Glucose and Fructose Syrup: Health Effects

Glucose and fructose syrup are concentrated liquid sweeteners found across a wide range of everyday UK food and drink products, from soft drinks and confectionery to savoury sauces and ready meals. Derived from starch crops such as wheat or maize, they are added to improve sweetness, texture and shelf life at low cost. Understanding what these syrups are, how to identify them on ingredient labels, and what NHS and NICE guidance says about their health effects can help you make more informed dietary choices, particularly if you are managing conditions such as type 2 diabetes, obesity or liver disease.

What are glucose and fructose syrup and where are they found?

Glucose and fructose syrup are starch-derived liquid sweeteners used widely in processed foods including soft drinks, biscuits, cereals and sauces. UK labels must name them specifically, with word order reflecting which sugar predominates.

Glucose and fructose syrup are concentrated liquid sweeteners derived primarily from starch crops such as wheat, maize or potato, and are widely used by food manufacturers as low-cost alternatives to sucrose (table sugar). They are ingredients and added sugars under UK food law, not food additives in the regulatory sense (additives are substances with a specific technological function and are assigned E-numbers). Glucose syrup is produced by breaking down starch into shorter sugar chains, yielding a thick, sweet liquid composed mainly of glucose. Fructose syrup is processed further to convert a proportion of the glucose into fructose, producing a sweeter end product. The equivalent term used in North America is high-fructose corn syrup (HFCS), which appears mainly on imported products rather than on UK-produced goods.

Under UK food labelling law (retained EU Regulation 1169/2011, as applied by the Food Standards Agency), these sweeteners must be declared in the ingredients list by their specific name. The most common UK label terms are:

• Glucose-fructose syrup (where glucose predominates)

• Fructose-glucose syrup (where fructose predominates)

• Glucose syrup

• Fructose syrup

The order of the words in the name reflects the relative proportions of each sugar: glucose-fructose syrup contains more glucose than fructose, while fructose-glucose syrup contains more fructose.^[3] The term "isoglucose" is an industry and regulatory term and is rarely seen on UK consumer labels; "high-fructose corn syrup" appears mainly on imported North American products.

These sweeteners are found in a broad range of everyday products, including soft drinks, confectionery, biscuits, breakfast cereals, flavoured yoghurts, sauces, ready meals and processed breads. Because they improve texture, extend shelf life and enhance sweetness at relatively low cost, they are widely used across the UK food supply. Consumers who wish to reduce their intake should be aware that these ingredients can appear even in products not typically considered sweet, such as salad dressings, soups and savoury snacks. Reading the full ingredients list, rather than relying on front-of-pack labelling alone, is the most reliable way to identify their presence.

What does NHS and NICE guidance say about high-sugar sweeteners?

NHS and NICE guidance recommends limiting free sugars, including glucose and fructose syrups, to no more than 5% of daily energy intake. NICE also supports reducing availability of high-sugar products to lower the risk of obesity and type 2 diabetes.

NHS and NICE guidance consistently recommends reducing overall free sugar intake, which includes glucose syrup, fructose syrup and other added sweeteners, as a key component of a healthy diet. The NHS Eatwell Guide, underpinned by the Scientific Advisory Committee on Nutrition (SACN) Carbohydrates and Health report (2015), advises that free sugars, meaning sugars added to food and drink rather than those naturally present in whole fruit or milk, should make up no more than 5% of daily energy intake. For adults, this equates to no more than approximately 30 g of free sugars per day.

NICE guidance on obesity prevention and lifestyle weight management (including PH53 and NG7) highlights the role of sugar-sweetened beverages and high-sugar processed foods in contributing to excess calorie intake, weight gain and increased risk of type 2 diabetes.^[8] NICE recommends that commissioners, local authorities and employers take steps to reduce the availability and promotion of high-sugar products, and supports reformulation efforts by manufacturers to lower added sugar content.

The UK government's sugar reduction programme set voluntary targets for manufacturers to reduce sugar in key food categories by 20% between 2017 and 2020.^[9] Oversight and reporting for this programme now sits with the Department of Health and Social Care's Office for Health Improvement and Disparities (OHID). Progress has been variable across categories, as documented in OHID's sugar reduction programme progress reports, and glucose and fructose syrups remain prevalent in many reformulated products. The UK Health Security Agency (UKHSA) has a separate remit covering health protection and is not responsible for dietary policy.

For individuals managing conditions such as type 2 diabetes, metabolic-associated steatotic liver disease (MASLD, previously termed non-alcoholic fatty liver disease or NAFLD) or obesity, NHS clinical teams typically advise minimising intake of foods containing these syrups as part of broader dietary modification.^[15][16] Anyone with specific health concerns should seek personalised advice from their GP or a registered dietitian.

How can you spot and reduce these syrups in your diet?

Check ingredients lists for terms such as glucose-fructose syrup, fructose-glucose syrup and glucose syrup, which must appear in descending order by weight. Practical reductions include choosing whole foods, swapping sweetened drinks and cooking from scratch.

Spotting glucose and fructose syrup in your diet requires careful attention to ingredient labels, as these sweeteners appear under multiple names and are often listed partway down a long ingredients list rather than prominently. Under UK food labelling law (retained EU Regulation 1169/2011), ingredients must be listed in descending order by weight, so if a syrup appears near the top of the list, it is present in a relatively large quantity.^[2][4] Checking for terms such as glucose-fructose syrup, fructose-glucose syrup, glucose syrup and fructose syrup is a practical starting point.

Practical steps to reduce intake include:

• Choosing whole foods such as plain vegetables, legumes, whole grains and unsweetened dairy, which naturally contain no added syrups

• Swapping sweetened drinks for water, plain sparkling water or unsweetened tea and coffee

• Selecting plain or reduced-sugar versions of cereals, yoghurts and sauces, comparing labels between brands

• Cooking from scratch where possible, as home-prepared meals allow full control over added sweeteners

• Using the NHS Food Scanner app (available via the NHS website), which can help identify sugar content in packaged products quickly

The front-of-pack traffic light labelling scheme is a voluntary but widely used system in the UK, supported by FSA guidance, with red indicating high sugar content.^[10][11] Not all products carry it, so checking the full ingredients list remains important. Bolt Pharmacy is a GPhC-registered UK online pharmacy offering online weight-management consultations, with prescriber review and pharmacist support, for those seeking structured guidance on dietary and lifestyle changes alongside clinical assessment.

Gradual reduction is generally more sustainable than abrupt elimination. Replacing high-syrup products one at a time, rather than overhauling the entire diet simultaneously, tends to support long-term dietary change.

How do glucose and fructose syrup affect your blood sugar levels?

Glucose causes rapid blood sugar spikes and insulin release, while fructose is metabolised in the liver and promotes fat synthesis and raised triglycerides. Together, they deliver both a glycaemic spike and a hepatic metabolic burden simultaneously.

Glucose and fructose syrup affect blood sugar levels in distinct but complementary ways, and regular high intake of either is associated with adverse metabolic effects, as outlined in the SACN Carbohydrates and Health report (2015) and supported by NHS and Diabetes UK guidance on sugars and glycaemic control.

Glucose is absorbed rapidly from the gut into the bloodstream, causing a swift rise in blood glucose concentration. This triggers a corresponding release of insulin from the pancreas to facilitate cellular uptake of glucose. Frequent, large spikes in blood glucose and insulin, driven by regular consumption of glucose syrup, can over time contribute to insulin resistance, a key feature of type 2 diabetes.^[5][12]

Fructose follows a different metabolic pathway. Unlike glucose, fructose is metabolised primarily in the liver rather than being taken up directly by peripheral tissues. It does not stimulate insulin release to the same degree in the short term, which means it produces a lower immediate glycaemic response. However, high fructose intake is associated with increased hepatic fat synthesis (de novo lipogenesis), which can contribute to metabolic-associated steatotic liver disease (MASLD), raised triglyceride levels and, over time, worsening insulin resistance.^[12][13] This makes fructose syrup particularly relevant for individuals with existing liver or metabolic conditions.

For people living with type 2 diabetes or prediabetes, both glucose and fructose syrups can complicate blood glucose management. The combination of the two, as found in glucose-fructose syrup, delivers both the rapid glycaemic spike of glucose and the hepatic metabolic burden of fructose simultaneously. NHS and Diabetes UK guidance for people with diabetes emphasises limiting foods and drinks containing these added sugars as part of an overall balanced, lower-glycaemic dietary approach. It is worth noting that total dietary pattern and overall energy balance are the key determinants of metabolic risk, rather than any single ingredient in isolation.

Anyone noticing possible symptoms of raised blood glucose, such as increased thirst, passing urine more frequently than usual, unexplained fatigue, blurred vision or recurrent infections, should contact their GP promptly for assessment.

Scientific References

1. Approved additives and E numbers.
2. Packaging and labelling (Food Information to Consumers Regulation 1169/2011).
3. Food standards: labelling and composition (glucose and fructose syrup specifications).
4. Food labelling and packaging: Ingredients list.
5. SACN Carbohydrates and Health Report.
6. Sugar: the facts.
7. The Eatwell Guide.
8. Overweight and obesity management (NG246).
9. Sugar, salt and calorie reduction and reformulation (Sugar Reduction Programme).
10. Check the label (traffic light labelling).
11. Food labels – how to read food labels.
12. A review of recent evidence relating to sugars, insulin resistance and diabetes.
13. Effect of fructose instead of glucose or sucrose on cardiometabolic markers: a systematic review and meta-analysis of isoenergetic intervention trials.
14. The Impact of Dietary Glycemic Index and Glycemic Load on Postprandial Lipid Kinetics, Dyslipidemia and Cardiovascular Risk.
15. EASL position paper on preclinical models of steatotic liver disease.
16. Current Update on Nomenclature, Diagnosis, and Management of Metabolic Dysfunction-associated Steatotic Liver Disease: Radiologists' Perspective.

Frequently Asked Questions