The Effects Of Artificial Sweeteners On The Human Body
Introduction
In this extended essay I will be looking at the effects of artificial sweeteners including Aspartame and Stevia on the human body. The reason for choosing to include sucrose in my research findings is to establish a baseline for sugar consumption. I will be comparing their effects with the effects of sucrose in the body. To do this I will be analysing several different studies conducted by multiple international universities and research institutions and consider the validity of findings for each. All effort was made to ensure that studies selected for inclusion in this report were free from any third party interests. They were not funded from companies that use artificial sweeteners in their products nor were they any artificial sweetener companies who are obvious industry stakeholders with a vested interest to see only positive outcomes of such research. Artificial sweeteners have become a staple in the industry of food production and have made their way into thousands of different products in our supermarkets and yet there is still so much controversy surrounding their effects. This topic has always intrigued me as I feel there has been a lot of mixed information regarding the effects of artificial sweeteners. I want to know exactly what happens to my body when I am consuming these sweeteners. I have specifically narrowed it down to two different sweeteners one being a man made compound and the other a natural plant to see if there is a big contrast in their effects on our body. Through my research I intend to determine if my consumption of artificial sweeteners has a measurable and demonstrable negative impact on my overall health. This is important to me as I prioritise good health and fitness throughout my life and I know that I consume both of these sweeteners on a regular basis. What is Stevia “Stevia is a sugar substitute extracted from the leaves of a plant species called Stevia rebaudiana, native to Brazil and Paraguay”. The fact that is has zero calories makes it very appealing to most people and as a result it is widely used in the natural foods and health food industries which produce zero calorie natural sweetener for teas, weight-loss blends and soy sauce. As illustrated in the graph the number of products containing stevia has dramatically increased since 2010 and is counting to rise. Due to its popularity Stevia is also available in the powder form which can be used for baking, teas, coffee, cereal, yogurt and any other foods that would otherwise be sweetened with sugar. Stevia was first approved in 2008 by the FDA and given the status of 'generally recognised as safe.”
The projected global market value of stevia is $490.08 million US dollars. Stevia is very potent as the raw leaves of the plant are around 40 times sweeter than sucrose and the powdered sweetener derived from them is up to 150-400 times sweeter. What is Aspartame? Aspartame is one of the market's most popular artificial sweeteners. Aspartame is sold under the NutraSweet and Equal brand names. It's also found in approximately 6,000 products, especially foods and drinks labeled as 'diet.' Aspartame-containing products include diet and ‘no sugar’ soft drinks, sugar-free ice cream, low-calorie fruit juice, gum, yogurt and sugar-free candy. Around two million people around the world consume aspartame regularly. Molecular structure, digestion and absorption of Aspartame Aspartame is made up of three metabolites: Methanol, Phenylalanine and Aspartic acid. Methanol has had the most controversy as it is one of a host of alcohols normally produced during the fermentation of carbon-based compounds. When it’s in the body it is then converted into formaldehyde, however there is no evidence that this conversion will result in any harmful levels of formaldehyde in the body. This is due to the fact that the amount of methanol that you get from aspartame is very small. There is more methanol in fruits and vegetables than in a can of diet soft drink, for example there is four to six times more methanol in a glass of tomato juice than in a 375ml soft drink can. Therefore the amount of methanol and formaldehyde produced is very insignificant and might not t have any harmful effects. I say this without 100% certainty as little research using adequate sample sizes has been conducted into properly analysing the effect, so this is an area which Aspartame requires further study. Our body produces formaldehyde at levels one thousand time higher on its own. Aside from methanol the other metabolites in aspartame are just amino acids. These amino acids can be found in foods that we eat on a daily basis, so therefore there is no harm in eating them. The acceptable daily intake for Aspertame is 50 mg per kilo of body weight per day. To put this into perspective, a person who weights 80kg would be able to consume twenty one cans of diet soft drink per day for the rest of their life and still not reach harmful levels of aspartame. “The American cancer society found no link between Aspartame and increases in cancer after studies with over five thousand people showing no association between aspartame and an increase in cancer.” Molecular Structure, digestion and absorption of Stevia Stevia is isolated stevia extract and is composed of one or more sweet tasting compounds called steviol glycosides. There are multiple steviol glycosides which are converted to steviol in the colon, in which the steviol is then absorbed and after-excreted through faeces. The body does not metabolise the glycosides in stevia and therefore it contains zero calories. “Steviol glycosides are poorly absorbed in the body and pass the upper gastrointestinal tract, including the stomach and small intestines, fully intact. Once steviol glycosides reach the colon, gut bacteria hydrolyze steviol glycosides into steviol by snipping off their glucose units. Steviol is then absorbed via the portal vein and primarily metabolised by the liver forming steviol glucoronide, and then excreted in the urine”. In summery stevia by products are not absorbed by the human body during digestion. Aspartame, Stevia and Sucrose effects on appetite control When we consume artificial sweeteners our brain still gets the message that we ate something sweet, yet our body doesn't have any calories to pair it to.
Therefore it has been thought that we might have a greater desire for that sweetness later on in the day. In turn, this craving created by artificial sweeteners will result in cravings that increase your total caloric intake for the day resulting in weight gain. This study conducted in 2010 by the Pennington Biomedical Research Center concluded that there was no increase in hunger, consequently no weight gain. Groups consuming a pre-load meal one coating just regular sugar (sucrose) and the other group consuming a pre-load meal containing a mix of both aspartame and stevia. This study showed that the group that had the artificially sweetened meal did not compensate later in the day or display an increase in appetite as ‘reported hunger and satiety levels did not differ by condition at any time point’ ”The overall caloric intake for the full day for the group who consumed aspartame and stevia was less than the group that consumed sucrose sweetened pre-load meals.” The physiological effects of both aspartame and stevia include that there is no effect on appetite control and hunger. This study; however, was conducted over a very limited period of time (one day). In order to be fully confident in these results the experiment needs to be repeated over an extended period of time e.g. several weeks to ensure long term results are accurate with the short term results obtained. This will produce more reliable results. Sucrose (digestion and absorption) Sucrose is common table sugar. It is a disaccharide (meaning it is two single sugars bonded together), a molecule composed of two monosaccharides: glucose and fructose. Glucose and fructose are digested, https://en.wikipedia.org/wiki/Sucrose absorbed and metabolised separately, but both result in the same end product that your body uses for energy. Sucrose digestion does not begin until the sugar reaches the small intestine. The body is unable to absorb polysaccharides as it is, therefore it must first break down saccharose into its parts. Water assists in breaking down the glycosidic bond to separate the glucose and fructose molecules; one molecule of water is needed for each molecule of sucrose, this process is called hydrolysis. However, this reaction naturally occurs very slowly. The presence of sucrase, an enzyme in the small intestine, accelerates this reaction. After leaving the liver, glucose, the primary source of energy, travels to nearly every cell in the body, and the hormone insulin facilitates its uptake into cells. During a process called glycolysis, glucose is then converted to pyruvate. Glycolosis is the process whereby glucose (a six carbon sugar) is broken down to two (three carbon molecules) called pyruvate. Pyruvate, which is an acidic compound, can then enter either aerobic or anaerobic respiration to produce energy. Neurological Effects of Sucrose Brain functions such as thinking, memory, and learning are closely linked to glucose levels and how efficiently the brain uses this fuel source.
If there isn’t enough glucose in the brain, for example, neurotransmitters, the brain’s chemical messengers, are not produced and communication between neurones breaks down. In addition, hypoglycaemia, a common complication of diabetes caused by low glucose levels in the blood, can lead to loss of energy for brain function and is linked to poor attention and cognitive function. Although the brain needs glucose, too much of this energy source can be a bad thing. A 2012 study in animals by researchers at the University of California, Los Angeles indicated a positive relationship between the consumption of fructose, another form of sugar, and the ageing of cells, while a 2009 study, also using an animal model, conducted by a team of scientists at the University of Montreal and Boston College, linked excess glucose consumption to memory and cognitive deficiencies. The effects of glucose and other forms of sugar on the brain may be the most profound in diabetes, a group of diseases in which high blood glucose levels persist over a prolonged period of time. Type 1 diabetes is a disease in which the immune system destroys the cells in the pancreas that produce insulin, a hormone used by the body to keep blood glucose levels in check. Type 2 diabetes, caused by dietary and other environmental factors, is a condition in which cells become overwhelmed by insulin and fail to properly respond; they become resistant to insulin. These are some of the harmful effects of a poor diet which is characterised by excess consumption of sucrose. Neurological effects of Aspartame Aspartame compromises the blood–brain barrier, increasing its permeability and altering concentrations of catecholamines, such as dopamine, in the brain. Due to this, aspartame ingestion may have a role in the pathogenesis of certain mental disorders. Such claims have been refuted, however, by authors citing the high-aspartame concentrations needed for detrimental effects. Similarly, the role of aspartame in depression and mood has been studied with mixed results. When 40 participants with depression and 40 participants without depression were given aspartame (30 mg/kg body weight/day) or confectioners’ sugar in a randomised, double-blind, crossover trial over 20 days with two 3-day washout periods (this is the time between treatment periods where aspartame is washed out of the patients system from the first period) and two 7-day treatment sessions and self-reported symptoms, the study was stopped by the institutional review board after only 13 participants completed the trial, due to the severity of adverse reactions in the depressed participants who consumed aspartame. In contrast, when 133 women of normal weight and 53 overweight women blinded to treatment condition who consumed standard doses of aspartame or sucrose-sweetened beverages over 4 weeks and completed a daily 10-item visual analog scale to measure mood, there were no differences in mood between those who drank aspartame-sweetened and sucrose-sweetened soft drinks. We must note that the study that showed negative adverse effects was conduction in 1993 and the other one that showed no differences in mood between those who consumed aspartame and those who did not was undertaken in 2007-2010.
The conflicting reports of the neurobehavioral effects (cognition, mood, depression, and headaches) of aspartame consumption may be due to study design issues. No reports have been found of indirect calorimetry to determine individual energy needs and portion sizes when calculating the numerological effects of Aspartame. An additional study Healthy adults who consumed a study-prepared high-aspartame diet (25 mg/kg body weight/day) for 8 days and a low-aspartame diet (10 mg/kg body weight/day) for 8 days, with a 2-week washout between the diets, were examined for within-subject differences in cognition, depression, mood, and headache. Measures included weight of foods consumed containing aspartame, mood and depression scales, and cognitive tests for working memory and spatial orientation. Aspartame intake affected certain aspects of neurobehavioral performance. Spatial orientation was weaker and irritability and depression were more frequent after high-aspartame consumption than low aspartame consumption when subjects served as their own controls. Furthermore, seven participants experienced clinically significant neurobehavioral conditions following the higher level of aspartame consumption. A diet high in aspartame did not influence working memory or headaches. Investigators who previously had explored the neurobehavioral effects of aspartame consumption did not control the effects of non-study food and beverage intakes in their participants’ diets or administered single-dose treatments, such as aspartame-sweetened beverages or capsules, followed by cognition, mood, and/or depression testing. Because of this, this study represents an advance over previous work. The authors have acknowledged that the research this study has provided was supported he U.S. Army Biomedical Research Grant Award and the National Institutes of Health. This has allowed me to conclude there are no conflicts of interest of bias within this study. Neurological effects of Stevia In this study by the biology department of the College of Science from De La Salle University, 20 mice were used to determine if there is an effect of consuming the maximum allowable dose of the non-nutritive sweeteners on the memory retention and on the histology of the hippocampus. “The mice were distributed into four groups and the treatments were given via oral gavage: Group 1 (water), Group 2 (aspartame: 1 000 mg/kg), Group 3 (stevia: 1 000 mg/kg) and Group 4 (sucralose: 16 000 mg/kg). Treatments were administered to the different experimental groups for 32 days, after which memory retention was tested using the two-day water maze protocol. After the tests, the mice were sacrificed and the brain was analysed histologically for neurotrophic effects.” Based on the results of the two-day water maze protocol, there were no differences between the non-nutritive sweeteners and the control group. This study concluded that there was no significant effect on the memory of the mice.
Further research is required in order to determine if similar effects are found in humans. Evaluation and conclusion Upon evaluation of research findings for aspartame and stevia, it can be said that there is a significant benefit which sucrose imparts on the human body but is absent in the consumption of aspartame and stevia. This relates to the brain needing glucose neurotransmitters to be produced in brain, which allows for communication between neutrons. However it is important that sucrose is consumed in moderation as excess amounts will lead to memory and cognitive deficiencies according to a team of scientists at the University of Montreal and Boston College. According to the data I have analysed, I am able to conclude at this point in time I am confident that stevia has very little negative effects neither physiologically or neurologically, while aspartame consumption may result in few negative effects including possible increase in depression and impaired spacial orientation. Both sweeteners have no effect on appetite control and hunger as shown in a study carried out by the Pennington Biomedical Research Center in 2010. However there were limitations of the studies reviewed including small sample sizes, studies involving animals as well as my own possible implici bias in terms of selection of research for inclusion in this report. Moreover, as seen within the study in Asian Pacific Journal of Tropical Biomedicine, where 30 mice were used to determine if there is an effect of consuming the maximum allowable dose of the non-nutritive sweeteners on the memory retention and on the histology of the hippocampus they concluded that there was no significant effect on the memory of the mice. Although research findings based on animal testing can not automatically be applied to the effect on humans, it is a somewhat reliable indicator for further research into the true impacts on the human body.
