Bone development in young people

Start early

Regular physical activity, like running and jumping, is essential for optimal bone development in childhood and adolescence.

It is never too early for children to learn about bone health. Childhood – the peak bone producing years – is the time to teach children about building strong bones. Developing good dietary and exercise habits when young will help children to have strong, healthy bones throughout their lives. Inversely, poor diet and lack of exercise, especially between the ages of ten to 18 years, can result in weaker bones in adulthood.

Several lifestyle factors, particularly nutrition, physical activity, and sun exposure can substantially influence the gain of bone mass during childhood and adolescence.

Body weight and bone health

Excessive leanness in adolescence leads to a low peak bone mass. Many girls struggle to stay thin in order to participate in dance, competitive sports and to emulate an emaciated self-image perpetrated by the fashion industry. Besides being of debatable aesthetics, an obsession with thinness can lead to eating disorders such as anorexia which can in turn damage a girl's skeleton.

Role of nutrition

Good nutritional habits, which begin early in life, will help promote bone health over a lifetime.

In addition to calcium, protein plays a key role in bone mass acquisition. During growth, undernutrition including insufficient caloric intake and protein, can severely impair bone development. Low protein intake can be detrimental for skeletal integrity by lowering both the production and action of a growth factor, IGF-1, which enhances bone formation. In addition this growth factor stimulates both the intestinal absorption of the bone mineral elements, calcium and phosphate, via an increase in the renal production of calcitriol, the hormonal form of vitamin D. Therefore, during growth and pubertal maturation, an impaired production and/or action of IGF-1 due to a low protein intake may result in reduced bone development. This is why we find a positive correlation between protein intake and bone mass gain in children.

There is enough evidence from studies on bone development in children and adolescents so that the following recommendations for bone growth in children and adolescents can be made:

Ensure an adequate calcium intake which meets the relevant dietary recommendations in the country or region concerned
Avoid undernutrition and protein malnutrition
Maintain an adequate supply of vitamin D through sufficient exposure to the sun or oral supplementation
Increase the general level of physical activity
Avoid smoking
Educate adolescents about the risk of high alcohol consumption

Celebrities speak out

“Girls often ask what makes someone beautiful. For me, a big part of beauty is being physically fit, healthy, and taking pride in your body and also in your personal values. Don’t let others tell you what you should look like and how you should behave. Don’t be a slave to fashion. My advice is respect yourself, respect your body, and that includes looking after your bones.”

Justine Pasek, Miss Panama, Miss Universe 2002

Key facts

During puberty, the speed of building up bones in the spine and hip increases by approximately five times.
During growth the gain in bone mineral mass is mainly due to an increase in bone size with very little change in bone density, i.e. in the amount of bone tissue within the bones. Just because a child is growing tall, this does not mean that his or her bone mass is growing at a sufficient rate.
From birth to the onset of the sexual maturation, the bone mineral mass at any given age is the same in girls as in boys.
During puberty bone mass increases more in boys than in girls, mainly due to a more prolonged period of accelerated growth in males, resulting in a larger increase in bone size and thickness of the cortical shell of the bones.
Young children who engage in 40 minutes of normal vigorous activity each day have significantly stronger bones than their less active peers.
A Finland study showed that the most physically active young girls gain about 40% more bone mass than the least active girls of the same age.
In girls, the bone tissue accumulated during the ages of 11 to 13 approximately equals the amount lost during the 30 years following menopause.
It is important for teenage girls not to drink or smoke and have a healthy diet overall. Smoking, drinking alcohol and eating disorders such as anorexia nervosa or bulimia can increase a girl's risk of developing weaker bones.

For further information about bone development in youth, see the IOF report "Invest in Your Bones: How diet, life styles and genetics affect bone development in young people".