Are probiotic claims justified?

Probiotics are all the rage, promising a happy gut and a host of other health perks. But with so many yogurts, pills, and potions boasting these live cultures, it does make us wonder if the miracle workers are all they're made out to be. / The link between marriage and weight gain (19:06). On the show: Steve Hatherly, Niu Honglin & Yushan