MP fed C. elegans worms have a weak but significant increase in life-span. -- represents survival of wild-type (N2) animals fed with standard agar; --- represents survival of wild-type animals fed with agar containing 20 μg/ml peptides. Control: n = 40, m = 13; Milk peptides (MP): n = 40, m = 15 (P = 0.0136). n represents the number of animals observed in each experiment. m represents the median adult life span.