This is what apples really do to your heart and gut health
Scientists have discovered a new method of squeezing apple juice which may help to boost its health benefits.
The study, by researchers at Hochschule Geisenheim University and published in Food Research International, found that this new method boosted polyphenol content by four times as much as regular apple juice.
Polyphenols are natural plant compounds found in fruit, red wine, and cocoa which are antioxidants, and are thought to have a range of health benefits for the heart and brain, and may protect against disease.
Researchers say they can maximise these compounds in the juice by using a new method called a spiral filter press, which actively takes out oxygen by vacuum-driven pressing.
Oxygen is excluded from all other processing steps, therefore reducing nutrient deterioration, according to the experts.
A 280 ml serving of the new apple juice would be enough to provide 100% of the ideal intake for a key group of polyphenols, called flavan-3-ols, which help promote a healthy blood flow, cholesterol concentrations, and blood sugar.
The ideal intake of 400–600 milligrams per day for cardiovascular health was proposed by an international consortium of scientists in 2022.
The British Heart Foundation estimates that there are 7.6m people living in the UK with heart or circulatory diseases. Meanwhile, data from the 2021 census show that 32% of adults suffered from high blood pressure (hypertension) and three in 10 of those (29%) were undiagnosed; equating to approximately 4.2 million adults with undiagnosed hypertension.
Commenting on the findings lead author of the paper, Professor Ralf Schweiggert, says: "Apple juice is already a source of polyphenol compounds, but you would need to drink several glasses to reach the levels recommended by scientists for heart health effects. The new juicing method that we’ve investigated takes the polyphenol content to a new level by minimizing the nutrient losses we typically see during juicing."
Co-Researcher of the study, Stefan Dussling, adds: "Nutrient losses are commonly due to the presence of oxygen which quickly degrades some of the nutrients in apple juice like flavan-3-ols or vitamin C. This would happen when we juice apples at home or buy a ready-made product. We hope that the new juicing method will be used more widely in the future to help people get more of these beneficial natural compounds simply by drinking one glass of juice".
Gut health benefits of apples and apple juice
As well as having a positive impact on the heart and brain, apples are also good for the gut.
"Apples contain a type of fibre, called pectin, and polyphenols such as quercetin which have been found to have positive effects in the gut," explains Dr Carrie Ruxton, a dietitian from the Fruit Juice Science Centre.
Studies show that apple consumption changes the balance of gut bacteria and boosts short-chain fatty acids in the colon.
"These substances are produced by ‘friendly’ types of bacteria and have been found in research to have beneficial health effects, including immune support and increased calcium absorption," Dr Ruxton explains.
"Although apple juice is lower in fibre than whole apples, some pectin is still present. Both apples and apple juice contain similar amounts of polyphenols".
Apples also contribute to more regular bowel movements because they are a good source of fibre, which is key to supporting healthy digestion.
There is also some suggestion, by the Happy Apple Plan, that eating an apple before a meal can aid weight loss. "The apple helps to increase the overall fibre content of the meal, and that means you feel full and satisfied for longer, preventing mindless snacking between meals," nutritionist Rob Hobson writes in a blog post for British Apples and Pears.
It seems there is some truth in the old "apple a day," saying after all.
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