What Does Kefir Do to Milk?

The lactic acid bacteria in fermented dairy foods — like kefir and yogurt — turn the lactose into lactic acid, so these foods are much lower in lactose than milk. They also contain enzymes that can help break down the lactose even further.

Why kefir is bad for you?

Kefir can cause side effects like bloating, nausea, intestinal cramping, and constipation, especially when first started. These side effects usually stop with continued use.

What kefir does to milk?

Like yogurt and other cultured and fermented products, milk kefir is full of probiotics, which aid healthy digestion. The fermenting process also changes some of the protein structures in the milk, making it easier to digest. Some people who can't tolerate milk often do better when drinking milk kefir.