During your teenage years, your skeleton is actively getting bigger and stronger. Bone strength is dependent upon many things such as the size, shape, composition and heaviness of bone¹⁰⁰. By the end of your teens, roughly 90 per cent of your ‘peak bone mass’ (the point at which your bones are at their strongest) will have been achieved¹⁰¹. The precise age at which peak bone mass is reached is still not entirely known.

Peak bone mass generally means the point at which your bones are at their ‘strongest’. The higher your peak bone mass, the greater protection your skeleton has against the effects of ageing. Therefore, it is vital that you attain a high peak bone mass during your teen years to withstand the effects of age related bone loss later on. Osteoporosis is a condition which results in a loss of bone strength, making bones more fragile and more likely to break.

Bone production

Bone is living tissue made up of specialised bone cells and, like the rest of the body, it is constantly being broken down and renewed. From birth, more bone is made than is broken down, and so bone is able to grow. Bone growth is nearly complete by the end of puberty, with only a small increase in bone mass occurring after the late teenage years. From the mid-30s on, more bone is broken down than is produced. This results in a gradual decrease in bone strength with increasing age in both men and women.

Achieving your peak bone mass

Surprisingly, your potential peak bone mass is largely determined by genetic factors¹⁰¹. Also, males tend to have heavier bones than females¹⁰² and different ethnic groups will vary in their bone development. However, in order to fulfil your full potential to develop peak bone mass, your diet, physical activity and hormone production must be optimal.

Physical activity

Involvement in any form of physical activity, particularly weight-bearing exercises, during your teen years will have a positive effect on bone development and will increase the likelihood of developing a high peak bone mass. The best way to do this is to take part in some form of sport, either through school or outside school hours. 

Healthy eating

It is important to have a healthy, well-balanced diet during your teen years so that growth and development can progress normally. It is particularly important that your calcium intake meets the requirements of your growing skeleton. The main source of calcium comes from eating dairy products. Children and teenagers need three to four serves of dairy products per day. For instance you could have a glass of milk, milk with cereal, a tub of yoghurt and a serve of cheese daily. Smoking and excessive alcohol are not good for maintaining bone density.

Hormones

Growth hormones and sex hormones (oestrogen and testosterone) are important in bone development. During your teens, the increased levels of sex hormones and growth hormone lead to an increase in size and bone mass of the skeleton.

Special considerations

Osteoporosis is a condition most often associated with increasing age, as loss of bone mineral is part of normal ageing. However, some young women may develop osteoporosis at an earlier stage of life due to various illnesses or hormonal deficiencies.

Eating disorders

Women who develop eating disorders in early adolescence, when the skeleton is in the process of growing, can severely reduce their ability to achieve peak bone mass. This can lead to the development of osteoporosis at a young age, especially if the eating disorder persists for several years. It is not uncommon for women who have had an eating disorder since their teenage years to develop osteoporosis by their early 20s. Even women who develop an eating disorder after their skeletal growth is complete will have reduced bone mineral density.

Athletes

Whilst exercise in general is beneficial, adolescent females and young women who are involved in elite training and develop amenorrhoea (menstruation stops) or disordered eating habits are at high risk of developing osteoporosis in later life.

Late first menstrual period

It is advisable for any girl who has not had her period by the age of 16 to see her doctor for an assessment. Most often these delays in puberty are simply that – just delays. Many teenagers can be a bit slower in their development than others, but most catch up. Any teenager found to have a hormone problem can have this medically treated.

Resources

Assess your Risk	Exercise
Conditions, lifestyle choices, hormonal states or treatments Questionnaire	Achieving peak bone mass and maintaining healthy bones
Calcium Requirements	Vitamin D Requirements
Recommended daily calcium intake Teen years and calcium	Why Vitamin D is important

Content updated 29 July, 2011