It’s one of the oldest sayings in health — passed down like gospel and printed on lunchboxes. But does eating an apple every day actually make a difference to your health?
Surprisingly, Dr. Emily Leeming, dietitian at King’s College London and author of Genius Gut: The Life-Changing Science of Eating for Your Second Brain, says this classic wisdom has more truth to it than you might think.
“Apples are a rich source of phytonutrients that are important for your immune system,” she says — including vitamin C and antioxidants.
Vitamin C helps your body produce antibodies and allows your immune cells to move more efficiently to where they’re needed. Meanwhile, antioxidants help reduce excess inflammation, which means your body may bounce back faster from infections.
But what really sets apples apart is what they do for your gut health — which is tightly connected to your immune system.
“About 70% of your immune cells live in your gut,” says Leeming. “So maintaining a healthy gut microbiome is key to overall immunity.”
Apples support the gut in two powerful ways:
🍎 They’re full of microbes — A single apple contains around 100 million microbes that contribute to gut diversity and help break down food.
🌾 They’re packed with fibre — An average apple delivers about 4g of fibre, which feeds your gut’s “good” bacteria — the ones that help regulate your immune response.
Looking to mix it up? Pomegranates, kiwis, and raspberries offer even more fibre per serving.
While apples are fantastic, no single food is a silver bullet.
“A variety of fruits and vegetables gives you a wide range of fibres, nutrients, polyphenols, and antioxidants,” Leeming notes.
She also recommends incorporating:
whole grains
beans and legumes
nuts and seeds
All of these are rich in fibre and help you hit the 30g daily target — a key number for gut and immune health.
Good news:
“As little as three days of better eating can start to shift your gut microbiome,” says Leeming.
And once your gut is supported, your immune system follows suit.
An apple a day won’t make you invincible — but it’s a strong start. With fibre, friendly microbes, and key immune-supporting nutrients, apples absolutely earn their reputation. Just don’t stop at one.
