A new study from Sweden was recently published comparing the health effects of milk to fermented milk products such as cheese, yogurt and kefir.
This large study showed that milk intake was associated with higher rates of osteoporosis and fractures in addition to increases in all causes of death.
Fermented dairy product intake was associated with lower rates of osteoporosis and fractures and decreases in all causes of death.
The cause appears to be a compound called D-Galactose which is a natural sugar found in milk. Chronic exposure to D-Galactose causes deleterious health effects including increased oxidative stress, increased inflammation and decreased immune function. Fermentation naturally degrades most or all of the D-Galactose in the milk.
There is also research linking Vitamin K2 intake to lower rates of osteoporosis and fracture. Fermented milk products happen to be naturally rich in Vitamin K2!