Yoghurt can help lower stroke and heart attack risk
Scientists have discovered that a daily dose of ‘good bacteria’, or probiotics contained in yoghurt, boosts microbes in the gut that protect against the effects of salty food.
In a wide-ranging new study, experiments on humans and mice fed an unhealthy salty diet found the addition of daily yoghurts reduced inflammation-triggering cells that cause hypertension.
Probiotics are commonly found in yoghurts as well as fermented products such as sauerkraut.
But the American and German team of scientists warned that while eating the dairy product was beneficial, it was not a licence for people to consume as much salt as they liked.
There’s some promise in developing probiotics
Professor Eric Alm, who led the study at Massachusetts Institute of Technology, said: “I think certainly there’s some promise in developing probiotics that could be targeted to possibly fixing some of the effects of a high-salt diet.
“But people shouldn’t think they can eat fast food and then pop a probiotic and it will be cancelled out.”
It is hoped the findings could lead to yoghurt-based therapies to tackle high blood pressure, or hypertension, that affects one-in-four Britons.
A diet high in salt is known to be a major risk factor, with high blood pressure then raising the risk of heart disease and heart attack.
Heart disease remains the biggest killer in the UK, taking around 160,000 lives a year.
The addition of daily yoghurts reduced inflammation
The British Heart Foundation has welcomed research into the benefits of probiotics but has also warned that lifestyle and diet choices are additionally important to maintaining a healthy heart.
A spokeswoman said: “Having high blood pressure puts you at greater risk of cardiovascular disease including heart attack and stroke, so it’s vital we do all we can to keep our levels in check.”
But she added: “There are a number of well-established lifestyle changes that we can make to keep our blood pressure healthy. Eating less salt, more fruit and vegetables and being physically active and maintaining a healthy body weight are all tried and tested ways to do this.”
Adults in the UK currently eat about 8.1g of salt a day – well above the recommendation of no more than 6g.
Professor Alm and colleagues found that a high-salt diet shrank the amount of a certain type of beneficial gut bacteria known as Lactobacillus murinus.
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As a result, pro-inflammatory cells of the immune system known as Th-17 – which have been linked with high blood pressure – grew in number.
In the new study conducted on healthy humans, adding 6 grams of table salt to their daily diet for a fortnight reduced the lactobacillus bacteria in their gut.
As a result, their blood pressure went up – along with their counts of Th-17 cells.
But when the participants – all male and aged 18 to 50 – were given a commercially available probiotic (yoghurt) for a week before going on the high-salt diet, their gut lactobacillus levels and blood pressure remained normal.
This followed similar results in mice. For two weeks table salt made up 4 percent of their diet – eight times more than normal.
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This led to a drop in lactobacillus, more of the troublesome Th-17 cells – and a rise in blood pressure.
But when they were given a probiotic containing Lactobacillus murinus the inflammatory cells went down and hypertension was reduced.
It is still unclear exactly how Th-17 cells contribute to the development of high blood pressure and other ill effects of a high-salt diet.
Professor Alm said: “We’re learning the immune system exerts a lot of control on the body, above and beyond what we generally think of as immunity. The mechanisms by which it exerts that control are still being unravelled.” It is hoped the findings, published in Nature, will shed more light on the association between a high-salt diet and disease.
A shocking 16 million people in the UK suffer from high blood pressure
“If you can find that smoking gun and uncover the complete molecular details of what’s going on you may make it more likely that people adhere to a healthy diet.”
Scientists have long known a high-salt diet can lead to cardiovascular disease. As it accumulates in the bloodstream the body retains more fluid to dilute it.
It means the heart and blood vessels have to work harder to pump the extra volume of water.
This can stiffen the blood vessels – potentially leading to high blood pressure, heart attack and stroke. Recent evidence has also implicated the body’s immune system in some of the effects of a high-salt diet.
A shocking 16 million people in the UK suffer from high blood pressure – the biggest risk factor for stroke and heart attacks – with over half unaware they have the condition.