HIGH BLOOD PRESSURE
DYNAMIC EXERCISE NORMALISES RESTING BLOOD PRESSURE IN
MILDLY HYPERTENSIVE PREMENOPAUSAL WOMEN
Endurance exercise is advocated as adjuvant treatment for
hypertension because participation in a dynamic exercise
program lowers resting blood pressure. Recently, exercise
has been shown to acutely and transiently reduce systolic
blood pressure and/or diastolic blood pressure in hypertensive
men, an effect that has been termed post-exercise hypotension
(PEH). Therefore, a study was carried out on 18 premenopausal
women (7 hypertensive and 11normotensive) to determine if
PEH occurs in women and to elucidate possible haemodynamic
and hormonal mechanisms. Participants wore an ambulatory
blood pressure monitor throughout the day after 40 minutes
of a rest sham session and 40 minutes of cycle exercise,
of which 30 minutes was performed at 60% of maximal oxygen
consumption. It was found that systolic, diastolic, and
mean arterial blood pressure decreased in the hypertensive
women by a mean of 9.5 ? 2.8 mm Hg, 6.7 ? 2.4 mm Hg, and
7.7 ? 2.4 mm Hg, respectively, for up to 7 hours after versus
before exercise, whereas blood pressure was similar in the
normotensive women.
After exercise, total systemic vascular resistance was
lower, and cardiac output, catecholamines, and plasma renin
activity were greater than before exercise in both groups
of women. Thus, PEH was observed for up to 7 hours after
exercise in mildly hypertensive women and was not explained
by the haemodynamic and hormonal adjustments that occurred
after exercise. The magnitude and duration of PEH may be
sufficient to normalise the blood pressure of certain hypertensive
women throughout most of the day.
Pescatello, L.S. et al
AM. HEART J. 1999, 138 (5 pt 1) 916-21
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
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
VITAMIN C LOWERS BLOOD PRESSURE
Research has finally confirmed that vitamin C, in the large
doses that have frequently been derided by some sceptical
doctors, does lower blood pressure. In the study blood pressure
was reduced by nearly 10% in people taking at least 500mg
daily.
THE TIMES, 23rd December, 1999.
WALKING TO WORK AND THE RISK FOR HYPERTENSION IN MEN
There is good evidence that physical activity reduces the
risk for cardiovascular disease, possibly by lowering blood
pressure. However, it is not known whether mild physical
activity, especially walking, reduces the risk for hypertension.
Therefore, a study was carried out to investigate the association
of the duration of the walk to work and leisure-time physical
activity with the risk for hypertension.
The study group comprised 6,017 Japanese men aged 35 to
60 years with systolic blood pressure less than 140 mm Hg,
diastolic blood pressure less than 90 mm Hg, normal glucose
intolerance, and no history of hypertension or diabetes
at baseline. During 59,784 person-years of follow-up, 626
cases of hypertension were confirmed. It was found that
the duration of the walk to work was associated with a reduction
in the risk for incident hypertension. The multivariate-adjusted
relative risks were 1.00 for a walk of 10 minutes or less
(reference category), 0.88 for an 11- to 20-minute walk,
and 0.71 for a walk of 21 minutes or more.
It is therefore estimated that for every 26.3 men who walk
more than 20 minutes to work, one case of hypertension will
be prevented.
Hayashi, T. et al,
ANN. INTERN. MED. 1999, 130 (1) 21-6
EFFECTS OF DIETARY PATTERNS ON BLOOD PRESSURE
High blood pressure is a major cardiovascular risk factor
affecting nearly 50 million adults in the United States
and significantly increasing their risk of heart failure,
heart attack, stroke, and kidney failure. Diet is an important
determinant of blood pressure. Therefore, a study was carried
out to determine the effects of dietary patterns on blood
pressure in subgroups.
Dietary Approaches to Stop Hypertension (DASH) was a randomised
controlled feeding study conducted at 4 academic medical
centres. The study group consisted of 459 adults with untreated
systolic blood pressure less than 160 mm Hg and diastolic
blood pressure 80 to 95 mm Hg. After 3 weeks on a control
diet the participants were randomised to 8 weeks of
(1) control diet;
(2) a diet rich in fruits and vegetables; or
(3) a combination diet rich in fruits, vegetables, and low-fat
dairy foods, and reduced in saturated fat, total fat, and
cholesterol (the DASH combination diet).
It was found that the combination diet significantly lowered
systolic blood pressure in all subgroups, and significantly
lowered diastolic blood pressure in all but 2 subgroups.
The fruits and vegetables diet also reduced blood pressure
in the same subgroups, but to a lesser extent. Thus, the
DASH combination diet significantly lowered blood pressure
in virtually all subgroups examined, and was particularly
effective in African Americans and those with hypertension.
Svetkey, L.P. et al
ARCH.INTERN.MED. 1999, 159 (3) 285-93
TIGHT BLOOD PRESSURE CONTROL REDUCES RISKS OF TYPE 2 DIABETES
Many patients with type 2 diabetes have hypertension. In
three reports the United Kingdom Prospective Diabetes Study
Group shows that in hypertensive patients with type 2 diabetes
tight control of blood pressure (mean 144/82 mmHg over nine
years, compared with 154/87 mmHg in controls) resulted in
a 24% reduction in any diabetic complications (macrovascular
and microvascular) and a 32% reduction in death related
to diabetes (mostly from myocardial infarction and strokes).
Another report shows that tight control of blood pressure
is cost effective and comparable with other widely supported
preventative strategies.
Another study comparing the use of an ACE inhibitor and
a beta-blocker found that both were equally effective in
reducing blood pressure and incidence of diabetic complications.
UK Prospective Diabetes Study Group
BMJ no.7160, 703-713, 713-720, 720-726
FRUIT AND VEGETABLE CONSUMPTION IN LATER LIFE
Fruit and vegetable consumption may reduce the risk of
several chronic diseases, including cancers, cardiovascular
disease, coronary heart disease, hypertension and stroke.
The World Health Organisation therefore recommends the consumption
of at least 400g, or 5 portions of fruit and vegetables
a day. Most adults’ consumption falls short of this
recommendation, so a study was carried out to assess the
levels of fruit and vegetable consumption in elderly people,
and to examine the socio-economic, physical and psychological
factors which influence this consumption. The subject group
was 445 elderly people (aged 65+) living in the East Midlands.
The recommended target of 5 portions of fruit and vegetables
a day was achieved by less than half the respondents: 37%
of those living in the urban area and 51% of those living
in the rural area. Low fruit and vegetable consumption was
particularly associated with being male, smoking and having
low levels of social engagement. Health programmes promoting
fruit and vegetable consumption may not be successfully
reaching elderly people and need to target those particularly
at risk of low consumption.
Johnson, A.E. et al
AGE & AGEING 1998, 27 (6) 723-8
EXCESSIVE DIETARY INTAKE OF VITAMIN A IS ASSOCIATED WITH
REDUCED BONE MINERAL DENSITY AND INCREASED RISK FOR HIP
FRACTURE
Age-adjusted rates of hip fracture incidence vary more
than sevenfold in Europe; the highest rates are found in
northern Europe, particularly Sweden and Norway. When dietary
patterns in Europe were compared, a large variation in vitamin
A intake was found: median intake was up to six-fold higher
in Scandinavian countries than in southern Europe. Therefore,
a study was carried out to investigate whether excessive
dietary intake of vitamin A is associated with decreased
bone mineral density and increased risk for hip fracture
in a group of Swedish women. Retinol intake was estimated
from dietary records and a food frequency questionnaire.
In multivariate analysis, retinol intake was negatively
associated with bone mineral density. For every 1mg increase
in daily intake of retinol, risk for hip fracture increased
by 68%. For intake greater than 1.5 mg/d compared with intake
less than 0.5 mg/d, bone mineral density was reduced by
10% at the femoral neck, 14% at the lumbar spine, and 6%
for the total body and risk for hip fracture was doubled.
Thus, a high dietary intake of retinol seems to be associated
with osteoporosis.
Melhus, H. et al
ANN. INT. MED. 1998, 129 (10) 770-8
CALCIUM FOR HYPERTENSION
A double-blind randomised placebo-controlled trial took
place involving 116 adolescents to determine whether an
increased intake of calcium can lead to a reduction in blood
pressure. Subjects were given 1.5g/day of calcium or placebo.
Results confirmed that there was a decrease in diastolic
blood pressure in the group receiving a calcium supplement.
The effect was greater in those whose diets were low in
calcium.
AM. J. CLIN. NUTR. 1998, 68 (3) 648-655
TALKING RAISES BLOOD PRESSURE
According to a group of researchers in Paris, people who
chat to their doctor during a check-up could be prescribed
drugs they do not need. On the contrary, reading a book
causes a mild drop in blood pressure. Readings of both systolic
and diastolic B.P. rose sharply (from an average of 145/95
to 155/110).
NEW SCIENTIST, 11th April 1998, p22
GINSENG AND WARFARIN
A possible interaction between warfarin and Ginseng (Panax
ginseng) has been reported. A 47-year-old man had been taking
warfarin for 5 years following the insertion of a mechanical
heart valve. His International Normalized Ratio (INR) had
ranged from 3.0 to 4.0 for 9 months. In February 1995 the
patient started taking Ginseng capsules (Ginsana) 3 times
daily. Two weeks later his INR dropped to 1.5. After the
Ginseng was discontinued it returned to 3.3 in 2 weeks,
i.e. the Ginseng appeared to reduce the effectiveness of
the warfarin.
AMERICAN J. HEALTH-SYSTEM PHARMACY 1997, 54, 692-3
Courtesy Kerry Bone, MODERN PHYTOTHERAPIST 1998, Vol. 4,
No. 1, 35
GARLIC PROLONGS ELASTICITY OF THE AORTA
German researchers studied the effects of long-term garlic
use (Allium sativum L.) on elasticity of the aorta in healthy,
nonsmoking adults. Results suggested that regular long-term
garlic powder intake attenuated age- and pressure-related
increase in aortic stiffness, but the precise mechanism
remains elusive.
Breithaupt-Grogler K. et al,
CIRCULATION 1997, 96 (8) 2649-2655
Courtesy HERBALGRAM No. 43
