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~485~
Journal of Pharmacognosy and Phytochemistry 2017; 6(3): 485-487
E-ISSN: 2278-4136
P-ISSN: 2349-8234
JPP 2017; 6(3): 485-487
Received: 11-03-2017
Accepted: 12-04-2017
Malamige Minoli Weroshana
Aponso
Department of Food Science and
Technology, Faculty of Applied
Sciences University of Sri
Jayewardenepura, Sri Lanka
GO De Silva
Department of Food Science and
Technology, Faculty of Applied
Sciences University of Sri
Jayewardenepura, Sri Lanka
AT Abeysundara
Department of Food Science and
Technology, Faculty of Applied
Sciences University of Sri
Jayewardenepura, Sri Lanka
Correspondence
Malamige Minoli Weroshana
Aponso
Malamige Minoli Weroshana
Aponso, Department of Food
Science and Technology, Faculty
of Applied Sciences University of
Sri Jayewardenepura, Sri Lanka
Emulsifiers as food additives: An overview on the
impact to obesity and gut diseases
Malamige Minoli Weroshana Aponso, GO De Silva and AT Abeysundara
Abstract
Emulsifiers, which are added to most processed foods to aid texture and extend shelf life, can alter the
gut microbiota composition and localization to induce intestinal inflammation that promotes the
development of inflammatory bowel disease (IBD) and metabolic syndrome. Inflammatory bowel disease
(IBD), which comprises Crohn’s disease and ulcerative colitis, affects many people and is often severe
and devastating. Metabolic syndrome is a group of very common obesity-related disorders that can lead
to type-2 diabetes, cardiovascular and/or liver diseases. Addition of emulsifiers to food promotes
bacterial translocation across epithelial cells which also augments main features of obesity namely
adiposity and metabolic inflammation. Studies have proven that emulsifiers might affect the gut
microbiota to promote these inflammatory diseases. Clinically designed experiments using mice have
been conducted to test this possibility. Results of current studies with regards to the effect of emulsifiers
to gut health highlight that existing means of testing and approving food additives may not be sufficient
to preclude the use of chemicals that promote diseases driven by low-grade inflammation and/or which
will cause disease primarily in susceptible hosts.
Keywords: Emulsifiers, Gut health, bacterial translocation, metabolic syndrome, Inflammatory Bowel
Disease
Introduction
Food additives are natural or artificial constituents that could be incorporated to food in minute
quantities to perform technological functions such as extending shelf life, adding colour and
flavour. Following the EU regulation, preservatives are food additives that protect against the
action of microorganisms (fungi and/or bacteria) and thereby extend the shelf life of foodstuff
[1]. In processed food products, lipids need to be stabilized using emulsifiers [2]. Emulsifiers are
a type of food additives that can be used to improve the texture of food and prevent mixtures
from separating. Emulsifiers are used in margarine, mayonnaise, creamy sauces, candy, ice
cream, packaged processed foods and baked goods. In present, two common emulsifiers
namely carboxy methyl cellulose (CMC) and polysorbate-80 (P80), are in question due to the
increased risk of obesity and irritable bowel syndrome in mice tested using these emulsifiers.
Based on the results of the clinical trials using mice, drastic disruptions in the gut bacteria of
mice were recorded even in extremely low concentrations of emulsifiers. The intestinal tract is
inhabited by a large and diverse community of microbes collectively referred to as the gut
microbiota. While the gut microbiota provides important benefits to its host, especially in
metabolism and immune development, disturbance of the microbiota-host relationship is
associated with numerous chronic inflammatory diseases, including inflammatory bowel
disease and the group of obesity-associated diseases collectively referred to as metabolic
syndrome [3]. Therefore, new research studies suggest that emulsifiers could alter the delicate
composition of microbes in the gut, trigger intestinal inflammation and increase the risk of
inflammatory bowel disease and a cluster of obesity-related conditions known as metabolic
syndrome in human as well [4]. It is recorded that obesity is allied with altered gut microbiota
and low-grade inflammation. Both dietary habits and food composition contribute to the onset
of such diseases [5]. Emulsifiers, in a variety of foods, have shown to induce body weight gain,
low grade inflammation and metabolic disorders. These dietary compounds promote gut
microbiota alteration and gut barrier dysfunction leading to negative metabolic alterations. As
mentioned in previous research studies, there is an impact of dietary emulsifiers on the
accessibility of specific nutrients to the gut bacteria [6]. Emulsifiers are detergent-like
molecules; CMC and P80 affect lipid absorption in the intestine, increasing lipid and bile acid
flux into the gut lumen. This phenomenon contribute not only to the modulation of the gut
microbiota composition, but also gut inflammation. Hence, emulsifiers contribute to the
modulation of energy sources in the gut.
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Journal of Pharmacognosy and Phytochemistry
Structure and function of emulsifiers
An emulsifier is a molecule that holds surface activity due to
the amphiphilic properties, where hydrophilic and lipophilic
regions exist within the same molecular structure. This
structure helps the emulsifier to interact with both phases
especially in an oil in water emulsion, developing a protective
layer at interface in which dispersed phase droplets are
prevented from amalgamation [7]. Function of emulsifiers in
food systems can be characterized as to promote emulsion
stability, control agglomeration of fat globules, and stabilize
aerated systems; to improve texture and shelf life of starch
containing products by complex formation with starch
components; to modify rheological properties of wheat
doughs by interactions with gluten proteins; to improve
consistency and texture of fat-based products by controlling
polymorphism and crystal structure of fats [8].
Mechanisms of action of emulsifiers on the gut lining
Gut is lined with mucus that keeps the microbes at a safe
distance. Things that interrupt the interactions between gut
bacteria and the protective mucus may have the probability to
promote the onset of diseases associated with chronic gut
inflammation [5]. Dietary emulsifiers such as carboxy methyl
cellulose (CMC) and polysorbate-80 (P80) are used in
numerous foods at concentrations up to 2%. A recent study
suggested that the growth in dietary emulsifier consumption
over the past half century may contribute to a higher
incidence of inflammatory bowel disease (IBD) and metabolic
syndrome [3]. P80 has been studied for toxicity and
carcinogenic potential [9] and is permitted by the US Food and
Drug Administration for consumption in selected foods at up
to 1.0%. CMC has not been extensively studied but is
considered ‘generally regarded as safe (GRAS)’ and used in
various foods at up to 2.0% [10]. To study the underlying truth
between the relationship of obesity, gut diseases and dietary
emulsifiers, clinical trials have been conducted using mice.
Mice were administered with the emulsifiers, carboxy methyl
cellulose (CMC) or polysorbate-80 (P80) via drinking water
(1.0% w/v or v/v) respectively for 12 weeks. At regular
intervals, the composition of the microbes in the guts of the
mice were tested using advanced genetic methods. Carboxy
methyl cellulose consumption was shown to have long-lasting
negative effects, such as increased adiposity and
myeloperoxidase activity in the intestine, whereas the
deleterious effects of polysorbate-80 were reversible [11]. An
alteration in the microbial types and numbers in the gut over
time was observed [3]. The study has showed that both
emulsifiers are involved in the development of inflammation
that resembles inflammatory bowel disease (IBD) since they
promote chronic gut inflammation leading to vigorous colitis
in mice, lacking Toll-like receptor 5 (TLR5 _/ _), or Interleukin
10 (Il10 _/ _), that lead to developing intestinal inflammation
[12]. TLR5 _/_ receptor is shown to be involved in the onset of
many diseases, which includes inflammatory bowel disease
[13]. Interleukin 10 is a cytokine with multiple, pleiotropic,
effects in immune regulation and inflammation [14].
Alterations in microbiota composition included reduced levels
of bacteroidales, associated with health [15-17], and increased
levels of several mucolytic operational taxanomic units
(OTUs) including Ruminococcus Gnavus [18]. Gut bacteria
have been suggested to be involved in the development of
low-grade inflammation in obese individuals [19] since they
produce pro-inflammatory molecules such as
lipopolysaccharides (LPS), flagellins and peptidoglycans. It is
reported that emulsifier consumption has reduced the overall
microbial diversity and raised the microbiota pro-
inflammatory properties, remarkably via an increase in
flagellin and lipolysaccharide (LPS) release [20]. Flagellin is a
globular protein and it is the principle component of bacterial
flagellum which causes inflammation in body and endotoxin
LPS is a cell wall constituent of Gram-negative bacteria,
which becomes liberated into the gut lumen upon bacterial
cell lysis [21]. The inflammation caused by flagellin and LPS
have links to inflammatory bowel disorders such as Crohn’s
disease and ulcerative colitis as well as metabolic syndrome
and diabetes [21]. It is also reported that high-energy diets, in
particular high-fat diets, are associated with high plasma LPS
concentrations in humans and mice [22-25].
Bacterial translocation due to emulsifiers
A new study using mice has highlighted how emulsifiers
added to various foods, promotes an effect called “bacterial
translocation”, where bacteria move across epithelial cells [3].
This, triggers the ill-health effects. Furthermore, as the
microbes changes the mucus layers of the intestine and alter
it, some bacteria makes a transition into this region. This is an
area normally devoid of bacteria. Remarkably, based on the
previous studies using mice, these changes have corresponded
with chronic colitis which developed in the mice.
Consumption of emulsifiers in processed foods may promote
Crohn's disease (CD) by increasing bacterial translocation [26].
Crohn's disease is a type of inflammatory bowel disease
(IBD) that may affect any part of the gastrointestinal tract
from mouth to anus [27]. Emulsifiers increase gut permeability
which results in increased bacterial translocation which causes
inadequate clearance of intra macrophage bacteria such as E.
coli and formulate granulomata, abscess and fistula [26].
Dietary emulsifier-induced low-grade inflammation and
colon carcinogenesis
Recent findings suggest that low-grade inflammation in the
intestine is promoted by consumption of dietary emulsifiers,
an omnipresent component of processed foods which alter the
composition of gut microbiota [28]. Gut microbiota is the
mutual term for the large assorted community of
microorganisms that resides in the intestine, play an important
role in health by promoting immune system development and
metabolism [29]. Alterations in microbiota composition, plays
a crucial role in the pathogenesis of many intestinal disorders
comprising inflammatory bowel disease (IBD) which is also
associated with Colorectal cancer [30]. It is suggested that
emulsifiers could be involved in colorectal cancer
development through the elevation of low-grade intestinal
inflammation and alterations of the intestinal microbiota. This
has been tested by a well-established murine model of colitis-
associated cancer (CAC) using the carcinogen azoxymethane
(AOM), followed by two cycles of dextran sulfate sodium
(DSS) in mice subjected to chronic exposures of two
frequently used emulsifiers, CMC and P80. It was resulted
that dietary emulsifying agents are responsible to create and
maintain a pro-inflammatory environment in the colon,
associated with alterations of the proliferation/apoptosis
balance that resulted in aggravated carcinogenesis [28].
Conclusion
Dietary emulsifiers alter microbiota localization, composition
and pro-inflammatory potential. It is also suggested through
several studies that emulsifiers promote colitis and metabolic
syndrome. However, it cannot be simply decided that
emulsifiers are responsible for obesity. Current studies have
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Journal of Pharmacognosy and Phytochemistry
only been conducted in rodents that where chronically
exposed to P80 and CMC. Large scale human studies need to
be conducted to afford proof for a related connection amid
emulsifiers, gut microbiota and metabolic syndrome. But
current studies are capable and sufficient to explain that it is
important to revise the food additives, especially emulsifiers
that are prone to arouse complex diseases such as metabolic
syndrome driven by alterations in microbiota composition and
low-grade inflammation.
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