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Want to avoid stroke? Watch your blood pressure

We all know that diet and lifestyle can have a profound effect on wellbeing, but which aspects matter most? Is smoking more dangerous than drinking? And how do both compare with being overweight or stressed? Questions that an international team of researchers have just answered in relation to one of the biggest threats to our health: strokes.

Whether caused by a brain haemorrhage or a blood clot, strokes vie with cancer and heart disease as the biggest killers — and disablers — in the western world. And it is not just the elderly who are at risk. Every year in the UK there are 10,000 strokes in people under 55.

The Interstroke study, published in the this edition of The Lancet, identifies the ten most important modifiable risk factors for stroke and ranks them in importance (see below). The factors themselves won’t raise too many eyebrows among Times readers (I hope), but their relative importance might.

Blood pressure is also the easiest risk factor on the list to miss

high blood pressure headlines with medical instruments

High blood pressure tops the list by some margin, having nearly double the impact of physical inactivity, which is second in the ranking, and nearly ten times that of stress, which sits close to the bottom of the list. To put it another way, if you want to take one sensible precaution against an early stroke it should be to keep an eye on your blood pressure.

Blood pressure is also the easiest risk factor on the list to miss. Contrary to pub lore it rarely gives you a red face or constant headaches. It tends to be silent and pernicious, and the longer it remains undiagnosed the greater the damage to the delicate lining of the blood vessels resulting in the changes responsible for most strokes.

High blood pressure can develop at any age but is most common in the over-forties, affecting at least one in five adults in the UK to some degree at some time. The only reliable way to pick it up is to monitor it regularly — at least every five years from the age of 35 and annually if it’s found to be borderline.

But what is normal? It depends where the reading is taken. In your GP surgery you are likely to be told you have high blood pressure if your readings are consistently above 140/90. Yet in the more relaxed environment of your home the upper limit of “normality” is thought to be lower at 130/80-85.

Simple blood pressure chart showing systolic (top) and diastolic (bottom) reading

Simple blood pressure chart showing systolic (top) and diastolic (bottom) reading

Once a series of higher than ideal readings has been recorded the next step is to do something about it. This is where many people go wrong. It is not all about taking a pill to correct the numbers, although that will be an essential part of therapy for many people. Rather your first step should be to look at the risk factors identified by Interstroke and mitigate as many as you can. This can lower your blood pressure and have myriad other benefits too.

The next question is how low should you go? Up until now doctors have generally been content to see their patients’ blood pressure readings drop just below the upper limit of normal, but there is evidence that lowering it further offers protection. Recent American research suggests that aiming for 120/80 could reduce cardiovascular complications such as stroke, heart attack and heart failure by nearly a third more than the current targets.

However, there is a downside to having too low a pressure. It can make you feel lightheaded, particularly on standing or getting out of a warm bed or bath, and that carries a risk of falls, particularly in the elderly. And the type and dose of the more aggressive medication needed to achieve these lower targets tends to have more side-effects, including kidney problems. It is a matter of balance.

Fortunately, lifestyle interventions — such as taking up exercise, losing weight, eating a Mediterranean, low-salt diet, etc — have few if any worrying side-effects. So start with self-help measures and use medication as an adjunct, not a substitute. Treat your whole body and not just the numbers.

MODIFIABLE RISK FACTORS FOR STROKE IN ORDER OF IMPACT

  • High blood pressure, physical inactivity, abnormal blood fats (not just high cholesterol), poor diet and obesity are the top five accounting for most strokes
  • Smoking and underlying heart issues (such as atrial fibrillation) sit in the middle of the ranking with alcohol, stress and diabetes at the bottom
  • For an overview of the UK guidance on measuring and diagnosing high blood pressure visit Nice for guidelines

Take the fluctuating diktats of nutritionists with a good pinch of salt.

Several specific government food targets — however well intentioned — contain a modicum of guesswork, claims this article from the Sunday Times. “Five-a-day, 14-21 alcohol units a week, 20-30g of saturated fat, 18g of fibre: none of these targets has any precise evidence for them,” Zoë Harcombe, who co-authored last week’s study, has written.

The less salt that we eat in our diet, the harder our kidneys have to work to reabsorb it

One of the most staunchly held truisms of modern nutrition is that salt is bad for you. “Salt: the facts”, begins a taxpayer-funded website. “Many of us in the UK eat too much salt,” it affirms. “Too much salt can raise your blood pressure, which puts you at increased risk of health problems such as heart disease and stroke . . . Cutting down on salt lowers blood pressure.” It adds that we should eat “no more than 6g of salt per day”.

“Why six?” asks Harcombe. “I have no idea and nor does the NHS. Why not seven? Why not five? Why have a target at all?”

The evidence that salt causes high blood pressure is decidedly shaky and has been repeatedly called into doubt. It rests for the most part on a couple of not especially recent or thorough trials. In the 1970s a Long Island scientist induced high blood pressure in rats by feeding them sodium that equated to a human eating 2,500g of salt a day. (Most of us eat around 8.5g of salt a day, or about 1½ teaspoons.)

salt shaker

In 1997 another study was held, ostensibly looking into whether a low-salt diet could control high blood pressure. Its participants followed a diet that not only featured minimal salt, but also contained fresh vegetables and fruits, lean protein and whole grains; it was low in saturated fat and, perhaps most crucially, contained little sugar.

Unsurprisingly, rates of high blood pressure in the group were lower than in the general population. But a lack of salt could not be isolated as the reason behind this. More than that, the low-salt group had higher rates of bad cholesterol, leading some researchers to call the results “one-sided”.

Avocados contain about 25g of fat, which led people to shun them in the 1980s. Now they are thought to raise good cholesterol. And have you ever met someone who got fat from avocado?

avacado

In contrast, the evidence that salt has a negligible effect on blood pressure — at least in most people — is now considerable. In January an international study, which followed more than 150,000 people across five continents, found that consuming less than 3g of sodium a day — or about 7.5g of salt — was associated with a 27% increase in cardiovascular disease and death. Eating between 3g and 6g of sodium, which is roughly the amount we normally eat, was associated with a lower rate of heart disease, while consuming more than 7g (about 18g of salt, or almost three times the UK average) was associated with a higher risk of heart disease and death.

This study has been buttressed by at least 10 others during the past 30 years, collectively following hundreds of thousands of people. One from 2011, which followed almost 4,000 Europeans for eight years, found that the risk for heart disease was 56% higher in a low-salt group than among those who ate the most salt.

These studies have repeatedly found that low-sodium diets — the same that you are exhorted to follow when you read websites such as “Salt: the facts” — could be more likely to kill you than simply eating the amount of salt that tastes right. We seek out foods that contain salt because without it we die.

“Restricting sodium in the diet to prevent hypertension and cardiovascular disease is the greatest con in preventative nutrition and medicine,” says James DiNicolantonio, a cardiovascular research scientist and an associate editor of the British Medical Journal’s online publication Open Heart. “Among people who lower their salt intake, the same percentage who get a reduction in blood pressure also get an increase in it.”

The rise of low-carb diets, including Atkins, led to people rejecting the first food of civilisation. But sourdough bread in particular is full of iron, zinc and magnesium, antioxidants, folic acid and other B vitamins. One study found it was safe for gluten-intolerant people.

He adds: “Low sodium stresses the heart. This increases the risk of atherosclerosis, heart failure and hypertension: the exact conditions that most governments and health institutes are trying to prevent by promoting low-salt intake for everyone.”

DiNicolantonio points out that our brains drive sodium intake: “That is one reason [why], over the past 50 years across diverse populations, consumption has been in a such a narrow range.

“In Britain, sodium intake has only fallen about 10-15% during the past decade. The authorities are shooting for 50% — a figure that would likely induce harm. Restricting sodium is also associated with increased mortality, worsened cognition and gait, increased risk of falling and subsequent fractures and worsened thyroid function — just to name a few.”

Despite decades of instructions exhorting people to cut down on the amount of salt they eat, the actual rates of salt consumption in developed countries are thought to have been relatively stable since the Industrial Revolution. Put simply: people are ignoring the advice not to eat more salt.

In part, this is because about 80% of the salt we eat in Britain comes from processed foods: cereals, frozen ready meals, pies, supermarket pizzas and so on. Barely a fifth is added in cooking or at the table. If salt caused high blood pressure, the past 30 years would have seen a spike in salt consumption. They have not. What we have seen instead is a surge in the consumption of refined carbohydrates and, especially, sugar.

DiNicolantonio points out that telling the food industry to lower the salt in processed foods may mean that people eat more of those foods to get the salt their physiology demands.

“So low-salt policies may lead to increased consumption of processed foods and the added sugars they bring with them,” he says, “which might in turn lead to increased type 2 diabetes, cardiovascular events and chronic metabolic disease.”

Sonia Pombo is a campaign co-ordinator and a graduate in nutrition who works at the Consensus Action on Salt and Health pressure group. She says those studies that fail to show a link between blood pressure and sodium are “limited and methodologically flawed”.

She adds: “It is evident that salt, in the amounts we eat, is a direct toxin that puts up our blood pressure, which is the biggest cause of strokes, heart attacks and heart failure and is the commonest cause of death and disability in the UK.”

Olive oil contains six times the saturated fat of pork, and is less chemically stable than butter and lard, which are therefore better for cooking.

olive oil

“A ‘direct toxin’?” says DiNicolantonio. “Salt is an essential micronutrient that our body can retain or excrete to maintain the perfect amount. The less sodium we eat, the harder our kidneys have to work to reabsorb it.”

I ask Harcombe whether, after butter and possibly salt, any other foods might be ready for rehabilitation.

“Eggs, certainly,” she says. “The evidence shows that eating cholesterol has no effect on the cholesterol in our own bodies — the American guidelines were just updated to reflect that. And eggs are high in cholesterol because a healthy chicken — or, indeed, a human — needs it to survive. Egg farmers went out of business because of that flawed advice, while cereal manufacturers made huge profits.”

Harcombe also believes that milk, lard and red meat are due to come back into favour. “The media often lump red meat with processed meat as equally likely to cause bowel cancer. The former is one of the most nutritious things on the planet: the latter is probably toxic,” she says.

The message to take from this dispiriting tale will be familiar. It is to eat fresh and wholesome food: vegetables, fruit, whole grains and nuts. Enjoy meat, fish and animal fats as accompaniments rather than as the basis of a dish. Don’t overdo sugar, but remember that food is as much about pleasure and the communion of the species as it is about fuel. Above all else, take the fluctuating diktats of nutritionists and killjoys with the best seasoning of all — a good pinch of salt.

Too much salt in bread

One in four loaves of bread contains as much salt per slice as a packet of crisps, new research has found.

Consensus Action on Salt & Health (CASH), a campaign group of medics, surveyed the salt content of 294 fresh and packaged loaves from supermarkets and their in-store bakeries as well as chain and independent high street bakeries, and found many were packed with hidden salt.

Most people wouldn’t realise that bread contains so much salt, as it doesn’t taste salty.

It found 28 per cent of loaves surveyed contained as much salt per slice as a packet of crisps – or more in some cases.

CASH has called for clearer labelling on bread from in-store supermarket and high street bakeries, which often have no nutritional labelling, making it impossible for consumers to know how much salt they are eating.

It also found that as well as being unlabelled, some high street chain bread contains more than three times as much salt per 100g than bread baked in supermarkets.

The findings come after the Department of Health announced that bread is the largest contributor of salt to our diet, providing almost a fifth (18 per cent) of our current daily salt intake. Current salt intake in the UK is 8.6g, with the maximum daily recommendation at 6g.

CASH campaign director Katharine Jenner said: “Most people wouldn’t realise that bread contains so much salt, as it doesn’t taste salty. It is scandalous that there is no labelling on fresh bread. Without it, how are we supposed to know where salt is hidden and cut our intake to less than 6g a day?”

CASH found the highest standard packaged bread was Cranks Seeded Farmhouse at 2.03g per 100g, which contained nearly four times more salt than the lowest – a Marks & Spencer’s Simply More Eat Well Healthiest White Bread (0.58g per 100g).

It said speciality breads, such as rye bread, were often perceived as healthier but could be high in salt.

The CASH chairman, Professor Graham MacGregor, said: “With bread being the biggest contributor of salt to our diets, it is frankly outrageous that bread still contains so much salt.

“The Department of Health needs to ensure that all bread is clearly labelled and that all manufacturers reduce the salt of bread to less than the salt target of 1g per 100g.

“It is the very high levels of salt that is hidden in everyday food, such as bread, that puts up both adults’ and children’s blood pressure.

“If all manufacturers went beyond these targets and cut the salt in their breads by a half, it would reduce our salt intakes by half a gram per day, which is predicted to prevent over 3,000 deaths from strokes and heart attacks a year.”

British Retail Consortium food director Andrew Opie said: “Our members have made fantastic progress reducing the levels of salt in food in recent years. It’s good to see that many of the loaves of bread with the lowest levels of salt are supermarket own-brands.

“These are the breads which sell at the greatest volume and that people are likely to eat every day, so reducing the salt in them makes a significant difference to the health of the nation.

“Reducing salt levels in speciality breads is much harder. Retailers and manufacturers have just announced they are choosing to fund independent scientific research to try and find ways of meeting new salt-reduction targets for a range of products, while still making foods which consumers want to buy.

“There’s a danger if salt is reduced further that products will no longer taste the way customers want them to.”

A Department of Health spokesman said: “We welcome the considerable salt reductions that bread makers have already made, and it is very pleasing to see that around 60 per cent of the products sampled already meet the salt targets for 2012.

“This is an important step in helping to reduce salt intake, as well as lowering the risk of high blood pressure and resulting strokes and heart disease.

“We look forward to seeing further reductions as more companies meet the targets.”

Unhealthy Eating Would You like Statins To Go With That

Fast food chains and restaurants should provide a side-order of statin drugs free of charge so that customers can neutralise the unhealthy effects of burgers, chips and other fatty food, experts said yesterday.

Unhealthy Eating

Researchers from Imperial College London said that taking a low dose-statin — a pill designed to lower cholesterol — could offset the increased risk of a heart attack after eating a cheeseburger and a milkshake.

Unhealthy Food

Although the drugs don’t cut out the health risks of fatty foods completely, they could be offered in fast-food restaurants alongside unhealthy condiments such as ketchup and mayonnaise, the researchers suggest.

But the British Heart Foundation warned that the drugs should not be considered a “magic bullet” against the risk of heart attacks and strokes, which kill about 140,000 Britons a year.

Darrel Francis, who led the latest research at the National Heart and Lung Institute at Imperial, said: “Statins don’t cut out all of the unhealthy effects of burgers and fries. It’s better to avoid fatty food altogether.

“But we’ve worked out that in terms of your likelihood of having a heart attack, taking a statin can reduce your risk to more or less the same degree as a fast food meal increases it.”

The number of British adults taking cholesterol-lowering statins has doubled to six million in the past five years despite concerns that they are being over-used and have unpleasant side-effects.

Mostly the drugs are prescribed by a doctor, to patients at particular risk of a heart attack or stroke, to reduce the amount of unhealthy “LDL” cholesterol in the blood.

But one statin, simvastatin, is already available in low doses (10mg) over the counter at pharmacies without a prescription. Doctors are divided on the benefits of the drugs for otherwise healthy people, however.

The Imperial College researchers point out that the cost of the tablets has fallen sharply in recent years, from about £40 a month to £1.50 a month.

Dr Francis said yesterday that it was “ironic” that people are free to take as many unhealthy condiments in fast food outlets as they like, “but statins, which are beneficial to heart health, have to be prescribed”.

“Everybody knows that fast food is bad for you, but people continue to eat it because it tastes good,” he said. “We’re genetically programmed to prefer high-calorie foods.

“It makes sense to make risk-reducing supplements available just as easily as the unhealthy condiments that are provided free of charge. It would cost less than 5p per customer — not much different to a sachet of ketchup.”

Previous research has shown a clear link between total fat intake and blood cholesterol, which is strongly linked to heart disease. Recent evidence suggests that trans fats, which are found in high levels in fast food, are the component of the Western diet that is most dangerous in terms of heart disease risk.

In a study to be published in the American Journal of Cardiology this week, Dr Francis and colleagues analysed data from a large cohort study to quantify how a person’s heart attack risk increases with their daily intake of total fat and trans fat.

They compared this with the decrease in risk from various statins, based on a meta-analysis of seven randomised controlled trials.

The results showed that most statin regimes are able to compensate for the relative risk increase from eating a cheeseburger and a small milkshake.

“When people engage in risky behaviours like driving or smoking, they’re encouraged to take measures that minimise their risk, like wearing a seatbelt or choosing cigarettes with filters,” Dr Francis added. “Taking a statin is a rational way of lowering some of the risks of eating a fatty meal.”

A very small proportion of regular statin users experience significant side effects, with problems in the liver and kidneys reported in between 1 in 1,000 and 1 in 10,000 people.

The Imperial researchers said statins have among the best safety profiles of any medication, but they said studies should be conducted to assess the potential risks of allowing people to take statins freely, without medical supervision.

A warning on the packet could emphasise that no tablet can substitute for a healthy diet, and advise people to consult their doctor for more advice, Dr Francis said.

However, the idea has practical drawbacks, including that restaurants or food chains may require a license from medicines regulators before they could distribute medication.

Professor Peter Weissberg, Medical Director at the British Heart Foundation added: “The suggestion that the harmful effects of a junk food meal might be erased by taking a cholesterol-lowering statin tablet should not be taken literally,” he said.

“A junk food diet has a wealth of unhealthy consequences beyond raising cholesterol. It can cause high blood pressure through too much salt, or obesity through eating meals loaded with calories. These are all risk factors for life-threatening health problems such as heart disease, type 2 diabetes and stroke.

“Statins are a vital medicine for people with — or at high risk of developing — heart disease. They are not a magic bullet.”