Nutrition and bone health in the elderly.

Abstract: Osteoporosis is the main threat against bone health in the elderly population leading to fragility fractures of the hip, wrist and vertebrae. Although genetic factors play a major role for peak bone mass, which is determined before the age of 30 years, bone mineral density and bone strength may be influenced later in life. For example, sun exposure provides vitamin D, and physical activity improves bone strength and muscle fitness. Nutrition plays an important role in maintaining bone integrity in senescence. Calcium and vitamin D are crucial nutrients for the bone and usually gain the focus for nutritional measures. Dairy products and fish are rich in calcium, e.g. a glass of milk contains ~300 mg calcium. Oily fish is also rich in vitamin D, and dairy products are often fortified with vitamin D. In the very old (>80 years old) and in institutionalized elderly people supplementation with 1200 mg calcium and 20  μg (800 IU) vitamin D daily is advocated by most regulatory bodies. Whether younger postmenopausal women with manifest or increased risk of osteoporosis should also receive calcium and vitamin D supplementation is today controversial, although such treatment is advocated by many. To prevent secondary hyperparathyroidism and bone resorption circulating vitamin D should never be less than 50 nmol/l. Low body mass index shows a strong correlation to osteoporosis and fracture risk. For the elderly a sufficient energy intake is needed to avoid weight loss and underweight, i.e. BMI 2 . Both low and high protein intakes are associated with osteoporosis. However, recent research advocates a somewhat higher protein intake, e.g. meat and fish, for the elderly than is usually recommended, i.e. 1–1.5 g/kg body weight per day. For the elderly subjects who have sustained a hip fracture and are thin, supplementation with energy and protein is recommended. Fruit and vegetables contain antioxidants and phytoestrogenes, both with potentially beneficial effects on bone health. Although no human intervention studies on fruit and vegetable intake for bone health have been performed, it is safe to follow the general recommendation of five servings or 500 g fruit and vegetables/day. Oily fish contains n-3 fatty acids, which are shown experimentally to have positive effects on bone integrity. As with fruit and vegetables, oily fish is most likely a good component of a healthy diet for the elderly, i.e. 2–3 fish meals per week is recommended. In conclusion, daily intake of dairy products (Calcium+vitamin D), fruit and vegetables (anti-oxidants and phytoestrogenes) combined with fish meals (Calcium+vitamin D+protein+n-3 fatty acids) several times/week in combination with daily outdoor activities providing sun exposure (vitamin D) and physical training (bone and muscle strength) will most likely reduce the fragility fracture risk in the elderly.