Calcium is one of the most important elements in the body and, together with magnesium, is vital for cardiovascular health. In the main calcium is used by the body extracellularly (along with sodium), as opposed to potassium, magnesium and zinc which are largely found intracellularly.
Ninety-nine per cent of all calcium in the body is found bound to phosphorus in bones and teeth. However, more important to us is the ionic form of calcium which is found in the body. Around 60 per cent of all the calcium in the bloodstream is in the ionic form (Ca++) where its degree of concentration ranges from 9 to 11 milligrams per 100 millilitres of serum. This ionic calcium is very important in the body economy, being instantly available for use chemically, especially in relation to coagulation of blood, as well as heart, muscle and nerve function and the permeability of cell membranes.
The distribution of calcium in the body in good health and disease varies greatly. Under ideal conditions, largely controlled by the activity of the parathyroid hormone, calcium levels are as follows:
- The bulk of stored stable calcium in the body is approximately 1 kilo in the bones and teeth.
- Between 2 and 4 grams of the calcium in the bones is in the ionic form which is 'exchangeable' with the amount of calcium 'transported' daily, into and out of bone, commonly around 3 grams.
- This interchange is between bone and the calcium held extracellularly (around 1-1.5 grams) and intracellularly (4-10 grams), in the plasma (less than .5 gram) and in interstitial fluids (under 1 gram).
Under certain circumstances, as in osteoporosis, deposition of calcium takes place around joints (soft tissues) and in arteries. Such abnormal calcium deposits are known as metastatic or dystrophic deposits, some of which contain ionic calcium.
Parathyroid hormone (which is markedly influenced by the degree of acidity of the blood, and production of which is stimulated by EDTA infusion - see below), as well as calcitonin and vitamin D3, control and regulate calcium flux between extracellular and intracellular calcium, so vital in cellular function as well as in those enzyme systems which influence muscle contractility, nerve transmission and some hormone activities.
The transfer of substances including water across cell membranes involves the activity of ionic forms of many minerals including sodium, potassium, magnesium and calcium. It is in the mitochondria of cells that intracellular calcium is found, most usually bound as a phosphate rather than in ionic (free) form.
In an adult, 20 per cent of the total bone calcium is re-absorbed and replaced each year, in normal health, but when replacement is inadequate, serious problems arise. Thus, apart from its role in providing structural integrity to the skeleton and teeth, calcium is also of vital importance in the processes of growth and development, and the maintenance of health, and yet it presents us with an apparent paradox.
It is now known that, if overall nutrient imbalances exist, a high-protein diet is capable of speeding up the removal of calcium from bones and of contributing to osteoporosis. This has occurred in many millions of women in Europe, America and other industrialized nations of the world. Post-menopausa women in particular are thus vulnerable to easily fractured bones, after even slight injury. Many factors contribute towards this, but one of the major elements appears to be an imbalance in the ratio of calcium-to-phosphorus in the diet. Phosphorus is found in very large quantities in meat and in most other proteins as well as in carbonated drinks.
Stone-age man ate abundant meat (in excess of 700 grams daily), as do current hunter gatherers, and yet their bone structures remained, and remain, sound into old age.
This is a paradox.
The complex process which occurs when a high-protein diet is consumed may be linked to a high degree of acidity in the body. Increased acidity increases parathyroid hormone production and a consequence of this is additional resorption of calcium from bone into the bloodstream. If additional vitamin D is also present in the body this progression may be limited (and the body of course makes vitamin D when sufficient sunlight is available to it).
Another factor which appears to prevent decalcification is exercise. It is possible that these two protective factors, sunshine and exercise, which were abundantly available to stone-age man, may account for the difference noted in the effect of a high-protein diet in those people, as opposed to such a diet in a sedentary individual, where decalcification is more common.
We are obliged to ask therefore why, if an EDTA infusion stimulates parathormone production and subsequent calcium withdrawal from bone (as well as from pathological deposits in atheromatous plaque, etc.), this does not lead to osteoporosis?
Bruce Halstead (1979) answers this as follows:
Physicians having extensive clinical experience with EDTA in the treatment of atherosclerosis have generally observed that the bone structure improves with the administration of EDTA. The explanation of the apparent paradox is to be found in the role parathormone plays in relationship to osteoblastic function. When EDTA is administered intravenously into the body there is a rapid complexing of ionic serum calcium and excretion of calcium EDTA through the renal tubules. This causes a drop in circulating calcium and a stimulation of parathormone production . . . which results in withdrawal of ionic calcium from metastatic deposits and also increases the conversion of preosteoblasts to osteoblasts . . . leading to an increase in total collagen synthesis or new bone formation . . . This basic biochemical mechanism of bone metabolism has been well documented experimentally and provides a reasonable explanation as to why EDTA generally improves bone structure rather than producing osteoporosis clinically.
Increased sugar in the blood causes a decrease in the circulation of vitamin D, which if present helps to neutralize the sequence of events described:
High protein = high acidity levels in the blood = high parathyroid hormone = low levels of calcium in the blood = decalcification.
(Recall that if EDTA infusion is the cause of this sequence the final result is not decalcification of bone, only of metastatic deposits.)
Interestingly there is a family of plants which contain a material which acts very much like vitamin D in protecting against bone decalcification where blood acidity stimulates decalcification. This is the solanaceous family of plants, which includes tomatoes, potatoes, green peppers and aubergine.
One of the most critical elements in the whole equation of balances and imbalances involved in this highly complex scenario relates to the ratio between calcium and phosphorus in the diet. It has been found that the demineralization of bones ceases, and actually reverses (bone begins to remineralize) when the ratio of calcium to phosphorus is 1 (that is, one part of calcium for every one part of phosphorus in the diet: 1 / 1 = 1). Commonly the diet in Western society achieves a ratio of less than 0.5 parts of calcium to each part of phosphorus (1/2 / 1 = 1).
Stated simply this means that whilst experimentally it can be shown that a high-protein diet increases calcium excretion and bone loss, this does not appear to be nearly so likely when the overall diet is balanced, even though there is a high protein intake.
Some experiments which appeared to implicate a high-protein diet as the major cause of calcium loss have been shown to be seriously flawed, as the type of protein used was a concentrated, often liquid, protein, bearing little resemblance to the forms of protein normally eaten. Such concentrated purified proteins are the types often used in crash slimming programmes as well as in some emergency refeeding programmes, where malnutrition exists.
Phosphorus itself is now seen to be useful and necessary in achieving a balance against the acid side-effects of a high-protein diet. So phosphorus and calcium, in balance, produce the situation in which a sound bone structure can be achieved even where there is a high meat intake. A high vegetable content in the diet ensures lowered acidity as well as calcium replenishment.
Calcium from vegetables
Some of the best sources of calcium are from green leafy vegetables such as dandelion greens, mustard greens, turnip and beet tops, watercress, broccoli and kale.
Other protective factors
The other important elements in maintaining healthy nerve and bone structures include exercise and daylight. Exercise taken in an environment in which light is available is therefore important. Direct sunlight is not important as even indirect daylight has beneficial effects in the production of vitamin D.
Thus there is no real paradox: a high-protein diet is not going to result in decalcification unless there is an imbalance between calcium and phosphorus and unless acidity clearly outweighs alkalinity. Neither of these is likely if sound eating patterns are followed, and even less likely if exercise and light are obtained in liberal quantities.
The start of arteriosclerosis and atherosclerosis
We have seen a variety of often interacting influences on calcium status in the body. If for any reason calcium levels in the blood are too low, the action of parathyroid hormone withdraws ionic calcium from other (often metastatic) sources to meet this imbalance. If EDTA is the cause of the reduction in ionic calcium levels in the blood, then (as explained by Bruce Halstead above) osteoblasts are stimulated to start the process of bone calcification. However, if calcium levels increase in the bloodstream (as they would if withdrawn from bone as in osteoporosis), calcitonin produced by the thyroid lowers it, often causing it to be deposited in metastatic forms. In good health, around one gram of calcium should be absorbed from the intestines daily, but if far more calcium is ingested, or the intake of magnesium is low, excess calcium will either be excreted via the kidneys or added to the dystrophic depositions in soft tissues (arteries, etc.). If this occurs in arteries it may be in one of two forms. There might be localized, discrete deposits which show up well as radiopaque shadows on X-ray; or there may be a more generalized, diffuse deposition in which calcium is secreted in the previously elastic fibres of the arteries. Generalized calcification of arteries is not radiopaque until it is well advanced.
With passing time multifaceted influences (diet, life-style, toxic exposure, stress, lack of exercise, etc.), interacting with the normal ageing process may lead to one or other of these forms of arterial degeneration. As the general calcification described above proceeds, there is a gradual lessening of the ability for oxygen and nutrients to be transported and absorbed, with consequent deterioration of the status of the tissues being fed. This is arteriosclerosis and it may impair circulation to any body part, including the brain, leading in such a case to impaired ability to concentrate, remember or think, or to transient dizziness; hearing and sight might be impaired; tinnitus might develop; the extremities, especially the legs, might feel colder or be subject to cramp; the heart muscle itself might become starved of oxygen and nutrients, developing the symptoms of angina; the ageing process may be seen to be advanced steadily, and as it progresses, in time muscular spasm may completely shut down one or other of the arterial channels of circulation.
In atherosclerosis, where more localized deposits of atheromatous material form on the artery wall, there is an inevitable turbulence and increased pressure of the flow of blood at that point. The atheromatous deposit could continue to increase in size until it obstructed the artery or there is always the chance of a fragment of such a plaque deposit breaking away and being carried to a point too narrow for its passage, completely or partially blocking this. A cerebral accident or coronary infarct would then have occurred.