# Healthy eating habits/Calcium and Bone Health for Women

It is essential that we take good care of our bones.
Our bones are important for carrying our weight, holding our body upright, storing essential minerals and producing blood cells. Without paying special attention to our bone health, our bones can become very weak which can lead to dangerous health problems such as osteoporosis (a condition where bones become porous and weak due to loss of essential minerals such as calcium). We are also more likely to fall if our bones become weak.
Females in particular need pay special attention to their bone health because bones weaken more in females than males. To make matters worse for females, bones weaken even more during and after menopause.

## What is Calcium?

Calcium is a mineral nutrient needed for strong bones and teeth, muscle functioning and preventing osteoporosis. There is more calcium than any other mineral in the body.
Calcium is mainly found in dairy foods such as milk, cheese, yoghurt. Calcium is also found in some vegetables (such as broccoli and spinach), fruits (such as dried figs and oranges) and some wholegrain breads and cereals.
Calcium has many important roles in the body, however is most important for bone health.

## Why is Calcium Important for Bones?

Calcium plays an essential role in bone structure and maintenance, which is incredibly important as our bones provide the framework for our bodies. Around 99 per cent of the body’s calcium is stored in bones and teeth, and the remaining 1 per cent can be found circulating in the blood or in cells.
Our bones provide quick access to calcium when the body is in need. If calcium levels in the blood drop, the blood will borrow calcium from the bones to restore it to a healthy level. If calcium levels in the blood rise, the blood will return any extra calcium back to the bones.
Calcium bone stores can become depleted if calcium intake in the diet is poor. This can result in weaker bones which are susceptible to osteoporosis.
For this reason, it is extremely important to consume adequate amounts of calcium-containing foods to ensure strong and healthy bones.

## What are Good Dietary Sources of Calcium?

Dairy foods such as milk, cheese and yoghurt are excellent sources of calcium. Dairy is an easy way to get your daily calcium needs. Additionally, dairy not only provides calcium, however also provides vitamin D, phosphorus and protein, all of which are important for building strong bones, teeth and muscles.
There are also many non-dairy sources of calcium, some of which include tofu, green leafy vegetables and canned salmon with the bones.
To assist the population with meeting its recommended daily calcium intake, the National Health and Medical Research Council (2006) have developed specific dietary guidelines for the consumption of milk, cheese yoghurt and alternatives. These guidelines explain what a serve is, and how many serves are recommended each day in order for Australians to maintain healthy bones (see Australian Dietary Guidelines outlined below.

## What Constitutes a Serve of Milk, Yoghurt, Cheese or Alternative?
#### Dairy sources and non-dairy milks

According to the Australian Dietary Guidelines 2013 a serve of milk, cheese, yoghurt or alternative is equal to:
* 1 cup (250ml) fresh, UHT long life, reconstituted powdered milk or buttermilk
* ½ cup (120ml) evaporated milk
* 2 slices (40g) hard cheese e.g. cheddar
* ½ cup (120g) ricotta cheese
* ¾ cup (200g) yoghurt
* 1 cup (250ml) soy, rice or other cereal drink containing at least 100mg added calcium per serve.
It is important to note that consuming low-fat dairy products are recommended when possible. The calcium content does not vary between full-fat and low-fat products, it is only the fat content that varies.

#### Non-dairy sources

The following foods contain around the same amount of calcium as the above sources:
* 100g almonds (with skin on)
* 60g sardines, canned in water
* ½ cup (100g) canned pink salmon with bones
* 100g firm tofu (check label as calcium content may vary).
It is important to note that most of the calcium in canned pink salmon and sardines comes from the bones. Therefore the bones should be eaten. They can be mashed into the salmon or sardines to make them more palatable.

## How Many Serves of Dairy or Alternatives Should I Be Having Each Day?
#### Women

| Age | Number of Serves Per Day |
| 19 - 50 Years | 2 ½ |
| 51+ Years | 4 |
Adapted from the Australian Dietary Guidelines (2013)

## Post-menopausal Women

Calcium absorption decreases with age, as well as before and after menopause. Furthermore, more calcium is excreted in the urine after menopause, which means more calcium is lost from the body. For this reason, it is extremely important that post-menopausal women increase their daily calcium intake to compensate for these losses.

## Green Leafy Vegetables and Calcium Fortified Products
#### Green leafy vegetables

Green leafy vegetables provide a good source of calcium, although they are not as calcium-rich as dairy products or canned fish with bones. Nonetheless, they are still an extremely important component of the diet, and can be easily included into dishes or eaten on their own. Some of these include:
* Bok choy
* Broccoli
* Kale
* Parsley
* Watercress.

#### Calcium fortified products

Calcium fortified products are another excellent source of calcium which can easily be included into the diet. Such products include fortified fruit and vegetable juices and fortified cereals and breads. These can generally be purchased from the supermarket.

## Tips For Increasing Calcium Intake

* Try adding an extra serve of milk, yoghurt or cheese each day
* Homemade fruit smoothies are a great way to increase intake
* Include cheese in sandwiches
* Add yoghurt to soups or salads
* Add yoghurt to cereal
* Add milk or milk powder to soups or casseroles
* Enjoy a glass of warm milk before bed
* Include a variety of green leafy vegetables such as broccoli, kale or bok choy
* Add shaved/ grated parmesan or mozzarella cheese to pasta
* Choose calcium fortified products such as fortified tofu, milk, cereals or juices.

## Other Factors To Consider

It is possible to protect bones with lifestyle. This involves spending some time in the sun and being physically active wherever possible.

#### Sun exposure

Spending some time in the sun is important for our skins to make vitamin D. To increase vitamin D absorption, aim for 10-15 minutes of sunlight everyday (if possible).

##### Vitamin D

Vitamin D helps calcium get absorbed. Since many Australian women are Vitamin D deficient, taking a Vitamin D supplement may be necessary. It is recommended that a GP or dietitian is first seen prior to commencing supplementation.

#### Foods that increase calcium excretion

Excessive amounts of caffeine, alcohol, soft drink and salt increase calcium excretion, which means that more calcium than normal is lost from the body through urine. Caffeine, alcohol, soft drink and salt should not be consumed in excessive amounts.

#### Physical activity

Regular physical activity will help. Weight-bearing exercise, walking, jogging, playing tennis, yoga, gardening and vacumming are examples of activities that can be important for bone health.

## Additional Resources

* Australian Dietary Guidelines 2013
* Australian Guide to Healthy Eating
* Osteoporosis Australia

## References

* ↑ Whitney, E., Rolfes, S., Crowe, T., Cameron-Smith, D. & Walsh, A. (2011). Understanding Nutrition – Australia and New Zealand Edition. Melbourne: Cengage Learning Australia Pty Limited.
* ↑ Whitney, E., Rolfes, S., Crowe, T., Cameron-Smith, D. & Walsh, A. (2011). Understanding Nutrition – Australia and New Zealand Edition. Melbourne: Cengage Learning Australia Pty Limited.
* ↑ Whitney, E., Rolfes, S., Crowe, T., Cameron-Smith, D. & Walsh, A. (2011). Understanding Nutrition – Australia and New Zealand Edition. Melbourne: Cengage Learning Australia Pty Limited.
* ↑ National Health and Medical Research Council. (2013). Australian Dietary Guidelines. Retrieved from http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n55_australian_dietary_guidelines_130530.pd
* ↑ National Health and Medical Research Council. (2013). Australian Dietary Guidelines. Retrieved from http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n55_australian_dietary_guidelines_130530.pd
* ↑ National Health and Medical Research Council. (2013). Australian Dietary Guidelines. Retrieved from http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n55_australian_dietary_guidelines_130530.pd
* ↑ National Health and Medical Research Council. (2008). Australian Guide to Health Eating. Retrieved from http://www.eatforhealth.gov.au/sites/default/files/files/public_consultation/n55d_draft_dietary_guidelines_agthe_111212.pdf
* ↑ National Health and Medical Research Council. (2013). Australian Dietary Guidelines. Retrieved from http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n55_australian_dietary_guidelines_130530.pd
* ↑ National Health and Medical Research Council. (2008). Australian Guide to Health Eating. Retrieved from http://www.eatforhealth.gov.au/sites/default/files/files/public_consultation/n55d_draft_dietary_guidelines_agthe_111212.pdf
* ↑ National Health and Medical Research Council. (2006). Nutrient Reference Values - Calcium. Retrieved from http://www.nrv.gov.au/nutrients/index.htm
* ↑ Whitney, E., Rolfes, S., Crowe, T., Cameron-Smith, D. & Walsh, A. (2011). Understanding Nutrition – Australia and New Zealand Edition. Melbourne: Cengage Learning Australia Pty Limited.
* ↑ Whitney, E., Rolfes, S., Crowe, T., Cameron-Smith, D. & Walsh, A. (2011). Understanding Nutrition – Australia and New Zealand Edition. Melbourne: Cengage Learning Australia Pty Limited.
* ↑ Osteoporosis Australia. (2013). Calcium. Retrieved from http://www.osteoporosis.org.au/