What is Bone Health?
Growth of the skeleton is a complex process that begins in the womb and continues into early adulthood. Around 70% of variance in bone mass is associated with genetic factors, but the researchers note that food intake, as well as exercise, lifestyle, keeping a healthy body weight and hormonal status are modifiable factors which are involved in bone health.
How to keep healthy bones?
A balanced diet and daily physical activity are key in stimulating bone health throughout life and preventing the risk for osteoporosis. As they are made of living tissue, it is crucial to consume the right nutrients for strong and healthy bones. The National Osteoporosis Foundation (NOF) released a position statement, providing strong evidence, which supports a positive effect of calcium intake and physical activity on bone accumulation, bone density and growth, especially during the late childhood and peripubertal years, a critical period for bone building.
Good evidence also supports the positive role of vitamin D and dairy consumption on building bone.
Dairy contains a robust nutrient package which are essential for maintaining bone and muscle. These nutrients include calcium, potassium, phosphorus, protein, vitamins A, D, B12 and riboflavin. The dairy food group is a substantial contributor of many of the above nutrients, all of which should work toward promoting bone and muscle health. Dairy, fatty fish, fruits, vegetables (and calcium and vitamin D fortified foods) are considered all as good options for building a bone healthy diet.
Bone Health at each stage of life
As bone formation starts already at the foetal stage, maternal nutrition may stimulate skeleton development. Bone building, size and strength is crucial during childhood and adolescence, when half of our bone mass is accumulated. At this stage, nutritional intake and physical activity support bone health in adulthood. Around the age of 40, we no longer replace bone tissue as quickly as we lose it. And seniors need bone thinning prevention and preservation of the muscle function to reduce the risk of falls and fractures. Each age group needs specific nutrients to support strong bones. Healthy nutrition during childhood, (including yogurt and fermented milk products), is a key driver for strong and healthy bones through life. At all ages, calcium and protein play a key role in bone health, with particular emphasis on bone growth during childhood and adolescence, as well as the preservation of bone strength (and prevention of osteoporosis) in the elderly.
Bone health is a main topic for postmenopausal women
From 50 years of age, postmenopausal women are at an increased risk of developing sarcopenia (a loss of skeletal muscle mass and strength) and osteoporosis as a result of deterioration of musculoskeletal health. Both disorders increase the risk of falls and fractures. This risk may be attenuated through healthy lifestyle changes, which include adequate dietary protein, calcium and vitamin D intakes plus regular physical activity/exercise, and hormone replacement therapy when appropriate.
The European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) recommends optimal dietary protein intake of 1.0–1.2 g/kg body weight/day with at least 20–25 g of high-quality protein at each main meal, with adequate vitamin D intake at 800 IU/day as well as calcium intake of 1000 mg/day, alongside regular physical activity/exercise 3–5 times/week combined with protein intake in close proximity to exercise, in postmenopausal women for prevention of age-related deterioration of musculoskeletal health. Because the type of protein consumed impacts the anabolic response of protein synthesis, the ESCEO TASK Force also advises to consume preferentially high quality protein such as that from dairy source.
Calcium is a key nutrient for Bone Health
Calcium is a major building block for the skeleton: 99% of the Ca kg found in our body is residing in our bones. It provides many vital functions in the body. The daily recommendations have been established primarily on the basis of bone health. This is because bone serves as a reservoir of calcium that helps to maintain normal blood levels of calcium. Since calcium is not produced by the body, you must supply it through your diet. Considering the physiology of the skeletal mineral metabolism, a certain amount of calcium needs to be associated with vitamin D to experience a beneficial impact on bone integrity (and to reduce the risk of hip or other fragility fracture in the elderly). Indeed vitamin D contributes to calcium absorption from food in the intestines and bone mineralization. Calcium-rich foods, combined with vitamin D, are essential to reach daily calcium goals.
Specific role of yogurt in bone health
Consuming fermented milk products such as yogurt is linked with healthy growth of bones when we’re young, reduced bone loss when we’re older, and a lower risk of broken bones in our old age. These benefits seen at all stages of life are achieved through several mechanisms.
The potential for yogurt to promote bone strength and physical function may be due to its unique mixture of macro- and micronutrients with bioactive compounds. It contains high concentrations of bone-promoting vitamins and minerals that have been associated with reduced frailty. It also contains proteins, bioactive peptides, and live bacteria that may contribute to maintaining healthy bones and muscles during aging. Indeed, yogurt contains prebiotics and live bacteria, which may benefit bone health by modifying the gut microbiota and increasing calcium absorption.
Intervention trials have shown that giving fermented dairy products to children and adolescents has a positive influence on their bone health especially their bone mineral density (BMD). A large-scale Irish study(1) showed that increasing yogurt intake was a significant predictor of bone health. Each increase of one serving per week of yogurt intake was associated with a 39% lower risk of osteoporosis in women and a 52% lower risk in men. In an US study(2), researchers concluded that milk and yogurt intake positively influence hip BMD and showed that 4 servings of yogurt weekly may reduce the risk of hip fractures.
Yogurt consumption is recommended to fuel adequate intake of calcium and vitamin D. People who suffer from lactose maldigestion or intolerance avoid dairy foods in general, which increases the risk of calcium deficiency and osteoporosis. Yogurt is the perfect alternative, as it contains live culture and is well tolerated. Furthermore, yogurt is accessible and convenient for consumption by older populations, making it a feasible option for enhancing the nutritional status of older adults.
Laird E, Molloy AM, McNulty H et al. Greater yogurt consumption is associated with increased bone mineral density and physical function in older adults. Osteoporos Int. 2017;28(8):2409-2419.