The oily fish with blood pressure powers



Originally published at, written by Christie Norris.

Many of us are familiar with fake food news — the harmless exaggerations fed to us by our parents growing up.

‘Eat your crusts, you’ll get curly hair.’
‘Finish your carrots, you’ll see in the dark.’
‘Drink your milk, you’ll grow big and strong.’

With adulthood comes the realisation that no amount of crust will lead to silky curls, but not all food claims are fake. We’re trying to unpick how ‘eating your oily fish could lower your blood pressure.’

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Omega-3 is key

Researchers have found that oily fish, such as mackerel, salmon, sardines or mussels, could help protect our hearts and brains from disease. They are found to be rich in an important type of polyunsaturated fat called omega-3, which has been shown to help lower blood pressure. Low blood pressure is something we should all strive for, as high blood pressure poses a serious threat to our health over time.

When blood pressure is consistently high, the blood flow through vessels is forceful, turbulent and causes stiffening, and sometimes damage, of the vessel walls. Over time this means the heart is having to work under strain, which dramatically increases the risk of conditions such as heart attack, stroke or heart failure.

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So we know a healthy, lower blood pressure is better for us. And we know oily fish can play a part in keeping it low. What we don’t know is how this works. Some scientists suggest that fish oils lead to the dilation — or relaxation — of blood vessels, which keeps pressure low. If you imagine a hose pipe getting wider, water would flow through it more smoothly and at a slower speed. Although a helpful piece of the puzzle, exactly how this happens is unclear.

The power’s in the pore

Dr Alister McNeish and team at the University of Reading are looking to understand exactly how eating oily fish lowers blood pressure. His team are exploring whether tiny pores in our blood vessel walls could be the leading character in this story. The pores, called potassium channels, are responsible for letting tiny molecules in and out of cells.

Dr McNeish believes that fish oils interact with these channels, causing them to open, and it’s this action that triggers blood vessel dilation. To prove or disprove their theory, the team are analysing mouse arteries to look at how fish oils interact with potassium channels and what effect this has.

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Fishing for answers

So why do we care? Although there are a number of blood pressure lowering drugs available, they don’t work for everyone. More than a third of people prescribed medication still have high blood pressure, and some will experience side effects such as tiredness and dizziness, resulting in them not wanting to take them

There are a number of theories as to why this occurs, one of which is the lack of personal suitability. Drugs aren’t a one-size-fits-all affair and in the same way as our body shapes are unique, our internal make-up is unique too. But before we can personalise treatments, we need to have a comprehensive understanding of what happens during the disease process. Research like this helps us build a more detailed picture of high blood pressure. If potassium channels play an integral role in lowering blood pressure, the drugs of the future could mimic their action.

Although we know oils in fish are good for us, that doesn’t mean we should forget the benefits of a balanced diet overall. Combining oily fish, as part of a traditional Mediterranean style diet, will give your body the best chance of staving off disease.

There are some ‘food facts’ that should be taken with a pinch of salt, but upping your oily fish intake isn’t one of them.

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The oily fish with blood pressure powers was originally published in British Heart Foundation on Medium, where people are continuing the conversation by highlighting and responding to this story.