Bone health

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Is it true that dairy products make our bodies more acidic, and that this is bad for our bones?

A theory exists that dairy products are ‘acid producing’ owing to their protein and phosphate content. Acid production could cause minerals to be leeched from the bones in order to neutralise the acid, which would, in turn, compromise bone health.

Scientific evidence does not support any of these claims. In fact, it is known that protein and phosphorus are essential nutrients for bone health. Milk and dairy products neither produce acid upon metabolism nor cause metabolic acidosis, and systemic pH is not influenced by diet. In addition, the role of calcium in building and maintaining bones is well recognised and dairy foods such as milk, yoghurt and cheese are among the best dietary sources of calcium.

What is the role of dairy in bone health?

Dairy contains many ‘bone-friendly’ nutrients, such as calcium, phosphorus, magnesium and zinc. Adequate intake of dietary protein is also recommended to promote bone health and to prevent osteoporosis. Owing to the interaction between calcium and protein, both should be consumed in adequate amounts to optimise the beneficial dietary effects on bone health. Dairy products – especially milk – have a high calcium–protein ratio. Without dairy intake, it is difficult to meet calcium requirements and some of the beneficial effects of this mineral appear to be dairy specific, possibly owing to the optimal proportion of nutrients in dairy (dairy matrix).

We should all strive to increase our consumption of dairy to ensure healthy bones throughout our life. The awareness about adequate intake of bone-building protein and minerals should start in childhood already and continue throughout life. Extra care should be taken to consume enough dairy during the teenage years, when 50% of your potential bone mass is acquired.
Promoting bone health also has an economic impact, as annual health care costs related to hip fractures can be considerably reduced if dairy intake is increased.

What can I do to ensure good bone health?

Your bone health and strength are determined largely by factors beyond your control, such as genetics, gender and age. However, factors such as diet and physical activity are in our control, and these are particularly important during adolescence, when bones are still developing. A balanced diet that provides ‘bone-friendly’ nutrients such as calcium, phosphorus, protein, vitamin D, zinc and magnesium is essential. Dairy foods are rich in a number of these nutrients. Regular participation in so-called weight-bearing activities (any activities that put the full weight of your body on your feet and legs) is also needed. Examples of such activities include brisk walking, running/jogging, tennis and most team sports. Maintaining a healthy body weight, avoiding excessive alcohol intake, getting exposure to direct sunlight for 10–30 minutes per day and not smoking are also good advice to keep your bones healthy.

How would I know if I have osteoporosis?

Osteoporosis is known as a ‘silent disease’ as it usually develops without any symptoms. A simple, painless scan of the hips and spine (called a DEXA scan) is currently the most accurate and reliable means of assessing bone mass and the presence or risk of osteoporosis. Signs to look out for and to report to your physician include: sudden and severe back pain, loss of height, or a broken bone resulting from low impact.

How common is osteoporosis?

Osteoporosis is the leading bone disease in the world. In South Africa the incidence of osteoporosis in the white, Asian (from the Indian subcontinent) and mixed-race populations appears to be similar to that in developed countries, although no fracture data exist. Osteoporosis of the hip is less prevalent in the black populations, although vertebral bone mass, and possibly also vertebral fracture prevalence, appear to be similar among black and white South Africans. Osteoporosis can affect both men and women and, although quite rare, even children.

What is osteoporosis?

Osteoporosis is a condition in which the quality and density of the bone weakens. This leads to an increased risk of fractures, commonly in the wrist, hip or spine. The condition actually develops much earlier than when the first signs are seen and is a result of insufficient calcium and vitamin D intake and too little resistance exercise over many years.

Osteoporosis is largely treatable, even preventable. However, without prevention or treatment, osteoporosis can progress to such an extent that it causes pain, disability and loss of independence.