Is 'one apple a day' a myth? Harvard-trained gut doctor explains its link to gut, liver and colon health

We’ve all heard it since childhood: an apple a day keeps the doctor away. But does it really work? For those curious about the science, apples are more than just a crunchy snack. They contain fibre, antioxidants, and compounds that interact with your gut, liver, and even your heart. From feeding good bacteria to potentially lowering disease risk, apples are quietly powerful—and new research shows why they deserve a regular spot in your diet.

Dr Saurabh Sethi, a Harvard-trained gastroenterologist from AIIMS, explains that a single apple a day is far from a myth. Regular apple intake is linked to a lower risk of colon cancer and improved liver health. Apples are rich in pectin, a type of fibre that feeds beneficial gut microbes and reduces inflammation. For best results, eat apples with the peel, washed carefully with water and baking soda.

Apples make you feel full

Healthline highlights that apples are also rich in polyphenols, a group of antioxidants that support overall health. High in both fibre and water, apples make you feel full, which may influence eating habits and weight management. One study found that eating whole apples increased feelings of fullness.

Effect on BMI

Some research suggests that regular apple consumption may help reduce Body Mass Index (BMI), a factor linked to heart disease, though results are mixed and more studies are needed to confirm long-term weight effects.

Heart health

Apples may also benefit heart health. Eating 100–150 grams of whole apples daily has been associated with lower risks of heart disease and high blood pressure.

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May help with diabetes

For diabetes, apples may offer protection against type 2 diabetes. A 2019 review suggested that regular apple consumption could reduce the risk, possibly due to the high polyphenol quercetin.

May help with gut health

Gut health is another major benefit. Apples contain pectin, a prebiotic fibre that reaches the colon intact, promoting the growth of good bacteria. Pectin improves the ratio of Bacteroidetes to Firmicutes, two main types of gut bacteria, and may help protect against obesity, type 2 diabetes, heart disease, and cancer by maintaining a healthy gut microbiome.