What is Hypertension? Quiet Killer! The Pressure is On!
What is Hypertension? Quiet Killer! The Pressure is On | Hypertension is the medical name for high blood pressure. Like diabetes, medicine has made impressive progress in the clinical treatment of hypertension, and this has resulted in a decline in mortality from strokes, for example, over the last three decades.
But that’s not the full picture. A recent survey among 3.000 Scots in the forty-five to sixty-four age group revealed that nearly forty per cent of them had high blood-pressure. And we know that raised blood pressure is one of the key risk factors in the development of heart disease and cerebrovascular disease.
The United Kingdom government estimate that over 240,000 people die every year as a result of a hypertension-related disease.’ Put another way, thirty- three per cent – one third – of all deaths that occur in people aged less than sixty-five years are attributable to hypertensive causes.
What is Hypertension?
Blood-pressure is measured by the height in millimetres of a column of Mercury that can be raised inside a vacuum. The more pressure there is the higher the column will rise. Since blood-pressure varies with every heartbeat, two measures are taken – one that measures the pressure of the beat itself (called systolic blood pressure) and the other that measures the pressure in between beats, when the heart is resting (this is called diastolic blood-pressure, and is the background’ level). These two figures are written with the systolic figure first followed by the diastolic figure, like this – 120:80
When we’re born, our systolic blood pressure is about forty, then it doubles to about eighty within the first month. Thereafter, the increase is slower, but inexorable, for the rest of our life. Many people do not realize they suffer from hypertension. There may be no symptoms, and it may only be discovered during a visit to the doctor’s surgery for another complaint.
May include headache, dizziness, fatigue, and insomnia. A pressure of 150:90 would be considered above average in a young person, and 160:95 would be abnormally high. In older people, systolic pressure could be 140 at age sixty, and 160 at age eighty years. Comparitively small changes in the pressure of those people who are in the ‘at risk’ category could have very worthwhile results.
This was emphasised by the recent NACNE report which states: It has been estimated that a relatively small reduction (2-3mm) in mean blood pressure in the population, if the distribution were to remain similar to the present distribution of blood pressures, would result in a major benefit in terms of mortality, and that a shift of this magnitude would be comparable to the benefit currently achieved by antihypertensive therapy. This estimated benefit seems applicable to mild as well as severe hypertension.
If this is true – that a small change in the population’s blood-pressure could be as beneficial as all the drugs that people are now taking – then what are we waiting for?
What is Hypertension? The Pressure is On
Scientists have known for a long time that some populations are apparently ‘immune’ from hypertension, and do not display the rise in blood pressure that is associated in the West with getting older. These populations generally tend to have a high level of physical activity, are not overweight, have a low level of animal fat
in their diet, and don’t take much salt (sodium) in their food.
In other words, hypertension seems to be an illness of our Western way of life. The problem is, of course, that the majority of us are stuck with it. We can’t suddenly emigrate to a tropical paradise, or even change our lifestyles to a significant extent.
As long ago as 1926, it was experimentally shown that certain dietary components could be connected to hypertension. In that year, a pioneering Californian study had shown that the blood- pressure of non-meat using people could be raised – by as much as ten per cent – in just two weeks of eating a diet that is centred around meat. Subsequent experiments have confirmed this effect. Further large-scale studies began to be conducted, and different population groups began to be compared with each other to see just how the variations in diet affected blood-pressure.
Meat in their diets
One such study was undertaken in Australia. Two groups of people were selected, one of which regularly ate meat in their diets, and the other didn’t. Most of the meat-eaters consumed it at least once every day. The non-meat eating group was composed of Australian Seventh Day Adventists. The following graph shows how
the two groups compared:
Bottom line shows the non-meat eaters, and the bottom axis shows the five age groups that were surveyed. You can see that, at all ages, blood-pressure is significantly lower in the non-meat eaters. Amongst the meat-eaters, there is a steady rise in blood pressure with advancing age. But amongst the non-meat eaters there is very
little increase – and, in fact, a surprising drop in blood-pressure in the oldest age group. These results were adjusted to exclude other factors such as exercise, tea or coffee consumption or alcohol.
Another study was carried out in Britain, and again compared the blood-pressure levels in people who didn’t eat meat to those who did.’ The results showed exactly the same pattern. This was true in men as well as women. This chart shows the mean results that were obtained:
What is Hypertension? Diastolic blood-pressure
The meat users are shown in black, and non-meat users are shaded. The difference in the ‘underlying blood-pressure (diastolic), which is generally thought to be a better guide to the real health of the individual, is considerable. On average, diastolic blood-pressure was fifteen per cent less in the non-meat users than in the meat-eaters.
Fibre Fans Fight Fat
After the connection between the intake of dietary animal fat and elevated blood pressure had been established, scientists started looking round for other important dietary factors. It was suggested that a high-fibre diet might somehow give protection against developing high blood pressure, and from experimental evidence it does seem as if there is some truth in this.
To test this theory, scientists at Southampton University set up an experiment on humans. First, they recruited ninety-four volunteers from the staff and students of the university. Then they divided them into two groups – those who had a high fibre intake in their diets, and those with a low fibre intake. Just as had been expected, the group with the high fibre intake had a lower mean blood pressure than the other group.
What is Hypertension? After four weeks
The next stage in the experiment was to switch the diets over. So the group who normally ate a high fibre diet was put on a low fibre diet. And the other group was given a diet that was much higher in fibre than the one they had been used to. After four weeks of eating these new diets, the results were measured. Just as you’d expect, the group with the low fibre diet now had raised blood-pressure, and the group on high fibre now had lowered their blood-pressure. The changes were in the region of five per cent, which is a significant amount.
Of course, most meat-oriented diets are essentially low in dietary fibre Meat itself contains absolutely none
So it was beginning to look as if a high-meat, low-fibre diet was the worst possible diet for hypertension, particularly when you remember that most meat contains significant quantities of sodium.
Two Further Studies
There is now considerable evidence to show that a meat-freehigh-fibre diet can lower blood pressure, so we will just mention two more in America, a high plant-fibre diet was devised, including whole grain cereals, bran cereals, whole-grain breads, vegetables, beans and pulses – but including very little meat or other animal fat. Interestingly, the group put on this diet was allowed to use as much salt in their food as they wanted to. This group was ther compared to a standard control group, who carried on eating normally.
The average blood-pressure of the men on the plant fibre diet was ten per cent lower than the control group.
The other study well briefly mention took place in Australia, wher fifty-nine healthy subjects aged twenty-five to sixty-three were randomly allocated to one of three groups. The first was th control which acted as a comparison and continued to eat a ordinary diet for the fourteen weeks that the experiment lastec. The second and third groups were alternately put on a meat-free diet for six weeks each, and then swapped over.
What is Hypertension? Blood-pressure-changing
The results revealed a neat pattern. When the first group were on the meatless diet, their blood-pressure dropped significant. After six weeks, they resumed eating meat, and their blood-pressure went up again. At this point, the second group stopped taking mean and their pressure dropped, rising again six weeks later when the experiment concluded. The mean changes were 6mmHg (systolic) and 3mmHg (diastolic).
The Possibility of Healing?
We know – from studies such as those mentioned above-th people on meat-free diets generally exhibit a lower blood-pressure. But could this be used in the treatment of hypertension? Another Australian study tried to do just this, 10 Fifty-eight people with mild hypertension were selected scientists at the Royal Perth Hospital.
Like the previous study, were divided into three groups, with the first acting as the contre group. Once again, blood pressure fell significantly, by an avera of 5mmHg (systolic). The scientists wrote: If the usual aim of treatment of mild hypertensives is to reduce systolic blood pressure to bellow 140mmHg then thirty per cent of those eating a meat-free diet achieved this criteria compared with only eight cent on their usual diet.
What is Hypertension? Costs of drugs and hospitalization
When the decrease in blood pressure was considered for the entire group the scientists wrote, ‘it was found
that it occurred at the time when most of the medicines were withdrawn. Of the twenty-six patients, twenty had given up their medication completely after one year while six still took some medicine, although the dose was lower, usually halved: Several other benefits were found, as well. Their serum cholesterol levels were found to have dropped by an average of fifteen per cent. And the health authorities computed that they had saved about £1,000 per patient over the year, by reducing the costs of drugs and hospitalization.
Hypertension is sometimes prefixed with the word ‘essential’ which rather confusingly means that the cause is of it is not definitely known to medical science. Nevertheless, we have presented some convincing evidence that implicates meat and other sources of animal fat, while showing that a high plant fibre diet can go some way towards reducing blood pressure.
Since hypertension develops so insidiously, and since prevention is the best form of treatment, we should consider the implications of the above evidence when it comes to establishing good long-term eating patterns in our young children. For those people who have already developed hypertension, it would seem to make sense to investigate the serious possibility of dietary modification following the example of the Swedish experiment.