Our body needs the mineral Calcium to build and maintain bones and teeth, clot blood, transmit nerve impulses, and to regulate the heart’s rhythm. The body gets the calcium it needs from diet or calcium supplements, and from calcium stored in the bones. 99% of the body’s calcium is stored in the bones and teeth.

Dairy products are good sources of highly bioavailable calcium.Inadequate intake of calcium-rich foods will force the body to draw calcium from bones. This loss in calcium need to be replaced to maintain bone health.

Bone is living tissue. It is constantly in the process of being broken down and built up. Osteoblasts are bone cells that build bone, while bone cells called osteoclasts break down bone if calcium is required. Bone production exceeds bone destruction in healthy individuals up to about age 30. After that, breakdown typically exceeds creation.

Osteoporosis is a condition in which bones weaken due to bone destruction exceeding bone creation. Aging typically causes bone losso despite consuming the recommended intake of calcium for optimal bone health.Adequate calcium intake up to age 30) lays the foundation for the future but does prevent bone loss later in life. Bone loss with aging can be attributed to genetic factors, physical inactivity, and lower levels of hormones, estrogen in women and testosterone in men.

Postmenopausal women account for 80% of all cases of osteoporosis because estrogen production declines rapidly at menopause. Men tend to develop osteoporasis 5 to 10 years later than women, since testosterone levels do not fall abruptly the way estrogen does in women. It is estimated that osteoporosis will cause half of all women over age 50 to suffer a fracture of the hip, wrist, or vertebra.

Osteoporosis can be prevented by making the strongest, densest bones for the first 30 years of life and limit bone loss in adulthood and old age. Factors to limit bone loss include regular exercise, especially resistance exercises and adequate calcium, vitamin K, vitamin A and Vitamin D intake.When blood levels of calcium begin to drop, the body converts vitamin D into its active form, which moves to the intestines to encourage greater calcium absorption into the blood, and to the kidneys to minimize calcium loss in the urine.Vitamin K in green, leafy vegetables regulates calcium and bone formation. Low levels of circulating vitamin K is associated with low bone density that leads to hip fractures.Vitamin A directs the process of withdrawing and redepositing calcium in bone.

Moderate consumption of one or two glasses of milk per day of milk in addition to normal diet, benefits bone health. Adequate levels of calcium intake can maximize the positive effect of physical activity on bone health during the child's growing years.

Studies in children and adolescents have shown that supplementation with calcium, dairy calcium-enriched foods or milk enhances the rate of bone mineral acquisition.Calcium and vitamin D supplementation reduces rates of bone loss and also fracture rates in older male and female adults, and the elderly.

A prospective cohort study by Khan et al.(2015) investigated the long-term associations between dietary calcium intake and fractures in 41,514 adults aged 40 to 69 years from the Melbourne Collaborative Cohort Study.There was an inverse relationship between dietary calcium intake and fracture risk;Adults with increased dairy consumption were less likely to have fractures after the age of 50.

Data on 3,251 Caucasian women aged 20 to 90 years from the National Health and Nutrition Examination Survey (NHANES) III were used in a cross-sectional study. The relationship between bone health, including osteoporotic fracture, and childhood and adolescent milk intake was investigated.

Among women aged ≥50 years, low milk intake during childhood, but not adolescence, was associated with a greater likelihood of lifetime and osteoporotic fractures. Among women aged 20 to 49 years, childhood and adolescent milk intake did not appear to be associated with the incidence of lifetime fracture.

In a 2014 prospective cohort study, 5,718 Caucasian adults aged 26 to 85 years from the Framingham Offspring Study were followed for 12 years to study the relationship between milk products and bone mineral density as well as hip fracture.

There was a non-significant inverse relationship between milk intake, as well as that of yogurt, and hip fracture risk;

Participants in the highest one third of fluid dairy intake (milk and yogurt combined) had a 60% lower risk of hip fracture than those in the lowest one third.

The substantial research evidence suggests an inverse association between the consumption of milk and milk products and risks of fractures in men and women.