We can’t see our bones, so we often forget that we need to keep them healthy. In this blog, written by our intern Hannah, we will look at why bone health is important, what affects it, and how you can improve it. 

Why are healthy bones important?

Our bones have several functions. They:

  • protect internal organs
  • help with movement
  • store calcium and other minerals
  • contain bone marrow, which is where blood cells are made.

For our bones to do these jobs well they need to be strong and healthy. Poor bone health can lead to thinning of the bones (osteoporosis). With this condition bone density is very low, so bones are weaker and more likely to fracture.

What makes bones unhealthy?

Osteoporosis can be caused by a number of factors:

  • Age – Your bones weaken as you get older.
  • Gender – Osteoporosis is more common in women. This is because after the menopause women lose bone density more quickly as their oestrogen levels fall.
  • Family history – Having a parent with osteoporosis increases your risk of developing it.
  • Smoking – Several studies have shown that smoking reduces bone density.
  • Alcohol – Drinking over 21 units of alcohol a week may reduce your bone density.
  • Diet – Not eating a balanced diet can reduce bone strength, especially if you don't get enough protein, calcium or vitamin D.
  • Weight – Body mass index (BMI) is a measure of healthy weight. Guidelines recommend that for healthy bones your BMI should be 19 to 25kg/m². NHS Choices have a calculator you can use to work out your BMI. You can also ask your GP.

Some cancer treatments also affect bone health

  • Hormonal therapy for breast cancer – Some hormonal therapy drugs for breast cancer reduce oestrogen levels. This can sometimes cause bone loss and increase the risk of fractures.
  • Hormonal therapy for prostate cancer – Some hormonal therapy drugs for prostate cancer reduce testosterone levels. A side effect of this is bone loss.
  • Chemotherapy drugs – Some chemotherapy drugs can reduce oestrogen or testosterone levels. This can lead to bone loss.
  • RadiotherapyRadiotherapy can cause bone loss in the area being treated. This is most likely when women are given radiotherapy to the pelvic area. This can lead to what doctors call pelvic insufficiency fractures (PIFs).
  • Steroid therapy – High-dose steroid treatment or taking steroids for over three months can cause bone loss.
  • Targeted therapies – Some drugs target changes within cancer cells to stop them growing. This may affect the level of calcium in your blood.
  • Surgery – Removing the testicles or ovaries can reduce hormone levels and may lead to bone loss.

Your doctor or cancer specialist can give you advice on whether the treatment you have will affect your bone health.

How to keep bones healthy: the do’s and don’ts 

Quote from Christine which reads: ‘I have had long-term side effects from my cancer treatment, like osteoporosis and stiffness. However, these side effects have encouraged me to make changes in my life: better diet and exercise and a more balanced way of life.’

As Christine says, there are lifestyle changes you can make to keep your bones as healthy as possible. Here are just a few: 

Do eat well:

  • Foods that contain calcium and vitamin D are especially important for healthy bones. 
  • We have more information about eating a balanced diet.

Do exercise:

  • Exercise that is weight-bearing is good for your bone health. Jogging, hiking, and racket sports are good weight-bearing exercises. 

The diagram has three columns that show how much physical activity is recommended for adults in the UK. The first column is ‘Be active – keep your heart and mind healthy’. Beneath this is a row called ‘How often’ and it shows that you should aim do 150 minutes of moderate activity a week or 75 minutes of vigorous activity a week. Under the 150 minutes there are three icons showing that walking, gardening and swimming count as moderate activity. Under the 75 minutes are icons showing that running, sports and taking the stairs count as vigorous activity. The second main column is called ‘Build strength – strengthen muscles, bones and joints’. In the ‘How often’ row, it suggests doing these sorts of exercises 2 days a week. Below the ‘How often’ row are three icons showing that going to the gym, doing aerobics and carrying bags of shopping are strength exercises. The third main column is called ‘Improve balance – reduce your risk of falling’. In the ‘How often’ row, it suggests doing these sorts of exercises 2 days a week. Below the ‘How often’ row are three icons showing that dancing, tai chi and bowling are balance exercises.  A final row at the bottom is called ‘Sit Less’. This has icons of a TV, a sofa and a computer. Under these it says ‘Break up long periods of sitting down to help keep your muscles, bones, and joints strong’.

Don't smoke:

  • If you smoke, giving up will be good for your bones and general health. 
  • We have more information about giving up smoking.

Don't drink excessively: 

  • Drinking guidelines recommend that men and women drink no more than two units of alcohol a day.

Where can I get more information and support? 

We have a booklet called Bone Health. It has more information about the importance of bone health, the impact of cancer treatments and how to look after your bones. 

We also have information about bone health on our website.

Another organisation that can offer lots of information about osteoporosis and bone health is the National Osteoporosis Society

If you would like support, our cancer support specialists can also help – you can speak to them by calling 0808 808 00 00. Macmillan can offer a range of emotional, practical and financial support.


To see what else Macmillan's cancer information team has been blogging about, please visit our blog home page! You can subscribe to receive our blogs by email or RSS too.

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The Macmillan team is here to help. Our cancer support specialists can answer your questions, offer support, or simply listen if you need a chat. Call us free on 0808 808 00 00.

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