Building strong bones from youth until old age

Osteoporosis is considered a global epidemic, characterised by a loss of mineral from bones leading to weakness and brittleness.

Around 1 in 2 women over the age of 60 are affected by osteoporosis, however 1 in 3 men in this age group also suffer from osteoporosis. Men and women with osteoporosis are at increased risk of fractures due to their fragile, thin bones.

Men and women are at equal risk of osteoporosis from factors such as family history, a sedentary lifestyle, having a small or thin frame, smoking, excessive alcohol, use of certain medications (such as steroids) and a diet deficient in calcium and fat.  Women are also at additional risk during the menopause when the levels of bone promoting oestrogen decline. Diet and lifestyle play an important role in the prevention and treatment of osteoporosis.

Calcium is the mineral most people think of when they think of bones. However, bone health is determined by a dynamic interplay between a range of nutrients and hormones. For instance, adequate levels of magnesium, potassium, zinc, boron and vitamins D and K, are necessary for calcium metabolism and bone health.

While quality supplements are usually necessary for individuals with weak bones, it is a good idea to focus on getting more calcium from the diet. Indeed, ingesting too much supplemental calcium can interfere with absorption of other minerals such as iron and may also cause kidney stones.

Calcium-rich foods include:

• the dairy group (milk, cheese, yoghurt)
• leafy greens – especially broccoli, bok choy, kale
• sardines or salmon with bones
• dried fruit – especially figs
• nuts & seeds – especially almonds, sesame seeds & tahini.

Note that full-fat dairy contains the natural vitamin D which is essential for calcium absorption. Vitamin D is a fat soluble vitamin that we make in our skin from sun exposure but is also found in the fatty portion of a food. For example, when cream is removed to make low fat dairy products the vitamin D is lost.

Many factors can interfere with calcium uptake such as iron supplements, excess phosphorus found in soft drinks, caffeine, oxalates in spinach and phytates found in whole grains. Poor digestion, antacid use and some medications can also decrease calcium absorption.

Aside from diet, exercise is another crucial aspect to bone density. Regular exercise has a dual role – in the younger years it maximises the density of your bones while they are still growing and then in later life exercise minimises bone loss.  Weight bearing exercise is the most effective form of exercise to enhance bone formation.  For instance, when we lift heavy objects, the pull of muscle on bone sends a message to the bone building cells to lay down more calcium, and the bones get stronger.

Weight bearing exercise includes:

• walking
• jogging
• weight training
• gardening

Activities such as cycling and swimming are not as beneficial, while yoga can help improve balance and coordination and might decrease fracture risk by preventing falls.

Clearly we need to work on developing strong bones from a young age and not wait until midlife to try and reverse osteoporosis. For example, in a recent study on young women, lifestyle choices including the contraceptive pill, smoking and alcohol were shown to decrease bone strength development.

Young women with poor diets or eating disorders are also at increased risk of osteoporosis due to lack of nutrition during the crucial bone building phase of adolescence and young adulthood.

The key to developing and maintaining strong bones for all age groups is to embrace regular exercise, get adequate sun exposure and eat a healthy, nutrient dense diet.