By Rick Miller, Clinical and Sports Dietitian, Harley Street, London

We all know that a healthy and balanced diet full of fibre-rich foods reduces the risk of developing diabetes, obesity, cardiovascular disease and colon cancer, and can even reduce the risk of inflammation-mediated diseases such as arthritis.

The problem is, most of us aren’t incorporating enough fibre into our diet.

The average person in the UK only eats 18g of fibre per day, which falls short of the recommended 30g per day guidelines set out by the Government in their ‘Five A Day’ campaign (equivalent to 400g of fruit and vegetables per day). The World Health Organisation suggests we should be pushing higher still, consuming 800g of fruit and vegetables per day.

Where do raisins come into it?

Just one 40g serving of California Raisins provides 1.6g of fibre and counts towards that ‘Five A Day’ goal.

What exactly is fibre?

Fibre is a type of dietary carbohydrate. The vast majority of carbohydrates in our diet come from plant-based foods such as grains and naturally occurring sugars in fruits and starchy vegetables. Dairy products also contain a naturally occurring sugar. While these sugars and starches are a great energy source, fibrous carbohydrates are resistant to our digestive juices and cannot be broken down in the small intestine.

We rely on the friendly bacteria which live in our colon to digest these fibres. They thrive in the nutrient-rich mucus secreted from the intestine wall and help make up the trillion-dense microbiota called the ‘Biofilm’.

In 2017 a study by the University of Florida showed that when participants incorporated 3oz of raisins a day into their normal diet, it reduced the amount of a potentially pathogenic bacteria in their gut called Klebsiella sp which is linked to urinary tract infections, gut inflammation and diarrhea.

What are the different types of fibre and what do they do?

Fibre can be classed as two types: soluble and insoluble. Soluble fibre gets its name from the fact it dissolves in intestinal fluids naturally present in your gut and forms a gel-like substance. Common sources of soluble fibre include oats, bananas, apples and root vegetables such as carrots and potatoes.

Soluble fibre can help to:

  • Reduce the amount of cholesterol in the blood by absorbing some of it in the gut
  • Lubricate the gut, helping to naturally support stool movement
  • Help the bowel contents to ‘swell’ promoting fullness which may support weight loss
  • Slow the release of other sugars into the blood stream, controlling blood glucose levels

Insoluble fibres actually absorb water in the gut, softening stools and helping to maintain healthy bowel movements. While raisins contain mostly insoluble fibre, they also have a soluble fibre element called inulin. This has all the benefits of other soluble fibres along with prebiotic effects, which means they contribute to the growth of healthy bacteria in the gut. Furthermore, they also contain a compound called tartaric acid which has a mild laxative effect. This helps to maintain normal bowel movements and prevent constipation.

A 2007 study carried out by the Health Research Studies Centre in California demonstrated that adding 120g raisins to the diet of participants improved bowel movements and had the added bonus of beneficially altering the ratios of two common short-chain fatty acids (SCFAs) – lithocholic and deoxylithocholic acid – in the colon. These SCFAs are a marker for colon cancer; indeed, raisins reduced the alkalinity in the colon. Both the faster transit and lowered pH are associated with reduced colon cancer risk.

Another study by the University of Connecticut found that raisins lowered the risk for inflammatory damage by decreasing one of the markers of inflammation associated with diabetes and coronary heart disease.


California Raisins are a convenient, low-cost, high-fibre snack with a host of added health benefits – and they also count as one of your ‘Five A Day’.

Tip: if you do increase your fibre intake, drink plenty of water to help keep things moving.

For further details please email

About the Author:

Rick Miller is a registered Clinical and Sports Dietitian based in Harley Street, London.

You can find out more about Rick at