Type 2 Diabetes: Eating to improve your blood glucose

Type 2 Diabetes: Eating to improve your blood glucose


Carin Hume

BSc Dietetics, MSc Sports Nutrition

Carin Hume is a consultant dietitian at London Medical. She also consults privately at clinics in Reading and Great Missenden.

If you have diabetes you may fall into the trap of focussing too much on what not to eat, for example, no carbs, no sugar, less red meat, less alcohol, not too much fruit. It is just as important to focus on including certain foods in your diet for the purpose of feeding the microbes in the gut, which in turn may lower insulin resistance and improve your health.

A few facts:

  • The gut microbiota is the collection of microorganisms that live in the digestive tract. Research has shown that the microbiota of people with diabetes differs compared to someone without diabetes.
  • In a way we can think of the gut being outside of the body. The lining of the gut forms an essential barrier function, where its job is to prevent waste products of bacteria from getting through the gut barrier and into the bloodstream. Imagine the gut barrier looking like a picket fence and not a wall, where certain substances can get through the picket fence (gut barrier) without causing problems. But, when the picket fence isn’t maintained and the gaps between the pickets are too wide, this causes too much to get through the fence (gut barrier). This leads to a state of low grade inflammation.
  • We think about inflammation as swelling and redness, for example in a joint or if you have sprained your ankle. But, we can have low grade inflammation which is not visible to us and which can cause insulin resistance. Insulin resistance is at the root of type 2 diabetes.

The above is not all ‘doom and gloom’, as our diet can have an impact on the gut microbiota and gut barrier. This is where fibre, and in particular a kind of fibre referred to as prebiotics, comes into the spotlight. Prebiotics are special fibres which we as humans can’t digest, these fibres can therefore be ‘eaten’ by the ‘good bugs’ in the large intestine. The gut bacteria use the prebiotic fibres to produce special substrates (for example butyrate) which feeds the cells lining the gut, thereby aiding in strengthening the gut barrier, in addition to a host of other beneficial factors.

We can have low grade inflammation which is not visible to us and which can cause insulin resistance. Insulin resistance is at the root of type 2 diabetes.

Carin Hume – Consultant Dietician


A few practical take home messages:

  • Refer to the table below which shows the prebiotic content of vegetables which are particularly high in inulin, a kind of prebiotic. If those vegetables aren’t a regular part of your diet, can you slowly incorporate them into your diet? Think simple changes such as using leeks more than onions; adding red onion to a salad; go for convenience by purchasing roasted globe artichokes (preferably in olive oil).
  • Research has suggested that people with diabetes aim for at least 10 g of prebiotic fibres a day.
  • Aim to include a diverse range of plant foods in your diet – gut researchers believe that we should have at least 30 different plant foods in a week.
  • Consider your total dietary fibre intake – research indicates that people with diabetes aim for 35 g fibre a day (most people don’t achieve this target).
  • Note, do not try to increase your fibre intake by having high carbohydrate cereals such as All bran or bran flakes for breakfast.
  • There may be a role for prebiotics and/or butyrate in a supplement form, but best to discuss this with a dietitian.
  • Lastly, always ‘start low and go slow’ when increasing your fibre intake to allow your digestive system to adjust.

Table of examples of vegetables high in the prebiotic fibre, inulin 

Vegetable Serving size Grams of prebiotic fibre
Asparagus 5 spears 3.1
Dried chicory root 1 tablespoon 3.5
Garlic 1 clove 0.5
Globe artichoke 1 small 6.1
Jerusalem artichoke 1 cup 47.3
Leeks 1 small 14.5
Onion 1 tablespoon 0.8

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