Consuming Diet Sodas Soft Drinks in Comparison to Regular Sodas
Afr Health Sci. 2013 Sep; 13(3): 541–545.
A comparative study of the effect of diet and soda carbonated drinks on the histology of the cerebellum of adult female albino Wistar rats
MA Eluwa
1 Department of Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Calabar, Nigeria
II Inyangmme
1 Department of Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Calabar, Nigeria
AO Akpantah
1 Department of Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Calabar, Nigeria
TB Ekanem
1 Department of Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Calabar, Nigeria
MB Ekong
2 Department of Anatomy, Faculty of Basic Medical Sciences, University of Uyo, Uyo, Nigeria
OR Asuquo
1 Department of Anatomy, Faculty of Basic Medical Sciences, University of Calabar, Calabar, Nigeria
AA Nwakanma
3 Department of Anatomy, Faculty of Basic Medical Sciences, Anambra State University, Uli, Nigeria
This article has been cited by other articles in PMC.
Abstract
Background
Carbonated drinks are widely consumed because of their taste and their ability to refresh and quench thirst. These carbonated drinks also exist in the form of diet drinks, for example Diet Coke®, Pepsi®, extra.
Objectives
A comparative effect of the diet and regular soda carbonated drinks on the histology of the cerebellum of female albino Wistar rats was investigated.
Methods
Fifteen adult female Wistar rats weighing between 180–200g were divided into 3 groups; designated as groups A, B and C, and each group consisted of five rats. Group A was the Control group and received distilled water, while groups B and C were the experimental groups. Group B was administered 50 ml of regular soda (RS), and group C was administered 50 ml of diet soda (DS) each per day for 21 days, and the rats were sacrificed on Day 22, and their cerebellums excised and preserved.
Results
Histological result of the sections of the cerebellum showed shrunken and degenerated Purkinje cells with hypertrophied dendrites, especially in the DS group, which was less in the RS group compared to the control group.
Conclusion
These results suggest that diet soda has adverse effect on the cerebellum of adult female albino Wistar rats.
Keywords: Carbonated drink, Diet soda, regular soda, Cerebellum, Wistar rats
Introduction
Carbonated drinks elicit a sensation that is highly sought after, yet the underlying neural mechanisms are ill defined. Carbonated drinks could be soft or hard, depending on the absence or presence of alcohol respectively. Soft drinks could be regarded as regular or diet depending on the sweetening agent. Sugar is used as sweeteners in regular soft drinks, and it has been reported to result in obesity upon consumption1 , 2.
Diet coke® (DC) on the other hand is a non-caloric beverage that is sweetened with aspartame, except for the splendor-sweetened version, which is sweetened with both splendor, or sucralose, and acesulfame potassium, and which is also known as Ace K3 , 4. These sweeteners in diet coke are non-nutritive and non-caloric. DC also contains caffeine, depending on the quantities consumed5. Caffeine is linked to anxiety and sleep disruption when consumed in excess6.
Aspartame as contained in DC is hydrolyzed in the intestine to its components; aspartic acid, methanol and phenylalanine7. Each of these components is toxic and affects different body organs including the central nervous system. About fifty per cent of aspartame is made up by phenylalanine, which could cross the blood-brain barrier and act as a precursor of catecholamine in the brain, as well as leading to phenylketonuria. Forty per cent of aspartame is composed of aspartic acid, an excitotoxin that contributes to free radical damage in the brain. Methanol which forms 10% of the by-products of aspartame is a toxic compound converted in the liver to formaldehyde that is neurotoxic and carcinogenic7.
Reports on the effects of aspartame in body cells is controversial; while8 links brain tumors to worldwide Aspartame use,9 showed that Aspartame consumption might result in seizures, memory loss, dizziness, headache and behavioural changes. A more recent study reported non-association between aspartame and cancer in any tissue and, indicating that aspartame is safe for consumption10 , 11.
As most of the previous studies were concerned about the effect of aspartame on memory, learning and behavioral changes, this study investigates the effect of aspartame and non-aspartame products on the histology of the cerebellar cortex of adult female albino Wistar rats.
Methods
Fifteen (15) adult female albino Wistar rats were breed in the animal house of the Department of Human Anatomy, University of Calabar, Calabar. The animals were fed with normal rat chow and water was provided ad libitum throughout except during the treatment period. The animals were divided into three group designated A, B and C, each consisting of five rats. Group A animals were the control and groups B and C were the experimental animals.
Experimental protocol
The rats weighed between 180–200g before the commencement of the experiment. 50 mls each of Regular soda, RS (coke) and Diet soda, DS (coke), were administered daily to groups B and C respectively. The quantities of beverages consumed by the rats were measured daily and were replaced the next day. The control group received distilled water. All administrations were by oral gavages.
The administration lasted for 21 days, and the animals were sacrificed by chloroform inhalation on day 22. Each animal's brain was excised after dissection of the skull, and preserved using 10% buffered formalin. Following complete fixation of the whole brain, the cerebellum was excised. Routine histological processing was carried out and staining was done using the haematoxylin and Eosin technique.
On staining the slides were mounted on a light microscope and a low power magnification (x100) and a high power magnification (x400) were observed, and photomicrographs were made by means of a Bresser LCD Microscope (Meade Instruments Europe, Germany) linked to a computer.
Results
Observation
The DS group consumed less than 20mls of the diet soda each day (about 3–24ml of the diet coke), while the RS group consumed almost all 50mls of regular soda each day (about 32–50ml of regular coke)
Histological observation
Group A (Control): The section of the cerebellum showed the normal histology of the cerebellum and its layers: the outer cerebellar cortex and inner medulla. The cerebellar cortex presented three layers; the outer molecular, intermediate Purkinje and inner granular, layers. In the molecular layer were sparsely distributed cells. The Purkinje cell layer, which is one-cell thick, showed large pyriform shaped Purkinje cells with deeply stained basophilic nucleus. The granular layer presented numerous, thickly populated cells (figure 1a & 2a).
Control cerebellum showing its three distinct layers and white matter (W)
Control cerebellum showing three distinct layers.
The molecular layer containing few nerve cells (M), the purkinje cells layer containing a monolayer of Purkinje cells (P), the granular layers consisting of densely-packed granular cells.
Group B (RS): The histological sections of the cerebellum of the RS group showed vacuolations (spongiosis) between cells fibers of the white matter (Figure 1b). The cellular arrangement of the cerebellar cortex presented the three layers showing loss and slightly degenerated Purkinje cells, and hyperplasia of the cells in the molecular and granular layers (Figures 1b & 2b).
Cerebellum-50mls of Regular Coke showing Vacuolations (spongiosis) in its white matter (W)
Cerebellum - 50mls of Regular coke showing increase in the number of cells in the molecular (M) and the granular layers (G), loss and slight degeneration of Purkinje cells (PD)
Group C (DS): The histological sections of the cerebellum of the DS group showed Purkinje cells with prominent hypertrophied dendrites (Figure 2c). Halo of empty spaces appeared around the Purkinje cells. The cells of molecular layer appeared hypertrophied with enlarged stellate and basket cells (Figures 1c & 2c).
Cerebellum-50mls of Diet Coke showing its white matter (W) with no vacuolations in it.
Cerebellum - 50mls of diet coke showing hypertrophy, elongation and increased molecular (M) cells and granular cells (G), degeneration and increase in number of Purkinje cells (PG).
Figure 1 (a-c): Photomicrographs of cerebellum of control and treated groups which received 50mls of Regular coke and diet coke (H & E X 100 for all Figures).
Figure 2: Photomicrographs of cerebellum of control and treated groups which received 50mls of Regular coke and diet coke (H & E X 400 for all Figures).
Discussion
In this study, the Diet soda (DS) group revealed shrunken and degenerated Purkinje cells with hypertrophied dendrites. The Purkinje cells are the only cerebellar efferent neurons12. These alterations in the shape of the Purkinje cells may lead to inadequate signals from the cerebellum to higher centres, a possible non motor coordination function.
DS contains caffeine and aspartame. Caffeine is linked to anxiety and sleep disruption when consumed in excess6. These symptoms may be due to disruption of the physiological or/and anatomical role of the brain areas involved in this function. Aspartame on the other hand has been linked to seizures, memory loss, dizziness, headache and behavioural changes9. These may be directly or through its constituents; aspartic acid, phenylalanine and methanol.
Aspartic acid is an excitatory neurotransmitter in the central nervous system. It acts by increasing the depolarization at the postsynaptic membrane. This might cause rapid firing of the neurons12. Increased level of these substances could change the activity of the brain and alter its normal functioning13.
Olney et al.8 reported that aspartic acid caused excessive stimulation of the excitatory glutamate receptors leading to their hypertrophy and eventually hyperplasia. As glutamate is a constituent of this soda, this may have been a reason for the changes observed in this study.
Phenylalanine decreased catecholamines neurotransmitter level12 , 14. Methanol has been reported to cause an increase in the metabolizing enzymes of the cerebellum as well as other sites in rat brain15.
Pan et al.16 reported apoptotic Purkinje cells with increased number of cells in the molecular layer of aspartame treated animals. Glutamate is a neurotransmitter which sends excitatory signals in the cerebellum17.
Furthermore, it was observed that the DS group consumed less than 20mls of the drink showing the significantly (at p<0.05) lowest consumption as compared to the RS group which had the significantly (at p<0.05) highest consumption. This could be due to their loss of appetite.
Vacuolations found principally in the white matter of the RS group can be attributed to the loss of cellular components of the tissue or organ. This is in line with the work done by Llinas et al.18 who reported increased vacuolation and loss of Purkinje cells. The hypertrophy of stellate and basket cells of the molecular layer, and that of the granular layer observed in the DS group may also be due to excessive excitation of these cells. This is in line with a report that the excitotoxins acting at different sites within the central nervous system could strip myelin from fibers and destroying neurons19.
Lutsey et al.20 reported that consuming just a can of diet soda increases one's risk of developing metabolic syndrome. Abeer21 reported aspartame resulted in the loss of the pyriform shape of Purkinje cells, condensed nuclei with affected processes, vacuolations in the granular and molecular layers, with gliosis and cell death which showed incomplete restoration of the normal structure of the cerebellar cortex upon stoppage21. The observed vacuolation and neuronal loss in the cortical layers of the RS group may adversely affect cerebellar function22.
Conclusion
This study shows that DS may have adverse effect on the histology of the cerebellum of female albino wistar rats; hence its consumption should be in minimal quantity.
References
1. Malik VS, Schulze MB, Hu FB. Intake of sugar-sweetened beverages and weight gain: a systematic review. American Journal of Clinical Nutrition. 2006;84(2):274–328. [PMC free article] [PubMed] [Google Scholar]
2. Vartanian LR, Schwartz MB, Brownell KD. Effects of soft drink consumption on nutrition and health: a systematic review and meta-analysis. American Journal of Public Health. 2007;97(4):667–675. [PMC free article] [PubMed] [Google Scholar]
3. Leif GT, Barnard RJ. An analysis of FDA passive Surveillance reports of seizures associated with consumption aspartame. Jamaican Dietary Association. 1992;72(5):598–601. [PubMed] [Google Scholar]
4. Posch L, Vences M. The effect of aspartame on rat brain xenobiotic metabolizing enzymes. Hum Exp Toxicology. 2007;25(25):453–459. [PubMed] [Google Scholar]
5. Roberts HJ. Direct and indirect cellular effects as aspartame on the brain. Eur J Clin Nutr. 1992;62(4):451–462. [PubMed] [Google Scholar]
6. Ebbeling CB, Feldman HA, Osganian SK, Chomitz VR, Ellenbogen SJ, Ludwig DS. Effects of decreasing sugar-sweetened beverage consumption on body weight in adolescents: A randomized, controlled pilot study. Pediatrics. 2006;117(3):673–680. [PubMed] [Google Scholar]
7. Humphries P, Pretorius E, Naude H. Direct and indirect cellular effects of aspartame on the brain. Eur J Clin Nutri. 2008;62(4):451–462. [PubMed] [Google Scholar]
8. Olney JW, Farber NB, Spitznagel E, Robins LN. Increasing brain tumor rates: is there a link to aspartame. J Neuropathol Exp Neurol. 1996;55(11):1115–1123. [PubMed] [Google Scholar]
9. Tollefson L, Barnard RJ. An analysis of FDA passive Surveillance reports of seizures associated with consumption of aspartame. J Am Diet Association. 1992;1(5):598–601. [PubMed] [Google Scholar]
10. Ekong MB. Aspartame: sweet or bitter. The Internet Journal of Health. 2009;9(1) [Google Scholar]
11. Magnuson BA, Burdock GA, Doull J, Kroes RM, Marsh GM, Pariza MW, Spencer PS, Waddel WJ, Walker R, Williams GM. Aspartame: of safety evaluation based on current use levels, regulations and toxicological and epidemiological studies. 2007 [PubMed] [Google Scholar]
12. Gartner LP, Hiatt JL. Color Textbook of Histology. 2nd ed. New York: Saunders; 2001. [Google Scholar]
13. Koeppe RA, Shulkin BL, Rosenspire KC, Shaw LA, Betz AL, Mangner T, Price JC, Agranoff BW. Effect of aspartame-derived phenylalanine on neutral amino acid uptake in human brain: A positron emission tomography study. J Neurochem. 1991;56(5):1526–1535. [PubMed] [Google Scholar]
14. Coulombe RA, Sharma RP. Neurobiochemical alterations induced by artificial sweetener aspartame {Nutrasweet} Toxicol Appl Pharmacol. 1986;83(1):79–85. [PubMed] [Google Scholar]
15. Holten AT, Gunderson V. Glutamine as a precursor for transmitter glutamate, aspartate and GABA in cerebellum: a role for phosphate-activated glutaminase. J Neurochem. 2008;104(4):1032–1042. [PubMed] [Google Scholar]
16. Pan HH, Suda Y, Ohe Y, Sumi M, Yoshioka M. Effect of aspartame on Nmethyl-D-aspartate-sensitive L-[3H] glutamate binding sites in rat brain synaptic membranes. Brain Res. 1990;520(1–2):351–353. [PubMed] [Google Scholar]
17. Christian B, McConnaughey K, Bethea E, Brantley S, Coffey A, Hammond L, Harrell S, Metcalf K, Muehlenbein D, Spruill W, Brinson L, McConnaughey M. Chronic aspartame affects T-maze performance, brain cholinergic receptors and Na+,K+-ATPase in rats. Pharmacol Biochem Behav. 2004;78(1):121–127. [PubMed] [Google Scholar]
18. Llinas RRK, Walton D, Lang EJ. Cerebellum. In: Shepherd GM, editor. The Synaptic Organization of the Brain. New York: Oxford University Press; 2004. [Google Scholar]
19. Brace H, Latimer M, Winn P. Neurotoxicity, blood barrier breakdown, demyelinization and remyelination associated with NMDA-induced lesions of the rat lateral hypothalamus. Brain Res Bull. 1997;43(5):447–455. [PubMed] [Google Scholar]
20. Lutsey P, Steffen L, Stevens J. Dietary intake and the development of the metabolic syndrome: the atherosclerosis risk in communities study. Circulation. 2008;117:754–761. [PubMed] [Google Scholar]
21. Abd El-Samad AA. Light and electron microscopic study on the effect of aspartame on the cerebellar cortex of male albino rat. Egypt J Histol. 2010;33(3):419–430. [Google Scholar]
22. Ajibade AJ, Fakunle PB, Shallie PD. Some histological observation and microstructural changes in the Nissl substances in the cerebellar cortex of adult albino Wistar rats following artesunate administration. 2006 [Google Scholar]
Consuming Diet Sodas Soft Drinks in Comparison to Regular Sodas
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3824455/