Bones are growing and constantly changing
Both during bone growth in children and adolescents and after a bone fracture, bone tissue initially forms, known as woven bone. Because it is built up quickly, its structure is still disorganized. The collagen fibers, which are not yet aligned, are also poorly mineralized and therefore less stable. Once the bone has grown to a certain size, the body gradually replaces the woven bone with what is known as lamellar bone. This consists of spongy tissue inside the bone (substantia spongiosa) and the harder, denser outer layer (substantia compacta). “Spongy” may sound less stable, but just as support beams in house construction are positioned exactly where they need to be to stabilize the building, the alignment of fibers in lamellar bone follows the forces acting on the bone to make it as stable as possible.
Put simply, bone growth in children and the maintenance of bones in adults mainly depend on the activity of two different bone cells: osteoblasts and osteoclasts. Osteoblasts produce bone substance and ensure it is mineralized (i.e., hardened), while osteoclasts are responsible for breaking down excess bone tissue. In this way, osteoclasts prevent uncontrolled bone growth on the one hand and, on the other, play an important role in converting woven bone into lamellar bone. Even after bone growth itself is complete, bones remain in constant remodeling throughout life to adapt to current demands, such as changing loads.
A whole range of hormones are involved in bone growth, including parathyroid hormone, calcitonin and, above all, the female sex hormone estrogen. They influence bone formation in many ways and are involved in the hardening (mineralization) of bone.
To produce robust bone tissue, osteoblasts need certain building blocks. They produce collagen as a base, which is then mineralized, i.e., hardened. In short, phosphates and calcium are incorporated into the bone to make it more stable. Without enough vitamin D, however, the body cannot absorb sufficient calcium from food for bone formation. If bone mineralization is disrupted, this is called rickets in children. The condition leads to unstable (“soft”) bones, which can cause pain and may even result in bone deformities. A common cause is vitamin D deficiency. Adults can also develop softening of the bones if the body does not have enough vitamin D, calcium or phosphorus available. In this case, the condition is called osteomalacia.
A balanced diet is therefore also important for bone growth. Calcium is found, for example, in milk and dairy products, but also in vegetables such as broccoli, kale and arugula, as well as certain mineral waters. Phosphates occur in almost all foods, so a deficiency usually only arises due to insufficient intake from the diet—for example, if there is not enough vitamin D. Dietary sources of vitamin D are mainly fortified foods such as margarine, certain fatty fish and types of mushrooms, cheese and eggs.
Infants and toddlers in particular need relatively large amounts of vitamin D because they are growing, but it is usually found only in small amounts in foods. Our bodies can produce vitamin D themselves, but only when we are exposed to sunlight. However, infants and toddlers should not be exposed to strong sunlight, and depending on the region and weather there may be only a few hours of sun. Therefore—especially in the winter months—it may be advisable to have vitamin D levels checked by a doctor and, if necessary, seek advice about a vitamin supplement. During the child’s first year of life, and sometimes the second as well, parents receive a vitamin D supplement from the pediatrician’s office to cover the increased vitamin D requirement during this developmental phase.
Although proteins do not directly speed up or promote bone growth, adequate protein intake from food is just as important for building bone as it is for building muscle. That’s because proteins contain amino acids, the body’s basic building blocks. Protein deficiency is rare in industrialized countries such as Germany. There are other nutrients that are important for healthy, strong bones in both children and adults, such as magnesium, vitamin K and zinc. A balanced diet that provides all essential nutrients is therefore crucial for bone formation. People with a restricted diet should pay particular attention to eating a balanced diet.
3. Exercise is healthy at any age. Studies show that playing sports at a young age can have long-term positive effects on bone health even after you stop. Those who dedicate their youth to professional sports therefore have, on average, a lower risk of bone fractures later in life. But how exactly does exercise strengthen our bones? The basis is the continuous rebuilding of bone.
In childhood, our bones are built up once and grow to their final size as we mature into adults. But even when it’s no longer bone growth, our skeleton can still adapt to the stresses of everyday life. Every physical load a bone experiences sends our body a signal about what function the bone serves—or should serve. If, for example, we regularly jump rope, each impact on the ground signals that the bones in our legs are experiencing a certain load. Accordingly, the structure of the bones can adapt to that load to withstand it better.
While high-impact movements such as jump rope, CrossFit or tennis strengthen bones particularly well, overuse isn’t good either. With any athletic activity, it’s important to take breaks and minimize the risk of injury.
Liquid Calcium with Magnesium
*Calcium and vitamin D are needed for healthy growth and bone development in children. Additionally, magnesium, vitamin K, and zinc support the maintenance of healthy bones.
Who is at particularly high risk of vitamin D insufficiency?
A whole range of factors influence the body’s production of vitamin D (cholecalciferol), including how often we are exposed to direct sunlight, how strong it is, what clothing we wear, and how much pigment our skin contains. People at particularly high risk of developing a vitamin D deficiency include:
Sunscreen also reduces vitamin D production because it blocks some of the sunlight. However, the benefits—preventing skin damage and reducing cancer risk—outweigh this, so sun protection should not be skipped. Vitamin D can also be stored to a certain extent, which is why vitamin D produced in summer can sometimes be enough through the winter months. If you are concerned that your vitamin D supply is too low, you can have your blood vitamin D level checked at your family doctor’s practice.
While rickets is a condition that typically affects children and is quite rare in Germany at around 400 cases per year, osteoporosis is one of the most common conditions worldwide in adulthood. Osteoporosis almost always occurs in older people, especially women after menopause. One reason is the decline in estrogen levels. But other factors also contribute to bone mass decreasing with age and the risk of fractures increasing. For example, in older age there are more frequent cases of malnutrition and limited mobility, and older people more often take medications such as glucocorticoids, which reduce calcium absorption from food and can therefore impair bone metabolism. For this reason, older people with an increased risk of osteoporosis are sometimes given vitamin D as a preventive measure. They should also pay close attention to their diet to ensure they consume enough calcium.
Similar factors are important for bone growth in children as for maintaining healthy bones in old age. An adequate supply of nutrients—especially calcium and vitamin D, but also magnesium, zinc and vitamin K—ensures the body can form bone tissue. The necessary minerals and vitamins can often be obtained through diet or, as with vitamin D, produced in the body with the help of sunlight. In some cases, it may be helpful to have your calcium or vitamin D level checked by a doctor. Because bones need to regenerate constantly, regular exercise and physical activity are important to strengthen bones both in youth and in later life.
