Osteoporosis and osteopenia are defined by a decrease in bone mineral density and an increased risk of bone fractures. Causes, in addition to hormonal disorders, may be physical inactivity, smoking and deficiency of a number of micronutrients. Physical inactivity causes the development of osteopenia and osteoporosis not only in the elderly and postmenopausal women, but also in young people. Regular physical activity promotes osteogenesis. The mechanical action of contracting muscles and body weight stimulates the formation and activity of osteoblasts. The main protein of the organic part of the bone is collagen. The inorganic part mainly consists of hydroxyapatite crystals. In this regard, adequate intake of protein, calcium and phosphate is essential for the normal synthesis of bone components. For optimal absorption and metabolism of calcium and phosphate, carotenoids, vitamins D and K are also needed. Magnesium, zinc and fluorine can be included in hydroxyapatite. Normal collagen synthesis is possible with sufficient intake of protein, copper, manganese, silicon, vitamins C and B₁₂. The proliferation and activity of osteoblasts is enhanced by copper, silicon, vitamins D, C and B₁₂, as well as ω-3 polyunsaturated fatty acids. At the same time, zinc, carotenoids, vitamin K and the amino acids leucine, glutamine and tryptophan are necessary to suppress the excessive activity of osteoclasts. Sufficient potassium intake prevents pH drop and bone resorption. At the same time, increased consumption of retinol stimulates the work of osteoclasts. Smoking inhibits the action of vitamin D and parathyroid hormone, which disrupts calcium metabolism, provokes the release of pro-inflammatory factors and enhances bone resorption. Alcohol in large doses intensifies inflammatory reactions in the body. Sleep deprivation is associated with bone loss, probably through increased stress and cortisol production. Prevention of osteoporosis should include adequate nutrition, regular exercise, smoking cessation, and timely diagnosis of bone metabolism disorders.