Dem bones, dem bones…. A few words of the old familiar lyric may bring a smile to the face, but bone decay is no laughing matter. Sandi Nye discusses the many factors – far more than calcium alone – that contribute to bone health.
Preventing bone decay should start early in life, as the development of strong bones requires continuous maintenance. It is generally accepted that the longer one lives, the more likely the risk of developing porous and brittle bones, or osteoporosis. However, there is much more associated with the risk of developing osteoporosis than ageing alone. Factors such as lifestyle, hormones, drug side-effects and more, all play a crucial part in keeping the skeleton well-nourished or not.
Most readers would probably agree that good nutrition is essential for preventing bone decay. But how many are aware that at least 18 bone-building nutrients are required for optimum bone health? These include phosphorus, magnesium, calcium, manganese, zinc, copper, boron, silica, fluorine, vitamins A, C, D, B6, B12, K, folic acid, essential fatty acids and protein. Space limits us to look at only the most important nutrients.
Calcium is an essential mineral needed for healthy bone development and for the maintenance of healthy teeth and gums – but it is not the alpha and the omega of bone health. It is however one of the most abundant minerals in the human body, accounting for approximately 1.5% of total body weight.
The body’s calcium needs change throughout life. Generally we consume more calcium than we lose, until about age 35 (whether you’ve been a ‘chalk chewer’ or not!). But from about 45 onwards we lose more calcium than we take in, ending up with what is referred to as a ‘negative calcium balance’.
About 99% of the body’s calcium resides in bones and teeth, while the remaining 1% is distributed in other areas. Calcium is also important for: (i) the maintenance of a regular heart- beat, because muscle contraction is controlled by blood calcium levels; (ii) the transmission of nerve impulses; (iii) muscular growth and contraction – and for the prevention of muscle cramps; (iv) blood clotting; (v) regulation of enzyme activity, acid/base balance; (vi) cell membrane function; and (vii) lowering blood pressure (possibly).
In addition, calcium lowers cholesterol levels, helps prevent cardiovascular disease, helps prevent cancer, reduces menstrual pain, and helps to keep the skin healthy.
Calcium deficiency can be caused by several factors, e.g. inadequate dietary intake, poor calcium absorption, and excessive loss through urine or faeces, which is relatively well-known, but I wonder how many folk are aware that stress causes increased calcium excretion. So to prevent bone decay, make de-stressing a priority!
Vitamin D, one of the fat-soluble vitamins, is absolutely essential for the development and maintenance of bone.
FOOD SOURCES OF CALCIUM
If there is inadequate calcium in the diet the body simply takes it from the bones, so although good dietary calcium is the first prize, often the quality and quantity of appropriate calcium is not ideal, and supplementation is required. The amino acid lysine is needed for calcium absorption. Food sources of lysine include cheese, eggs, fish, lima beans, milk, potatoes, red meat, soy products, and yeast. In general, food sources of calcium include: cheese – especially Swiss, mozzarella, ricotta, and cheddar, low-fat yoghurt, milk (goat’s milk is higher in calcium than cow’s milk), salmon, sardine, shrimp, brewer’s yeast, blackstrap molasses, corn, artichokes, almonds, peanuts, prunes, dried figs (but take care of excessive sugar intake), pumpkin seeds, sesame seeds (and tahini), cooked dried beans including soya, lentils, tofu, cabbage, beet greens, spin- ach, garlic, dark green leafy veg – especially bok choy and broccoli, and the herbs parsley, thyme, oregano and basil. Sounds like prime ingredients for yummy pizzas!
- Supplements – the worst calcium supplements are bone meal, oyster shell and dolomite because they cannot be efficiently absorbed and may contain the heavy metal, lead. For best absorption, calcium should be in one of the following forms: calcium citrate, calcium malate, calcium aspartate, calcium lactate, or (if no other form is available) calcium carbonate, which is cheap and certainly readily available. To improve absorption of calcium carbonate it should be taken with meals, as the presence of food in the stomach causes the secretion of hydrochloric acid, a compound that breaks down calcium carbonate. However, if the stomach contents empty before absorption has taken place it could be a bit dodgy to depend on this form of calcium for one’s daily needs. Chelated calcium is generally considered a superior supplement option. Chelated calcium is calcium bound to an organic acid, such as citrate, malate, lactate, or gluconate; or to an amino acid, such as aspartate. There is plenty written in the nutritional literature to indicate that calcium chelates, especially calcium citrate, are more bio-available than calcium carbonate. Calcium is also available as hydroxyapatite (the phosphorus-containing building block of the bone mineral matrix), sometimes formulated with boron – but this form is quite expensive and not always that readily available in all countries.
- Calcium and magnesium compete with each other for intestinal absorption, so supplements of these two should not be taken simultaneously.
- Calcium is best absorbed in the evenings when it can also help with sleep.
- Haeme and non-haeme iron absorption is decreased by calcium – so take this into account if you’re anaemic.
- Calcium can decrease the absorption of tetracycline antibiotics, thereby reducing the effectiveness of these drugs – so don’t take them at the same time, and advise your health care provider if you’re taking calcium supplements.
- Toxicity from calcium is not common because the gastrointestinal tract normally limits the amount of calcium absorbed. Short-term intake of large amounts of calcium does not generally produce any major side-effects other than constipation, and a potential increased risk of renal calculi (kidney stones). Excessive long-term intake of calcium (more than 3 000 mg per day) may however result in elevated blood calcium levels and a condition known as hypercalcaemia, which can lead to soft tissue calcification.
Calcium synergists/enhancers: Boron, copper, CoQ10, lactose, magnesium (also helps prevent calcium oxalate crystals from forming, which is what kidney stones are made from), potassium, strontium, titanium, and vitamins C, D, K and B5.
Calcium antagonists/inhibitors: Alcohol, bismuth, caffeine, chromium, fatty meals, germanium, insoluble fibre (wheat fibre and husks of certain other whole grains), iron, lecithin, magnesium, manganese, mineral oil, niacin, oxalic acid, PABA, phosphorus (found in carbonated sodas), phytic acid, high-protein meals, sulfur, vitamins A and C (in high doses), too much vitamin D (although it is vital for calcium being transformed into a useable form by increasing calcium absorption in the small intestines and retention by the kidneys), and zinc.
Intestinal pH strongly affects calcium absorption. Absorption is optimal with normal stomach acidity generated at meal times. Persons with reduced stomach acidity, e.g. the elderly, or those taking acid-reducing (heartburn) medicines, do not absorb calcium optimally. So think twice before reaching for the antacids and maybe rather chat to your health care provider about the value of digestive enzymes for your particular condition.
As previously referred to, one of the most notorious calcium deficiency disorders is osteoporosis, or brittle bone disease, about which screeds have been written. Another disorder of calcium dysregulation is tetany, which is caused by low levels of free ionised calcium in the blood. It manifests as excessive nerve activity, causing muscle pain and spasms, as well as tingling and/or numbness in the hands and feet. Calcium also plays an important role in minimising toxicity from certain heavy metal poisoning. It protects the bones and teeth from lead toxicity by inhibiting absorption of this metal, since if there is a calcium deficiency, lead can be absorbed by the body and deposited in the teeth and bones.
Magnesium is another mineral that is crucial for bone density; it is referred to as calcium’s ‘comrade-in-arms’ by nutritional guru Patrick Holford. Magnesium is also essential for many other body processes such as muscle impulses, nerve conduction, protein synthesis, plus certain hormone and enzyme processes. Unfortunately, these days the calcium/magnesium ratio is totally out of whack due to our modern high-dairy diets. The ideal calcium to magnesium ratio is considered to be 2:1, i.e. twice as much calcium as magnesium. Since cow’s milk calcium/magnesium ratio is 10:1, and the ratio for cheese is 28:1, the imbalance is self-evident. Therefore, relying purely on dairy products for calcium is likely to soon result in a magnesium deficiency and imbalance. Seeds, nuts and crunchy vegetables like kale, cabbage, carrots and cauliflower provide both these minerals and others, which are more beneficial for the nutritional health needs of humans. Milk is for baby cows – not humans.
Magnesium synergists/enhancers: Boron, calcium, chromium, CoQ10, insoluble fibre, vitamins B2, B6 and D, and zinc.
Magnesium antagonists/inhibitors: Alcohol, calcium, choline, copper, folate, insoluble fibre, iron, lithium, manganese, niacin, PABA, potassium, selenium, silicon/silica, sodium, uric acid, vitamins A, B1, D, E and K.
For optimal benefit, magnesium should be in the form of magnesium aspartate, citrate or glycinate.
A heaped tablespoon of crushed sesame and sunflower seeds daily will provide calcium, magnesium and zinc – and you’ll have happy bowels into the bargain!
A few other important nutritional elements for bone health include boron, silicon, vanadium and zinc.
Zinc is vital for bone and collagen formation, as well as protein synthesis and a host of other beneficial functions in the body. It is found in brewer’s and torula yeasts, dulse, egg yolks, fish, kelp, lamb, legumes, lima beans, liver, red meats, mushrooms, pecans, oysters, poultry, pumpkin seeds, sardines, seafood, soy lecithin, soybeans, sunflower seeds, nuts, whole grains and fortified breakfast cereals. Herbs that contain zinc include alfalfa, burdock root, cayenne, chamomile, chickweed, dandelion, eyebright, fennel seed, hops, milk thistle, mullein, nettle, parsley, rose hips, sage, sarsaparilla, skullcap, and wild yam.
Compounds called phytates, which are found in grains and legumes, bind with zinc so that it cannot be absorbed. Zinc and iron supplements should therefore be taken as different times, as they interfere with each other’s activity.
The two main vitamins associated with bone health, which will be expanded on here, are vitamins D and C.
Vitamin D, as previously mentioned, is a fat-soluble vitamin that is essential for the development and maintenance of bone, working together with PTH on the bone and kidney. [PTH is normally released by the four parathyroid glands in the neck in response to hypocalcaemia (low calcium levels in the bloodstream).] It is necessary for intestinal absorption of calcium, magnesium and phosphorus, ensuring the correct renewal and mineralisation of bone tissue. Vitamin D is formed in the skin after exposure to natural sunlight/ ultraviolet radiation, and is converted by the liver and kidneys to the active form needed by the body – vitamin D3 or cholecalciferol. Vitamin D levels decline with age, during winter months, and whenever there is inadequate sunlight. Vitamin D2 or ergocalciferol is the plant origin version of this vitamin.
Besides sunlight, vitamin D is also obtained from fortified foods such as milk, margarine, and in a natural diet from cereals, as well as from eggs, cottage cheese, chicken liver, salmon, sardines, herring, mackerel, swordfish, oysters and fish oils like halibut and cod liver oils. Fried foods rob the body of vitamin D – and that’s before I even get started on the perils of trans-fats! As with calcium deficiency, severe vitamin D deficiency results in inadequate mineralisation of the bone matrix, leading to growth retardation and bone deformities such as rickets in children, and osteomalacia in adults.
Excessive vitamin D intake results in above- normal serum calcium levels, which can lead to calcium loss from bone. High doses can be potentially toxic, i.e. 1 250 mcg. Hence, it’s a bit of two-edged sword vitamin, since supplementing with high-dose vitamin D may offer protection from several types of cancer, and certain neurodegenerative conditions like multiple sclerosis (MS), while overdosage can lead to osteoporosis, and calcification of arteries and other soft tissue. Moderation is therefore key when it comes to supplementing.
Vitamin D synergists/enhancers: Boron, lycopene, selenium, UV light, vitamins C and E.
Vitamin D antagonists/inhibitors: Alcohol, cadmium, calcium, light (vitamin D2), mineral oil, strontium, vitamins A, K and D2.
Vitamin C, or ascorbic acid, is the water-soluble vitamin well known as a powerful antioxidant, immune booster, and cell protector. It is also essential for the maintenance of bones, teeth, and gums, and has recently been recognised as an important agent in the prevention and treatment of osteoporosis due to its ability to increase bone density. Conditions associated with vitamin C deficiency include cardiovascular diseases, cancers, joint diseases, cataracts, respiratory infection and other lung-related ailments, poor wound healing, and scurvy (fortunately relatively rare in First-World situations these days).
Vitamin C is so critical to living creatures that almost all mammals can use their own cells to make it. Unfortunately, humans, gorillas, chimps, bats, guinea pigs and birds are some of the few animals that cannot synthesise their own vitamin C, having to rely instead on their diet for daily needs. Green vegetables (broccoli, brussel sprouts, etc.), red cabbage, red peppers, sprouts, pawpaw, citrus fruit, guavas, blackcurrants, redcurrants, kiwifruit, and rosehips are all good natural sources.
N.B. As with all things in life, many of the substances mentioned are dose-dependent. They can be considered co-factors at normal levels, yet antagonists at higher levels.
Ultimately, the fact remains that health in general – and good bone health in particular – is not something that one gets from pills, potions or wishful thinking. It is a balance between good sense, quality nutrition, and a measure of genetic benevolence, tempered with some basic knowledge and mindfulness. It is possible, with a little effort, to take care of this wonderful body/mind vehicle, with which we have been blessed, to traverse our Earth journey.