Our team of dietitians answer your common questions about bone health and dairy foods based on scientific evidence. Have another question about bones? Feel free to drop us a line at enquiries@dairyaustralia.com.au

 

  • At what age do I need to start paying attention to my bones?

    Bone health is important throughout all life stages. From childhood, we need to keep developing and building our bones until they are big and strong. This is called our peak bone mass. Most people need to keep building their bones until they reach peak bone mass between the ages of 25-30 years old.i We then need to keep our bone density and strength.

    After we turn 40, we slowly lose bone mass and our bones become weaker. Age related bone loss occurs due to increased calcium losses by the kidneys and reduced calcium absorption in the gut. Following menopause, women begin to lose bone mass rapidly and by the age of 65 both men and women lose bone mass at the same rate.i Therefore it is vital we maintain our bone health to prevent fractures and breaks.


  • Why do I need to look after my bones?

    Bones are the body’s foundation, providing support and structure and giving protection to organs. Looking after your bones is important to keep them strong and healthy. This will reduce aches and pains, as well as your risk of fractures and even osteoporosis. Strong bones are key to leading long, healthy, active and independent lives.

     

  • How should I look after my bones?

    Genes and lifestyle impact how strong bones are. It is thought that lifestyle choices (such as diet and exercise) influence 20-40% of adult peak bone mass and genetic factors (those you are born with and can’t change, such as gender and race) account for the rest.ii

    Good bone health throughout life relies on a daily supply of calcium, vitamin D, and weight bearing exercise.iii Dairy foods like milk, cheese, and yoghurt are a great source of calcium. You can get vitamin D from regular time in the sun, just by spending a few minutes outdoors most days of the week. Weight bearing exercise can be done through walking, running, jumping and dancing. Lots of fun games and sports count as weight bearing exercise!

  • What role does calcium play in bone health?

    Calcium combines with other minerals (like phosphorus) to form hard crystals that give bones their strength. As well as providing a frame for our bodies, bones serve as a calcium store to support other functions of the body like muscle contraction, especially the heart.

    Because your body can’t make calcium, it must come from your diet. As long as you are getting adequate calcium from your diet, your body will ensure that you have the right amounts of calcium circulating in your body. If your calcium intake is too low to maintain adequate calcium blood levels, calcium will be released from your bones and this can weaken them.

  • Is dairy the best source of calcium?

    Dairy products are some of the most calcium rich foods, with almost a third of the recommended daily calcium intake for adults in just 1 glass of milk, 1 tub of yoghurt or 2 slices of cheese. Milk, yoghurt and cheese are all convenient and readily absorbable sources of calcium.iv

    There are also other sources of calcium, such as sardines, salmon with bones broccoli or Brussels sprouts. See also ‘Can I get calcium from non-dairy sources?

  • Can I get calcium from non-dairy sources?

    Some non-dairy foods also contain calcium.iv

    These include certain vegetables (e.g. broccoli or kale), whole canned fish with soft edible bones, such as sardines, some nuts and calcium-set soy products (eg. tofu, soy milk).

    You can use the list below as a guide to sources of calcium and the equivalent serves you would need.

    1 serve of dairy is equal to:  1 serve of a calcium alternative could be: 

    • 1 cup (250ml) fresh, UHT long life, reconstituted powdered milk or buttermilk
    • ¾ cup (200g) yoghurt ½ cup (120ml) evaporated milk
    • 2 slices (40g) or 4 x 3 x 2cm cube (40g) of hard cheese, such as cheddar
    • ½ cup (120g) ricotta cheese 

    • 1 cup (250ml) soy, rice or other cereal drink with at least 100mg of added calcium per 100ml
    • 100g almonds with skin
    • 60g sardines, canned in water
    • ½ cup (100g) canned pink salmon with bones
    • 100g firm tofu (check the label as calcium levels vary) 

    Some plant foods contain phytates and oxalates that can interfere with calcium absorption.



  • How much dairy should I be consuming per day?

    That depends on your age and gender. The Australian Government make recommendations for milk, cheese, yoghurt and/or alternatives. iv

    The recommended daily intake varies between 1 serve for toddlers to 4 serves of dairy per day if you’re a woman over 50.iv As children grow, their recommended dairy intake increases too.

     

  • How much is ‘a serve’ of dairy?

    A serve of dairy might be 1 cup (250ml) of milk, 2 slices (40g) of hard cheese, such as cheddar or a ¾ cup (200g) of yoghurt.iv

     1 serve of dairy is equal to:

    • 1 cup (250ml) fresh, UHT long life, reconstituted powdered milk or buttermilk
    • ¾ cup (200g) yoghurt ½ cup (120ml) evaporated milk
    • 2 slices (40g) or 4 x 3 x 2cm cube (40g) of hard cheese, such as cheddar
    • ½ cup (120g) ricotta cheese 

     

  • I’ve heard that dairy is acidic and can leach calcium from the bones to neutralise the acid, is this true?

    Milk and other dairy foods are not acid producing and do not make the body acidic.vi  Studies have shown that consuming milk and other dairy foods leads to positive calcium levels, and more calcium is absorbed than excreted.vii, viii This helps bones become stronger and reduces risk of fractures and osteoporosis later in life.

  • Is milk good for your bones?

    Not only does a cup of milk contain a third of an adult’s daily calcium, the main building block of bone, milk and other dairy foods are filled with nutrients that are essential for good bone and teeth health, including calcium, protein, magnesium, zinc, potassium and phosphorus.ix

    While you can get the equivalent amount of calcium from other foods, milk is a rich source of readily available calcium as well as other nutrients required for healthy bones. See also 'Can I get calcium from non-dairy sources?'

  • Hasn’t it been proven that countries with higher milk intakes have higher rates of osteoporosis and fractures?

    Some studies have reported that countries with higher milk intakes have higher rates of osteoporosis and fractures. These largely observational studies do not imply a direct cause and effect and do not account for the many factors involved in the development of osteoporosis and fractures.

    Countries with higher rates of fractures tend to be countries with longer life expectancies (e.g. Nordic countries). Fracture rates are now rising in non-Western countries (e.g. China) as they see increasing longevity in parallel with sedentary lifestyles.x

    Genetics (race, sex, family disposition) and other lifestyle habits such as physical activity, smoking, alcohol-use, as well as certain medications and diseases, also have a major role to play in osteoporosis and fracture risk.xi, xii 

    Dairy food intake is not responsible for higher fracture rates, nor does dairy consumption alone guarantee strong healthy bones.xiii

  • Is the protein in dairy bad for bone health?

    Dairy foods are a good source of protein which plays an important role in bone health as it helps build and repair bone tissue and muscles. As people become older, protein requirements increase to help maintain bone and muscle mass and reduce fractures.xiv

  • What is osteoporosis?

    Osteoporosis is a common disease affecting the bones. The disease makes bones become brittle leading to a higher risk of breaks than in normal bone.

    Osteoporosis occurs when bones lose minerals, such as calcium, more quickly than the body can replace them, causing a loss of bone thickness (bone density).xv 

     

  • What is low bone density?

    Low bone density is known as osteopenia. This is the range of bone density between normal and diagnosed osteoporosis, which means you need to take immediate action to support your bone health. If you are found to have osteopenia your doctor will ensure you have adequate calcium and vitamin D, and recommend exercise to optimise your bone density.xvi

    Bone density is determined via a test which measures the density of your bones (usually at the hip and spine) using a simple scan. The results of this test show if your bones are in the range of normal, low bone density or osteoporosis.

  • How can you prevent osteoporosis?

    The most important measures people can take to prevent osteoporosis include ensuring adequate calcium intake and getting enough vitamin D and weight bearing exercise.xvii While there are many sources of calcium, dairy, as part of a balanced diet, is a good source of calcium.

    Habits like smoking and excessive alcohol intake are bad for bones. There are also a number of other risk factors for low bone density, including family history of osteoporosis and certain medical conditions and medications.

    For independent information on how to prevent osteoporosis, visit Osteoporosis Australia.

  • Can dairy help to prevent osteoporosis?

    There is evidence that dairy foods specifically are a potential solution to preventing osteoporosis and fracturesxviii however there has never been a research trial investigating this, until now. In a world-first, Australian researchers are leading a major internationally funded clinical trial into the impact of increased dairy consumption on bone fractures. Dairy Australia is one of six partner organisations involved in the five-year trial. Research findings are expected in 2019.

  • How likely am I to get osteoporosis?

    Many Australians are at risk of developing osteoporosis – among those aged 50 and over almost one in four Australian women and one in 20 men live with the condition.xix This means, osteoporosis affects more than one million Australians.

    To reduce your risk, you can make sure you’re maintaining good bone health by getting enough calcium and vitamin D and doing weight bearing exercise like jogging, aerobics and tennis.

  • How much vitamin D do I need?

    The main source of vitamin D for Australians is from exposure to sunlight. The amount of sun exposure required to produce enough vitamin D depends on the time of year and where you are in Australia. In August, you should be receiving around 20-25 minutes of sunlight per day. Osteoporosis Australia’s fact sheet on vitamin D provides detailed recommendations.

  • How does exercise affect bone density?

    When we exercise, our muscles pull on our bones, which in turn builds bone. The ability of an exercise to build stronger, denser bone depends on the specific way that stress is applied to the bone during the exercise. This means there are specific types of exercises that are better for strengthening bones, including:

    - Weight bearing exercise (exercise done while on your feet so you bear your own weight). For example: brisk walking, jogging, skipping, basketball/netball, tennis, dancing, impact aerobics, stair walking.

    - Progressive resistance training (becomes more challenging over time). For example: lifting weights - hand/ankle weights or gym equipment.

    To learn more about exercise and bone density, see the guidelines by Exercise and Sports Science Australia on exercise for bone health.

  • References

    i. http://share.iofbonehealth.org/WOD/Compendium/IOF-Compendium-of-Osteoporosis-WEB.pdf

    ii. Weaver, C.M., Gordon, C.M., Janz, K.F. et al. Osteoporos Int (2016) 27: 1281. https://doi.org/10.1007/s00198-015-3440-3

    iii. https://www.healthdirect.gov.au/healthy-bones

    iv. https://www.eatforhealth.gov.au/food-essentials/five-food-groups/milk-yoghurt-cheese-andor-their-alternatives-mostly-reduced-fat

    v. Weaver CM, Proulx WR, Heaney R. Choices for achieving adequate dietary calcium with a vegetarian diet. Am J Clin Nutr. 1999; 70(3 Suppl): 543-8S.

    vi. https://www.researchgate.net/publication/221717440_Milk_and_Acid-Base_Balance_Proposed_Hypothesis_versus_Scientific_Evidence 

    vii. Heaney RP. Dairy and bone health. J Am Coll Nutr. 2009;28(Suppl 1):82S–90S. doi: 10.1080/07315724.2009.10719808.

    viii. Caroli A. et al. Invited review: dairy intake and bone health: a viewpoint from the state of the art. J Dairy Sci. 2011;94(11):5249–5262. doi: 10.3168/jds.2011-4578.

    ix. Rozenberg S et al. Effects of Dairy Products Consumption on Health: Benefits and Beliefs—A Commentary from the Belgian Bone Club and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases. Calcif Tissue Int. 2016; 98: 1–17. Published online 2015 Oct 7. doi: 10.1007/s00223-015-0062-x

    x. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3004072/

    xi. https://www.ncbi.nlm.nih.gov/pubmed/25907388

    xii. https://www.iofbonehealth.org/sites/default/files/media/PDFs/Regional%20Audits/2013-Asia_Pacific_Audit_0_0.pdf

    xiii. https://onlinelibrary.wiley.com/doi/pdf/10.1002/jbmr.279

    xiv. Ebeling P, Daly R, Kerr D, Kimlin M. Building bones throughout life: an evidence-informed strategy to prevent osteoporosis in Australia. Med J Aust. 2013;199(7 Supp):S1.

    xv. https://www.osteoporosis.org.au/what-it

    xvi. https://www.osteoporosis.org.au/faq

    xvii. https://www.osteoporosis.org.au/prevention 

    xviii. Weaver, C.M., Gordon, C.M., Janz, K.F. et al. Osteoporos Int (2016) 27: 1281. https://doi.org/10.1007/s00198-015-3440-3

    xix.https://www.aihw.gov.au/reports/arthritis-other-musculoskeletal-conditions/estimating-the-prevalence-of-osteoporosis-in-austr/contents/summary