You don’t have to look far these days to find a headline about how sugar is bad for our health. This universal sweetener has come under heavy fire of late and appears to have earned the position of public health enemy number one. We’ve known for decades that sugar promotes tooth decay but with the spotlight now on the scientific evidence linking sugar with obesity and the top chronic diseases of type-2 diabetes, heart disease(1), stroke(2), dementia(3) and cancer(4), governments around the world are starting to take action by taxing sugary drinks, placing limitations on advertisers and simple labeling to show consumers just how much sugar they’re consuming.
The latest World Health Organisation (WHO) guidelines recommend less than 10% of total calorie intake from “free-sugars,” adding that a further reduction to 5% or roughly 25 grams (6 teaspoons per day) would provide additional health benefits.(5)
Despite these new guidelines and government attempts to curb sugar consumption, the world’s sweet tooth is showing no signs of decay. From 2009 to 2014 sugar consumption grew two percent per year and is predicted to increase another 3g per day by 2019.(6) While the world’s appetite for all-things-sweet may not be in decline, the “naturally healthy” category is winning the hearts and minds of the health-conscious consumer and today represents the largest food category valued at a whopping $276b per annum.(7) This trend is driving manufacturers to use more natural, less-refined sweeteners that are perceived by the consumer to be a healthier choice. Are these so-called “natural” sugars really more healthy than plain table sugar? To answer this we must first look at the different types of sugar molecules found in nature because different kinds of sugars are digested, absorbed and metabolized in different ways.(8)
Found mostly in plants, sugars are simple carbohydrate molecules that the body can breakdown and use for fuel to make energy. The three most common sugars found in our diet are the monosaccharides, glucose and fructose, and the disaccharide, sucrose. Oligosaccharides are more complex carbohydrate molecules that we will not be discussing in detail in this article.
Glucose is the most important sugar molecule and is the body’s primary fuel source, found most abundantly in starchy foods like potatoes and grains. Most of our cells require glucose to make energy, however, the liver can make enough glucose to cover our energy needs through a process known as gluconeogenesis, so it isn’t essential that we consume foods that contain glucose. However, when we do, glucose is the easiest of sugars for our body to utilise, and blood glucose levels can rise rapidly. Our body has a sophisticated way to ensure blood glucose levels are maintained as too much or too little glucose in the blood can be life threatening.(9) Insulin is a hormone made by the pancreas that signals to our cells to absorb glucose and store fat. Without insulin our cells can’t use glucose, but too much insulin, like too much blood sugar, is not a good thing either.
The glycemic index (GI) is a rating system that reflects the impact a certain food has on blood sugar when eaten on its own. A higher GI rating means the food is easier to breakdown and convert to glucose and will therefore lead to a more rapid rise in blood sugar. Pure glucose has a GI of 100. We know that erratic blood sugar levels are associated with obesity, type-2 diabetes and heart disease and therefore avoiding blood sugar spikes is a key tenant to good health.(1)
Fructose occurs naturally in fruit and is often marketed as “fruit sugar,” which can be perceived as a more natural and therefore healthier choice. It is more than twice as sweet as glucose gram for gram and, because of how it is metabolised by the body, has very little effect on blood sugar levels and does not trigger insulin production.(10) For this reason it is considered a low-GI sweetener. However, although it is very similar to glucose chemically, our cells do not use fructose directly, and it is therefore metabolised exclusively by the liver. With normal consumption levels (i.e. when eating fruit) the liver can remove all fructose from circulation. However, with larger intakes (i.e. when drinking quantities of fruit juice or fructose-sweetened beverages) the liver can’t keep up and converts the excess fructose into fat. Research has shown that fructose raises triglycerides (fats) in the blood (a risk factor for heart disease) and can cause fatty liver disease and increased visceral fat (the fat around your mid-section) which can then contribute to metabolic disorders such as insulin resistance and type-2 diabetes.(11)
Another side effect of exaggerated fructose consumption is overeating.(12) Ghrelin and Leptin are the primary hormones that regulate satiety. They take their lead from insulin and as fructose does not trigger insulin the brain doesn’t get the signal that it has had enough.
Sucrose is the white stuff that most people think of as sugar and is produced from sugar cane and sugar beets. Common names for sucrose include granulated sugar, caster sugar or table sugar. Sucrose is called a disaccharide because it is made up of one glucose molecule bound with one fructose molecule. For this reason, sucrose has a lower GI than glucose as the body must first break apart these two molecules in order to access the glucose for cellular energy before sending the fructose to the liver for processing.
Now we’ll explore several so-called “natural” sweeteners, looking at what they’re made of and the effect they have on our bodies to determine whether they are any better for us than plain table sugar.
Honey has been consumed by humans for millennia and prior to industrial sugar production in the eighteenth century it was the world’s principal sweetener.(13) Extracted from flowers and manufactured by bees, when it comes to the claim “natural,” honey is hard to beat. The composition and nutritional value of honey can vary widely depending on the flower nectar and the extent that it is refined. The sugars found in honey are mainly fructose and glucose in relatively equal measures (see table 1) but raw unpasteurized honey also contains enzymes, polyphenols, organic and amino acids, vitamins and minerals(14), which, while marginal, appear to have a synergistic effect that has benefited human health throughout history. Honey has long been relied on for wound healing(15) and treating coughs(16) but also has been shown to possess numerous medicinal properties including antibacterial, antifungal, antiparasitory, antitumor, anti-inflammatory and antioxidant effects.(14)
Maple Syrup is a natural sweetener made by boiling the watery, colourless sap collected from certain species of maple trees between late winter and early spring. The result is the concentrated syrup with its characteristic flavor and smell that is roughly two thirds sucrose and one third water.(17) It has a slightly lower GI than table sugar (see table 1), contains numerous minerals and is a very good source of manganese, an essential trace mineral important for bone formation, metabolism and the normal secretion of insulin among other functions with just one tablespoon providing a third of the daily reference value.(18) Maple syrup is also rich in antioxidants with more than 50 phytochemical compounds identified to date, some of which are unique only to maple syrup and have been shown to possess anti-cancer properties(19) as well as being beneficial for energy metabolism and blood sugar management.(18)
Agave Nectar comes from the agave plant native to Mexico (the same plant used to make tequila). It is an amber syrup that is runnier than honey and often marketed as a natural sweetener. Due to its high fructose percentage, as much as 85%(20), it has little effect on blood sugar and insulin production. The juice from the agave is rich in a natural complex form of fructose called inulin, an oligosaccharide that, in itself is not sweet, but when subjected to prolonged heating or by adding a special enzyme is converted to fructose. A few years ago agave nectar was thought to be a healthy alternative sweetener because of its low GI and was in fact promoted as “diabetic friendly,” however, agave nectar has more recently been branded as a sweetener to avoid due to its very high fructose content and the respective association with fatty liver disease, insulin resistance and obesity.(11)
Coconut Nectar is a natural sweetener much like maple syrup that is derived from the milky white sap extracted from the coconut blossom. It is typically made in small batches as skillful climbers are needed to scale to the top of the trees where the blossoms grow. The nectar is made by gently heating the sap for 90 minutes to concentrate the natural sugars (mostly sucrose) into a caramel-coloured syrup.(21) Further evaporation of the nectar produces the crystals that are sold as coconut palm sugar. Both the nectar and sugar have a low GI(22) and are reported to contain numerous minerals – including 4 times the potassium of maple syrup(23) polyphenols, essential amino acids and indigestible carbohydrates known as fructo-oligosaccharides (FOS) that promote healthy gut flora.(24)
Evaporated Cane Juice – The process of extracting sugar from sugar cane involves evaporation of the pressed juice to form crystals. The refining process involves spinning the crystals to remove the molasses and with it the remaining micronutrients. Evaporated cane juice foregoes this spinning process and is considered unrefined sugar which reportedly has a slightly molasses-like flavor. But don’t be fooled by this marketing play on words. Evaporated cane juice is not much more than granulated sugar (sucrose) with a more natural sounding name, and the FDA agrees by recently issuing labeling guidance for manufacturers using evaporated cane juice to include the word sugar.(25)
Stevia is the generic name for a natural sweetener that comes from the Stevia Rebaudiana plant. It has been used for centuries in Latin America and more recently has gained popularity in the west as a zero-calorie, zero-carb, zero-GI sweetener sold as either a powder or a liquid extract. The chemical compounds that give stevia its sweetness are known as steviol glycosides which are reportedly between 100 to 300 times sweeter than sugar.(26) Some of the compounds can have a bitter aftertaste and are sometimes blended with other sugars or artificial sweeteners which can add calories and impact blood sugar levels, so reading the label is recommended. A recent study showed that dried stevia leaf significantly lowered blood sugar levels and can be used as a safe anti-diabetic herb for those with type-2 diabetes, possibly preventing the associated risks of cardiovascular disease.(27)
Xylitol is a type of carbohydrate known as a sugar alcohol, or polyol, most commonly obtained from the Birch tree. Xylitol is converted in the liver to glucose but only about half is absorbed and therefore it has a very low GI and fewer calories per gram than sucrose despite being equally as sweet.(28) A common additive to sugar-free chewing gum, it has been shown to reduce cavities as xylitol is harder for the bacteria in the mouth to utilize than regular sugar and therefore it slows acid production and reduces plaque.(29) It can cause gas in some people and in larger quantities (>50g) it can have a laxative effect. One word of warning: xylitol is highly toxic to dogs, causing raised insulin and liver damage(30), so keep any foods containing xylitol well away from man’s best friend.
Here are some of the key takeaways when it comes to using natural sweeteners:
- Too much sugar, natural or otherwise, can be harmful to the body, so with all added sugars, moderation is best. Stay within the WHO guidelines.
- “Intrinsic” sugars are OK. These are the naturally occurring sugars within fruits and vegetables that are bound with other health-giving compounds such as fibre, antioxidants, phytochemicals, enzymes, vitamins and minerals.
- When choosing a natural sweetener, the less processed and refined the better, as it’s more likely to contain additional micronutrients that impart some health benefits. And although the additional micronutrients are in small amounts, every little bit helps. Consider using honey, maple syrup and coconut nectar.
- Despite its lower glycemic index and seemingly more natural origins, the evidence stacks up against fructose as the more sinister of sugars so use high-fructose sweeteners like agave nectar and refined “fruit sugar” sparingly. This does not apply to the natural fructose contained in whole fruits.
- Stevia and Xylitol can be used in place of sugar to significantly reduce blood sugar levels without the negative effects of fructose. In cooking, stevia may require some experimenting because of its high sweetness. Care should be taken with large amounts (>50g) of xylitol because of the potential laxative effect.
- Fruit juice and fruit juice concentrate are recognized by the WHO as “free-sugars.” Both are high in fructose and should be consumed sparingly. Far better to eat the whole fruit than to extract only its juice.
- Read the labels carefully for hidden sources of sugar. Some manufacturers use ingredients like apple juice concentrate in place of sugar and claim “no added sugar” on their labels. This is against EU regulations(31) but not all manufacturers are informed. Unfortunately it is largely up to the consumer to monitor.
- NHS Choices (2015) How does sugar in our diet affect our health? http://www.nhs.uk/Livewell/Goodfood/Pages/sugars.aspx
- Quinn TJ et al (2011). Sugar and stroke: cerebrovascular disease and blood glucose control. Cardiovasc Ther; 29(6):e31-e42.
- Fitzgerald S (2013). High glucose levels associated with increased risk for dementia. Neurology Today; 13(18):20-22.
- Jiang Y et al (2015). Dietary sugar induces tumorigenesis in mammary gland partially through 12 lipoxygenase pathway. Cancer Res; 75(15 Suppl): Abstract nr 3735.
- WHO (2015) Sugars intake for adults and children. Guideline. http://www.who.int/nutrition/publications/guidelines/sugars_intake/en/
- Bandy L (2015) Nutrition Trends: The sugar-free consumer. Euromonitor international.December 15th 2015 http://blog.euromonitor.com/2015/12/nutrition-trends-the-sugar-free-movement.html
- Hudson E (2015) Health and wellness market performance 2015: what’s new? Euromonitor International. November 17th, 2015 http://blog.euromonitor.com/2015/11/health-and-wellness-market-performance-2015-whats-new.html
- Bray GA et al (2004). Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity. Am J Clin Nutr; 79(4):537-43.
- Mayo Clinic (2016) Diseases and Conditions: Diabetic Coma. http://www.mayoclinic.org/diseases-conditions/diabetic-coma/basics/definition/con-20025691
- Ludwig DS (2013). Examining the health effects of fructose. Jama; 310(1):33-4.
- Stanhope et al (2013). Adverse metabolic effects of dietary fructose: Results from recent epidemiological, clinical, and mechanistic studies. Curr Opin Lipidol; 24(3):198-206.
- Teff KL et al (2004). Dietary fructose reduces circulating insulin and leptin, attenuates postprandial suppression of ghrelin, and increases triglycerides in women. J Clin Endocr Metab; 89(6):2963-72.
- Crane E (1975). History of honey. In Crane E (ed): “Honey, a comprehensive survey.” London: William Heinemann, pp. 439-88.
- Bogdanov S et al (2008). Honey for nutrition and health: a review. J Am Coll Nutr; 27(6):677-89.
- Molan P & Rhodes T (2015). Honey: A Biologic Wound Dressing. Wounds; 27(6):141-51.
- Paul I et al (2007). Effect of honey, dextromethorphan, and no treatment on nocturnal cough and sleep quality for coughing children and their parents. Arch Pediat Adol Med;161(12):1140-46.
- Philippe St-Pierre et al (2014). Comparative analysis of maple syrup to other natural sweeteners and evaluation of their metabolic responses in healthy rats. J Funct Foods;11:460–71.
- SelfNutritionData (2014) Syrups, maple nutrition facts & calories. http://nutritiondata.self.com/facts/sweets/5602/2
- González-Sarrías A et al (2012). Anticancer effects of maple syrup phenolics and extracts on proliferation, apoptosis, and cell cycle arrest of human colon cells. J Funct Foods; 4(1):185-96.
- Willems JL & Low NH (2012) Major Carbohydrate, polyol, and oligosaccharide profiles of agave syrup. application of this data to authenticity analysis. J. Agric. Food Chem; 60(35):8745-54.
- Purnomo H (1992). Sugar components of coconut sugar in Indonesia. ASEAN Food Journal; 7(4):200-1. Abstract: https://www.cabdirect.org/cabdirect/abstract/19930319960
- Trinidad P et al (2010). Glycemic index of commonly consumed carbohydrate foods in the Philippines. J Funct Foods; 2:271–4.
- Coconut Palm Sugar (2016) Macro-micro nutritional information. http://coconutpalmsugar.com/Nutritional_Information.html
- Trinidad T (2015). 079: Characterizing coconut sap sugar and syrup as a promising functional food/ingredient. BMJ Open Abstracts; 5:079.
- FDA (2016) Guidance for Industry: Ingredients Declared as Evaporated Cane Juice. http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/LabelingNutrition/ucm181491.htm
- Goyal SK et al (2010). Stevia (Stevia rebaudiana) a bio-sweetener: a review. Int J Food Sci Nutr; 61(1):1-10.
- Ritu M & Nandini J (2016). Nutritional composition of stevia rebaudiana, a sweet herb, and its hypoglycaemic and hypolipidaemic effect on patients with non-insulin dependent diabetes mellitus. J Sci Food Agric; Jan 19. doi: 10.1002/jsfa.7627. [Epub ahead of print]
- IFIC Foundation (2015) Sugar alcohols fact sheet. http://www.foodinsight.org/Sugar_Alcohols_Fact_Sheet
- Twetman S & Stecksén-Blicks C (2003). Effect of xylitol-containing chewing gums on lactic acid production in dental plaque from caries active pre-school children. Oral Health Prev Dent; 1(3):195-9.
- Dunayer EK et al (2006). Acute hepatic failure and coagulopathy associated with xylitol ingestion in eight dogs. JAVMA; 229(7): 1113-7.
- Regulation (EC) No 1924/2006 of the European Parliament and of the Council of 20 December 2006 on nutrition and health claims made on foods. Annex. http://eur-lex.europa.eu/eli/reg/2006/1924/oj