What is reactive hypoglycaemia?

Reactive hypoglycaemia is a condition that results in episodes of low blood glucose (blood sugar) levels after eating. These episodes usually occur two to four hours after a meal. It is thought that reactive hypoglycaemia is caused by the over-production of the hormone insulin (which lowers blood glucose levels) following a meal that is high in carbohydrates. Reactive hypoglycaemia is closely linked to what you eat and can often be managed by changes to your diet.

What are the symptoms?

If these symptoms occur within one to four hours of eating, you may be experiencing reactive hypoglycaemia:

• fatigue
• dizziness or light-headedness
• feeling sweaty
• irritability or anxiety
• cravings for sweet foods
• increase in appetite (some describe an incurable hunger)
• increase in heart beat
• confusion
• feeling shaky
• difficulty co-ordinating movement
• slurred speech.

If you have a blood glucose monitor you can confirm hypoglycaemia symptoms with a capillary blood test, any result below 4mmol/l is considered a low reading.

Treating severe symptoms of hypoglycaemia

If you experience severe symptoms of hypoglycaemia (confusion, difficulty coordinating, slurred speech) then you will need to consume around 15g of fast acting carbohydrate (in glucose form) to rapidly increase your blood glucose levels.

For example:

• four large jelly babies
• five glucotabs
• five dextro energy tablets
• four wine gums
• 60ml lift juice glucose shot.

After 15 to 20 minutes of taking fast-acting carbohydrates your symptoms should begin to improve. If blood glucose remains less than 4 mmol/l then repeat rapid acting treatment and test again after another 15 to 20 minutes. When blood glucose is more than 4 mmol/l it is important to have a starchy carbohydrate with a source of protein to help stabilise blood glucose levels. For example; one to two oat cakes or one slice wholegrain toast with cheese/ peanut butter/ cooked meats, or your next meal if this is due.

The purpose of treating hypoglycaemia is to rapidly increase your blood glucose level and reduce the risk of more severe symptoms of hypoglycaemia such as, loss of consciousness. However, it is possible that a rapid increase in blood glucose levels (after treating hypoglycaemia), may trigger a further episode of reactive hypoglycaemia. If you notice that this happens consistently, then you could try to reduce the initial amount of fast acting glucose taken. It has been suggested that a dose of eight to 12 grams of carbohydrates may be suitable. As advised above, follow this up with a starchy carbohydrate and protein snack to help stabilise your blood glucose levels.

Which foods contain carbohydrate?

Carbohydrates can be divided into two groups; starchy (or complex) carbohydrates and free sugars.

Carbohydrates are found in; pasta, couscous, breakfast cereals, crackers, rice, milk, yoghurt, fruit (fresh, tinned, dried), and starchy vegetables such as potatoes, yam and sweet potato. All of these are digested by your body to release glucose (sugar). Some processed foods that contain carbohydrates (free sugars) include; cakes and biscuits, sweets, chocolates, fruit juice and smoothies, jam, marmalade and honey.

Carbohydrates

Starchy carbs

• bread
• potatoes
• rice
• oats
• cereals
• pasta.

Sugars

• natural sugars, e.g. fruit sugar, milk sugar
• free sugars, e.g. table sugar, honey, biscuits, fruit juice.

Adapting your diet to manage reactive hypoglycaemia

Eat small portions of food more regularly across the day

Make sure meals and snacks are structured and spaced three to four hours apart so you do not have long gaps between eating. Eating three small meals and two to three snacks across the day can help to stabilise your blood glucose levels and avoid symptoms that may be caused by eating large portions of food (or carbohydrates).

Try to limit your carbohydrates. Aim for 30g of carbohydrates at each main meal and 15g for snacks

Some studies have shown that limiting the amount of carbohydrates at mealtimes can help to avoid rapid rises in blood glucose levels after eating. This can minimise the risk of excess insulin secreting and therefore avoid rapid drops in blood glucose levels.

To begin with, it may be helpful to calculate the grams of carbohydrates you are currently having at mealtimes and if this amount causes symptoms then decrease it. For example, if you are having two thin slices of bread (around 20g carbohydrate) and this causes symptoms, then halve this to one slice (10g carbohydrate) to see if this prevents reactive hypoglycaemia.

To calculate the carbohydrate content of foods the ‘carbs and cals’ book or app by Chris Chyette and Yello Balolia is a useful resource. Alternatively, Diabetes UK has a carbohydrate reference list available at www.diabetes.org.uk/resources-s3/2017-11/carbs_count_reference_list_2012.pdf

Choose low glycaemic index carbohydrates

Carbohydrates are absorbed at different rates. Low glycaemic index (LGI) carbohydrates are digested and absorbed more slowly than high glycaemic index foods. Including a small amount of LGI carbohydrates at your meals may slow down the rise in blood glucose levels (after eating) and keep your blood glucose levels more stable afterwards. This may help to prevent (or reduce) episodes of reactive hypoglycaemia.

Here are some everyday examples of lower GI carb choices:

• multigrain, granary, rye, seeded bread, sourdough bread
• new potatoes in their skins, sweet potato, yam, cold boiled potatoes
• all pasta cooked until al dente, instant noodles
• basmati rice, long grain or brown rice
• bulgur wheat, barley, couscous, quinoa
• porridge, muesli, some low-sugar oat and bran-based cereals.

More information can be found on the British Dietetic Association website: www.bda.uk.com/resource/glycaemic-index.html

Meet your protein recommendations (average of 70 to 100 grams/day)

Eat protein at all of your main meals and choose protein-rich foods for snacks. Protein is important to preserve your muscle mass and it helps you to feel fuller for longer. Remember to prioritise protein, always eating this first during your meals or snacks. Protein foods include; meat, poultry, cheese, eggs, fish, beans, lentils and nuts.

Eat more fibre

Fibre-rich foods move more slowly from your stomach in to your small intestine. This can help to delay the increase in blood glucose levels after eating, decrease insulin secretion and therefore help to reduce the risk of reactive hypoglycaemia. Try to eat more fibre-rich LGI foods such as oats, beans and pulses, granary bread, brown pasta, brown basmati rice and vegetables.

Avoid eating and drinking together

Avoid drinking less than 15 minutes before and wait 30 minutes after meals or snacks. Eating and drinking together can increase the rate at which food empties from your stomach into your small intestine that can cause a rapid rise in blood glucose levels and rapid secretion of insulin.

Avoid sugary drinks

Avoid sugary drinks such as fruit juice, fizzy drinks, smoothies and milk shakes as these drinks are a source of carbohydrates (in liquid form) and are easily absorbed by the body. Sugary drinks can cause a rapid increase in blood glucose levels, as well as insulin and increase the risk of reactive hypoglycaemia. Suitable alternatives include; water, sugar-free squash, tea, and coffee (with sweetener).

Avoid alcohol

Alcohol can affect the way your liver produces and releases glucose so consumption may increase the risk of reactive hypoglycaemia.

Keep a food, symptom and activity diary

This can be useful and you can use it as a tool for reflection. Keeping a record of the times you eat, your symptoms and physical activity can help you identify triggers for your symptoms. In the long term if you are aware of your triggers, you can modify your diet to help you with managing your symptoms.