OSTEOPOROSIS
A generalized, progressive reduction of bone mass as bone
re-absorption outstrips bone formation, causing skeletal
weakness and fractures.
Causes and Incidence The causes of primary osteoporosis
are unknown, but contributing factors include an inadequate
calcium intake, early menopause, thin body habitus, sedentary
life-style, and a familial history of the disease. Secondary
osteoporosis may be caused by endocrine disorders such as
hypogonadism, hyperthyroidism, hyperparathyroidism, and
diabetes mellitus; prolonged use of substances (corticosteroids,
tobacco, barbiturates, or heparin); underlying disease (renal
or liver disease, malabsorption syndrome, chronic obstructive
pulmonary disease, rheumatoid arthritis, or sarcoidosis);
and prolonged weightlessness or immobility. Postmenopausal
women are the most susceptible to primary osteoporosis;
an estimated 33% of these women develop the disease.
Research
MAGNESIUM - A VITAL MINERAL
Magnesium is a mineral that is abundant both in nature
and in the human body, where it is involved in the activation
of more than 300 enzymes and body chemicals. The Department
of Health has set the Reference Nutrient Intake (RNI) for
magnesium at 300mg per day. However, many nutritionists
now feel that the average world RNI should be set at 450mg
per day. A survey in 1994 showed that 72% of women and 42%
of men aged between 19 and 50, and 89% of females aged 16-18
years do not achieve the RNI for magnesium. Low levels of
magnesium in the diet and in our bodies increase susceptibility
to a variety of diseases, including heart disease, high
blood pressure, kidney stones, cancer, insomnia, PMS, and
menstrual cramps. Signs and symptoms of magnesium deficiency
are fatigue, mental confusion, irritability, weakness, heart
disturbance, problems in nervous conduction and muscle contraction,
muscle cramps, loss of appetite, insomnia and predisposition
to stress. Magnesium is essential for the proper functioning
of the entire cardiovascular system. Because magnesium contributes
greatly to the strength of contraction by heart muscle,
magnesium supplementation has been found to be helpful in
the management of angina, atherosclerosis, intermittent
claudication and high blood pressure.
One of the most important components of any osteoporosis
programme is magnesium. As much as 60% of all magnesium
in the body is found in the bones. A defect of bone crystal
formation in magnesium-deficiency women is thought to be
one of the factors that increase fracture risk.
Magnesium works in many ways to preserve the health of
the nervous system. During times of stress, magnesium stores
are depleted and large amounts of this mineral are lost
in the urine. With its ability to exert a calming effect
on the nervous system together with its muscle relaxing
role, magnesium, taken 30-40 minutes before retiring, may
help those suffering stress or insomnia.
Studies have shown a low intracellular magnesium content
in patients with bronchial asthma. Magnesium deficiency
can also increase the release of histamine into the bloodstream.
Thereby increasing allergic reactivity in general.
Magnesium also plays a central role in the secretion and
action of insulin. Without adequate magnesium levels within
the body’s cells, control over blood sugar levels
is impossible.
Magnesium has also been found to play a role in the aetiology
of migraines, fibromyalgia, PMS, kidney stones and attention
deficit hyperactivity disorder (ADHD).
Williams, E.
NUTRIT. PRACT. 1999,1 (3) 27-9
FIBROMYALGIA: A RISK FACTOR FOR OSTEOPOROSIS
Fibromyalgia (FM) is a poorly understood chronic musculoskeletal
disorder characterised by widespread pain, decreased pain
threshold, non-restorative sleep, fatigue, stiffness, mood
disturbance, irritable bowel syndrome, headache, paraesthesias,
and other less common features. A characteristic central
nervous system feature of FM is accompanying anxiety and/or
depression. It has recently been shown that bone mineral
density (BMD) is decreased in women with past or current
depression. Therefore researchers carried out a study to
investigate associations of BMD and osteoporosis in patients
with fibromyalgia. The patients’ ages were 33 to 60
years and none used steroids or other bone demineralising
agents. Simple T tests were used to compare hip and lumbar
spine BMD of FM cases to controls by 3 decades (31-40, 41-50,
51-60 years). It was found that the patients with FM in
all 3 decades had a lower mean BMD of the spine. The femoral
neck BMD were also lower, but reached significance only
in the 51-60-age group.
Thus, fibromyalgia in this pilot study was frequently associated
with osteoporosis. Early detection and implementation of
appropriate nutritional supplementation (calcium/vitamin
D), resistive and weight bearing exercise, and specific
bone mineral enhancing pharmacological therapy may be indicated
in pre, peri, and postmenopausal subjects.
Swezy, R.L. and Adams, J
J. RHEUMATOL. 1999, 26 (12) 2642-4
HIGH BLOOD PRESSURE AND BONE-MINERAL LOSS IN ELDERLY WHITE
WOMEN: A PROSPECTIVE STUDY
High blood pressure is associated with abnormalities of
calcium metabolism, leading to increased calcium losses,
secondary activation of the parathyroid gland and increased
movement of calcium from bone. Therefore, researchers investigated
the prospective association between blood pressure and bone-mineral
loss over time in elderly white women. Over 3,000 elderly
women (mean age 73 years) were studied over 3.5 years. It
was found that after adjustment for age, initial bone-mineral
density, weight and weight change, smoking, and regular
use of hormone-replacement therapy, the rate of bone loss
at the femoral neck increased with blood pressure at baseline.
In the quartiles of systolic blood pressure, yearly bone
losses increased from 2.26 mg/cm¬2 in the first quartile
to 3.79 mg/cm2 in the fourth quartile. For diastolic blood
pressure, there was an association with bone loss in women
younger than 75 years.
Thus higher blood pressure in elderly white women is associated
with increased bone loss at the femoral neck. This association
may reflect greater calcium losses associated with high
blood pressure, which may contribute to the risk of hip
fractures.
Cappuccio, F.P. et al
LANCET 1999, 354 (9183) 971-5
NUTRITIONAL DIFFERENCES IN PATIENTS WITH PROXIMAL FEMORAL
FRACTURES
Hip fractures are classified into 2 main groups, trochanteric
and intracapsular, according to their anatomical location.
The ratio of these two fracture types varies with the age
and sex of patients. Why a patient should sustain a fracture
of one part of the hip rather than another is unclear, but
it does not appear to be related directly to factors such
as different fall mechanics. Therefore, a study was undertaken
to assess possible nutritional differences in patients with
proximal femoral fractures. The study group consisted of
119 patients over the age of 65 with a hip fracture. Triceps,
biceps and supra-iliac skin-fold thickness were measured,
as was mid upper arm circumference on admission and on the
fifth pot-operative day. Body mass index was calculated
for patients and used to classify them as severely, moderately
or mildly malnourished, normal, overweight or obese.
It was found that according to their body mass index, 31%
of patients were classified as malnourished and 11% as severely
malnourished. Patients with intracapsular fractures were
significantly more malnourished than patients with trochanteric
fractures. Thus patients with intracapsular fractures are
more malnourished whereas those with trochanteric fractures
tend to be overweight.
Maffulli, N. et al
AGE & AGEING 1999, 28 (5) 458-62
LACTOSE MALABSORPTION AND RATE OF BONE LOSS IN OLDER WOMEN
Although an impaired ability to absorb lactose is considered
a risk factor for osteoporosis, there is no consensus in
evidence to support the relationship between malabsorption
and decreased bone density. Therefore, a study was carried
out to investigate the prevalence of lactose malabsorption
with increasing age and to determine whether lactose malabsorbers
consume less dietary calcium, have lower bone mineral density
or have faster bone loss than lactose absorbers.
80 healthy Caucasian women, aged between 40-79 years were
studied for 1 year. Breath hydrogen exhalation was measured,
bone density assessed and total dietary calcium intake estimated.
It was found that lactose malabsorption increased with age
(15% in participants aged 40-59 compared with 50% in participants
aged 60-79; p ? 0.01). Malabsorbers in the 70-79 years age
group consumed significantly less lactose than lactose absorbers
of the same age (p ? 0.05). Baseline total body calcium
values were lower in malabsorbers than in lactose absorbers
but this difference was eliminated by age adjustment. Bone
change (% per year) was correlated with dietary calcium
intake but was not statistically greater in malabsorbers
than absorbers.
It was concluded that the ability to absorb lactose declined
in the 7th decade and that this may contribute to decreased
dietary intake of milk products and calcium. However, malabsorption
without decreased calcium intake has minimal effect on bone
mineral density or rate of bone loss.
Goulding, A. et al
AGE AND AGEING 1999, 28 (2) 175-80
KEEPING OSTEOPOROSIS AT BAY
In the past, it was believed that bone minerals acted as
buffers against the acid load from the diet. Therefore scientists
inferred that consuming a diet favouring an alkaline environment
may help to preserve bone mineral density and reduce the
risk of fractures in the elderly. Such a diet would include
fruits, vegetables, vegetable protein and moderate amounts
of milk. In addition too this, potassium and magnesium also
have a buffering effect.
To test the hypothesis, a retrospective study was conducted
involving members of the original Framingham Heart Study.
Results showed that increased intakes of potassium, and
to a lesser extent magnesium, helped to maintain bone health
in the elderly. Fruit and vegetable intake was found to
reduce bone loss.
Scientists concluded that alkaline-producing foods, especially
potassium, magnesium and fruits and vegetables, help to
maintain bone density by reducing bone loss.
AM. J. CLIN. NUTR. 1999, 69, 727-36
Courtesy QUEST RESEARCH BULLETIN
BONE HEALTH AND MAGNESIUM SUPPLEMENTATION
Magnesium supplementation has previously been shown to
increase bone mass in both pre- and post-menopausal women.
A study was carried out to examine the effects of 30 days
of supplementation with magnesium carbonate (providing 365mg
elemental magnesium) on bone turnover in 12 healthy men
and age-matched controls. The researchers measured parathyroid
hormone levels (PTH), responsible for calcium release from
bone alongside the serum biochemical markers for bone formation
and resorption.
Results showed a significant reduction in serum PTH hormone
(unrelated to changes in serum calcium), together with reduced
bio-markers for bone turnover.
Diami H.P. et al,
J. CLIN ENDOCRINOLOGY & METAB. 1998, 83 (3) 2742-8
SOY PROTEIN AND ISOFLAVONES – THEIR EFFECTS ON BLOOD
LIPIDS AND BONE DENSITY IN POSTMENOPAUSAL WOMEN
A study was carried out on 66 postmenopausal women with
high blood cholesterol levels to investigate the effects
of soy protein containing two different isoflavone concentrations
on blood lipid levels and bone density.
Results showed an increase in HDL cholesterol and a decrease
in non-HDL cholesterol in both soy protein groups, although
the total cholesterol concentration was not affected. Bone
mineral content and density in the lumbar spine was significantly
increased in the group with the higher isoflavone concentration.
It was concluded that soy protein may protect against cardiovascular
disease in postmenopausal women, and isoflavones may have
a protective role in maintaining bone mineral density.
Potter, S.M. et al,
AM. J. CLIN. NUTR. 1998, 68, 1375S-1379S
IS PREMATURE GREY HAIR A RISK FACTOR FOR OSTEOPOROSIS?
The hypothesis that premature hair greying was associated
with osteopenia was studied in a population of 404 normal
post-menopausal women involved in studies of osteoporosis
prevention at the University of Auckland, New Zealand. Analysis
of data indicated that the majority of hair greying before
age 40 was associated with a lower bone mineral density
at most skeletal sites. Premature grey hair could be an
invaluable risk marker for osteoporosis.
Orr-Walker, B.J. et al,
J. CLIN. ENDOCRINAL. METAB. 1997, 82, 3580-3583
Courtesy Lamberts Nutrition Bites
EFFECT OF CALCIUM AND VITAMIN D SUPPLEMENTATION ON BONE
DENSITY IN MEN AND WOMEN 65 YEARS OF AGE OR OLDER
A study was carried out to determine the effects of three
years of dietary supplementation with calcium and vitamin
D on bone mineral density, biochemical measures of bone
metabolism, and the incidence of nonvertebral fractures
in 176 men and 213 women 65 years of age or older. They
received either 500mg of calcium plus 700 IU of vitamin
D (cholecalciferol) per day or placebo. The mean changes
in bone mineral density in the calcium-vitamin D and placebo
groups were as follows:
femoral neck, +0.50 and -0.70%, respectively; spine, +2.12
and +1.22%;
total body, +0.06 and -1.09%.
The difference between the calcium-vitamin D and placebo
groups was significant at all skeletal sites after one year,
but it was significant only for total-body bone mineral
density in the second and third years.
Dawson-Hughes, B et al.
N. ENGL. J. MED. 1997, 337 (10) 670-6
MORE EFFORT NEEDED TO HALT OSTEOPOROTIC BONE LOSS
At a recent British Society for Rheumatology meeting it
was announced that steroid-induced osteoporosis is a problem
that is not being effectively tackled. About 0.5% of the
general population is receiving long-term steroid therapy,
but a survey showed that only about 14% had taken some form
of preventative treatment for bone loss. It was reported
that the C-terminal (CTX) and N-terminal (NTX) peptides
of type-1 collagen were helpful biochemical markers for
prediction of bone loss in osteoporosis. CTX and free deoxypyridinoline
have also proved highly predictive of hip-fracture rate
in osteoporosis, independent of bone mass. It was suggested
that patients on prednisolone 7.5 mg or more per day for
6 months or longer should be targeted for prophylactic therapy
for bone loss. Vitamin D and calcium supplementation should
be considered in all patients.
Clark, S.
LANCET 1998, 351 (9112) 1335
ALUMINIUM, ALZHEIMER’S DISEASE AND BONE FRAGILITY
The incidence of fragility fractures has increased epidemically,
especially in patients with senile dementia (including Alzheimer’s
disease). Aluminium inhibits bone mineralisation, is neurotoxic
and may, in addition to genetic factors, play a role in
the development of Alzheimer’s disease by contributing
to the formation of the characteristic beta-amyloid and
neurofibrillary tangles. A pilot study of 26 hip-fracture
patients (13 patients with Alzheimer’s disease and
13 controls) was carried out.
The aluminium content, determined mass-spectrometrically,
was higher in trabecular bone biopsies from the patients
with Alzheimer’s disease than from the controls. The
aluminium content was also higher in the younger of the
26 patients. The findings agree with the hypothesis that
aluminium plays a role in the development of Alzheimer’s
disease and bone fragility.
Mjoberg, B et al.
ACTA. ORTH. SCAND. 1997, 68 (6) 511-14
