Drinking milk is often emphasised when we growing up as it helps to build strong teeth and bones, but what happens when we already adults? Does the need for dairy disappear? Or should we still be trying to drink a glass of milk a day? Is milk the only source of calcium?
A closer look at bonehealth
Our bones are made up of minerals (60%), organic matrix (30%) and water (10%). Type I collagen is the basic building block of the bone matrix fibre network. Due to the aging process (around 45 55 years old) the mass and strength of our bones decreases and as a result there is an increased risk of fractures. Calcium forms part of the skeletal muscle and bone structure and is also part of the mineral reservoir for blood. We lose calcium every day through our urine, faeces and skin (about 150-300mg/day). These losses can only be balanced by having enough calcium through the foods we eat. Along with vitamin D, protein and inorganic phosphate, calcium works to help with bone formation and to decrease bone resorption.
Bone resorption is the process whereby the body breaks down its own bones in order to release the minerals contained in the bone, back into the blood. This occurs when the body doesn’t get enough of these minerals from food. Serum calcium concentration is regulated at 2.25-2.6 mmol/l by our body and if this balance is not maintained, the body will use our bones. If there is insufficient vitamin D and low calcium absorption, then there is an overproduction of parathyroid hormone which leads to an increase in bone resorption. Bone resorption is what makes our bones brittle. Postmenopausal women, vegetarian, lactose intolerant or cow’s milk allergy individuals or individuals with osteoporosis are at risk of a calcium deficiency.
How can dairy help our bones?
Milk, yoghurt, maas, cheese and butter are all examples of dairy foods. Dairy contains calcium, phosphate and protein, all of which are needed for healthy bones. The National Osteoporosis Foundation of South Africa recommends a daily intake of 1000-1200mg of calcium and 800-1000 IU vitamin D. One serving of dairy contains 300mg of calcium, therefore we require three servings of dairy a day. A serving of dairy is regarded as a glass of milk (240 ml), which contains 300mg of calcium, 42g cheddar cheese which contains 303mg of calcium or 240ml of yoghurt which contains 300 mg of calcium. There are other sources of calcium such as red and white beans, broccoli, spinach, sweet potato, sardines with bones and salmon, however all these foods contain less than 300mg calcium per typical serving size.
How can I practically fit in this daily dairy requirement?
Fitting dairy into your daily day may seem daunting but it doesn’t need to be. Have a cup of milk with cereal in the morning, yoghurt with fruit as a snack and add some cheese with your supper tonight.
Try different recipes and don’t be afraid to try different sources of calcium until you find one you enjoy. What do you believe about dairy that prevents you from having this food group?
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