You can take action to minimise your risk of developing osteoporosis and a first fracture. Bone health is maintained in the body by getting adequate Calcium, Vitamin D and exercise.
Calcium is essential for building and maintaining bone. It combines with other minerals to form the hard crystals that give bone its strength. Almost all the body's calcium (about 99%) is found in the bones. The remaining 1% is dissolved in blood and other fluids, which is essential for maintaining healthy functioning of the heart, muscles, blood and nerves.
Our bodies cannot make calcium, so it must come from our diets. When you are not getting sufficient amounts of calcium in your diet, some of the calcium crystals in the bone dissolve, and give their calcium back to the bloodstream. Bones therefore, act like a calcium bank, storing calcium and releasing it into the blood stream when needed. So if your calcium intake is too low and there are more withdrawals than deposits from your calcium bone bank, you risk losing bone strength.
Calcium intake is important and how well the calcium is absorbed is also important. Calcium absorption may be reduced by excessive caffeine and alcohol, soft drinks containing phosphates and diets high in animal proteins. As well, calcium is continually lost from your body each day through your skin, nails, sweat and urine.
Peak bone mass
By age 30, peak bone mass (maximum bone density) is reached and most of this is achieved by puberty, when there is the greatest rate of bone growth.
The higher your peak bone mass, the more likely it is that you will maintain better bone health even during times of rapid bone loss such as menopause. This is why calcium is so important for children and teenagers.
Your daily calcium needs depend on your age and sex.
In adults, dietary calcium is vital in order to maintain bone strength. Also, as we age, calcium is absorbed less effectively from the intestine, so that intake needs to be increased. When the body can no longer replace calcium fast enough to keep the bones healthy, they become thinner and weaker, resulting in osteoporosis.
Less than half of all Australian adults get their daily recommended intake of calcium.
- Children 5 to 9 years should aim for 2 to 3 serves of calcium-rich foods each day to reach a total intake of 800 -1000 mg/day.
- Children and adolescents aged 9 to 18 years should aim for at least 3 serves of calcium-rich foods a day to reach a total intake of 1000 - 1300mg/day.
- Adults up to the age of 51 years should aim to consume at least 2 serves of calcium-rich foods a day to reach a total intake of 1000 mg/day.
- Postmenopausal women should aim for at least 3 serves of calcium-rich foods to reach a total daily intake of 1000 -1300 mg/day.
- For adults over 70 years, 1300 mg of calcium a day is recommended.
Sources of calcium
For most Australians, dairy foods are the main source of calcium. Dairy foods are the most convenient way to obtain adequate calcium because milk, yoghurt and most cheeses are particularly high in calcium. Small amounts of calcium are found in nuts, breads, cereals, fruits and vegetables. Three servings of dairy products each day will generally provide you with the recommended daily calcium intake around 1000 mg/day.
Practical tips for getting more calcium in your diet
- Calcium is more easily absorbed from dairy products than most other food groups. Aim to get at least half your daily intake of calcium from dairy foods.
- Eat two to three serves of food each day that are high in calcium, eg a glass of milk, a container of yoghurt, a slice of hard cheese.
- Eat canned fish with bones, particularly canned salmon and sardines (the fish bones contain calcium).
- Add milk or skim milk powder to soups or casseroles.
- Use yoghurt in soups, desserts and salads.
- Some soy products such as tofu (bean curd) and a number of brands of soy milk are high in calcium, or fortified with calcium. Check the labels, as some unknown substances in soy products may impair calcium absorption.
- Eat more broccoli, beans, almonds, tinned salmon and sardines in your regular diet.
- If you cannot eat dairy foods, eat other types of food that contain calcium or that are fortified with calcium. Note: People with lactose intolerance are often able to eat yoghurt and cheese as the lactose levels in these foods have been broken down.
- Get advice from a dietician or nutritionist if you need help with increasing the calcium in your diet or for general advice on healthy eating.
If you cannot get enough calcium in your diet, your doctor may suggest that you take a calcium supplement.
Supplements can be in the form of calcium phosphate, calcium carbonate and calcium citrate taken in pill, chewable or liquid form. Talk to your doctor about the type of supplement they recommend.
An extra 500-700mg of calcium per day is sufficient for most people. The easiest way to do this is with a single calcium tablet containing 600mg of calcium.
Vitamin D is essential for bone health, because it helps:
- increase the absorption of calcium and phosphorous from the stomach
- regulate the amount of calcium in the blood
- strengthen the skeleton.
For Australians, the main source of vitamin D is from exposure to sunlight. Vitamin D3 is formed by the action of sunlight (UV light) on the skin. A deficiency of vitamin D can contribute to osteoporosis because without it, calcium will not be fully absorbed by your body.
Vitamin D is found in small quantities in a few foods (eg, fatty fish like salmon, herring or mackerel, liver, eggs and fortified foods). However adequate vitamin D is unlikely to be achieved through diet alone.
The Importance of Sunlight
To get enough sunlight to produce vitamin D, a person needs to expose their hands, face and arms (around 15% of body surface) to sunlight for about 6 - 8 minutes, 4 - 6 times per week (before 10am or after 2pm Standard Time in summer, for moderately fair people).
This would produce around 1000 IU of vitamin D, around 1/3 of a minimal erythemal dose (MED). Note: one MED (minimal erythemal dose) is the amount of sun exposure that produces a faint redness of the skin.
Older people need exposure to sunlight 5-6 times a week. Dark skinned people need longer exposure times of around 15 minutes.
Exposure to sunlight between 10 am and 2 pm in the summer months (11am- 3pm in daylight saving) is not advised or recommended, due to the cancerous effects of sunlight at that time. This outweighs any possible benefits from vitamin D production.
Vitamin D supplements
If you have low vitamin D levels in your blood, your doctor may suggest that you take a vitamin D supplement.
Regular physical activity on a long-term basis has a particularly important role in maintaining healthy bones. Exercise can maintain and increase bone strength by increasing bone mass or by slowing age-related bone loss. Muscle strength is also increased, which is important for supporting the joints and preventing falls.
Exercise has also been shown to improve co-ordination and balance, which helps to prevent falls and to improve general physical health and well-being.
Be aware that any positive gains in bone strength are lost when you stop exercising, so that it is important that your exercise is regular and ongoing.
Caution: Someone who has established osteoporosis (one or more fractures) may not be able to do as many types of activities as someone without osteoporosis. Talk to your doctor and physiotherapist about activities you can do.
Exercises for bone health
(assumes you don't have osteoporosis, otherwise see section below on exercise if you have osteoporosis)
There are two main types of exercises that are beneficial to bone health:
- Weight-bearing exercise
- Resistance exercise (lifting weights with arms or legs)
Weight bearing exercise
Weight-bearing exercise means any exercise that is done while you are on your feet, so that gravity is exerting a force.
Your bones become stronger when they bear weight during exercise and when some amount of 'impact' or extra strain is placed on those bones.
If the 'strain' level is too low, then the bone will not become stronger and may still lose mass. Too much 'strain' could result in injury. The best 'strain' is from activities that may be new to your body, which means your bones are getting a variety of forces and loads on them.
Examples of weight-bearing activities are jogging, walking, tennis, dancing, golf and netball. Swimming and cycling are not considered weight-bearing exercises (but are good for muscle strength).
Activities that are high-impact, such as aerobics, running and jumping, have a greater effect on bone strength than 'low-impact' activities, such as walking and cycling. Everyday activities such as normal walking are not considered to be especially bone-building because they produce a strain that is 'normal' for the body, although very fast walking has been shown to help maintain bone strength.
High-impact activities may not be suitable for everyone, especially if you have problems with your joints or other medical conditions. If you are unfit or inactive, lower intensity exercise is a safe starting point and you can progress to more moderate intensive exercise over time.
Everyday ways to increase your level of weight-bearing exercise:
- walking some or all of the way to work,
- including some hills or specific exercises in your daily walk,
- using stairs instead of lifts.
It is important to talk to your doctor or physiotherapist about the best type of weight bearing exercise before you start.
Resistance exercises (lifting weights with your arms or legs)
Resistance exercises, also called strength training, can have a good effect on the health of your bones and have been shown to reduce the number of falls in older people. The strong muscle contractions required to move a heavy weight, place stress or 'strain' on the bone that the muscles are attached to. When bone feels a 'strain' repeatedly, (as also happens in regular exercise training) it responds by increasing bone mass so as to become stronger.
Targeting specific muscle groups around the hip, spine and arms with weight-lifting is also a good idea.
Everyday activities do not produce enough 'strain' to change bone mass, so resistance exercises need to be increased as the body adapts to each new level.
This can be done by:
- increasing the resistance
- increasing the number of repetitions
- changing the exercise so that a new strain pattern begins
- when it starts to feel easy, you need to increase the weight and do more repetitions.
Planning Your Exercise Program
Before you start, it is important to talk to a doctor or physiotherapist about the best type of resistance exercise for you.
Exercise Tips for Strong Bones
- To have an effect on bone, exercise needs to be regular, fairly vigorous, have variety (put different loads on it), and include short, intense bursts.
- The amount and type of exercise will vary depending on your age and bone health. Overall, most people should aim to exercise for 30 to 40 minutes, four to six times each week, and include some weight-bearing and resistance exercises in the program. You can build up to this level over time.
- Start slowly and progress gradually. Try to get into an exercise routine. You can break it up into several smaller amounts throughout the day.
- Set short term goals for what you want to achieve. They must be realistic, achievable and measurable. For example, adding 50 jumps to your regular walk over a 3-month period.
- The process of bone building is slow, it starts to happen as soon as you start regular exercise but it takes at least 6 months to be able to measure the effects.
- Good exercises for bones: fast walking, jogging, dancing, tennis, volleyball and lifting weights. Choose exercises that you enjoy and vary your program to keep it interesting.
- If you are having pain while exercising, stop and talk to your doctor or physiotherapist.
Exercise: if you have osteoporosis
If you have been diagnosed with osteoporosis and/or have already had a fracture, you should see your doctor or physiotherapist about starting an individual exercise program.
- Your aim is to maintain bone strength and reduce the risk of fractures and falls by improving posture, balance and muscular strength.
- Because of the higher risk of fracture, exercising at a level high enough to produce stress on the bones is not recommended.
- Appropriate exercises include Tai Chi for balance, flexibility and muscle strength, gentle weights for muscle strength, water-based exercises (hydrotherapy) and walking.
- Avoid high impact activities (eg running).
- Avoid jarring & twisting movements (eg golf swing).
- Avoid heavy lifting and lifting objects some distance from your body (eg picking up grandchildren).
- Avoid abdominal curls (sit-ups).
- Avoid bending forward from the waist.
- Avoid sudden, abrupt movements.
- Don't overdo it (especially if you have not done any activity for many years)