Abstract: A method of improving sleep in a mammal having a sleep disorder is disclosed. The method includes identifying the mammal having a sleep disorder and then administering Lactobacillus acidophilus CNCM I-2274, Lactobacillus acidophilus CNCM I-2132, Lactobacillus helveticus CNCM I-2275, Streptococcus thermophilus CNCM I-1520, Streptococcus thermophilus CNCM I-2272 or mixtures thereof. The method increases the length of the non rapid eye movement sleep phase and decreases the length of the rapid eye movement sleep phase. The bacteria can be administered in an orally consumable food product or a dietary supplement.

Abstract: Non-pathogenic lactic acid bacteria have cell walls which are susceptible to digestion by muramidase-type enzymes, which produce fragments referred to as muramylpeptides. The ingestion of muramylpeptides, either directly, or by digestion of non-pathogenic lactic acid bacteria, promote sleep and improves the quality of sleep. In particular, non-rapid eye movement sleep phase is enhanced. The muramylpeptide digestion-products of non-pathogenic lactic acid bacteria promote monocyte production of superoxide anion and the cytokines of IL-1&bgr; and TNF&agr;.