Known for its important role in skeletal health and the prevention of osteoporosis, a reduced dietary calcium intake and an increased physiological need can have a profound effect on the individual beyond bone health. In this article, we review the functions of calcium within the body and look at dietary and supplemental sources of calcium. We take a closer look at the rationale for supplementation across the lifespan and showcase the role of calcium D-glucarate supplementation, looking at its unique role in hormone regulation.
Calcium is an essential macronutrient found in abundance in the body, with 99% stored in teeth and bone.1 This mineral is involved in several biochemical processes, including:
- Hormonal secretion
- Nerve impulse transmission
- Muscular function
- Vascular contraction
- Vasodilation
- Intracellular signalling. 1,2
Lifespan calcium requirements
Calcium plays an important role in women’s health, with intake requirements differing across the lifespan.
Higher doses of calcium are required during pregnancy and breastfeeding3 to:
- Minimise bone mineral loss
- Aid skeletal growth of the child4
- Support milk production4
- Prevent pre-eclampsia.3
Higher doses are also needed for menopausal and post-menopausal women, as the drop in oestrogen necessary for bone formation causes more bone resorption, increasing the risk of osteoporosis and osteoporotic fractures.5
Calcium deficiency
With the wide-ranging role of calcium throughout the body, Fig. 1 depicts some of the physical expressions of calcium deficiency.
Calcium in the diet
Meeting the requirements for calcium can be challenging - 1 in 10 Australians do not meet their daily calcium requirements through diet.6 While dietary intake of calcium in childhood is generally sufficient, intake drops during adolescence in Australia.7 A staggering 90 per cent of women between the ages of 12-18 years and over 50 years were found to have insufficient dietary calcium in Australia, despite an increased need.6 The number of Australians choosing to avoid animal products and switching to plant-based alternatives is increasing and while plant-based milk and dairy alternatives provide a dairy replacement from a taste perspective, unless they are fortified with calcium, they often do not provide the calcium benefits of dairy products.7
Generally, dietary intake of calcium is sufficient for most people, provided their diet contains no restrictions. There are, however, some individuals who may benefit from supplementation including individuals who:
- Take corticosteroids
- Diagnosed with osteopenia or osteoporosis
- Follow a vegan or dairy-free diet or those with a lactose intolerance
- Women with amenorrhea
- Residents of aged / long-term care facilities
- Individuals with gastrointestinal (GI) diseases, given dietary calcium is largely absorbed in the small intestine.2,8
Supplemental calcium
The two most common forms of supplemental calcium include calcium carbonate and calcium citrate, followed by calcium hydroxyapatite. Several factors for consideration when prescribing are outlined in the table below (See Tables 1 and 2). Regardless of the form chosen, absorption is best when taken with food, in divided doses of 500mg or less at a time and when given concurrently with vitamin D.9
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