By MingMing Yang
Sugar is an inevitable part of everyone’s diet. In fact, sugar is an abundant component in most foods, such as fruits, carbohydrates and sugary snacks. However, the excessive consumption of sugar can lead to a wide range of problems including tooth decay, obesity, and increasing risk of developing chronic diseases like Type 2 diabetes (Eating too much sugar: Effects and symptoms. 2020). A study by the American Heart Association (How much sugar is too much? ) showed that an average American adult consumes an average of 77 grams of sugar per day, despitethe recommended amount for men being 36 grams and for women 25 grams.
Fortunately, more and more people are starting to recognize the risks and are trying to limit their daily sugar intake through different means. This also showed the emerging market of sweeteners, where people started to choose these alternatives so as to reduce sugar intake and at the same time fulfil their sweet tooth.
There are mainly three types of sweeteners according to Mayo Clinic definition(Pros and cons of artificial sweeteners. ). Artificial sweeteners, also known as intense sweeteners, are synthetic sugar substitutes. Novel sweeteners are a loosely defined group, including sweeteners that are derived from natural sources and provide different sweetness and calorie content. The last group is sugar alcohols. They are lower in calories than sugar, thus making them another suitable alternative.
The United States Food and Drug Administration authority (FDA) has approved 5 artificial sweeteners, also called non-nutritive sweeteners (NNSs), for use in humans, including saccharine, aspartame, sucralose, neotame, and acesulfame-K(Sharma et al., 2016). Although these NNSs are recognized as safe, nothing in excesses considered good for our body. Recently, extensive marketing by the manufacturers has led to the overuse and abuse of NNS, by the population, since people believe that these sugar and calorie-free options can effectively help them control their body weights.
In a study of bladder cancer risk factors with 1860 bladder cancer patients and 3934 controls(Sturgeon et al., 1994), it was found that heavy sweetener consumption(>1680 mg per day) significantly increased the relative risk of bladder cancer. Another study on the associations of artificially sweetened soda with albuminuria and kidney function(Lin & Curhan, 2011) discovered that consumption of 2 or more servings of artificially sweetened soda per day is associated with a 2-fold increase odds for kidney function decline in women. NNSs are widely used by diabetics who have to carefully monitor their blood glucose levels and thus reduce the intake of sugar. However, surprisingly, in a study conducted during acute exercise in 14 men with type 2 diabetes(Ferland, Brassard & Poirier, 2007), it was observed that aspartame meal induced a similar rise in glucose and insulin levels at baseline than the sucrose meal, even when the aspartame meal had the same taste, and was 22% lower in calories and 10% lower in carbohydrates, with an inferior glycaemic index. Although this was a small study, it still put the use of NNSs at question.
As for novel sweeteners, a famous example is Stevia. Stevia is a zero-calorie sweetener made of steviol glycosides, compounds extracted and refined from the leaves of the Stevia rebaudiana plant. Stevia leaves are naturally 200 times sweeter than traditional white sugar and have been used for centuries as a sweetener and herbal supplement (Stevia side effects: What you need to know. 2017). However, the FDA stated that only the use of highly pure steviol glycosides (95%) is safe for human consumption as a non-medical ingredient up to 4 mg per kg of body weight per day (Gasmalla, Yang & Hua, ), while the whole-leaf varieties and raw stevia extracts are currently not approved. Current available studies have concluded that steviol glycosides is safe, and it has even been proved to have anti-diabetic effect on albino rats, and therefore could be promising nutraceutical therapy for the management of diabetes and its associate complications. In the study by Ahmad & Ahmad, 2018), it was found that the intake of stevia extract led to significant decrease in random and fasting blood glucose, and glycosylated haemoglobin (HbA1c) in diabetic rats, with insulin and liver glycogen levels significantly improved. However, further study is needed to assess its toxicological effects on human health due to overuse.
Sorbitol, mannitol, xylitol, isomalt, and hydrogenated starch hydrolysates are some common sugar alcohols (polyols) found in food. They are carbohydrates from plant products altered through a chemical process, and are widely used as sweeteners as they are not well absorbed and thus provide fewer calories than table sugar(Awuchi, 2017). Apart from the calories and impact of blood glucose level, polyols do not promote tooth decay since bacteria in the mouth do not readily convert them to acids. Xylitol may even have a protective effect on teeth(Deshpande & Jadad, 2008). Despite the seemingly positive effects, excessive consumption of polyols can cause abdominal bloating, excessive gas, or diarrhoea. This is because as they are only partially digested and absorbed in the small intestine, they travel to the large intestine and are fermented by bacteria. This fermentation leads to the production of compounds that serve as nutrients for colon cells and result in the formation of gas. In addition, water follows the undigested and unabsorbed polyols into the large intestine where it is reabsorbed. The non-absorbed water softens the faeces and lead to possible diarrhoea (Polyols & Gastrointestinal (GI) Effects. ).
Dr. Robert Lustig, professor of paediatrics and director of the weight assessment for teen and child health at University of California San Francisco once said, “Diet sweeteners are like methadone — they are better than sugar but the goal is to use them as a method of getting off sweets, and not as a substitute for sugar”(Park, ). Methadone is a drug used to treat heroin addiction. No matter how safe it is to use sweeteners, they definitely cannot be used as an excuse to keep eating sweet foods, and an overdose of sweeteners will never be considered healthy.
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