Diabetes is the commonest metabolic and lifestyle diseaseaffecting millions. Along with frequent question of when will oral insulin beavailable, are questions of diet precautions, using or avoiding of tablesugar/sugar rich foods and the role of sugar substitutes. Overweight and obeseindividuals may come up with queries regarding sugar substitutes.
Sugar substitutes or artificial sweeteners are ingredientsused to sweeten foods and beverages instead of table sugar and containrelatively less energy (either a zero calorie or low calories).Thesesubstitutes may satisfy the purpose of giving the longing taste of sweetness,but there still are issues which are debated and unanswered. What types of sugar substitutes are availablein the markets and whether it is safe to take them long term? This column mayanswer some of these queries.
All of us have sugar based meals throughout the day, be it ina cup of tea, biscuits, various types of sweets/chocolates, bakery or desserts,most of these contain table sugar or other sweeteners. Sugars are naturallypresent in variety of fruits and vegetables but are also commerciallyprepared. The table sugar (sucrose) isconcentrated sugar cane that is prepared by fermentation of the sugarcane juiceand then undergoes various chemical changes. Sometimes people use severalnatural sugars, coconut sugar, honey, maple syrup, date paste and molasses.Coconut sugar is got from sap of coconut palm; it has few nutrients, fiber andinulin but has good calorie content. Honey used since ages is particularly richin anti-oxidants, a bit of vitamins and minerals, but also has fructose. Maplesyrup is prepared by cooking the sap of maple tree, it is rich in antioxidants.Mollasses is a thick brown liquid prepared by boiling down sugar cane or sugarbeet juice.
Chemically sugars are simple monosaccharide (glucose,fructose and galactose) and complex disaccharide (sucrose, maltose,lactose). Fructose is a natural sugarsubstance which is different from glucose in that it causes only a modest risein blood glucose levels, does not require insulin for metabolism. However theproblem of ingesting large quantity of fructose is a rise in cholesterol andtriglycerides. One can take fructose containing fruits, vegetables and alsofructose-sweetened foods in moderation. Table sugar contains sucrose which is acombination of glucose and fructose. Lactose is naturally occurring sugar foundin milk. Some substances may have sugary taste (glycerol and sugar alcohols)but are not included in group sugars.
A tea spoon of sugar gives us 4 grams of sugar and 16calories and can raise the blood sugar varyingly by 10 to 20mg depending on thebody weight and requires 0.5 units of insulin to be metabolized. The averagedaily intake of sugar by an individual is about 30 grams meaning a total sugarconsumption of about 750 kg throughout life. Excessive sugars have beenimplicated in tooth decay, obesity, diabetes, cardiovascular disease andcancer. As per WHO, the daily consumption of sugars should amount to 5% of thetotal daily intake for proper health.
A sugar substitute or an artificial sweetener may be derivedthrough manufacturing of plant extracts (sorbitol, xylitol and lactitol) orprocessed by chemical synthesis. As it is not commercially feasible to extractthese products from fruits and vegetables they are produced from catalytichydrogenation of corresponding sugar (xylose to xylitol, lactose to lactitoland glucose to sorbitol, isomaltose to maltitol). These are called sugaralcohols, are less sweet than sucrose and are commonly used as sweeteners andbulking agents. Their absorption is limited and as such do not raise bloodsugar level if used in moderation. They are used in products labeled as sugarfree (chewing gum, ice creams, candy, cough lozenges). To enhance theirsweetness these alcohols are mixed with artificial sweeteners.
Six sugar substitutesproduced chemically have been approved (hence safe) for human consumption –aspartame, acesulfame, sucralose, neotame, saccharin and advantame. Moreover 2plant based sweeteners from stevia leaves contain steviol glycosides and from monk fruit extract are approved.
Aspartame which contains two major amino acids, aspartic acidand phenylalanine is 180 times sweeter than sucrose. It is not heat stable,once cooked or stored at high temperatures it breaks down into its constituentamino acids and hence cannot be used in baking and cooking. Acesulfame potassium is an odorless whitepowder, stable under heat and acidic conditions, allowing it to be used as afood additive in baking or in products that require a long shelf life. It is200 times as sweet as sugar and is used a tabletop sweetener, in frozendesserts, beverages, chewing gum, protein shakes and pharmaceutical products,especially chewable and liquid medications, where it can make the activeingredients more palatable. Other artificial sweeteners – sucralose (commonlyused), sacharin, rebiana are heat stable and hence can be used for baking andcooking purposes. These do not raise the blood glucose levels. Saccharin andacesulfame have a slight bitter after taste at high concentration hence blendedwith other sweeteners sweetener such as aspartame or sucralose. Stevia has nocalories, Aspartame has 3.6 cal,Sucralose has 3.3 cal Xylititol has 2.4cal andErythritol has 0.24cal per gram.
Sweetness intensity of an artificial sweetener compared totable sugar is called as multiplier of sweetness intensity (MSI) while asacceptable daily intake (ADI) is the amount that can be safely taken eachday(measured in mg per Kg of body weight per day). The commercially availableartificial sweeteners are tabulated along with trade names and their MSI andADI.
Artificial sweeteners have been in use (individual use orindustrial) and it has been scientifically established that they can be used asa safe alternative to sugar if used in moderation. They have not been shown toincrease risk of other diseases and their carcinogenic potential has not been documented in humans. So itcan be safely said as of today these products are neither unsafe or have anyimproved health outcomes.
Dr Muzafar Maqsood Wani is Consultant Nephrologist,SKIMS,Soura
mmmwani@gmail.com