, pH 2.5 for 2 h at 37°C, were significantly different among the Lactobacillus species. Lactobacillus acidophilus and L. plantarum strains exhibited high tolerance in acid and bile. Lactobacillus acidophilus strains exhibited high cholesterol assimilation activity and showed a significantly higher tolerance to 0.3% bile acid than other Lactobacillus strains (p<0.05). Based on these results, we selected the best strain, named NS1 (L. acidophilus) as a potential probiotics that can be utilized in the manufacturing of dairy foods and dietary supplements.

Probiotics are defined as live microorganisms that, when administered in adequate amounts, conferred a health benefits on the host by FAO/WHO. Probiotics can help to maintain the balance of microflora in the digestive tracts and these beneficial activities provide prevention from diseases to the host. Bifidobacteria and Lactobacilli strains are most commonly used as probiotics. In many categories, probiotics are applied to different types of products like foods, dietary supplements, functional foods, and even drugs. Fermented dairy products are the most popular and efficient vehicle for administration. Probiotics are part of the much larger functional food and beverage market and one of the prime beneficiaries of the latest growth trend of fortified and functional foods. Until 2011, Japan, U.S, and Western Europe were the largest markets for probiotics, both in terms of consumption as well as growth. Since 2011 however, Asia Pacific, Eastern Europe and Brazil have had a tremendous rise in revenue from probiotics and are expected to remain in the product growth stage over the next five years. The primary reasons for the success of probiotics fortified foods in these markets are the increasing awareness about their potency and efficacy and the willingness of customers to pay extra for something healthy. The global probiotics market revenue was 27.9 billion US dollars in 2011 and is expected to reach 44.9 billion US dollars in 2018 with 6.8% annual growth rate. Growing consumption of fermented milks and increasing concerns over digestive and gut health are major driving forces and these demands has translated into increased R&D spending and new product developments over the last three years.