Osteoporosis: lowering risk
An estimated 2 million Australians suffer from osteoporosis — a condition which results in weak and brittle bones that are predisposed to fracture. Doctors say that osteoporosis affects one in 2 women and one in 3 men in Australia — good reason for everyone to do what they can to keep their bones strong and healthy and reduce their risk of developing this disease.
A few simple steps can reduce a person’s risk of developing osteoporosis: getting enough calcium in their diet; getting enough vitamin D; and doing enough weight-bearing exercise. If you pay attention to these simple measures on a daily basis, you should go a long way to reducing your risk of osteoporosis.
Calcium: meeting your daily requirement
Calcium is an essential nutrient needed to create and maintain strong bones. Your body can’t make calcium – it obtains it from your food. And if there isn’t enough calcium in your food, your body will take it from your bones. So it’s important to make sure that your diet contains enough calcium to maintain the health of your bones.
People’s calcium needs vary according to the stage of life they are at. In 2006 Australia released Nutrient Reference Values and increased the recommended intakes of calcium from those of the previous guidelines.
The Nutrient Reference Values recommend that men and women over 19 years of age have an intake of at least 1000 mg of calcium per day, with women over 50 and men over 70 upping their intake to at least 1300 mg of calcium per day. These levels represent the RDI (Recommended Dietary Intake) which is an intake that is gauged to be sufficient to meet the nutrient requirements of nearly all healthy individuals in a particular life stage and gender group.
|Recommended dietary intakes of calcium|
|Group||Calcium RDI (Recommended Dietary Intake)|
|Women 19 to 50||1000 mg per day|
|Women over 50||1300 mg per day|
|Men 19 to 70||1000 mg per day|
|Men over 70||1300 mg per day|
|Source: Australian Government Department of Health and Ageing and NHMRC. Nutrient Reference Values for Australia and New Zealand Including Recommended Dietary Intakes, 2006. Endorsed 9 September 2005.|
Dairy foods such as milk, yoghurt and cheese are the richest dietary sources of calcium, with smaller amounts found in bony fish, some nuts, e.g. almonds, and legumes. Three serves of dairy per day providing approximately 300 mg of calcium each, such as a 250 mL glass of milk, a yoghurt and a 40 mg block of hard cheese, should provide nearly 1000 mg of calcium, whereas a person aiming for 1300 mg per day will need additional calcium. Other food sources providing roughly 300 mg of calcium include 150 g tinned salmon with the bones, 100 g of sardines, and 150 g of almonds.
Vitamin D also plays a major role in maintaining bone health. Vitamin D increases calcium absorption from the stomach and helps strengthen your bones.
Exposure to sunlight is the main source of vitamin D for most Australians. When we are exposed to ultraviolet light from the sun, vitamin D is formed in our skin. The amount of sun exposure you need to make adequate amounts of vitamin D depends on your age, your natural skin colour, where you live (northern or southern states) the time of day and the time of year. Most people get enough sun exposure during their typical day-to-day outdoor activities to achieve adequate vitamin D levels; sensible sun protection behaviour should not put you at risk of vitamin D deficiency.
Some foods, such as fatty fish (e.g. salmon, mackerel, and herring), eggs, liver, and foods fortified with vitamin D (e.g. margarine and some milks), also contain vitamin D. However, dietary intake alone is unlikely to provide adequate vitamin D to maintain healthy bones.
Vitamin D supplements, sometimes combined with calcium, may be recommended by your doctor if you have low levels of vitamin D.
Most men and women reach their peak bone mass by age 30. Peak bone mass is the maximum strength and density of your bones. Regular weight-bearing exercise before this age can help you to attain a high peak bone density, which will reduce your risk of osteoporosis later in life.
Weight-bearing exercise is the best type of exercise for your bones. Examples of weight-bearing exercise are walking, jogging, aerobics, dancing and tennis. Strength or resistance training (lifting weights with your arms or legs) also helps improve bone health. Incorporating 30 to 40 minutes of these types of activities (both weight-bearing and strength-training exercises), 4 to 6 times a week will help build and maintain strong bones according to Osteoporosis Australia.
Building weight-bearing exercise into your life by actions such as taking the stairs not the lift, walking the dog and playing a team sport can help your bone health and lessen your future chances of osteoporosis.
2. Australian and New Zealand Bone and Mineral Society, Osteoporosis Australia, The Australasian College of Dermatologists and the Cancer Council Australia. Risks and benefits of sun exposure Position statement (last reviewed 2007, May 3). Available at: http://www.cancer.org.au/cancersmartlifestyle/SunSmart/sunsmart/risksandbenefitsofsunexposure.htm (accessed 2009, Nov 13)
3. Cancer Council Australia [website]. Vitamin D (updated 2009, Oct 29). Available at: http://www.cancer.org.au/cancersmartlifestyle/SunSmart/VitaminD.htm (accessed 2009, Nov 16)