Strong bones for life
You might not think about your bones very much. They are hidden away inside your body and you don’t often realise how important they are.
This month’s feature, by the National Osteoporosis Society (NOS), explains why girls need to build healthy bones to prevent problems in later life, and the easiest ways to do this.
Your bones are alive!
You might have seen a bone in a museum and it probably looked old and crumbly. However, the bones inside your body are very different. Bones are alive, like the rest of your body, constantly growing and changing.
In fact, your skeleton is completely renewed in a process called ‘bone turnover’. In childhood it takes just two years for your skeleton to completely replace itself with new bone.
Bone building
When you are young, your bones are building strength for later in life. Bones stop growing in length between the ages of 16 and 18, but bone density continues to increase slowly until a person is in their mid 20s.
They are at their most dense (and strongest) between the ages of 25 and 30. After the age of 35, bone strength decreases very gradually as part of the natural ageing process. It is therefore important to build your bone strength before age 25 to make sure your bones are as strong as possible so you can prevent Osteoporosis when you are older.
Osteoporosis
Osteoporosis is often called the “fragile bone disease”. The disease causes the bones to become more porous and weaker. This means that bones can break or fracture more easily – particularly the wrist, hip or spine. The disease normally affects older people, and women are more likely to get fragile bones than men.
This image shows part of the spine (not a real one!). You can see how the top bones are more dense (lots more white connecting together); the second have more holes, which makes them weaker than the top bones. The bottom bones are the most porous (lots more holes). They would break much more easily than the top bones because they have less bone density.
This is why it is particularly important for girls to build strong healthy bones before their mid 20s – and now is the best time to do it!
There are lots of things that you can do to make sure that all of the 206 bones that make up your skeleton are as strong as they can be. This gives them the best chance of staying strong for life.
Food
The food we eat plays a big part in building strong bones. Foods rich in calcium are particularly important. These include dairy foods (like milk, yoghurt and cheese), leafy green vegetables and dried fruit (like apricots and figs).
Calcium
Our bodies contain more than one kilogram of calcium, 99% of which is found in our bones. Calcium is vital for strong teeth, forming part of the hard layer below the enamel. The remaining calcium in the body is found in blood and body fluids and is vital for life-supporting activities such as muscle contraction.
Men and women need different amounts of calcium at different stages of life.
To find out which foods contain calcium, check out these fact sheets.
Top Tips
Here are some great tips for getting more bone-building foods.
- Breakfast cereals are an easy calcium-rich start to the day. Milk bumps up the calcium content even more.
- Instead of snacking on crisps or sweets, eat nuts or dried fruit like apricots and figs, both excellent sources of calcium.
- Some bottled mineral waters can be a useful source of calcium and are a good alternative to fizzy drinks. Look out for calcium-enriched waters and orange juice in the supermarket.
- Milk and dairy products, like yoghurt, fromage frais and cheese, are an excellent source of calcium, including the low-fat varieties.
- Don’t bin the bones in tinned fish, like sardines. Mash them into the fish and you won’t notice them as they are quite soft – and you will benefit from the calcium they contain. Whitebait is also rich in calcium.
- Tofu (a vegetable protein made from soya beans) is high in calcium and low in fat.
- Green leafy vegetables, like watercress, broccoli and curly kale, are good sources of calcium.
Vegetarians and Vegans
A vegetarian diet contains no meat, poultry or fish and also avoids by-products such as gelatine. Vegans also omit all animal products from their diet, such as eggs and cheese.
If dairy products are excluded from the diet, care will need to be taken to include lots of other calcium-rich foods such as green leafy vegetables, almonds, sesame seeds, dried fruit, pulses (beans or peas), fortified soya drinks and soya protein tofu.
Be smart about what you drink
There is a lot of information on the internet about caffeine and fizzy drinks and how these are bad for your bones, as well as your health. Let's give you the facts as we currently know them.
Caffeine is a stimulant found in tea and coffee. It's possible that drinking around eight or more cups of coffee a day (not tea) could be a problem for your bones – but hopefully you would not be drinking this amount anyway!
It has not yet been proven that fizzy drinks – particularly cola-type drinks that contain caffeine and phosphoric acid – have a bad effect on bone health.
The biggest concern is that large quantities of fizzy drinks are now being consumed instead of more nutritious drinks, such as milk and water, so people are missing out on important nutrients. When you are thirsty, please think about your health, and keep fizzy drinks to a minimum.
Sport and Exercise
Just like your muscles, your bones need exercise to grow too. However, your bones respond best to certain types of exercise. Bones like any exercise that gives them a little jolt, such as:
- running
- skipping
- walking
- netball
- basketball
- football
- hockey
- tennis
- dancing
- gymnastics.
High impact, weight-bearing exercises like jogging and jumping, are very effective in building bones. They strengthen the bone by maintaining the normal balance of bone building and wearing away.
Exercise using resistance bands is also helpful.
Cycling and swimming are fantastic for general fitness, but they don’t help to build strong bones. This is because the body’s weight is supported and is therefore not getting the benefit of impact. Make sure that you also get plenty of impact exercise such as those listed above.
How much exercise do you need?
The government recommends 60 active minutes per day for overall health. To promote strong bones, it is recommend that in those 60 minutes, some exercise should be high impact and high intensity, like skipping, dancing or running.
The sunshine vitamin
You need vitamin D to help your body absorb calcium. The best source of vitamin D is sunlight, which your body uses to produce this vital vitamin in your skin. That’s why vitamin D is sometimes called "the sunshine vitamin". Almost all (about 90 per cent) of your vitamin D comes from sunlight.
You can also find vitamin D in spreads and egg yolks. Oily fish is also a good source, including:
- grilled herring / kipper / mackerel / salmon / rainbow trout
- smoked mackerel
- tinned pilchards / sardines in tomato sauce
- Bangladeshi curried fish
- cod roe (hard and fried in oil)
- cod liver oil.
You should be able to get most of your vitamin D without too much effort. The food you eat, as well as enjoying an active outdoors lifestyle during the summer months, will help to give you enough vitamin D.
Vitamin D is crucial for helping the body to make the most of the calcium from the foods we eat. This is vital for strong teeth and bones. It is stored by the body during the summer months for use during this time, and throughout the winter months. The body’s ability to store vitamin D is very important because it can only be formed by the skin during the summer months.
Even on cloudy days the sun’s rays can produce vitamin D and it is impossible for the body to make too much vitamin D.
Staying safe in the sun
If you are out in the sun, it is very important not to get sunburnt. Look after your skin by:
- wearing a hat
- using a protective high-factor sunscreen
- covering up at the hottest time of the day – usually between 11am and 3pm.
Test yourself!
Now you’ve learnt all about your bones, why not try our bone health quiz.
Can you beat the highest score on our Bones4Life game?
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The National Osteoporosis Society is dedicated to improving the diagnosis, prevention and treatment of osteoporosis. It aims to improve public awareness and understanding, to provide support for sufferers, and to promote excellence in health and social care. www.nos.org.uk Helpline: 0845 450 0230
The NOS has launched Bones4Life, aimed at educating young people about the importance of developing strong bones to prevent problems in later life. www.bones4life.org
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