What Is Osteoporosis?
The word ‘osteoporosis’ actually means porous bones. It is a disease characterised by a thinning and weakening of the bones. Osteoporosis affects many more women than men and is a particularly distressing problem for older people.
In New Zealand, osteoporosis affects more than half of women and nearly one third of men over the age of 60. This condition causes the bones to become fragile and be easily fractured. It can lead to back pain, humped shoulders, difficulty in walking and a shrinking in height. It is estimated that one in four women will suffer from osteoporosis after the age of sixty, and one in five women will be hospitalised for a hip fracture at some stage in life. Men also have problems with osteoporosis but at a later age than women. As men are living for longer, this is becoming a more common health problem in senior men. Most people know that children need plenty of calcium to build strong bones and teeth. However, few people realise that calcium is essential for everybody – throughout life – to maintain strong bones.
What Causes Osteoporosis?
Osteoporosis is an irreversible, but often, preventable condition. It is caused by a loss of calcium from the bones. To understand how this happens we need to look at the role and delicate balance of calcium in our bodies:
- 99% of your body’s calcium is stored in bones and teeth, which are your storehouses for calcium. To maintain these ‘storehouses’ you need to eat calcium rich foods every day
- 1% of calcium is dispersed in your body fluids, where it plays a crucial role in the clotting of blood and the functioning of nerves and muscles
- The calcium concentration of the body fluids must be kept constant. When the calcium concentration in the body fluids falls too low and not enough is gained from food, it is withdrawn out of the bones. A small bone loss of calcium over many years can lead to osteoporosis
The risk to women of developing osteoporosis increases once they reach menopause. This is because they lose the protective effect of the hormone oestrogen.The drop in the level of oestrogen results in a greater rate of loss of calcium from the bones. Men also have an increased risk of developing osteoporosis as they age but this occurs later than women.
People with low levels of the ‘sunshine’ vitamin (vitamin D) may have an increased risk of osteoporosis as their calcium absorption may be less. Some gastrointestinal diseases and medications can also affect calcium absorption. If you have concerns ask your doctor for more information.
How Can You Reduce Your Risk?
The more dense your bones are to begin with, the less your chances are of developing osteoporosis. It is important, especially for women, to build up sufficient calcium in their bones by mid-life. You can minimise the likelihood of osteoporosis by following these guidelines:
1. Eat calcium-containing foods
The Recommended Dietary Intake (RDI) of calcium for women and men has been set at 1000mg. Pregnant and lactating women do not have an increased requirement for calcium as long as they are meeting the 1000 mg per day RDI. Higher intakes of 1300 mg per day are required for 12-18 year old girls and boys as this is when the bones are growing most. Calcium needs are increased after menopause for women and age 70 for men who both need 1300mg each day. The richest sources of calcium are dairy foods such as milk, yoghurt and cheese. Calcium is also found in fortified breakfast cereals, fortified soy products (beverages, tofu and yoghurt), canned fish with edible bones, such as salmon and sardines, nuts, dried figs, dried apricots and dark green leafy vegetables.
2. Get the maximum calcium possible from your food
There are factors that can interfere with calcium absorption, so care should be taken in the consumption of these foods to ensure that your body gets the maximum calcium possible. These factors include: exceeding your recommended dietary intakes (RDI’s) of protein, sodium and phosphorus; consumption of too much caffeine from tea and coffee and cola drinks; smoking; aluminium from antacids and exceeding recommended consumption levels of alcohol.
The New Zealand Health Promotion Agency promotes responsible drinking with guidelines for men and women recommending no more than 2 standard drinks on any day for woman and three for men with a maximum of 10 per week for women and 15 per week for men. See www.alcohol.org.nz. Also, oxalates (present in tea, chocolate, spinach, asparagus, and rhubarb) and phytates (found in bran and wholegrain cereals) reduce the absorption of calcium. However, these factors are not significant if the foods eaten contain enough calcium.
Vitamin D helps calcium absorption so we all need to get some sunshine every day.
3. Do more weight bearing exercise
Another way to protect against Osteoporosis is to exercise regularly. Just as using muscles strengthens them, our bones become denser and stronger in response to mechanical stress. This stress primarily comes from weight-bearing exercise (in which your legs support your body) and strength-building exercise (such as weight lifting). For example, if you walk frequently your leg bones will respond by growing stronger. If you play tennis often, your arm bones will respond by increasing their mass.
Make weight-bearing exercise a priority in your daily life. Try activities like walking, running, cycling, golf, basketball, cricket, netball, aerobics, and hockey. Even housework and mowing the lawn count.
For more information see Osteoporosis New Zealand www.bones.org.nz
Sources Of Calcium
The best protection against osteoporosis is to build strong healthy bones from infancy through to your mid-twenties and then maintain them through adulthood by getting adequate calcium every day. This is especially important for women, you can do a lot now to prevent osteoporosis – for a stronger and healthier tomorrow.
This fact sheet contains general information. Please consult your healthcare professional for specific advice for your personal situation.
Osteoporosis New Zealand http://www.bones.org.nz
Osteoporosis Better Health Channel June 2009 www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/ Osteoporosis
Osteoporosis and exercise Better Health Channel Mar 2009 www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/ Osteoporosis_and_exercise
NHMRC 2009 Australian Guidelines to reduce health risks from drinking alcohol. www.nhmrc.gov.au/_files_nhmrc/file/publications/synopses/ ds10-alcohol.pdf