By: Angel Kaufman
Spring 2021
A thesis
submitted in partial fulfillment
of the requirements for a baccalaureate degree in Biology
in cursu honorum
Reviewed and approved by
Dr. Jill Callahan Professor, Biology
Thesis Supervisor
Submitted to
The Honors Program, Saint Peter's University Date of Submission
ABSTRACT
The human gut microbiome is more important to health than most people realize. It is filled with trillions of microbes ranging from fungi to bacteria, and viruses. This paper focuses on preservatives and emulsifiers and the effects they have on the gut microbiome. These two food additives affect different types of bacteria differently. Emulsifiers and preservatives increased bacteria that tend to have negative effects on the body while decreasing beneficial bacteria. This can have many different effects on the body from Crohn’s disease to dysbiosis and even increase antimicrobial resistance in bacteria. This review looks to explain why
preservatives and emulsifiers have such negative effects, why it is such a relevant and important topic, and alternatives to preservatives or emuslisers or ways to mitigate the effect of these two food additives.
Table of Contents Page 1- Abstract
Page 3- Introduction
Page 4- Bacteria Found in the Gut Microbiome, Bacteria Effect on Gut Microbiome Page 6- How Gut Microbiomes vary between people and age
Page 7- Effect of Polyphenols and Antibiotics on the Gut Microbiome Page 8- How diet affects the Gut Microbiome
Page 10- Figure 1 (Effects of various diets on bacteria of Gut Microbiome) Page 11- Diseases affecting Gut Microbiome
Page 12- What are preservatives? Page 13-What are emulsifiers?
Page 14- Effects of emulsifiers on Gut Microbiome Page 17- Effects of preservatives on Gut Microbiome Page 19- Alternatives to Preservatives and Emulsifiers Page 21- Discussion
INTRODUCTION
In society, today nutrition is a real global issue. What people eat not only affects their health but can have an effect on a person's future. A proper diet is key to a healthy and
successful life. Different dietary agents that people consume can have an effect on different parts of the body including the gut microbiome. This paper focuses on the effects of preservatives and emulsifiers. Preservatives used in food can be split into two groups: antioxidants and
antimicrobials. Using oxidative mechanisms antioxidants slow down the degradation of food through free radicals. Antimicrobials in food have been shown to stop the growth of
microorganisms and also extend the time before spoilage. Emulsifiers can improve the texture of food or change the flavor. There are many types of emulsifiers that can be looked at using a range of different characteristics. Emulsifiers exist as lipids and water due to the hydrophobic and hydrophilic components which is what lets us have things like salad dressings and even yogurt. (Vo .D Trung,2018) They can occur naturally or be synthesized artificially. They can either go into circulation and have a positive beneficial effect or remain in the gut microbiome. Different agents affect the growth of and even intracellular pH of different types of bacteria. Preservatives are very important in limiting the growth of microbes. They are used in many products from food to even cosmetics. Looking at different studies, diets among other factors have been shown to affect the gut microbiome together with emulsifiers and preservatives. Age, host factors, antibiotics, prebiotics, probiotics and other factors have been shown to affect the biome. ‘In the gut microbiome after the beginning of life, diet remains very important to the development, defining of the shape, diversity and even structure associated with it.’ (Hassan, 2019)
Bacteria Found in the Gut Microbiome
The microbiome is home to bacteria found in the body which is estimated to be about 100 trillion. The misconception with this bacteria is that they are not beneficial but many beneficial bacteria are found in the microbiome. These beneficial bacteria assist with human development and nutrition. There is a balance amongst these microorganisms and everyone’s composition of bacteria is different. This is due to factors such as heredity and diet, and the organisms
compositional (phenotypic) traits. There are a huge number of microorganisms found in our body and in particular the gut microbiome. There are about 1000 species of microorganisms found in the gut microbiome and majority of these are bacteria. Ninety percent of these microorganisms are either Bacteroidetes or Firmicutes. Bacteria that are closer to the ‘surface mucosa layer will have a role in the immune system.’ (Eamonn M. Quigley,2013) Also species of bacteria near or in the lumen have been shown to have an effect on metabolic interactions and digestion.
Bacteria Effect on Gut Microbiome
In the gut there is beneficial bacteria and bacteria that could be closely related to organisms that cause disease or that would be considered pathogenic. These harmful bacteria can include Staphylococcus(S.), Streptococcus, Enterobacter, Neisseria and Clostridium(C.) S.aureus can be acquired in any substance with staph enterotoxin. This can include meats, milk dairy and countless other products. It can also be spread by contaminated objects of an infected person as well. After getting in the body it can cause inflammation and swelling after settling in the small intestine. Diarrhea and fever are amongst other symptoms and can even in some cases cause bloodstream infections. C. difficile once prevalent in the gut has toxins that attack the
intestine. It attacks the lining, destroying cells, producing debris of cells that have decayed among other things. Interestingly enough these bacteria just don’t get in the gut and just start doing these things depending on the communal population of the gut. In people with C.difficile infections it has been shown that there is a lower level of Bacteroidetes and a higher number of proteobacteria. (Danfeng Dong,2018) Bacteroidetes(B.) play a big role in helping to process complex molecules and turn them into simpler ones. They are considered beneficial bacteria. An example of this can be seen in B. fragilis which help produce immune cells in the body. These kill harmful bacteria and if there were less of them it could allow harmful bacteria such as C. difficile or S. aureus to remain causing infections and problems. There are a lot of
proteobacteria with at least 460 different genera and over 1600 species of bacteria. While all are not considered almost pathogenic a majority of them are. They are linked to many intestinal, extraintestinal diseases as well as dysbiosis. Firmicutes(F.) one of two phyla that make up a huge amount of the gut microbiome plays a role in the gut. The role of this phyla is involved in energy reabsorption mostly like carbohydrates. An example of this can be seen in F. prausnitzii which converts unabsorbed carbohydrates through fermentation. (Siobhan F. Clarke,2012) This is not a good thing in which it can lead to increased energy being taken from the carbohydrates into the dietary intake. This can influence weight gain and obese children. Emulsifiers interact with nonpolar ingredients in food due to it being amphiphilic. In obese individuals it is seen as a higher population of Firmicutes and less Bacteroidetes. (Clarke,2012)
How Gut Microbiomes vary between people and age.
There are various factors that help develop and affect our gut microbiome. The transitions from birth, how we age and our dietary habits. It has been shown that the time we
spend in our mother's womb until we are born affects us. This is known as the gestational age. Infants that could be born before 37-42 weeks (preterm) have many factors deterring them. Since they are born early there is a chance of organ immaturity. One of the biggest worries with babies born premature is inflammatory diseases. These problems could affect many and if not all organs. Treatments for premature babies tend to be antibiotic based. This leads to the next problem in which too much antibiotics tend to lead to a gut microbiome in which some bacteria is abundant and others have decreased or are almost gone.
As we age there has been limited research done to show a correlation between age and our gut microbiome. ‘Experiments have shown a reduced gut microbiome correlation with the frailty of aging. This was shown by a reduced amount of bacteria in the gut such as
Bifidobacteria, lactobacilli and bacteroides.’ (Ravinder Nagpal,2018) While the research is limited, dietary factors are believed to play a part in helping the biome. One of the most important things are pre and probiotics. These products help stimulate bacteria and can help increase the good bacteria in the gut. It has been shown in older people (those over 65 years old) there is a huge variation in individuals. A study looking directly into the correlation showed a decrease of Bacteroidetes bifidobacterium, enterobacteriaceae and an increase in clostridium spp. (Juan Miguel Rodriguez, 2015) As people age there is a decrease in beneficial bacteria making it important to find alternative ways to add more to the communal population of the gut microbiome.
Effect of Polyphenols and Antibiotics on the Gut Microbiome
The prescribing of antibiotics has increased over the years. There is also the aspect of factory farming. Animals are left close together with little room to move. To make sure infection is stopped or prevented heavy doses of antibiotics is given. Through food and other things bacteria can acquire resistances. In experiments done with mice different results were shown. Along with pathogenic bacteria beneficial bacteria were also affected. Some bacteria took weeks to recover it’s population and others years. (Paula,Roca-Saavedra, 2017) With beneficial bacteria being affected this has a huge effect on our body. The gut microbiome plays a role in the immune system and the more it’s affected by antibiotics the more susceptible to pathogenic bacteria we may become.
The connection between antibiotics and preservatives is that preservatives can accelerate the horizontal transfer of bacteria genes that are resistant. The preservatives looked at were sodium nitrite, sodium benzoate, and triclocarban. They were looked at along with antibiotics such as ampicillin, chloromycetin, and tetracycline. The preservatives facilitated or made easier the transfer of antimicrobial resistance genes in E.coli. There was a correlation between levels of preservatives with those that inhibited the levels of transfer were higher. This occurred to the preservatives weakening a part of the outer membrane of bacteria making it easier to transfer antimicrobial-resistant genes. The effects of this can be explained by reactive nitrogen species (RNS) and reactive oxygen species (ROS). At low concentrations they play a beneficial role in signal transduction and mediate signaling processes. (Meo,2016) At high concentrations they can inactivate or block important molecules in cells from activating. They induce RpoS regulon and SOS response in cells. RpoS is a sigma factor that is in response to stress and helps cells
survive situations of stress and this was increased by the three preservatives. The regulon helps improve the rates of recombination of the intra chromosomes and helps the cell survive the oxidative stress caused by the SOS response. (Cen,2020) The SOS response causes stress in the cells which cause pores in the cell allowing for an increase in permeability of cells and this helps antibiotic resistant genes to get through. This allows more horizontal transfer of antibiotic resistant genes.
Polyphenols are categorized as plant compounds found in foods or drinks and can offer a variety of benefits to health. Tea has been shown to have components such as gallate, catechin and this inhibits pathogens such as Helicobacter pylori or E. coli. (Duda-chodak,2015)
Polyphenols found in citrus such as naringenin and diosmetin have been shown to affect the gut microbiome. When tested with 4 types of bacteria they showed to have low minimum inhibitory concentrations and others even showed to help the effects of probiotics adhere to the gut. They alter the environment of the gut by affecting the beneficial bacteria species of bacteria in the gut which leads to good benefits. Another example of this is drinking red wine daily. It was shown when tested for 4 weeks increased many positive bacteria groups such as enterococcus,
bacteroides and bifidobacterium. (Duda-chodak,2015) Indirectly polyphenols can affect a person's metabolism.
How diet affects the gut microbiome
In today’s society there are many diets that people believe can lead to a healthier lifestyle. Popular diets such as the Mediterranean diet, Paleo diet, juice cleansing along with many more diets are used today. The gut microbiome affects many things such as digesting fiber, controlling brain health, helping the immune system along with other functions. Do diets or what we eat
really impact the gut microbiome? There was a study conducted to look at something similar to this. This experiment looked to see how dietary interventions altered microbial communities in terms of a diet. There was a plant based diet along with an animal based diet. The results were that the macronutrient intake was shifted, fiber, fat, protein. What was really interesting as these diets showed transcriptional responses were consistent with the difference in genes between plant eating and carnivorous mammals. (Lawrence A. David, 2013)
A study compared Hadza, a tribe in Africa with Italian gut microbiomes. What came out of the study was they had really distinct differences. The Hadza was shown to have a lot more proteobacteria and spirochaetes which is rarely found in Italian gut biomes. Then in Italian gut biomes there was shown to be high Actinobacteria which is rare in Hadza. (Emanuele Rinniella,2019) Along with diet exercise is an important part of a lifestyle. Exercising daily has shown to increase the diversity of the gut. Daily exercise helps the Firmicutes (clostridiales, roseburia, lachnospiraceae and erysipelotrichaceae) be more prevalent in the gut biome. (Emanuele Rinniella,2019)
Effect of various diets on bacteria of Gut Microbiome.
Figure 1. A figure charting the effects of various diets on bacteria in the gut microbiome. Source: MDPI. 2019. Available
from:https://www.mdpi.com/2072-6643/11/10/2393/htm#B96-nutrients-11-02393) Diet is just as important as anything when dealing with the gut microbiome. Looking at the figure above we can see how some of the most popular diets affect the gut microbiome. These diets which are used by millions all seemed to have negative effects on the gut microbiome by affecting the bacteria populations. A gluten free diet caused the healthy bacteria to decrease. The ketogenic diet showed to decrease bacteria as well as the diversity.
The Western Diet decreased the diversity of bacteria. The only diet that showed a positive effect was the Mediterranean diet which increased microbiota diversity and stability. This was due to the fact that this diet focuses on things that are beneficial to the bacteria found in the gut microbiome and stays away from foods that have preservatives and emulsifiers that can negatively affect the bacteria. The Mediterranean diet is built on vegetables, fruits, nuts, herbs, whole grains, basically plant based foods. Dairy, poultry and red meat are still consumed but at minimal amounts. As mentioned before polyphenols can have a positive effect on the gut microbiome and this diet mainly focuses on foods with polyphenols.
Diseases affecting Gut Microbiome
One aspect overlooked is diseases or syndromes that directly affect the gut microbiome Dysbiosis is ether maladaptation or microbial imbalance mostly in the body. Two things common to it are the reduction or huge loss of bacteria. Another thing common too is an increase in growth of pathogens. The characteristics that differ is the loss of good bacteria, and or overgrowth of pathogens and or loss of the diversity of bacteria as a whole.
It has been shown that sometimes the gut microbiota changes precede the onset of illnesses (can be shown in Parkinsons among others). The gut microbiome has a link to many parts of our body. The gut microbiome contributes to many functions of the body (metabolic) and helps especially protecting against pathogens and boosting the immune system. Therefore a change in the bacteria in the gut would show precede the onset of an illness
It has been shown that other diseases such as obesity, diabetes mellitus, and autism spectrum disorders. ‘There seems to be a decrease in the diversity of bacteria more specifically a decrease of bacteroidetes and increase in Firmicutes’ (Ariana K. DeGruttola, 2016) Experiments
were done on mice to show the link. In diabetes mellitus there is a decrease in what are known as mucin lowering bacteria (these are prevotella, lactobacillus and Bifidobacteria) and an increase is shown in Clostridium and bacteroides. (Ariana K. DeGruttola, 2016) Again these were tested on mice and a link was shown again. With autism disorders the connection is a little more interesting. The connection between the two appears to be how the gut microbiome (specifically its metabolites) affect the central nervous system (CNS) through the gut brain-axis. (Ariana K. DeGruttola, 2016) The gut brain axis has over 500 million neurons that connect through the brain. In experiments done with mice it showed that the alterations in the gut microbiome led to the synthesis of many neurotoxins which affected the development of the brain and behavior as well. (Ariana K. DeGruttola, 2016)
A treatment that is currently being tested is fecal microbiota transplantation (FMT). FMT transfers a small healthy part of a person's feces and transfers it to the person or a recipient. This has shown positive results in treating C.difficile colitis. (Ravinder Nagpal, 2018) The interesting aspect about this is that it is currently being researched in treating other ailments that affect the gut. The main treatment however is to change diet.
What are preservatives?
There are what can be considered good and bad food preservatives. Natural preservatives don’t have their chemical composition changed and are not mixed with anything synthetic. Majority of time the properties they have are anti-oxidant properties. Artificial or chemical preservatives are used to delay contamination and the spoiling of food. These are not natural however, and are not produced differently. Things added to food or additives are usually added to food to stop some sort of chemical change and prevent (microbial) growth. Examples of this
are preservatives which prevent spoilage due to bacteria or microorganisms and artificial sweeteners that are used in place of sugar. Preservatives can either be antimicrobial or
antioxidant. Antimicrobial preservatives can inhibit the growth of things like bacteria or fungi. (Shee,2010) Antioxidant preservatives absorb oxygen which does not allow or stops oxidation of the components of the food. Salt, a well used preservative is known to stop growth in different foods. In a solution containing mutton broth along with salt was shown that the colonies of bacteria were not forming or forming way less then normal. (Shee,2010)
Preservatives have also been known to cause some health problems. To avoid risk of developing problems from preservatives or additives it is recommended to eat organic foods.
(Abdulmumeen,2012) What are emulsifiers?
Food emulsifiers is a food additive like a preservative or artificial sweetener. They can be found in about 75% of all approved food ingredients worldwide. (Shah,2017) The purpose of an emulsifier is to improve stability, inhibit the food from going stale thus making the shelf like longer and other effects. Emulsifiers can increase the risk of metabolic disorders as well as bowel diseases. There are concerns about how they can impair the function of the intestinal barrier or change the microbiota leading to an increase in syndromes or diseases. Emulsifiers in foods have been shown to have a variety of effects on the gut and diseases. Emulsifiers can stay in the gut microbiome. Here they can stimulate growth of certain bacterial groups most which seem to have a negative effect and change the composition of the biome. (Vo .D Trung,2018) Emulsifiers have been shown to cause weight gain, metabolic disorders and inflammation. This
compound seems to promote dysfunction in the barrier of the gut and leads to alterations or changes in the bacteria that have a negative effect. (Cani, 2015)
Effects of emulsifiers on Gut Microbiome
There are concerns about how emulsifiers can impair the function of the intestinal barrier or change the microbiota leading to an increase in syndromes or diseases. Emulsifiers have even been shown to alter the bacteria in the colon’s makeup There has been a correlation between consumption of emulsifiers and Crohn's disease. Looking at a mouse model of there are bacteria that are translated into the mesenteric fat through the blood. This is seen in models with
metabolic syndrome and a introduced diabetes using a high fat diet. In other studies it has shown that in Crohn's disease there has shown to be an increase in mucosally associated E.coli.
(Partridge,2019) This can be shown in about 40% of patients with this disease. The bacteria induce an inflammation and increase it through the activation of the NF-KB signaling pathway. This pathway is a collection of transcription factors that are conserved. The pathway regulates inflammatory responses, apoptosis and other cellular behaviors. The epithelial barrier of the gut plays an important role in regulating uptake of luminal antigens. (Gutierrez,2016) In Crohn’s disease patients after six months of remission with the bacteria are translocated into the blood. This increased the risk of Crohn's disease along with surgery and or hospitalization. In patients with this disease the microbiomes showed an increase in bacteria such as enterobacteriaceae, pasteurellaceae, fusobacteriaceae, neisseriaceae, veillonellaceae along with others. There was a decrease in Bifidobacteriaceae, erysipelotrichaceae, clostridiales and bacteroidales. (Shreiner, 2016)
The Western diet which is a popular diet which involves a lot of emulsifiers. Seventeen emulsifiers were looked at in either human colon cells, mice, rats and the results were looked at. Four of the emulsifiers looked at either had no effect on the bacteria composition of the gut microbiome or it was not determined. The rest of the emulsifiers showed bacterial overgrowth, encroachment in the microbiota, or altered microbiota composition. The effects of these thirteen were negative. In physiology it was shown to have decreased nutrient uptake, colitis, intestinal inflammation, altered bile acids, glucose intolerance as well as many other issues.
(Partridge,2019)
It is known that inflammatory bowel diseases have been associated with a change or alteration of the composition of the gut microbiome. (Gutierrez,2016) There was change in composition in the gut microbiome when looking at polysorbate 80 (p8o) and
carboxymethylcellulose (CMC) in mice. There was an increase in proteobacteria and
enterobacteriaceae which are associated with an increase in bacteria that show an increase in inflammation. There was a decrease in bacteria such as bacteroidaceae and this bacteria is associated with positive healthy associated bacteria. (Chassaing, 2017) Another experiment looked at chronic ingestion of carboxymethylcellulose and polysorbate-80 . These are two commonly used dietary emulsifiers that were looked at to see how they affected the mucus barrier, inflammation, metabolic disorders among other things. The mice used were either prone or resistant to obesity. There were signs of colitis, low grade inflammation and obesity. This was linked to the absence of the genus Bilophia which also can lead to an increase in the chance of colitis. (Cani .D Patrice) What was most interesting was the degradation of the mucus lining. The relationship between mucus and the gut microbiota has been shown to be systematic. An
example of this was shown in Western diet led to increased penetrability in the micro gut biome by the mucus layer. (Schroeder O Bjoern,2019) The layer is there to protect the bacteria of the gut microbiome. When more mucus gets in it can promote growth of negative bacteria while inhibiting the beneficial bacteria. This can contribute to metabolic disease and negative interactions.
Five commonly used emulsifiers are CMC, P8o, soy lecithin, sophorolipids and rhamnolipids. (Miclotte,2020) The first two are synthetic emulsifiers and are consumed by humans. They are used in food products and other products as well. Soy lecithin is used very widely even more than the first two mainly in products that can be found in bakeries. The last two are biotechnological emulsifiers which are considered novel food additives. Novel food additives mean there is no history of use within a place and before being used need to be authorized. They are to be used as alternatives to other emulsifiers. Most of them showed a similar effect in an increase in Bacteroides and Escherichia/Shigella. There was a decrease in Faecalibacterium and a decrease in Prevotella. This could be attributed to the low carbohydrate concentration favored Escherichia/Shigella which is more protein based and Bacteroides which are among the most versatile bacteria. Rhamnolipids and sophorolipids had the most effect on the gut microbiome. They had a decrease in cell counts as well as increasing pathogenic bacteria Escherichia and Fusobacterium. The decrease was shown in beneficial bacteria such as
Bacteroidetes and Barnesiella. An interesting thing noticed in the study was the elimination of bacteria in the gut microbiome. The amount of elimination and decline in cell counts was
comparable to the effects of antibiotics. (Miclotte,2020) This led to a conclusion that emulsifiers attack the cells and bacteria of the gut microbiome at the membrane level.
Effects of preservatives on Gut Microbiome
An experiment focused on microbial growth of chemical preservatives on a system of cold pre peeled potatoes. The chemical preservatives that were looked at were citric acid, ascorbic acid, and sodium bisulfite. What it showed was sodium bisulfite in certain
concentrations showed growth and others did not inhibit microbial growth. Citric acid had an inhibitory effect in that the more that was added the microbial growth decreased. This showed ascorbic acid to be a good agent for antimicrobials to decrease growth of bacteria. Another experiment used the fecal gut microbiome of a donor with no history of diseases and colonized them in adult mice with no germs. They tested three of the most used food additives sodium benzoate, sodium nitrate and potassium sorbate. After testing the preservatives they used
genomic DNA extraction, PCR sequencing and metagenomic analysis. The results showed that a mixture of these popular food additives has been shown to possibly induce dysbiosis in the micro gut microbiome. (Lucia Hrncirova, 2019)
Preservatives could affect antimicrobial resistance genes. Antimicrobial resistance is a serious problem that affects us from what we eat including livestock and fruits or vegetables. Preservatives are used in food, care products, and many more. They can be found in many of the things we use or eat today. Sodium bisulfite and sodium sulfite are two food preservatives that are recognized as safe for human consumption. You can find these in hair products, wine juices, seafood, and a variety of things. The primary use of it is to control microbial growth, prevent browning and food spoilage. (Irwin,2017) An experiment tested the effect of these two preservatives on four bacterial species that are beneficial to us. These species are known as probiotics and are Lactobacillus species casei, plantarum, rhamnosus, and Streptococcus
thermophilus. The results showed after 2 hours that the majority of all the bacteria ether showed a decrease or no growth at all in terms of the cell numbers in the concentration of preservatives between 250-750 ppm. In sodium sulfite bacteria species numbers for all 4 probiotics were viable but stopped increasing. Sodium bisulfite showed a similar response with the strains of bacteria by stopping the growth of cell numbers and even making some non-viable. Due to sulfite being a strong nucleophile it reacts with many biomolecules leading to it doing a substitution at an ‘electrophilic position which can cause many potential reactions that could damage the cell.’(Irwin,2017) It has been shown to inhibit key enzymes and could even lead to the death of cells.
Salt is considered a natural preservative. This natural preservative has a variety of uses to help preserve the food by for example curing food and can draw the water out of foods. Today with fast food and other restaurants a lot of people live on a high salt diet. This can cause cardiovascular disease like hypertension but change can be noticed in the gut microbiome through bacteria. An experiment looked at this through rats. Through their research comparing two groups and fecal samples they were able to show a correlation. There were differences in the taxa level. In the group of rats with the high salt diet Clostridia and general Anaerostipes (Bier,2018) were shown to be lessened in the high salt diet and Christensenellaceae and
Eubacteriaceae (Bier,2018) were shown to have been increased. The data from this experiment agreed with other studies done as well as was able to develop the correlation between bacteria and hypertension.
Along with preservatives other additives are added to food. Additives like titanium dioxide and silicon dioxide are a pigment used to add color, taste and or anti caking agents to
food. The toxicology of these additives (nanoparticles) were studied using microbiota data to see any adverse effects. (Yan, 2020) The results were significant. In all of the bacteria groups compared to the control group there was a decrease in family and genus levels. There was an increase in Firmicutes. There was a decrease in bacteroidetes, verrucomicrobia and
proteobacteria. The results were that diet is a very important factor in gut microbiome health. That a decrease in certain types of bacteria can make it harder to break down food or affect normal immune function and various others.
Alternatives to Preservatives and Emulsifiers
Studies of the gut microbiome have only become prevalent in the past few years. As seen the gut can affect many parts of the body and even increase chances of diseases. This is very important in the way that the things we eat affect the communal population of bacteria and gut. Preservatives have been shown to decrease beneficial bacteria like bacteroidetes and increase bacteria that have almost pathogenic effects. Emulsifiers showed similar effects to that of the preservatives in the way they affect the communal population. There are different preservatives and emulsifiers most of which affect the body in a negative way. The preservative
ε-poly-L-lysine is a natural preservative and harmless to us. ‘It is nontoxic and non mutagenic. It is used in Japan, Korea, and has achieved generally regarded as safe (GRAS) status in the United States.’ (Chheda H.A, 2015) An interesting thing is that it can be used by itself or with a combination of other additives in food. When used with other preservatives a synergetic reaction occurs and the preservation efficacy increases. It also is an antiobesity agent as well as
suppresses dietary absorption. Despite all the good things it can be used for it might lead to the loss of antimicrobial activity. It can interact with proteins and acidic polysaccharides. This of
course leads to the future where we need alternatives or more research to develop natural or artificial healthier alternatives. There is a wide variety of uses still for this preservative in the future. Using biosynthesis on the genes of ε-poly-L-lysine to create a more efficient system for it. ‘With the right research, it can be used in medicine, the environment, even agriculture, and a possible replacement to many other food preservatives.’ (Chheda H.A, 2015)
An alternative to artificial preservative may in fact be natural preservatives. While they are still preservatives they are safer alternatives. These alternatives come from nature like plants, animals and other things. Examples of this are algin, grapefruit seed extract, rosemary extract, vitamin E oil, Carrageenan, Citric Acid, Erythorbic acid, honey and many more.
(Chaudhari,2019) Alternatives used in food, pharmaceuticals and many other products already have this. Another would be to follow steps to improve the gut microbiome. These steps would be to avoid overeating late snacks and food filled with no nutritional value. Processed foods should be avoided, as well as artificials and antibiotics should be used sparingly. (Amersbach, 2018) Gut healthy foods should also be eaten for example like asparagus, bananas which contain inulin and restore healthy bacteria. Another important thing that should be eaten is probiotics. These can be found in food such as yogurt, cottage cheese or foods that have been fermented. Through the process of fermentation many positive effects can occur. Through these food lactobacillales increases and these have been shown to lower the pH of the gut this has been shown to help slow down the growth of negative bacteria as well as stopping them from
attaching to the digestive tract walls. Probiotics have been shown to increase the population of beneficial bacteria showing similar effects as fermented foods. Further research and
development would be needed but natural alternatives seem like an alternative route rather than artificial preservatives.
Discussion
The main aim of this paper was to show the effects of preservatives and emulsifiers on the gut microbiota. These can trigger a variety of effects in the gut but the common one was changing the communal population. As stated earlier there are bacteria that cause negative effects as well as those with beneficial effects. Looking at the bacteria these two food preservatives can effect can explain a lot of the effects seen from them.
Emulsifiers showed an increased population of Bacteroidetes E.coli Shigella, proteobacteria, and enterobacteriaceae. Bacteroidetes as explained above are beneficial bacteria. However, it can also have many negative effects. B. vulgaris along with E.coli have been found and linked to patients with Crohn's disease. (Wexler,2007) B. fragilis are also found in anaerobic infections and the most common cause of this in humans. From a disruption in tissue barriers this infection can occur in things such as trauma surgery like for example an animal bite. The thing that makes this group so dangerous is that due to beta lactamase it
produces the majority of the B. fragilis group are resistant to penicillins. Shigella can usually be spread through contaminated food or water and after it passes through the stomach it can
multiply. With emulsifiers helping to increase populations the negative effects of Shigella can cause diarrhea. Diarrhea is an infection of the gut also known as gastroenteritis. E. coli for the most part is harmless and in fact helps break down food and digests our food. Some strains of this bacteria are not harmless and can cause severe cramps, vomiting and other side effects. Some studies however show an increase of E.coli due to emulsifiers and these tend to be
pathovars of E. coli. (Viennois,2020) The term used for them is adherent-invasive E. coli
(AIEC). AIEC are mainly found in gut inflammation and Crohn's disease. Emulsifiers' effect on the AIEC causes a change in the expression of hundreds genes and turns on genes that impact the bacteria’s virulence factors. (Viennois,2020) These unregulated genes can increase the bacteria’s ability to infect and attack the host. In the right conditions there can be a raid induction of the gene expression.
Similar to emulsifiers, preservatives have shown to decrease the number of bacteria, affect antimicrobial resistance, and even inhibit key enzymes all which can have an impact on the gut microbiome. Negative bacteria such as Eubacteriaceae, and Firmicutes were shown to be increased in the gut. Eubacteriaceae were shown to cause inflammation and are a member of the Firmicutes phylum. This means that it can also affect energy reabsorption and could aid diabetes and obesity as well. Unlike the emulsifiers, preservatives were shown to affect
antimicrobial resistance. This was achieved from them weakening the membrane of the bacteria allowing transfer of the antimicrobial resistant genes to transfer.
The problems caused by these two food additives are relevant. These are problems that not only impact today but the future. As shown by an experiment preservatives were shown to accelerate the horizontal transfer of bacteria genes that are resistant to antibiotics. Over 700,000 people a year can die from infections of resistant bacteria. It is predicted by 2050 that about 10 million worldwide will die from infections like these and cost 100 trillion worldwide. (Lin,2017) To put this in perspective a resistant infection of S.aureus resistant to methicillin in the United States caused more deaths than AIDS and tuberculosis combined. (Lin,2017) Emulsifiers showed to have a correlation with an increase in Crohn’s disease in people as well as colitis.
Compared to 1999 to 2015 there was an increase of people being diagnosed with Crohn's disease or colitis in the United States. In 1999 there were 0.9% or 2 million adults and now in 2015 1.3% of US adults or 3 million adults are diagnosed with these. (CDC,2020) These conditions could lead to many other chronic health conditions and require management.
There is no clear solution to the problems preservatives and emulsifiers cause to the gut microbiome as well as diseases they could lead too. The main thing that is important is what people eat and what their diets are. Even popular diets still can lead to problems as shown by research above. Gluten free diets, ketogenic diets as well as the Western Diet all decreased the diversity of bacteria as well as decreasing beneficial bacteria. One way of managing the problem then is to cut down on foods with preservatives and emulsifiers. Organic foods should be eaten instead. Food that is beneficial to the gut should be eaten such as prebiotics, probiotics,
polyphenols, whole grains and fermented foods, vegetables and fruit. Prebiotics are specific foods like bananas, onions that when digested promote or help the activity of beneficial bacteria. This leads to an increase in beneficial bacteria and the effects help the gut. Studies have shown prebiotics to reduce the risk of bowel diseases and chronic diseases. (Conlon,2015) Probiotics are foods like yogurt and pickles that when eaten tend to benefit the host in terms of beneficial bacteria. They raise the genus of Lactobacillus and Bifidobacterium which can cause an improvement in immune health. (Conlon,2015) Polyphenols are foods like cloves, berries, beans, nuts, and soy. Polyphenols change the communal population of the gut microbiome while not increasing growth of pathogens and do this by acting on their growth and metabolism. There is no clear one bacterial population polyphenols increase because due to people different
food like buckwheat, quinoa and brown rice. Whole grains contain fibers that the human body can’t digest. These fibers are then fermented by the bacteria and cause an increase in beneficial bacteria such as Bifidobacterium, roseburia and eubacterium. (Cooper,2015) While these are ways to improve the gut microbiome research into the gut microbiome and how food additives affect it are a pretty recent topic of discussion. For the future more research needs to be done into these effects as well as research on more gut healthy food. Along with this better
information about diets and what should be eaten should be emphasized more. Most of the popular diets affect the bacteria in the gut microbiome in a negative way. If not dealt with the right way the problems these food additives can cause can have a negative impact in a multitude of ways not only today but in the future.
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