Why are calcium and dairy foods so important in the development of strong healthy bones? That was the focus of National Healthy Bones Week held earlier this month, and it’s a question I am often asked professionally.
I love dairy foods. I enjoy milk for recovery after training, enjoy the satiating qualities that yoghurts poses for a PM snack (the full-fat type) and can’t go past a lovely cheese platter over a catch up with friends. However, many do not share this same love.
Eight out of ten adults do not meet the recommended number of servings of dairy (or dairy alternatives such as soy products) a day as outlined in the Australian Dietary Guidelines.
I am very much aware that many people need to avoid or limit dairy foods due to intolerances or personal dietary preferences. Some others just do not share the same view when it comes to the health benefits of dairy foods. The many reasons that people may or may not include dairy in their diet can make it confusing for people trying to eat for health.
This led me to explore some of the views and evidence of the pro-dairy faction and have a look at other science-based views and most importantly determine how everyone can get enough calcium in their diets.
But let’s not forget that this all came about because of National Healthy Bones Week and calcium is just one piece of the puzzle.
The healthy bones puzzle
Building healthy bones is an area of our health that isn’t talked about a lot, especially during the crucial ages for bone building (our teenage years) when focus may be on eating for weight versus eating for health and wellness.
It is important to piece each part of the puzzle together to build healthy bones. This puzzle involves three main pieces including adequate dietary calcium intake, adequate vitamin D (which many of us are deficient in) and regular bone strengthening exercise such as jogging, brisk walking, balance exercises and resistance exercise. For more information on building healthy bones and weight bearing exercise checkout these great Motherpedia articles:
The role of calcium
Most people know that calcium is important to help build healthy teeth and bones. This occurs when the calcium deposits as a crystal onto our bones to give them their hard strength. Our body also requires calcium to help transmit nerves, regulate the hearts rhythm and assist with blood clotting.
Our body gets calcium through the foods that we eat. It can also borrow calcium from our bones when our blood levels start to drop to low. If this is not replaced our bones will lose their strength. So it’s pretty safe to say we need calcium in our diets!
While no one is questioning the important role of lifelong calcium intake for the health of our bones, the debate comes down to just how much calcium do we really need and what are the best sources of calcium in our diets?
When we sort through the opinion and look closely at the evidence, there’s no ‘final answer’ onhow much we need. But here is what we know about calcium, food sources and what our current recommendations are.
How much calcium do we need?
The Australian recommendations suggest that children require 500mg-1000mg, teens require 1300mg and adults require 1000mg-1300mg of calcium a day depending on their age and gender.
How to meet these recommendations
The new Australian Dietary Guidelines recommend 2 ½ - 4 serves of dairy foods a day for adults (depending on their age) to help meet calcium requirements and gain additional health benefits from dairy foods.
A serve of dairy contains approximately 350-450mg of calcium per serve with one serve equating to:
- 250ml of cows milk
- 250ml of soy milk (with at least 100mg of added calcium per 100ml)
- 200g of yoghurt
- ½ a cup of ricotta cheese, or
- 40g of cheese.
The list is endless when we think about how we can include these foods in our diets. Think:
- milk after exercise
- Greek yoghurt on curries
- ricotta cheese in salads, and
- plain yoghurt with fruit for dessert.
The Great Dairy Debate
Although the new Australian Dietary Guidelines are based on scientific evidence, some groups question if we really need this much calcium, particularly from dairy foods for bone health. However, contradictory studies only show correlation, not conclusive evidence that would alter the guidelines.
Consuming calcium through dairy foods may also offer benefits beyond bone health including lowering cardiovascular disease risk, improving body composition and potentially reducing the risk of type 2 diabetes.
So as far as I’m concerned, I will continue to enjoy my 2-3 serves of dairy a day and encourage the people around me to do the same.
Dairy alternatives
Dairy alternatives include soy, rice and almond products. Some people prefer these alternatives because of a lactose intolerance or personal dietary preference.
It is important to choose calcium fortified (added calcium) dairy alternatives. Calcium fortified soy milks and cow’s milk have a similar calcium content per serve. However, fortified almond and rice milks are generally much lower in calcium (approximately180mg versus approximately 350mg of calcium per 250ml serve) and many almond and rice products are not fortified.
Food is complex and it’s not just the nutrient content of a food that is important to consider, but how our body will use this nutrient.
Our bodies tend to use the calcium from dairy foods more effectively compared with some dairy alternatives. If dairy alternatives are fortified with calcium phosphate, the calcium absorption is generally 75% of the absorption from cow’s milk. If products are fortified with calcium carbonate the absorption is equivalent to cows milk. You can check the fortification method by reading the ingredients list on the label.
Fish sources
Calcium can also be found in fish with edible bones such as sardines (489mg per 90g serve) and salmon (279mg per 90g serve), which are absorbed well. These sources of oily fish also contain omega 3 fish oils and vitamin D and are great foods for building healthy bones.
Vegetable sources
Many people believe they can get enough calcium through vegetable sources, especially with vegetables such as kale that is becoming increasingly popular.
However, the amount of calcium per serve of these foods is quiet low and the absorption of the calcium is questionable. The absorption of calcium from almonds (30mg for 10 almonds), legumes (43mg per cup of baked beans) and dark green vegetables such as kale (100mg per cup) and broccoli (15mg per 2 florets) depends on the phytate content. Phytate is a plant compound that blocks the absorption of calcium in the gut.
Oxalates, another plant compound, also block the absorption of calcium. Although spinach has been labelled a good source of calcium in the past it should not even be considered as a source of calcium because of its oxalate content.
Although some of your favourite green leaves may not be as calcium rich as once thought, they do contain vitamin K, which has been shown to give some assistance in building healthy bones.
Final notes
- If you rely on vegetable sources to meet your calcium needs you may not be getting as much as what you initially expected.
- Consider including some calcium fortified soy products (seek advice if you have a existing or past breast cancer diagnosis) if you choose to leave dairy out of your diet.
- For all of those dairy lovers, continue to include milk, yoghurt and cheese in your diet for various health benefits beyond bone health.
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