We are regularly told of the importance of certain factors which will promote good bone health, ie. exercise and diet, but we are rarely informed of the likely factors which can cause your bones to deplete or become ‘unhealthy’.
One aspect of the difference between good and poor bone health is through the intake of calcium via protein in the diet.
Protein is of vital importance for tissue repair and growth, as well as for some of the body’s hormones (ie. blood insulin), chemicals, enzyme synthesis, and nucleic chemicals. For some years, scientists have supported the concept of consuming substantial amounts of protein (ie. between 120g and 185g every day), which reflects the theory of Liebig in the early 19th century, that physical activity actually consumes muscle protein and that the muscle proten itself should be constantly replaced.
The point that a substantial amount of protein is not completely necessary to the adult human, was first indicated in 1905 by Chittenden.
It is relatively recent, however, that scientists have proved that adult protein requirements are actually only approximately between 40 and 60 grams (or 1.5 to 2 oz) each day. For example, red meat, is only made up of about 25% of protein. Therefore a 6oz. low-fat hamburger will provide 1-1/2 oz. of protein, which meets the RDA (recommended daily allowance). Any other protein consumed on that day may lead to a loss of calcium. Consuming animal meat every day in greater proportions will most likely lead to calcium decline from your bones as well as increasing the chance of the onset of osteoporosis.
The ratio therefore, between the quantities of calcium absorbed and the quantities of calcium displaced in the urine, is known as the calcium balance. A negative calcium balance is caused by a high intake of protein, (ie., more calcium is actually excreted than was ingested and absorbed). This will cause the calcium to be taken away from the bones. In calculating a person’s protein intake, it is of the utmost importance to consider the protein content of particular dietary ingredients. You may find this list useful in understanding where calcium comes from in your diet:
- Poultry, cheese, and seafood – 25 to 30 % protein
- Most meat – roughly 25 % protein
- Other veggies – vary from 3.five to ten % protein
- Beans, peas, and nuts – roughly ten to twelve % protein
- One egg (egg white) – 0.22 oz of protein.
CALCIUM – THE BODY’S MOST ABUNDANT MINERAL
Calcium is one of the most important minerals and is vital for building and maintaining the human skeleton. Ninety-nine per cent of all the calcium in the body is needed in the bones, with just one per cent needed in the blood to perform important tasks such as regulating the heartbeat and enabling blood clotting. An adequate supply of calcium is essential during periods of rapid bone growth such as childhood and adolescence, as well as during breast-feeding and from the peri- to postmenopausal years.
But calcium does not work by itself; it needs to work alongside certain ‘companion’ nutrients in order to be absorbed properly, and to perform its bone-building tasks. These nutrients include vitamin D and the minerals phosphorus and magnesium.
Low-fat dairy products are considered to be the best source of calcium in the diet (low-fat dairy products contain more calcium per serving than full-fat versions). Low-fat yoghurt and skimmed milk are excellent sources of dietary calcium, and milk has the advantage of containing phosphorus. Dairy products are not a good source of magnesium, however.
Some people need to receive calcium from non-dairy sources, either because they cannot digest milk properly, because they are allergic to it or because they do not eat animal foods. For such people, calcium can be found in green leafy vegetables, nuts and seeds; these foods also contain the mineral magnesium.
As always, the best advice is to receive calcium from a wide variety of foods. It is important to note that certain drinks can inhibit calcium absorption – or promote its excretion – these include tea, coffee, alcohol and carbonated soft drinks; an excessive amount of protein or fibre in the diet can have the same effect. Even if a person’s diet contains plenty of calcium, it is still important to stimulate healthy bones by performing some form of regular weight-bearing exercise, such as going for a brisk walk, every day.