11 Physical activity and vitamin D metabolism are also important factors in bone integrity. The balance of these environmental factors, along with genetics, is clearly as important as calcium intake with regard to the risk of osteoporosis and fracture. For most adults, regular milk consumption can be expected to cause gastrointestinal symptoms, while providing no benefit for the bones. These products are enzymatically modified to cleave lactose into glucose and galactose, preventing stomach upset and other symptoms of lactose maldigestion. But even the lactase pills don't solve the problem, as individuals can still experience digestive symptoms.
Iron deficiency is more likely on a dairy-rich diet since cow's milk products are so low in iron.
A recent study linked cow's milk consumption to chronic constipation in children. Women consuming dairy products may have higher rates of infertility and ovarian cancer than those who avoid such products. 16 Susceptibility to cataracts 17 and food allergies are also affected by dairy products. Additionally, samplings of milk have found significant variation in the vitamin D content, with some samplings having had as much as 500 times the indicated level, while others had little or none at all. Too much vitamin D can be toxic and may result in excess calcium levels in the blood and urine, increased aluminum absorption in the body, and calcium deposits in soft tissue.