Expert Nutrition

Calcium (Ca+)

Good sources of Calcium

The body contains estimates between 750g and 1.3kg of calcium which makes calcium the most abundant mineral found in the body. The majority of calcium (99%) is found within our bones and teeth and it is not surprising that there have been numerous studies confirming that calcium is essential for the building and maintaining of these structures. Throughout life, bones are in a constant state of reformation as calcium is continually removed and redeposited in the bones which replace much of there mineral content every couple of years.

The remaining 1% of calcium in the body is found in both extracellular fluid and within the cells, where it is involved in numerous metabolic roles. Calcium is critical to normal nerve conduction, muscle contraction, blood clotting, cell division, and electrical conduction in the heart. Calcium also plays an important role in the regulation of blood pressure, in the prevention of osteoporosis and may also reduce the risk of colon cancer.

Life without calcium is impossible and small variations in plasma (a component of blood) calcium levels can have serious consequences. Calcium deficiency can cause a number of health related problems including rickets in children and osteoporosis in adults. In some cases, calcium deficiency is due to a lack of vitamin D which has an essential role in the absorption of calcium. The deficiency may also be the result of physical inactivity especially during complete bed rest, which increases calcium loss. This helps to explain why exercise plays an important role in the prevention of osteoporosis.

The best sources of calcium are dairy products including milk, cheese and yoghurt, however soy milk also contains calcium. Other good sources of calcium include nuts, canned fish, broccoli, spinach, cabbage, dried apricots and figs.

Calcium found in dairy products is more easily absorbed into the body than that found in plant foods. This is because calcium found in dairy products comes bound to proteins that make it more soluble and therefore more likely to be absorbed. Studies also suggest that lactose (milk sugar) promotes the absorption of calcium.

Soft bones (eg those found in tinned tuna and salmon) are also a good source of calcium that is easily accessed by the body. Although some plant foods contain large amounts of calcium it often comes in the form of inorganic salts or complexes with oxalates and phytates which are less soluble and therefore are less bioavailable to the body.

In post menopausal women, there is evidence that a high intake of calcium can slow the rate of bone loss and may reduce the risk of fracture. Numerous studies have confirmed that calcium supplemented at 500 to 1200mg per day can significantly reduce bone loss and accidental facture, which has proven not only to benefit the elderly but also children and adolescence. Given the role of vitamin D in the absorption of calcium a good supplement is likely to contain both of the nutrients.

"Based on the cost effectiveness and clinical efficacy, calcium and vitamin D should be the first line therapy in patients at risk for osteoporosis fractures"
- Paul Ullom-Minnich, MD University of Kansas School of Medicine


References:
1. Stanton R. Foods that harm, foods that heal: An A-Z guide to safe and healthy eating. Readers Digest; 2006, pp 256-261.
2. Mann, J., Truswell, S. Essentials of Human Nutrition. Oxford Medical Publications, New York. 2000
3. MacWilliam, L.D. Comparative Guide to Nutritional Supplements. Northern Dimensions Publishing; 2005
4. The Merck Manual of Medical Information 2nd Ed. Beers, M.H., Fletcher, A. J., Jones T. J., Porter, R., Berkwits, M., et al., editors. Pocket Books Reference; 2003
5. National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand. Department of Health and Ageing; 2006
6. Wahlqvist, M.L., et al. Australia and New Zealand: Food and Nutrition. 2nd Ed. Allen and Unwin, Sydney; 2002 pp 272-273.

Page copy protected against web site content infringement by Copyscape


New! Comments

Have your say about what you just read! Leave me a comment in the box below.

Please share our website with your friends


SiteSell Hosting


Site Build It!


[?] Subscribe To
This Site

XML RSS
Add to Google
Add to My Yahoo!
Add to My MSN
Add to Newsgator
Subscribe with Bloglines


Copyright  © 2008 -2011 www.expert-nutrition.com - All Rights Reserved