Artificial Sweeteners and Obesity

Let us learn about obesity which has become a global epidemic. Obesity is defined by a body mass index (BMI) exceeding 30 kg/m2, and an overweight person has a BMI between 25-30 kg/m2. Please calculate your own BMI using your phone app calculator or on the internet. A different chart is used to calculate the weights in children and adolescents. A recent WHO global estimate is shown below (World health Organization website 2018).

In 2016, more than 1.9 billion adults aged 18 years and older were overweight. Of these over 650 million adults were obese.
In 2016, 39% of adults aged 18 years and over (39% of men and 40% of women) were overweight.
Overall, about 13% of the world’s adult population (11% of men and 15% of women) were obese in 2016.
The worldwide prevalence of obesity nearly tripled between 1975 and 2016.

Raised BMI is a major risk factor for noncommunicable diseases such as: cardiovascular diseases (mainly heart disease and stroke), diabetes; musculoskeletal disorders (osteoarthritis – disabling and degenerative disease of the joints); and some cancers (endometrial, breast, ovarian, prostate, liver, gallbladder, kidney, and colon).

Top 10 Most Obese Countries (WHO, 2017)
United States of America – 109,342,839
China – 97,256,700
India – 65,619,826
Brazil – 41,857,656
Mexico – 36,294,881
Russia – 34,701,531
Egypt – 28,192,861
Turkey – 23,819,781
Iran – 21,183,488
Nigeria – 20,997,494

The statistics here at home in the United States, are far from comforting. According to 2007 statistics from the World Health Organization (WHO), the United States has the highest prevalence of overweight adults in the English-speaking world.[ Streib, Lauren 2007. “World’s Fattest Countries”. Forbes.] The overweight percentages for the overall US population were 39.4% in 1997, 44.5% in 2004, [ 2004 National Health Interview Survey], 56.6% in 2007, [2007 National Health Interview Survey] and 63.8% (adults) and 17% (children) in 2008.[“U.S. Obesity trends”.CDC 2011]. In 2010, the Centers for Disease Control and Prevention (CDC) reported higher numbers once more, counting 65.7% of American adults as overweight, and 17% of American children, and, 63% of teenage girls become overweight by age 11. In 2013 the Organisation for Economic Co-operation and Development estimated that 3/4 of the American population will likely be overweight or obese by 2020. (Figures 1a, 1b below) The health care costs from obesity currently exceed that due to smoking [Finkelstein, E.A. Fiebelkorn (2003), “National medical spending attributable to overweight and obesity: how much, and who’s paying”, Health Affairs].

If adult obesity in the US is epidemic, we should be even more concerned with childhood obesity. (Figure 2 below). In the past 30 years, the occurrence of overweight children has tripled and it is now estimated that one in five children in the US is overweight (17%). Prevalence of overweight is especially higher among certain populations such as Hispanic (16%), African American (19%), Mexican Americans, and Native Americans where some studies indicate prevalence of >85th percentile of 35-40%. Also, while more children are becoming overweight, the heaviest children are getting even heavier. Overweight or obese preschoolers are 5 times more likely than normal-weight children to be overweight or obese as adults. As a result, childhood overweight is regarded as the most common prevalent nutritional disorder of US children and adolescents, and one of the most common problems seen by pediatricians. (American Academy of Pediatrics. Prevention of Pediatric Overweight and Obesity: American Academy of Pediatrics Policy Statement; Organizational Principles to Guide and Define the Child Health System and/or Improve the Health of All Children; Committee on Nutrition. Pediatrics. 2003;112:424-430)

Potential Negative Psychological Outcomes:

Depressive symptoms
Poor Body Image
Low Self-Concept
Risk for Eating Disorders
Behavior and Learning Problems

Negative Health Consequences:

Insulin Resistance
Type 2 Diabetes
Asthma
Hypertension
High Total and LDL Cholesterol and triglyceride levels in the blood
Low HDL Cholesterol levels in the blood
Sleep Apnea
Early puberty
Orthopedic problems such as Blount’s disease and slipped capital femoral epiphysis
Non-alcoholic steatohepatitis (fatty infiltration and inflammation of the liver)

Further, obese children are more likely to be obese as adults, hence they are at increased risk for a number of diseases including: stroke, cardiovascular disease, hypertension, diabetes, and some cancers.

Obesity is rising due to over-consumption of calorie dense foods, sedentary lifestyle and lack of physical activity among other things, but today we will explore the relationship between obesity and artificial sweeteners. The global obesity epidemic mirrors the increased usage of non-caloric artificial sweeteners, such as aspartame – NutraSweet, Equal (Diet Coke) and sucralose – Splenda (Pepsi), in food products as shown in the Figure 3 below (Yang, Yale J of Bio and Med 2010).

The first artificial sweetener, saccharin, discovered in 1879, is 300 times sweeter than sucrose and is blended with a compound called cyclamate to improve taste. Both the products were banned at one point by the food and drug administration (FDA) secondary to carcinogenic concerns (Kaufman, 1978, and Kroger 2006). This was followed by the discovery of aspartame, 200 times sweeter than sucrose in 1965 (Schlatter, J Med Chem, 1970), sucralose, 600 times sweeter discovered in 1979 followed by Neotame, 7000 times sweeter in 2002 (Witt, World Rev Nutr Diet, 1999). Since then roughly, 6,000 new sweeteners have been introduced in the United States between 1999 and 2004. Currently, large number of so called low calorie and diet products contain one or more of FDA approved artificial sweeteners. A Nutritional Survey estimated that as of 2004, 15 percent of the US population was using artificial sweeteners and a consumer report stated that 65 percent of American households bought at least one sucralose-containing product in 2008 (Yang 2010). Figure 4 below show some of the foods containing artificial sweeteners which is present from baby food such as pedialyte to frozen foods and in particular carbonated beverages.

Inline image 1
Figure 3. Artificial sweetener use and obesity trends in the United States. Middle line: Percentage change in population who are obese (Body Mass Index >30) from 1961 to 2006. Ref: National Health and Nutrition Examination Survey. Bottom line: Percentage change of population consuming artificial sweetener 1965 to 2004. Ref: Mattes and Popkin, Am J Clin Nutr. 2009. Top line: New food products containing artificial sweeteners introduced in the American market from 1999 to 2004. Ref: Mintel Market Analysis.

The discovery of Splenda or Sucralose makes for an interesting read. (The New Yorker 2006). The substance in the flask seemed to have all the makings of an excellent insecticide. It was a fine crystalline powder, easy to imagine spraying over a field, and its molecules were full of chlorine atoms, like DDT. To make it, Shashikant Phadnis, a young Indian chemist at Queen Elizabeth College, in London, and his adviser, Leslie Hough, had begun by taking an eyedropper full of sulfuryl chloride—a highly toxic chemical—and adding it to a sugar solution, one drop at a time….On that late-summer day in 1975, Phadnis was told to test the powder, but he misunderstood: he thought that he needed to taste it. And so, using a small spatula, he put a little of it on the tip of his tongue. It was sweet—achingly sweet….Over the next year, Hough and Phadnis worked with the British sugar company Tate & Lyle to make more than a hundred chlorinated sugars, finally settling on one that had three chlorine atoms and was about six hundred times as sweet as sugar. “It isn’t of any use as an insecticide,†as per Hough. “That was tested.†But it has proved useful as a food. In its pure form, it is known as sucralose. When mixed with fillers and sold in bright-yellow sachets, it’s known as Splenda, the best-selling artificial sweetener in America.

Figure 4

The natural sugar, sucrose and others such as high fructose corn syrup are largely responsible for the obesity, metabolic syndrome, and diabetes epidemic. However, diet products (non-caloric artificial sweeteners), which are considered substitutes for sucrose, are wrongly presumed to be health foods partly, due to, the misinformation campaign spread by the smart marketing strategy of the food and beverage industries.

But when we put these claims by the food industry, under the lens of rigorous scientific studies, then we find the results are interesting and not what is being advertised. Large prospective studies have found positive correlation between artificial sweetener use and weight gain. The San Antonio Heart Study studied 3,682 adults over a 7 to 8 year period and after matching for baseline demographics and behavioral characteristics found that individuals on artificially sweetened beverages consistently had higher BMIs at follow-up in a dose-dependent manner (Figure 5). (Fowler SP, Williams K, et al. Fueling the obesity epidemic? Artificially sweetened beverage use and long-term weight gain. Obesity. 2008).

Figure 5

The American Cancer Society studied a homogeneous cohort of 78,694 women for 1 year and found a statistically significant weight gain in users of artificial sweeteners. (Stellman and Garfinkel . Artificial sweetener use and one-year weight change among women. Prev Med. 1986). Similarly, Saccharin use was associated with weight gain in 31,940 women studied over a eight year period in the Nurses’ Health Study. (Colditz GA, Willett WC, et al. Patterns of weight change and their relation to diet in a cohort of healthy women. Am J Clin Nutr. 1990). It seems the pattern is similar in children. The “Growing Up Today Study”, involving 11,654 children, ages 9 to 14 reported positive association between diet soda and weight gain (Berkey CS, Rockett HRH, et al. Sugar-added beverages and adolescent weight change. Obes Res. 2004). A cross-sectional study looking at 3,111 children and youth found diet soda drinkers had significantly elevated BMI. (Forshee and Storey. Total beverage consumption and beverage choices among children and adolescents. Int J Food Sci Nutr. 2003). Additionally, interventional programs, substituting artificially sweetened beverages in lieu of sugar sweetened beverages did not lead to weight loss in analysis. The weight reduction seen was due to caloric restriction. (Brown RJ, de Banate MA, et al. Artificial Sweeteners: A systematic review of metabolic effects in youth. Int J Pediatr Obes. 2010).

What is fueling the increased weight gain seen with artificial sweeteners?. Multiple human and animal studies have shown that consuming artificial sweeteners lead to over consumption of food and weight gain due to decoupling of taste and caloric content. (Lavin JH, et al. Int J Obes Relat Metab Disord. 1997; King NA, et al, Physiol Behav. 1999; Swithers SE, et al. Behav Neurosci. 2008; Pierce WD, et al, Obesity. 2007). Food shares the same brain circuitry associated with pleasure and behaviors associated with addiction. (Avena NM, et al. Evidence for sugar addiction: behavioral and neurochemical effects of intermittent, excessive sugar intake. Neurosci Biobehav Rev. 2008). Food reward consists of two components: initial sensory via the tongue receptors and the mesolimbic dopamine pathway and a postingestive component involving the hypothalamus of the brain. Increasing evidence suggest that artificial sweeteners do not activate the food reward pathways in the same fashion as natural sweeteners. Lack of caloric contribution generally eliminates the postingestive component. Sweetness decoupled from caloric content offers partial, but not complete, activation of the food reward pathways. Activation of the hedonic (mesolimbic dopamine pathway) component may contribute to increased appetite. We seek food to satisfy our inherent craving for sweetness, even in the absence of energy need. However, lack of complete satisfaction, due to the failure to activate the postingestive component, further fuels our food seeking behavior, sugar craving, dependence and likely obesity. The key to reversing obesity likely lies in unsweetening our diet.