# Healthy eating habits/Answering Questions about Healthy bones, Women and Calcium

The purpose of this guide is to answer common questions on serves of dairy for calcium requirements, different sources of calcium other than dairy and for using a variety of sources in meals for optimum calcium intake. It was developed for women over 35 years.

## Background

There are over 170 uses for calcium in our body and 99% is used for bone strength. The calcium makes our bones strong and the bones in turn serve as a storage reservoir for calcium. If our diet is lacking in calcium, the body will take it from the reservoir in the bones, making them weaker (Whitney et al, 2011). Osteoporosis is the weakening of the internal structure of the bone. 3.4% of Australians have confirmed osteoporosis and significantly, 82% of these cases are women (Osteoporosis Australia, 2014). Healthy bones will be denser while weaker bones will have a more porous structure, which will fracture more easily. From 35 years onward, the process of bone regeneration slows down and after 60 years, 50% of all women experience osteoporotic fracture (Whitney et al, 2011).

## How much Calcium do women need?
### How much is a serve of dairy?

* 250 ml or 1 cup milk or calcium fortified soy
* 200 g or ¾ cup yogurt
* 40 g hard cheese

### How many serves per day do women require?

* 2½ serves per day until 50 years
* serves per day after 50 years

### How I can incorporate serves in my day? Examples

* 125 ml on cereal at breakfast; 200 g tub yogurt as a snack; 40 g cheddar on a sandwich
* 200 g yogurt with oats at breakfast; 125 ml skim milk in a latte as a snack; 30 g Parmesan on pasta

## The Calcium in our food.
### Animal and plant sources of calcium

| ANIMAL SOURCES | SERVE SIZE | Mg Calcium | PLANT SOURCES | SERVE SIZE | Mg Calcium |
| Yogurt, low fat | 3/4 cup or 200 g | 450 mg | Tofu, calcium set | 1/2 cup | 135 mg |
| Sardines, with bones | 45 g | 212 mg | Bok Choy | 1/2 cup | 75 mg |
| Milk, reduced fat | 250 ml | 300 mg | Kale | 1/2 cup | ~75 mg |
| Cheese, Cheddar | 40 g | 300 mg | Tahini | 1 heaped tsp. | 129 mg |
| Egg, whole, chicken | 2 x 60 g | 50 mg | Broccoli | 1/2 cup | 40 mg |
| | | | Cauliflower | 1/2 cup | ~20 mg |
| | | | Almonds, raw, with skin | 30 g | 75 mg |

### Animal sources and plant sources NOT animal vs. plants!

When plant and animal sources are grouped together and served in the one meal, small milligrams of calcium add up to calcium rich meals. This adds variety to the diet as well as sources of Vitamins B, C, Folate and dietary fibre(Whitney et al, 2011). In addition there is increasing evidence that a dietary pattern with a wide variety of foods is important for good health, rather than the emphasis on one or two food groups (NHMRC, 2012).

## Bioavailability

Bioavailability is the rate and extent to which calcium (or any nutrient) can be absorbed by the body and utilised for the requirements. Plant sources have greater bioavailability than animal sources (Whitney et al, 2011).

### Calcium bioavailability of animal and plant sources

| Calcium bioavailability | Food Source |
| > 50 % | bok choy, cauliflower, watercress, Brussels sprouts, broccoli |
| ~ 30 % | cow and fortified soy milk, calcium set tofu, cheese and yogurt |
| ~ 20 % | almonds, sesame seeds (tahini), pinto beans and sweet potatoes |
| < 5 % | spinach, rhubarb, silverbeet |

### Bioavailability and plant sources

In countries like China where almost no dairy products are consumed, osteoporosis is uncommon, providing evidence that plant sources can play a vital role in strong bones. Grouping many different vegetables in the one meal not only provides for greater calcium, but takes advantage of the greater bioavailability of plant sourced calcium (Whitney et al, 2011).

## Examples of Meals and Recipes
#### Stir Fry of Bok Choy, Tofu, Almonds and Broccoli

Serves 2
1 bunch Bok Choy
2 cups broccoli florets
1 red capsicum cut into thin strips
1 cup calcium set tofu, cut into cubes and marinated in 2 tbsp. of tamari, 1 tbsp. of grated fresh ginger, 1 tbsp. grated fresh garlic, and juice of 1 lemon
60 g almonds, lightly toasted in oven
2 tbsp. peanut or grape seed oil
½ tsp. toasted sesame oil
1 tsp. grated ginger extra
Juice of ½ lemon
Bake marinated tofu cubes in moderate oven for 20-30 minutes. Heat peanut oil and stir fry capsicum first followed by green vegetables.
Add marinade drained from tofu and continue until vegetables are just cooked.
Add another tsp. of grated ginger, sir though and add juice of half a lemon
Add tofu, almonds and sprinkle with sesame oil, stir gently through. Serve with brown rice
Calcium note: 2 cups of raw Bok Choy (which will wilt) can contain as much as 300 mg of calcium, the same as 250 ml serve of cow’s milk.

### Sardine Fish Cakes with Sweet Potato

http://www.primalpalate.com/paleo-recipe/sardine-and-sweet-potato-fish-cakes/
Calcium note: Serve with a sauce of 3 heaped tsp. of tahini (387 mg calcium) thinned with 100 g of natural yogurt (225 mg calcium) and flavoured with finely chopped coriander.

### Cauliflower and Brussels Sprout Cheese Gratin

http://www.canadianliving.com/food/cauliflower_and_brussels_sprouts_gratin.php
Calcium note: combining dairy sources with good plant sources increases total calcium intake in one meal.

## Additional Resources
### General

Australian Guide to Healthy Eating, http://www.eatforhealth.gov.au/
Better Health Channel: Calcium (see Osteoporosis risk quiz in sidebar) http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Calcium?open
Osteoporosis Australia at http://www.osteoporosis.org.au/

### Individual Advice

Dietitians Association of Australia, http://daa.asn.au/ to find an accredited practicing dietitian

## References

Whitney, E., Rolfe, S., Crowe, T., Cameron-Smith, D. & Walsh, A. (2011) Understanding Nutrition, Australia, Cengage Learning
Osteoporosis Australia (2014) Main Page http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Osteoporosis
National Health and Medical Research Council (NHMRC) (2012) Australian Dietary Guidelines for Healthy Eating accessed 20/08/14
http://www.eatforhealth.gov.au/sites/default/files/files/the_guidelines/n55g_adult_brochure.pdf
Food Standards Australia and New Zealand (2010) Nuttab Online 2010 accessed 20/08/14
http://www.foodstandards.gov.au/science/monitoringnutrients/nutrientables/nuttab/Pages/default.aspx