Milk Consumption and Bone Health

Abstract

Increasing peak bone mass early in life and reducing bone loss later in life are 2 approaches for reducing risk of osteoporosis. This disease of low bone mass and fragility fracture affects a large portion of the elderly population. Milk consumption has long been held as an important strategy for building optimal peak bone mass. Therefore, it is assumed that milk consumption, especially during development of peak bone mass, reduces risk for osteoporosis.There is substantive mechanistic evidence for this inference from a variety of physiological perspectives, including structure-function relationships, homeostatic regulation of serum cations, and bone balance. Bone mineral composition in many respects reflects the mineral composition of milk. The most abundant mineral in bone is calcium, which composes approximately 32% of bone mineral content. Milk and other dairy products provide the majority of dietary calcium in the diets of most populations. Bone mineral acquisition during growth and retention in later life directly relate to calcium intake up to a threshold intake. 1 Other minerals, notably phosphorus and magnesium, are also important constituents in bone. Milk is a major dietary contributor of these minerals, although to a lesser extent than it is for calcium. Maintaining appropriate electrolyte concentrations in the blood and extracellular fluid compartments is essential to support myriad biological functions. If the serum calcium level decreases owing to inadequate calcium intake, parathyroid hormone is released to stimulate bone resorption to return blood calcium levels to the normal range. Long-term low calcium intakes lead to negative bone balance. Bone balance is a net result of bone formation and bone resorption. Increased dietary calcium suppresses bone resorption without altering bone formation rates, thereby improving bone balance. 2 It is not only the calcium in milk that influences bone health. Growing rats fed equal and adequate calcium intakes from milk or calcium carbonate with all of the recommended levels of other nutrients achieved larger, denser, stronger bones on the milk diet, and most of these advantages were retained through adulthood after switching both groups to an inadequate calcium intake provided by calcium carbonate. 3 Feskanich et al 4 report that milk intake during teenage years was associated with an increased risk of adult hip fracture in men (albeit borderline), but not women, in 2 prospective cohort studies. This observation is consistent with some reports of current milk consumption but not typically retrospective studies of milk consumption during growth. In a metaanalysis of prospective cohort studies by many of the same au-

Beneficial Effects of Bovine Milk Exosomes in Metabolic Interorgan Cross-Talk

“…Milk is not only a rich source of calcium and vitamin D3 but also contains different minerals and proteins, such as lactoferrin and whey proteins that are involved in bone remodeling processes [ 142 , 143 , 144 , 145 ]. Although different mechanisms support a positive role of milk intake in bone health and the prevention of bone fractures, some studies have failed to prove these effects [ 146 ]. Nonetheless, milk consists of a complex matrix, and the health effects of individual components might not be completely extrapolated [ 147 ].…”

The Population Attributable Risk of Nutrition and Lifestyle on Hip Fractures

“…Food and nutrition may also play a certain role in the prevention of hip fractures. Dietary calcium through the consumption of milk products is generally assumed to prevent fractures, although there is conflicting epidemiological findings and limited evidence for causation (17). However, the intake of dairy products is high in Nordic regions, and further increased intake may have a limited effect.…”

The potential nutrition-, physical- and health-related benefits of cow’s milk for primary-school-aged children

“…Childhood is a critical time for bone growth and lasting bone health (79,80) , and the nutritional composition of cow's milk has evolved to stimulate and support this (2,5) . The scientific opinion that regular cow's milk consumption is associated with greater physical stature has a long history, dating back to the 1920s (81,82) .…”

“…The scientific opinion that regular cow's milk consumption is associated with greater physical stature has a long history, dating back to the 1920s (81,82) . Cow's milk contains multiple nutrients that may support childhood growth (80) and lasting bone health (79) . The beneficial effects of cow's milk consumption on bone health in children may include increased bone mineral content (BMC) and bone mineral density (BMD), characteristics necessary for the prevention of bone-related diseases later in life (osteoporosis).…”