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What is prediabetes?

What is prediabetes?

If you’ve been diagnosed with prediabetes, you may be wondering how worried you should be. After all, the term does suggest you’re well on your way to becoming a type 2 diabetic.
But while that may be true, there’s also a very good chance that – by adopting a few simple lifestyle changes and making more healthy choices – you could either delay or prevent your progress towards having diabetes

What causes prediabetes?

Diabetes is a condition that’s caused by having too much sugar (glucose) in your blood. If you’ve been diagnosed with prediabetes, it means your blood sugar is higher than it should be, but not high enough for you to be diagnosed with diabetes.
Either way, having too much sugar in your blood is a result of problems with your body’s production of a hormone called insulin. Here’s what happens: the food you eat is broken down into sugar; this is delivered via your bloodstream into cells in your muscle, fat and liver, where it’s used to produce energy. For this to happen your pancreas – the organ just behind your stomach in your abdomen – needs to produce insulin to help ‘unlock’ the cells and let the sugar in.

What are the different types of diabetes?


  1. Your pancreas doesn’t produce any insulin at all (this means you have type 1 diabetes)

  2. Your pancreas produces some insulin but not enough (type 2 diabetes)

  3. Your pancreas produces insulin but your cells don’t absorb or use it very well – this is also called insulin resistance (also type 2 diabetes)

All of these problems amount to the same thing: high amounts of sugar accumulate in your bloodstream rather than entering your cells, which eventually can cause a number of serious complications.
If you have prediabetes it could mean your pancreas isn’t making quite enough insulin to keep your blood sugar levels normal. It can also happen when you have insulin resistance.
With insulin resistance, your pancreas works hard to produce more insulin to make up for your cells’ weak response to it. This is why some people with insulin resistance can have blood sugar levels that are still within the normal range. But over time, your pancreas can lose its ability to make enough insulin, leading to prediabetes and potentially type 2 diabetes.

How common is prediabetes?

Prediabetes goes by several different names. It’s often called borderline diabetes, or you may hear your doctor refer to it as impaired fasting glucose or impaired glucose tolerance. It’s also probably a lot more common that you may think. According to Diabetes UK, 13.6 million people in this country are at increased risk of type 2 diabetes – in other words, they have prediabetes (i). This compares with the 4.9 million or so people in the UK who have diabetes (i).
Thankfully progressing from prediabetes to type 2 diabetes isn’t inevitable, and it’s thought that up to half of people with prediabetes could prevent or delay the development of type 2 diabetes if given the right support (ii).

What are the symptoms of prediabetes?

Experts think that up to 80 per cent of people with prediabetes aren’t aware that they have it (iii). That could be largely explained by the fact that prediabetes doesn’t usually have any symptoms, so the only way you’d know you had it would be to have it picked up by a blood test.
Some people with prediabetes, however, may notice darkened skin in their armpits, elbows, knees, knuckles or on the back and sides of their neck, often accompanied by a lot of little skin tags. This condition, called acanthosis nigricans, is often a sign of insulin resistance associated with polycystic ovarian syndrome (PCOS)
You may, however, notice one or more of the following symptoms – though this would usually indicate that you’ve already developed type 2 diabetes:

  • Feeling very thirsty a lot or all of the time

  • Urinating frequently (especially at night)

  • Blurred vision

  • Tiredness and fatigue

  • Sores or cuts that are slow to heal

  • Unexplained weight loss 

  • Genital itching or frequent episodes of thrush 

If you experience any of the above, see your GP as soon as possible.
Since prediabetes doesn’t usually have any symptoms, it’s a good idea to be aware of the risk factors for type 2 diabetes.

Prediabetes risk factors:


  • Your family history: having a close family member with diabetes increases your risk by two to six times (ii).

  • Your age: if you’re white and aged 40 or older, or African-Caribbean, Black African or South Asian and over 25, your risk is higher.

  • Your ethnic origin: people of South Asian, African-Caribbean and Black African descent are two to four times more likely to develop type 2 diabetes than people from other backgrounds (ii). 

  • Your health: if you have or have had high blood pressure, your risk is higher (high cholesterol also increases your risk).

  • Your weight: people who carry extra weight, especially if it’s around their middle, are also more at risk. 

Other factors may make you more likely to develop prediabetes too, including:

  • Smoking

  • Drinking excessive amounts of alcohol

  • Doing very little exercise 

  • Experiencing sleep problems 

If you’re worried that you have one or more risk factors for type 2 diabetes, it’s a good idea to talk to a health professional about it. They may recommend one or more tests to check your blood sugar levels, the most common of which is a test that checks your HbA1c levels (this reveals your average blood sugar for the past two to three months). If the test shows your HbA1c level is between 42mmol/mol and 47mmol/mol, you will usually be diagnosed with prediabetes.
You don’t have to fast before the HbA1c test, though your doctor may want to do a fasting blood sugar test too (this measures your blood sugar level before you eat anything in the morning). 

How can I make my lifestyle healthier?


Most people who are diagnosed with prediabetes don’t need any medication, though some may be prescribed medicines if they’re at a high risk for diabetes and have other medical problems too. Instead, the primary treatment for prediabetes usually comes down to advice and support for changing your lifestyle so that you eat a better diet, do more exercise and maintain a healthy weight. All of this can help reverse your condition and reduce your risk of progressing to type 2 diabetes.

Why is choosing healthier foods important?

Having a healthy, nutritious diet is one of the most important things you can do if you want to reduce your risk of type 2 diabetes, whether you’ve been diagnosed with prediabetes or not. Try to eat plenty of fruit and vegetables (at least five portions a day) as well as wholegrains, lean proteins and lower-fat dairy foods, and limit your intake of foods that contain a lot of fat, sugar, salt and refined carbohydrates (white bread, cakes, pastries etc).
It’s also a good idea to make sure you’re getting enough fibre in your diet, since fibre can slow the rate at which sugar is released from your food into your bloodstream (this can mean your pancreas doesn’t have to produce so much insulin all at the same time). Aim to get at least 18g fibre every day, particularly soluble fibre (this is found in foods such as nuts, seeds, fruit, vegetables, beans and pulses).
Swapping what you drink can be helpful too, especially if you drink a lot of sugary drinks (including fruit juice). Try to choose water, tea, lower-fat milk and other unsweetened drinks instead, and if you must have some fruit juice, try diluting it with water (one quarter juice to three quarters water). 


Why is staying active important?

Most of us spend too much time sitting down, but being sedentary is thought to be linked to an increased risk of type 2 diabetes (ii). So even if you haven’t already had a diagnosis of prediabetes, it’s a good idea to stay as active as you can. This means being more active in general and making sure you don’t sit still for too long – try getting up out of your chair and having a walk around at least once every hour for a few minutes. Also try to follow the UK’s official physical activity guidelines for adults (iv), which includes:

  • Doing at least 150 minutes of moderate activity – or 75 minutes of vigorous activity – each week 

  • Doing strengthening activities that work all your major muscle groups at least twice a week (if you’re 65 or older, you should also do some activities that improve your flexibility twice a week too)

If, however, you haven’t been active lately or you have a medical condition, speak to your GP before launching into any new exercise routine. If you’re unfit, start exercising slowly and gradually build up to 150 minutes a week.

What about weight management?


Losing a relatively small amount of weight – just five per cent of your body weight, for example – can really help reduce your risk of developing type 2 diabetes if you’re overweight or obese. Eating healthily and being more active can help you lose weight, but if you need more advice on weight loss, ask your GP for support.
One very useful thing you can do if you’re trying to lose weight is to take care with your portion sizes. You may, for instance, be eating fairly healthily. But if your portion sizes are far too big, you can still gain weight. Weighing your portions may be accurate, but it can often be impractical. So here’s an easy guide to portion sizes that doesn’t involve kitchen scales, as advised by the British Nutrition Foundation (v):

Fruit About a handful
Vegetables Three serving spoons
Cereal About three handfuls
Dried rice or pasta About two handfuls
Baked potato About the size of your fist
Bread Two slices (or one as a snack)
Chicken breast About the size of your whole hand
Steak About the size of your palm
Dried lentils About two handfuls
Nuts and seeds The amount you can fit in your palm
Cheddar cheese About the size of two thumbs together
Yoghurt One individual pot or about four tablespoons

To find out more, read our guide to diabetes and your diet and lifestyle.


What supplements can help to lower blood sugar?

If you have prediabetes it means your blood sugar is higher than it should be. Adopting lifestyle measures can really help to get those levels back down to normal. But you may want to try some nutritional supplements that have been shown to help lower blood sugar too.

Please note, however, that supplements should never be used as an alternative to the advice your GP or specialist gives you. And if you’re taking any medication for prediabetes or type 2 diabetes, it’s important to speak to your doctor before taking these or any other supplements, since they could make your blood sugar too low (see our guide to diabetes for more about hypoglycaemia, which is a diabetes complication you may have heard of that’s also called hypos). 

The first supplement you may want to consider taking is a good-quality multivitamin and mineral, as it may help make sure your body is getting all the nutrients it needs to stay healthy. To find out more about multivitamin supplements and the variety of different formulations available, try reading our guide to multivitamins and daily requirements.

Meanwhile you may also want to consider one or more of the following:


A natural remedy that’s been used in traditional Chinese medicine for centuries, cinnamon is a spice that’s also often recommended by natural therapists for people with diabetes, as there is some evidence it may help improve blood sugar levels (vi).

Alpha lipoic acid

There’s also evidence to suggest this fatty acid and powerful antioxidant could help control blood sugar levels (vii) as well as improve insulin sensitivity in people with type 2 diabetes (viii). However, if you have diabetes always consult your GP before taking alpha lipoic acid as it may enhance insulin activity.


Some researchers have found that people who have diabetes may have low magnesium levels (ix), possibly because having diabetes or taking the medicines used to treat it may cause magnesium deficiency. Others have also discovered magnesium may help with blood sugar control (x).


Turmeric, the well-known curry spice, contains a compound called curcumin that’s believed to have a number of potential health benefits, including the ability to reduce blood sugar levels (though to date most studies have been carried out in animals rather than humans, meaning the available evidence isn’t as strong as it could be). However, one study has found that curcumin may help improve blood sugar level control after investigating its effects in people with diabetic foot ulcers (xi).

High-strength fish oils

Omega-3 fatty acids – particularly two called EPA and DHA found in oily fish such as salmon, trout, sardines and mackerel – are widely considered helpful for general health and wellbeing. According to the NHS, a healthy, balanced diet should include at least two portions of fish a week, including one of oily fish (xii). But if you can’t or don’t like eating fish, you could miss out on the benefits. The answer may be to take a high-strength fish oil supplement, or a omega oil supplement derived from marine algae instead of fish if you’re a vegetarian or vegan.


Fenugreek seeds have a long tradition of use in some parts of the world, including in Ayurvedic medicine. These days herbal practitioners often recommend fenugreek seeds to people with diabetes, as they may help the body to produce insulin. There’s also some evidence fenugreek seeds may be helpful in controlling type 2 diabetes and reducing insulin resistance, though supporting studies to date are small in scale (xiii). However, don’t take fenugreek if you’re pregnant or breastfeeding.

Vitamin D

Vitamin D is best known for helping the body to absorb calcium. However, a study published in the Journal of Clinical Endocrinology & Metabolism also suggests that people with prediabetes who take vitamin D supplements may significantly reduce their risk of developing type 2 diabetes (xiv). The study is a review of nine randomised controlled trials that included almost 45,000 participants, and suggests people with low vitamin D levels may be protected from diabetes by taking a supplement.
Vitamin D deficiency is common, including in the UK. Indeed, Public Health England advises adults and children over the age of one year old to consider taking a daily supplement containing 10mcg of vitamin D, particularly during autumn and winter (xv).
However if your skin is rarely exposed to the sun – if you spend most of your time indoors, for instance, or if your skin is always covered when you’re out and about – you may need to take vitamin D throughout the year. People with dark skin from Black African, Afro-Caribbean and South Asian backgrounds should consider taking vitamin D all year round too, PHE advises.

The recommended form of vitamin D is vitamin D3 or cholecalciferol, as it’s the natural form of vitamin D that the body makes when it’s exposed to sunlight. Vitamin D3 supplements are available in tablet form, and now you can get them in veggie-friendly drops too. However most vitamin D3 supplements are made from the fat of lamb’s wool, which means they’re unsuitable for vegans. The good news is that vegan vitamin D3 supplements sourced from lichen are now more widely available.

High-strength anthocyanidins

Diabetes comes with several complications because having high blood sugar levels can, over time, damage your blood vessels. Supplements that contain plant substances called anthocyanidins, however, help support blood vessel health. That’s because anthocyanidins – which are found in dark-skinned fruits such as blueberries, cranberries, raspberries, blackberries and red grapes as well as vegetables such as red cabbage, red onions and aubergines – protect collagen in the body (collagen is a structural protein that gives blood vessels their strength).
If you want to try an anthocyanidins supplement, look for one that also contains vitamin C, as vitamin C supports the body’s ability to produce collagen.
Being diagnosed with prediabetes doesn’t mean you will definitely develop type 2 diabetes – in fact, you have a good chance of reversing it and having healthy blood sugar levels again. But reducing your risk means making some changes to your lifestyle, including eating more healthily and being more active. You may have to be a bit more organised, but it’s a small price to pay for healthier blood sugar levels. Meanwhile, if you want more information on a wide range of other conditions, why not visit our pharmacy health library?



(i) Available online:
(ii) Available online:
(iii) Available online:
(iv) Available online:
(v) Available online:
(vi) Mang. B, Wolters. M, Schmitt. B, et al. Effects of a cinnamon extract on plasma glucose, HbA, and serum lipids in diabetes mellitus type 2. Eur J Clin Invest. 2006;36:340-344. Available online:

Akilen. R, Tsiami. A ,Devendra. D, Robinson. N, et al. Glycated haemoglobin and blood pressure-lowering effect of cinnamon in multi-ethnic Type 2 diabetic patients in the UK: a randomized, placebo-controlled, double-blind clinical trial. Diabet Med. 2010;27(10):1159-1167. Available online:

Pham. AQ, Kourias. H, Pham. DQ. Cinnamon supplementation in patients with type 2 diabetes mellitus. Pharmacotherapy. 2007 Apr;27(4):595-9.Available online:

Kirkham S, Akilen R, Sharma S, Tsiami A. The potential of cinnamon to reduce blood glucose levels in patients with type 2 diabetes and insulin resistance. Diabetes Obs Metab. 2009 Dec;11(12):1100-13. Available online:
(vii) Poh. ZX., Goh KP., A current update on the use of alpha lipoic acid in the management of type 2 diabetes mellitus. Endocr Metab Immune Disord Drug Targets. 2009 Dec;9(4):392-8. Available online:
(viii) Evans JL, Goldfine ID. Alpha-lipoic acid: a multifunctional antioxidant that improves insulin sensitivity in patients with type 2 diabetes. Diabetes Technol ther. Autumn 2000;2(3):401-13. Available online:
(ix) Elamin. A, Tuvemo. T. Magnesium and insulin-dependent diabetes mellitus. Diabetes Res Clin Pract. 1990;10:203-209. available online:

Barbagallow M, Dominguez LJ. Magnesium and type 2 diabetes. World J Diabetes 2015 Aug 25; 6(10):1152-57. Available online:
(x) Song. Y, He. K, Levitan. EB. Effects of oral magnesium supplementation on glycaemic control in Type 2 diabetes: a meta-analysis of randomized double-blind controlled trials. Diabet Med. 2006;23:1050-1056. Available online:
(xi) Mokhtari M., Razzaghi R, Momen-Heravi M. The effects of curcumin intake on wound healing and metabolic status in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial. Phytother Research: PTR (2020) 35(4):2099–107. Available online:
(xii) Available online:
(xiii) Yilmaz Z et al. Supplements for Diabetes Mellitus: A Review of the Literature. Pharm Pract 2017 Dec;30(6):631-638. Available online:

Kassaian N et al. Effect of fenugreek seeds on blood glucose and lipid profiles in type 2 diabetic patients. Int J Vitam Nutr Res 2009 Jan;79(1):34-9. Available online: .

Gupta A, Gupta R, Lal B. Effect of Trigonella foenum-graecum (fenugreek) seeds on glycaemic control and insulin resistance in type 2 diabetes mellitus: a double blind placebo controlled study. Physicians India 2001 Nov;49:1057-61. Available online:
(xiv) Barbarawi M et al. Effect of Vitamin D Supplementation on the Incidence of Diabetes Mellitus. The Journal of Clinical Endocrinology & Metabolism, Volume 105, Issue 8, August 2020, Pages 2857–2868. Available online:
(xv) Available online:


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Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.

Our Author - Christine Morgan


Christine Morgan has been a freelance health and wellbeing journalist for almost 20 years, having written for numerous publications including the Daily Mirror, S Magazine, Top Sante, Healthy, Woman & Home, Zest, Allergy, Healthy Times and Pregnancy & Birth; she has also edited several titles such as Women’ Health, Shine’s Real Health & Beauty and All About Health.

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