Now that you've been warned off HRT for preventing osteoporosis, you might be prescribed calcium. But should you take it? This article will tell you why preventing osteoporosis will take a lot more than calcium, which could do you more harm than good.
Nutritional Approaches to Osteoporosis
Fractures caused by thinning and brittle bones affects one in three women and one in twelve men. They are responsible for 200,000 breaks per year in the UK. That means someone suffers a fracture every 2½ minutes. This includes 70,000 hip fractures, 50,000 wrist fractures and 40,000 spinal fractures. Every day 40 people die as a result of it, making it a leading cause of death.
Bone mass peaks at around age 35. From then it’s downhill all the way, especially for women whose bone mass is 10% - 15% less than men’s at skeletal maturity and then suffer with accelerated bone loss for 8 - 10 years around the menopause when hormone levels decline.
Many women who might have relied on Hormone Replacement Therapy (HRT) to safeguard them against this debilitating condition can now no longer do so. On December 3rd, 2003, doctors were ordered by the government’s Medicines and Healthcare Products Regulatory Agency to no longer routinely prescribe HRT for osteoporosis. This is because of the increased risk of blood clotting, stroke, heart attack and cancer.
Another class of drugs called bisphosphonates appear to work well in remineralising bone and have a narrow target of action, but since it isn’t clear exactly how they work, it is hoped doctors remain cautious in their prescribing until more is known.
In terms of nutrition, conventional medicine is well aware of the importance of calcium and even go so far as to suggest it is taken with vitamin D to improve its absorption. However that appears to be the extent of their nutritional knowledge. I think we can do better than that.
Although bone strength in the main is thought to be genetically determined, it is made up of proteins, many minerals and various cofactors and these certainly influence bone formation.
In osteoporosis, bone mass, expressed as bone mineral density (BMD), declines. Bone quality, structure and turnover are also important but are difficult to measure.
In recent years there has been a growing understanding of the importance of maximising peak bone mass in the early decades of life. As one eminent endocrinologist put it, “senile osteoporosis is a paediatric disease.” This is particularly disturbing when you consider the quality of young people’s diets. The problem of osteoporosis is reaching epidemic proportions. Around 30 million Americans are believed to be afflicted. Figures for the UK are put at 3 million though I suspect it is much higher.
According to the late John R Lee these are:
Sudden insomnia and restlessness
Nightly leg and foot cramps
Persistent low back pain
Gum disease, loose teeth
Risk is Higher if:
Low calcium intake
Drink more than 2 alcoholic drinks a day
On chronic steroid therapy
On chronic anticonvulsant therapy
Taking drugs that cause dizziness
Eat too much animal protein
Use antacids regularly
Drink more than 2 cups of coffee a day
The Nutritional StrategyAlthough risk of developing fractures is related to BMD, it is also influenced by the protein matrix and other support structures in bone. Cells that form bone (osteoblasts) do this by making long protein chains that consist mainly of collagen. It is also influenced by the accumulation of micro-fractures from mild traumas over time. To prevent fractures the mineral mass must be preserved, and the protein matrix and support structures must be maintained. Optimal
repair mechanisms must be ensured.
99% of this mineral is found in the bones. Calcium is deposited in bone and withdrawn as needed largely by the actions of calcitonin and parathyroid hormone. The balance between these two are regulated by oestrogen and other substances especially magnesium.
Studies demonstrate a positive effect of calcium on BMD. Higher intakes are associated with higher bone mass at almost all measured skeletal sites. It is believed that variations in calcium nutrition early in life could account for a 5% to 10% difference in peak adult bone mass. This could make a tremendous difference to the number of fractures that occur later in life.
Studies on calcium supplements taken in the early postmenopausal period show only very small effects on BMD but they could still be important. At least 4 studies show a reduction of about 30% in fracture risk in postmenopausal women taking a 1000mg supplement per day.
National surveys indicate calcium intake to be lower than recommended. Mean intake of calcium in females over 9 years of age is only 657mg/day. Between ages 9 and 18 it should be 1300mg, between 19 and 50 recommended intake
is 1000mg thereafter 1200mg.
However osteoporosis is not a calcium deficiency disease and people’s requirements will depend on their overall diet and lifestyle. Taking a calcium supplement alone is not recommended. It won’t necessarily be absorbed into the bone. Instead it may remain in the blood and end up in the tissues causing its own health problems. While absorption is improved with vitamin D, it also has close relationships with magnesium and phosphorus.
While milk and dairy products are high in calcium they are also high in phosphorus and low in magnesium. Human milk has only a quarter of the calcium of cow’s milk yet, according to Frank Oski MD author of Don’t Drink Your Milk, the infant will absorb more calcium. This is because cow’s milk is rich in phosphorus which interferes with calcium absorption.
He goes on to state that Taiwanese and citizens of Guana only ingest 13mg and 8mg respectively of calcium from drinking milk. “These non-American people are neither toothless nor lying about immoblized because of repeated bone fractures.” He believes there are many good sources of calcium that are a better choice than milk.
Calcium combines with phosphorus to form calcium phosphate. Together they are incorporated into bone. 85% of the body’s phosphorus is bound to the bone. Intake has risen markedly over recent years with increased phosphate salts used in food additives, carbonated drinks and cola beverages. Red meat has a phosphorus to calcium ratio of 20 to 1. Dietary intakes range from 1000mg - 1500mg per day, well above the 700mg recommended.
Such excessive amounts could be detrimental to bone by depressing serum calcium and elevating parathyroid hormone. This hasn’t been proven scientifically though.
Two-thirds of the body’s magnesium is found in the bones. It plays a crucial role in calcium and bone metabolism. Deficiency causes decreased bone strength and volume and poor development. A positive association with BMD has been demonstrated in many population studies. Even if calcium intake is adequate, without sufficient magnesium, parathyroid hormone will be stimulated and calcium withdrawn from the bones.
This mineral is immediately below calcium in the periodic table and can act in a similar way.
In the early part of the 20th century studies showed strontium to be effective in stimulating rapid formation of bone and that strontium and calcium were superior to calcium alone in mineralizing bone.
In 1959 the Mayo clinic treated 22 patients with severe, painful osteoporosis, giving them 1,700mg of strontium daily. 18 markedly improved and 4 moderately so.
Conventional medicine has recently got very excited about strontium or rather strontium ranelate. Ranelic acid is a synthetic substance which has allowed drug companies to patent this compound as a treatment for osteoporosis, even though ranelic acid plays no part.
Recent trials have been very promising. In one there was a 41% reduction in vertebral fracture risk with BMD increasing by an astonishing 11.4% over 3 years.
In another there was an increase in lumbar BMD of 3% per year with a significant decrease in additional fractures compared to placebo.
Even postmenopausal women who didn’t have osteoporosis saw an increase in BMD with strontium and calcium alone.
Best food sources of strontium are spices, seafood, whole grains, root and leafy vegetables, and legumes.
Boron is important in retaining calcium. According to Dr Rex Newnham, a world authority on boron, both vitamin D and the parathyroid gland depend on this mineral. The parathyroid contains more boron than any other part of the body. He said boron “will help broken bones mend in about half the normal time.”
As if that wasn’t remarkable enough, just 3mg a day raised oestrogen levels as much as HRT in one study (FASEB J 1987 Nov;1 (5):394-7). But unlike HRT it did this safely, without exposing the body to dangerous amounts of this hormone. It also reduced calcium excretion by 44%.
Manganese is required to mineralise the bone and to synthesise connective tissue in bone and cartilage. Blood manganese levels in osteoporotic women were found to be only 25% of controls. Dr Richard Passwater found that deficiencies lead to abnormal bone and cartilage growth and degeneration of vertebral discs.
Silicon is biochemically very rigid and is therefore only used by the body at calcification sites of bones and other structures. The connective tissue matrix is strengthened by it, as it crosslinks collagen strands. Rats on a silicon free diet suffered bone deformity.
Essential for protein synthesis, for its strength and elasticity, zinc is necessary if bones are to form normally. It plays an important role in connective tissue metabolism. It also enhances the biochemical actions of vitamin D. Levels were low in elderly patients with osteoporosis.
Copper works in conjunction with zinc. Depletion leads to bone defects and calcium loss. Helps to strengthen connective tissue by crosslinking collagen strands.
Iron may play an important role in bone formation acting as a cofactor for enzymes involved in collagen synthesis. Deficiency may play a role in bone fragility.
The Role of VitaminsVitamin D
Vitamin D facilitates active calcium absorption in the intestines. It is also involved in bone turnover. Vitamin D status declines with age because of lower exposure to sunlight, decreased ability to activate precursors in the skin, decreased ability of the kidney and liver to hydroxylate it, reduced dietary intake and poorer absorption, as well as drug use, so deficiency in the aged is not uncommon.
Vitamin K is now receiving attention because of its role in bone metabolism. It is required to synthesise osteocalcin, a protein found uniquely and in large amounts in bone. This makes vitamin K essential for bone formation,
remodelling and repair.
The usual diet contains considerably more of the vitamin than is required, although since this nutrient is obtained primarily from green vegetables, one has to wonder about the wisdom of that.
Several population studies show low dietary or circulating vitamin K is associated with low BMD or increased fractures.
16 patients with osteoporosis had mean serum vitamin K concentrations at only 35% of the level of age-matched controls.
Other studies show vitamin K reduces urinary calcium excretion and improves the bone turnover profile.
Bone health can certainly be added to the long list of conditions that this vitamin can treat. It is required for collagen crosslinking. In scurvy the collageneous structure of the bone is weakened. Vitamin C may also protect the skeleton from oxidative stress especially for cigarette smokers. Smoking greatly increases the risk of hip fracture. High intakes of vitamin C together with vitamin E significantly decreased the risk of fracture for smokers in one study.
This vitamin is important in the bone remodelling process. Deficiencies are known to be detrimental to bone health.
The importance of this nutrient is related to offering protection from homocysteine. People with a genetic disorder in which large amounts of homocysteine accumulate also develop severe osteoporosis at an early age. Studies suggest menopause is associated with an increased requirement for folic acid because of decreased efficiency at converting homocysteine to less toxic compounds. For this reason other nutrients that offer protection from homocysteine such as vitamin B6 and B12 may also be important.
Food and Food Components
A more alkaline based diet might contribute to better BMD. A recent study which looked at dietary intake and BMD in elderly subjects concluded that alkaline-producing dietary components, specifically potassium, magnesium, fruit and vegetables contribute to the maintenance of BMD.
Isoflavones, a type of phytooestrogen derived from soy beans, including genistein and daidzein, have been studied in postmenopausal osteoporosis and generally found to have a positive effect in maintaining bone density and reducing fractures.
Bone health depends on a sufficient supply of a wide range of nutrients that goes well beyond calcium and vitamin D. Such an approach is likely to be far more successful than current orthodox drug approaches which leave a lot to be desired.
This article was first published in Enzyme Digest No. 63, New Year 2004
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