They’re packed with antioxidants, prebiotics, vitamins, minerals and fibre.
Medically reviewed by Dr Roger Henderson and words by Annie Hayes
The aphorism ‘an apple a day keeps the doctor away’ was coined in 1913 and still rings true today. Packed with antioxidants, prebiotics, vitamins, minerals and fibre, the health benefits of apples have earned them a place in the fruit bowls of households across the UK.
Cheap, versatile and readily available, there are more than 2,000 varieties of apples to choose from, ranging from tart and tangy to mild and sweet.
We asked Kim Plaza, nutritional advisor at Bio-Kult, to talk us through the various health benefits of apples:
12 health benefits of apples
‘Apples are the world’s second most consumed fruit, after bananas,’ says Plaza. ‘Along with fibre, vitamins and minerals, they also contain rich amounts of polyphenols. Thanks to these nutrients, apples are said to have a wide range of beneficial health effects.’
Here’s what science says about the health benefits of apples:
- High in antioxidants
‘Apples contain some potent antioxidants within their skin, including quercetin, catechin, chlorogenic acid, and vitamin C,’ Plaza says. Antioxidants protect cells against the oxidative stress caused by free radicals. Oxidative stress is implicated in inflammatory conditions, including diseases such as cancer, heart disease and diabetes. ‘Antioxidants work by stabilising cells within the body and reducing their potential damaging effects,’ she says.
- Excellent fibre source
Apples are a great source of both soluble and insoluble fibre. A medium 150 gram apple contains 5g of fibre, which is more than one quarter of the recommended daily intake of 18g. Insoluble fibre is also called roughage. It supports your digestive system by softening your stools, and helps to prevent conditions such as constipation and diarrhoea. Soluble fibre, meanwhile, is a gel-like fibre that slows digestion and lowers cholesterol levels.
- Packed with prebiotics
Prebiotics are fibres that stimulate the growth of ‘good’ bacteria. ‘Apples contain pectin, a soluble fibre, and this acts as the prebiotic,’ says Plaza. ‘It is the preferred food source for beneficial bacteria, and fermented within the gut. Short chain fatty acids are consequently produced, which can aid in healing the gut lining.’
- Loaded with nutrients
The main vitamins and minerals in apples are vitamins C and E, potassium and magnesium. ‘Vitamin C and E can work together to support other antioxidant compounds such as glutathione,’ says Plaza. ‘Vitamin C is useful for skin health, supporting collagen, has antihistamine properties and also has a role in regenerating vitamin E.’
The main vitamins and minerals in apples are vitamins C and E, potassium and magnesium.
Vitamin E, meanwhile, is useful for ‘scavenging free radicals in lipids’, she says, and is therefore good for liver and cardiovascular health, while magnesium is responsible for around 300 chemical reactions in the body and is important for ‘sleep, relaxation and supporting the immune system’.
‘Potassium is responsible for the control of ion balancing across cell membranes,’ Plaza adds. ‘This is important for a number of processes such as muscle contraction and blood pressure control.’ Nutritionally speaking, the skin is the best part of the fruit. Most of the fibre and antioxidants – including vitamin C – is concentrated in or just below the skin.
- Assists with weight loss
Not only are apples a low-calorie snack – a medium 150g apple contains around 80 calories – but the high fibre and water content and satisfying ‘crunch’ texture makes them filling and satiating. And that’s not all.
‘The prebiotic content of apples, as mentioned, may help to support a diverse range of beneficial bacteria,’ says Plaza. ‘Different compounds that are released from a healthy microbiome can influence appetite hormones and therefore may contribute towards blood sugar balance and possibly reduce food cravings.’
- Supports heart health
Apples may also lower your risk of cardiovascular disease, which includes heart disease and stroke. ‘Although more human trials are needed, there is some promising evidence emerging for the components of apple in cardiovascular disease,’ says Plaza.
‘Antioxidant properties have been shown to reduce inflammatory markers, which are associated with heart disease,’ she says. ‘Polyphenols in apples may improve vascular health and blood pressure, while apple pectin may have the ability to increase bile acids, therefore potentially improving cholesterol levels.’
- Promotes gut health
Pectin, the main soluble fibre in apples, produces short chain fatty acids which are crucial to gastrointestinal health. It also supports levels of butyrate-producing bacteria – butyrate is a nutrient produced in the gut – such as beneficial Bifidobacterium strains, says Plaza.
‘Polyphenols contained within apples may also help to influence the diversity of bacteria by inhibiting certain pathogenic bacteria through antimicrobial activity,’ she says. ‘These actions may therefore help to establish a healthy microbiome, supporting nutrient absorption and gut healing.’
- May protect against asthma
Certain antioxidant and anti-inflammatory compounds in apples help to regulate immune responses in the body and appear to protect against – and even relieve symptoms of – asthma.
‘There are some promising studies highlighting the benefits of apple consumption with asthma sufferers, although further research is required,’ says Plaza. ‘One study found that apple intake was associated with a 10 per cent reduction in asthma risk.’
This may be partly to do with the high vitamin C levels of apples. ‘Vitamin C is a natural antihistamine and therefore may be useful in managing asthmatic symptoms, especially since symptomatic asthma in adults is associated with lower intake of vitamin C,’ she adds.
- Supports bone health
While eating fruit is generally known to support bone health, some studies show that apples specifically have a positive effect. In a study by California State University, women ate a meal that either included fresh apples, peeled apples, apple sauce, or no apple products. Interestingly, those who ate apples lost less calcium from their bodies than those who ate none.
‘Minerals associated with fruit intake, such as potassium and magnesium are thought to play a role in neutralising effects of dietary acids, which have been attributed to bone loss,’ says Plaza. ‘Additionally vitamin C and phytochemicals are involved in the synthesis of the bone matrix.’
- Protects brain health
The link between the gut and the brain is a subject of intense scientific study and debate, but early science suggests what we eat has a huge impact on our brain health – for better and worse. ‘People with cognitive impairment commonly suffer with gastrointestinal dysfunction, increased gut permeability and an imbalance of gut bacteria,’ says Plaza.
‘One animal study showed that apple concentrate significantly improved cognitive-related performance.’
The healthful compounds in apples may contribute to the relationship between the brain and the gut. ‘Polyphenols provide antioxidant and anti-inflammatory properties that may influence the regulation of neuronal communication,’ she continues. ‘One animal study showed that apple concentrate significantly improved cognitive-related performance, however further human trials are needed.’
- Linked to lower diabetes risk
Eating apples is associated with a lower risk of diabetes, observational studies show. In a large review assembled by researchers at California State University, eating an apple a day was linked to a 28 per cent lower risk of type 2 diabetes compared to not eating any apples.
This may be due to their polyphenol content – polyphenols help to prevent tissue damage to beta cells in your pancreas, which are responsible for producing insulin. Beta cells are often found to be damaged in people with type 2 diabetes.
- Linked to lower cancer risk
Several lab studies have shown a link between plant compounds in apples such as flavanoids and polyphenols – collectively known as phytochemicals – and a lower risk of cancer. Researchers at Cornell University have identified 12 compounds in apple peel that either inhibit or kill cancer cells in laboratory cultures. While this research is extremely interesting, robust human studies are needed before any conclusions can be drawn.