Karson Does Micro

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How Does it Work?

Hey y’all! Welcome to the final blog of the semester! Today we’re discussing bone marrow transplants and how they work. For starters, we’ll be comparing two main kinds of transplant: autologous and allogenic. An autologous transplant is a transplant that comes from the patient’s own stem cells. On the other hand, an allogenic transplant comes from a different donor’s stem cells. Each of these processes come with their own unique benefits and risks!

Taking a look at both autologous and allogenic transplants, the set up involves extracting blood from the patient (or donor) through apheresis. These stem cells are then extracted from the blood through a process that separates out the different parts. Then, the patient has to undergo chemotherapy to reduce their immune system to help with the transplantation of the stem cells. Once it is time to transplant them, the stem cells are given intravenously. They then travel and repopulate the bone marrow. Pretty fascinating, right?!

HLA Compatibility

Now, we’re going to take a look at how donors and patients are matched for allogenic transplants. To do this, doctors use something called HLA matching to give the transplant the best chance of working. They are looking for a 10/10 match which means having matches at 5 loci: HLA-A, HLA-B, HLA-C, HLA-DRB1, and HLA-DQB1. The greatest chances of finding a 10/10 match are between siblings, because the genetic programming for these loci come from parents. This means the best odds of them lining up come from the alleles of parents combining in the same way.

Another form of matching is a haploidentical match. This type of match has been studied recently with more success and involves having a 5/10 match at the previously discussed loci. These donors are typically from parents (mother or father) and, again, siblings. Modern technology has helped with complications that have typically arisen from not having 10/10 matches in the past. We’ll take a look at one of these complications and what can be done to mitigate it in the next section!

Graft vs Host Disease (GVHD)

Alright, now that we have established what a bone marrow transplant is and how the different types work, we are going to look at GVHD, a common complication from allogenic transplants. GVHD is caused by donor T-cells attacking the host’s tissues and occurs in these three steps: tissue damage causing a cytokine storm, donor T-cell priming, and the effector phase. Essentially, the chemotherapy pretreatment that weakens the immune system also causes tissue damage. This causes the host’s tissue to release a storm of cytokines that activates the host APCs. Then, the donor T-cells recognize the HLA presented on the host tissue and interpret them as foreign, causing an attack. Finally, this attack manifests through inflammatory cytokines and cytotoxic granules which harms the host’s liver, skin, and gastrointestinal tract. Yikes!

Now we can take a look at the more apparent aspects of GVHD. The common symptoms of severe GVHD include: jaundice, diarrhea, vomiting, and rash. The severity of the effects of GVHD are typically affected by the match level at the 5 specific loci mentioned earlier. The less the donor and patient match at these loci, the more severe the symptoms of GVHD typically are, starting at a 9/10 match. The good news, is that GVHD is treatable at many different stages. Often, steroid treatment can prevent severe symptoms from manifesting, but if more is needed, treatments such as infliximab, pentostatin, sirolimus, and other drugs are used as a second treatment after steroids.

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High Fat

Hey y’all! Today we’re going to be taking a look at diet, and how it can affect our microbiomes. Surprisingly, our diet can cause some pretty big changes, so we’re going to take a look at exactly what is going on. For starters, we’ll be diving into high fat diets. One major risk from these high fat diets is a bloom of Bilophila wadsworthia which can be harmful to the gut. The study linked previously found that a high fat diet and the resulting bloom caused dysbiosis within the microbiome. This is largely because the high fat diet alters the bile composition.

When organisms like B. wadsworthia and other LPS-rich bacteria bloom, they act on toll-like receptors (TLRs). The inflammation produced by these bacteria is typically mediated by TLR-4. According to the study, this inflammation can lead to increased rates of obesity. Furthermore, high fat diets have been shown to increase the recruitment of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). This impacts the body by creating higher hepatic triglyceride infiltration.

High Sugar

Now, we’re going to take a look at what a high sugar diet does to the body and microbiome. When looking at a high sugar diet, researchers found that it increases Proteobacteria in the gut. This phylum has many LPS-rich bacteria in it that increase inflammation. Furthermore, high sugar diets can increase gut permeability. This causes leaky gut which allows LPS bacteria to enter the bloodstream and increase the inflammatory response.

The next thing that can be affected by a high sugar diet is butyrate production. Studies show that butyrate production is reduced in rodents with high sugar diet which is also typically associated with those who have inflammatory bowel disease. The LPS bacteria increase TLR signaling which increases inflammation in the microbiome. The TLR stimulation also increases inflammasome production in the body. Essentially, a high sugar diet increases the inflammation response in the gut, causing some serious issues!

Dietary Fiber

Okay, we’ve checked some things that can cause problems for our microbiome, now it’s time to look at what can be helpful: dietary fiber. Fiber has been shown to increase short chain fatty acid (SCFA) production in the gut. This increase in SCFAs results in an increase in IL-10 production in the body. The SCFAs also increase both the number and function of mucosal Tregs. Essentially, dietary fiber = great things for your gut.

Next, increase in dietary fiber intake is also associated with IL-6 and TNF-a levels. Specifically, since dietary fiber increases SCFAs, the SCFAs reduce IL-6 levels. This decrease helps reduce inflammation within the microbiome. So now, after getting a full review of diets and their impacts, you can see just how important of a role our diet plays in our gut health. Whether its a negative or positive impact, making healthy choices is important in our diets to ensure we keep our microbiome happy!

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Classical Complement System

Hey y’all! Today we’re going to get into the complement system and how it works. What’s even more interesting, is eventually we’ll look at what can happen in the body if it’s not working properly, so buckle up! First off, we need to take a look at what exactly the classical complement pathway is and how it works. This will lay the groundwork and let us know exactly how errors can affect us. Furthermore, it will help explain why we see the effects that we do when something goes wrong.

The complement system is broken down into four main functions: opsonization, inflammation, chemoattractions for PMNs, and lysis. This Nature article outlines the complement system well and covers these topics. Opsonization is initiated by C3b which tags them for phagocytosis. The key molecules for inflammation are C3a and C5a. Chemoattractions for PMNs are modulated by C5a which helps recruit the PMNs to the site of infection. Lysis occurs through C5a and C9 which form the membrane attack complex (MAC). This pathway is most useful for fighting extracellular bacterial infections.

The Complication

Next we’re going to take a look at how problems with the complement system can cause health issues. Specifically, we’ll be investigating Lupus erythematosus. This Nature article dives into what Lupus is and how it occurs. Lupus is an autoimmune disease that involves a loss of tolerance to self antigens. Women are much more susceptible to Lupus than men are and some racial disparities are found as well.

This Nature article specifically discusses the autoantibodies that typically contribute to Lupus. Specifically, antinuclear antibodies are very characteristic in Lupus. These antibodies target nucleic acids in the body. There are also anti-Smith antibodies that target the spliceosome. Additionally, looking at this PubMed article, a typical biomarker of Lupus is issues with the kidneys. Furthermore, these complications can be life-threatening and often fatal if not managed well.

The Pathway

Now we can see how the complement system specifically is involved with Lupus. This article on Frontiers, goes into how Lupus is characterized by low levels of C3 and C4 in the complement system. This deficiency has been linked to development of Lupus and is a common precursor. Furthermore, this PubMed article discusses how C3b exacerbates the condition through opsonization. The complement system activates flares in Lupus and can tend to target the kidneys as we discussed earlier.

Finally, despite all these issues, researchers are on a road to finding a treatment for Lupus. While no explicit complement system treatments designated for Lupus exist, there are promising studies. For example, this PubMed article goes into a treatment that blocks central complement activation. While there are no true treatment plans for Lupus developed yet, it shows promise as a potential treatment. The trials are currently in phase II and more research needs to be done… bummer. But, the research for complement treatments for Lupus are promising! There are many other avenues being explored and soon we might find something that is incredibly effective!

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Nobel News

Hey y’all! Today we’re going to be talking about vaccines again! I know, I know, we’ve already gone over them a lot. But buckle up, because this will be a fun ride where we look into specifically mRNA vaccines, which are part of a situation near and dear to our hearts (not really): the COVID-19 pandemic. But first, we have to go back in time a little bit to a 2005 article on PubMed, published by Karikó and Weissman (eventually winning them the 2023 Nobel Prize in Physiology or Medicine). They discovered the ability to use nucleoside modifications that prevent the innate immune system from recognizing the virus causing a less inflammatory cytokine production. This helped prevent an overactive immune response to the mRNA which eventually led to the ability to create a viable mRNA vaccine.

Before the COVID-19 pandemic, the promise of mRNA vaccines was being explored. Largely in part to the contributions of Karikó and Weissman in relation to mRNA stability. This PubMed article published in 2018 discusses the promise behind mRNA vaccines and how they were a viable technology for boosting immunity against viral pathogens. The discoveries of that article in 2005 led to a plethora of additional discoveries, creating a flexible system for developing quick and adaptable vaccines for multiple viruses. Pretty crazy, right?!

MERS and mRNA

Now this is great and all, but how exactly did we get to the COVID-19 vaccines that were used to help mitigate the virus. Well, one of the main guides in helping develop the vaccine was previous studies of MERS. This is partially explained by this PubMed article, which discusses the protein spike that exists on MERS which is similar to COVID-19 spike since both are CoV viruses. Furthermore, studies on vaccines for MERS showed promise for mRNA vaccines working effectively in a single dose format against these spike protein pathogens. It’s pretty cool how one vaccine can provide so much info for another!

Now, since the vaccine had shown progress for MERS, it meant it was time to adjust it for COVID-19. This article, demonstrates the importance of having a similar virus to do test trials on. This model helped speed up the process of creating a safe and effective vaccine for COVID-19. By having some work done ahead of time through MERS, researchers were able to specifically adapt to the COVID-19 virus which helped save millions of lives. Isn’t that crazy to think about??

COVID-19 and Cardiac Deaths?

What’s the meaning of all of this though? Well, it means we were able to save millions of lives by rolling out a vaccine early. This article estimates that the vaccine was able to prevent 2.5 million deaths (with an upper estimate of 4 million). That’s so incredible! This goes to show just how important being prepared for pandemics and having prep work done for organisms that can teach about new vaccines is.

However, while this seems all fine and dandy, some people are worried about adverse effects of the vaccines. For example, in rare cases, people developed myocarditis after receiving the COVID-19 mRNA vaccine. This article published on JAMA reports the incident rate of this occurring was about 50 per million to 100 per million depending on age and sex. While this is unfortunate, the amount of deaths averted seems to be worth it. But what do the experts think? Well, they pretty much overwhelmingly agree with what I just said. Take a look at this CDC article that discusses in terms of cost and benefit, the COVID-19 mRNA vaccine is safe and worth it. Vaccination is incredibly important for helping reduce the effects of viruses and also developing herd immunity for our communities. So do your part!

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Hey y’all! Today we’re going to dive into something that is a little extra important to me. We’re going to be talking about antibiotic use and how it specifically relates to asthma (which is important to me considering I have asthma). Anyway, there has been a little bit of research that has looked into the relationship to early exposure to antibiotics. Specifically, this article published on PubMed demonstrated a statistically significant link to early antibiotic exposure and the development of asthma in children. It was a meta-analysis of multiple studies that showed the link was very strong and needs further consideration in future medical contexts.

Beyond the link of early exposure causing asthma, studies have also explored specifically what antibiotics are linked to asthma. Take this article published in Nature for example. It’s research demonstrated that specifically azithromycin was an antibiotic that led to the development of asthma. That’s wild! What’s even crazier is this study also explained how important the microbiome is and how antibiotics mess with it. Early exposure was a key factor so make sure to be careful with your kiddos!

Gastrointestinal Disorders

What’s even crazier is that the effects of early antibiotics don’t stop there. Many studies have investigated the link between early antibiotic use and gastrointestinal problems later in life. This makes sense, because antibiotics can take a serious toll on our microbiome. Which, as we know, the microbiome is seriously necessary to stay feeling 100%. For example, this study published on PubMed demonstrated links between early antibiotic use and Celiac disease. So just one more thing to look out for!

If that’s not enough to convince you of the problems, there have been even more gastrointestinal problems linked to early antibiotic use. This PubMed article looks at the link between early exposure and inflammatory bowel disease (IBD). Specifically, exposure before the age of 5 caused a significant increase in risk. Essentially, we need to be a bit more careful before handing out antibiotics, especially to young children! The microbiome needs to be defended a bit more, and we can dive into how it hasn’t necessarily been a priority so far.

The Prescription Problem

As promised, here’s what’s been going on with antibiotic prescriptions. TLDR: antibiotics are getting prescribed when they’re not needed, unnecessarily harming our guts and building antimicrobial resistance. This NIH article goes into how acute bronchitis is viral for by over 90% of infections. However, research shows that around 58% of outpatient treatments for bronchitis in young children are antibiotics. Improper assessment and diagnostics are ruining our microbiomes and putting our young ones at risk. Yikes!

While you may not get right away why the link between these two things is a problem let me break it down. More than likely, the use of antibiotics when not needed (i.e. when you have a viral infection and antibiotics will do nothing for the infection) we’re hurting our microbiome and letting resistant strains thrive/development. This increases risk of hosting resistant bacteria in our body and creating problems down the line. We need to be EXTREMELY careful when prescribing antibiotics because proper use is incredibly necessary and sparing use will help in the war against resistant strains of illnesses. By not overprescribing antibiotics we can push back against these crazy issues.

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NDM-1

Hey y’all! Hope you enjoyed my cheeky Star Wars ride reference in the title, because today we’re talking about antibiotic resistance (I know… not nearly as cool). Specifically, NDM-1 which stands for New Delhi metallo-beta-lactamase 1. NDM-1 is a transferable genetic code in bacteria that creates resistance to antimicrobial agents. It originated in… you guessed it…. New Delhi, India. Before we get into all the craziness that surrounds antibiotic resistant genes and bacteria, it’s good to know the details of NDM-1 and its current effect.

For starters, according this NIH article, NDM-1 is encoded by the bla_NDM-1 gene. It is spread by horizontal gene transfer between bacteria. This process works by the bacteria fusing together into some sort of weird hug (handshake? melding of minds?) and the gene can be transmitted from one genome into the next. What exactly is so scary about this though? Well, according to a recent CDC report, there has been an increase to the tune of 460% for NDM related infections from 2019-2023. Basically, antibiotic resistant bacteria are no joke.

The Pharm Problem

So you may be asking, why can’t we do anything about this? Unfortunately the answer to this is the typical answer for most problems we see in the world: money. Put simply the cost of developing new antibiotics for pharmaceutical companies is just too dang high. According to this Pew infographic, the cost for companies can be as high as $1.3 billion and can take 10-15 years to develop. The ROI is just not there for companies to put a lot of effort into creating new antibiotics that bacteria aren’t resistant to.

In addition to the high cost of development, the profit just isn’t there to motivate pharmaceutical companies. For example, they can spend less and make more developing other drugs like cancer drugs. This NIH article, took a look at different cancer drugs that were developed and what the cost and revenue was. The drugs on average were ~$750 million to develop and had average revenues in the tens of billions. This demonstrates that many other types of drug development are more lucrative, creating even less motivation for these companies to pursue antibiotics.

Antibiotic Misuse

The last thing we’re going to cover today is how the current state of antibiotic usage is creating a problem. One major issue outlined in this OECD article, is the pressure from patients to receive antibiotics. Many times they are expecting a quick solution which could lead to being prescribed antibiotics when not needed. Additionally, when antibiotics aren’t used according to their prescribed dosage and duration, bacteria can grow resistant since the drugs can’t run their course and eliminate all bacteria. So make sure to listen to the prescribed duration of your antibiotics!

As if this isn’t bad enough, factory farming adds gas to the flame. This ACS article shows just how widespread the impact of antibiotics affects us. The quick rundown is, animals are pumped with antibiotics in their feed to help prevent death before it’s their time. Then, through manure spread, direct interaction with the animals, or even consumption of their products, these bacteria have a chance to make it in our systems. Once this occurs they could potentially transfer their genes to bacteria in our bodies and make us resistant to antibiotics. Yikes! While it does seem like the odds are stacked against us, through change in government policy and adhering to guidelines, we can resist this resistance!!

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The Wakefield Paper

Hey y’all! Last week we took a quick look at vaccines and how they’re tested. Well today we’re going to take this a bit further and look at a specific study questioning the validity of vaccines, specifically, the MMR vaccine. Back in the 80s, Andrew Wakefield published a study that linked this vaccine to autism. However, some things were a little off… The paper has since been retracted, but we’re going to see exactly why.

For starters, the sample size of Wakefield’s study was just 12 children. Additionally, there weren’t any controls in the group at all. Isn’t that wild?!?! Instead they observed children in the hospital and drew their conclusions from that. Even crazier than not using a control, many tried and failed to replicate his results. For example, this NIH article shows a failure to replicate the results when using a control.

Madsen’s Update

Now, if we fast forward a little bit to 2002, Madsen took a look at this study and tried to replicate it. However, unsurprisingly, the attempt was unsuccessful and no link was found between the MMR vaccine and development of autism. With a much larger sample size, and better designed study, Madsen was able to easily prove that there was no direct link between the MMR vaccine and development of autism.

So what exactly was different or “better” about Madsen’s study compared to Wakefield’s? Well, for starters, Madsen used a population size of over 500,000 children. This helped removed the possibility of bias and gave many data points to further inform the research. He also had a control group, and found that when compared, there was no significant difference between them, proving that MMR vaccines do no cause autism. The reason for this follow up was because the Denmark government had a program where children were getting vaccinated young and they wanted to prove that it wasn’t harmful. They were successful, and fears were eased.

Relative Risk Ratio

To tie this all together, we can take a look at relative risk ratio to understand how Madsen concluded that the MMR vaccine was safe. To define this term, the CDC shows an equation that compares the risk of exposed and unexposed populations. Essentially, if the rate of contraction (in this case autism) is the same for the two populations, then there is no reason to believe there is any causation happening. This is because the treatment isn’t showing to increase the chances of what they are checking.

Now, we can take the relative risk ratio and apply it to Madsen’s research. Looking at the results, the relative risk ratio for autistic disorder was 0.92 while for another autism spectrum disorder it was 0.83. These results show that the incidence of autism was fairly similar for vaccinated and unvaccinated children. AKA, the MMR vaccine does NOT cause autism, so nothing to worry about! This analysis helps prove there is no relation and further debunked Wakefield’s study before it was entirely retracted in 2010. Go science!!

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Phase I

Hey y’all! This week we’re getting into just exactly how vaccine trials work and the testing process required to get them approved. And in pretty straightforward nomenclature, each round is called a “phase”. According to the NIH, Phase I trials are for figuring out the safety of the vaccines. Additionally, side effects are observed and monitored to see if the vaccine can continue on to further stages of testing. It also provides the resources for researchers to discover the safe dosage range of the vaccine.

With each successive phase of vaccine trials, the amount of people increases. This means that phase I has the smallest amount of participants with about 20-80. This phase is essential because it is the first time that the vaccine is being tested on humans. This means that vaccine companies need to make sure there aren’t any unforeseen effects from the vaccine on humans. Making sure the vaccine is safe for humans is essential to advance to phase II.

Phase II

Okay, so the vaccine seems pretty safe now, right? Well… kinda. Phase II is necessary to make sure there weren’t any effects that were missed. This NIH article, discusses how the purpose of phase II is to expand the safety checks to double check nothing was missed and look for extreme cases that the small sample size of phase I couldn’t detect. Another major reason is to check the immune response and help dial in the dosage. Additionally, they are checking on timing and other various factors that influence efficacy.

By expanding to 100-300 participants, phase II trials have a more representative population than phase I. The researchers also sometimes introduce blinding and randomization at this point to help reduce bias. The data collection for this increased pool is typically a little more intense. Researchers collect immune response data such as antibody titers, T cell responses, and the duration of the immune response. All of these factors help set up for phase III by giving more information on dosage amounts and timing that will cause the greatest amount of benefit with the least amount of side effects.

Phase III

Finally, the long await phase III. Is it finally time to let the vaccine out to the public, and start saving lives? Not quite. Phase III is the final testing phase before public rollout. The participant pool for this phase is in the thousands, with some trials reaching the tens of thousands (we’ll discuss a case like this in a sec). They are randomly selected for which group they will be in to reduce bias from themselves and the researchers. This helps prevent systematic differences being created in the results and solidifies the authenticity of the results.

Now, let’s take a deep dive into a phase III study of the Moderna mRNA Covid vaccine. This study, published in the New England Journal of Medicine, outlines how these protocol were followed to test the efficacy of the Moderna vaccine. The study was double blind to prevent bias and ended up finding a 93.2% efficacy rate for the vaccine. And this efficacy was found for over 30,000 participants! Furthermore, it was 98% effective for severe disease. It’s crazy how this info relates to our personal lives! Hope you learned a little bit more about vaccines (I sure did) and can’t wait to get into some more micro things next week!

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Hey y’all! Looking at the title I’m sure lots of you are just as confused as I was when I first stumbled upon this acronym but trust, you know exactly what I’m talking about. If you haven’t figured it out yet, UPFs are ultra-processed foods (ohhhhh…. duh). But what exactly is an ultra processed food you ask? Well, according to this Cleveland Clinic podcast, UPFs are foods that are highly processed to increase shelf life, and typically don’t have a ton of actual nutrients. Some common examples include packaged foods and sodas. Basically, any food that doesn’t come from a fairly direct source and has undergone significant industrial processing.

This processing typically comes down to adding a few different types of additives with some of the most common being emulsifiers, artificial sweeteners, preservatives, and colorants/flavor enhancers. Each of these serve a different purpose, so let’s do a quick fly by to get the gist of what’s going on. Emulsifiers are used to help maintain texture in foods like mayo by stabilizing mixing oil and water. Be on the lookout for lecithin in your food, it’s a common emulsifier! Artificial sweeteners like aspartame, sucralose, and stevia are used to… you guessed it: sweeten foods. These have been linked to having some long term health effects so be careful! Preservatives (another fairly straightforward one) are used to help extend the shelf life of aka preserve the foods they are added to. Some common examples include sodium benzoate, BHA, and sulfites. Finally, colorants and flavor enhancers are used in foods to help make them look tastier and taste even tastier. Basically, companies pull out all the stops to trick you brain into wanting more, more, more! Watch out for MSG and disodium inosinate.

Your Gut

If you remember my first blog post talking about microbiology, you know all about the microbiome. Well guess what! UPFs are actively being studied to see what their effect is on the microbiome. This study published in Nutrients, details the negative impacts of UPFs on our gut microbiome. Specifically, the different additives we’ve already discussed were shown to directly disrupt the integrity of the gut microbiome. They decrease the diversity of microbiota within our gut and therefore make us unhealthier.

Diving a bit deeper into the research you can find that UPFs can directly affect some of the biological processes within our gut microbiome. For example, UPFs have been shown in studies to impact short chain fatty acid synthesis in the body. This MDPI article, details the effects of additives on short chain fatty acid synthesis. Additives have been shown to decrease short chain fatty acid synthesis which can in turn, cause internal inflammation. Yikes! So be on the lookout for additives and try to reduce your consumption.

IBS, MS, and Cancer, Oh My!

Even crazier than the general health issues that processed foods can cause, they have been linked to even more serious diseases. One of the more serious and intriguing ones to me was the link between UPFs and colorectal cancer. This PubMed article, details the specifics on how exactly the link exists, but I can give you a quick breakdown. Essentially, some of the compounds that come from nitrites and nitrates in the processing of meats has been proven to be carcinogenic. The heating processes release the carcinogenic factors that heavily increase the risk for cancer, specifically colorectal cancer.

All of these possible diseases and negative health effects of UPFs are very scary. Trust me, I also was shocked to discover all of this too. However, I do have good news for you, moderation is key. You don’t have to completely give up your favorite snacks (you should probably chill out a bit though). The main issue is that consumption of these foods is a lot of empty calories. They don’t have a ton of nutritional benefit and increase your daily calorie load significantly. Focus on whole foods, only allowing UPFs every now and then if necessary. But most importantly, stay safe! Know what is entering into your body and be aware of the effects and research surrounding it! The microbiome is incredibly important and we need to keep it safe!!!

Hey y’all! This week we’re going to dive in (pun intended) to some interesting information surrounding methylmercury consumption, seeing what it is, how it can affect us, and some common sources. First off, methylmercury is the main form of mercury we consume through seafood. Additionally, watch out! It’s toxic! Specifically, methylmercury is a neurotoxin that can cause serious complications especially for vulnerable populations like infants and children. According to the EPA, fish and shellfish are the main reasons for methylmercury to be circulating in our body.

But how in the world is mercury getting into seafood?! That’s exactly what I was wondering, and through a little digging I learned that mercury enters water sources through pollution and runoff. Consequently, this mercury is absorbed by organisms like plankton which are then eaten by fish which are eaten by bigger fish, like our main culprit: tuna. Since there are no good ways for them to excrete methylmercury, and they tend to eat a lot, they get a lot of buildup in them. What’s even crazier is that different types of tuna have different buildup. Research done in Raleigh showed that albacore tuna had the highest concentration while light tuna and yellowfin tuna had lower concentrations. The main reason for this difference is because albacore are much larger and live longer so they eat more fish and have more tissue to accumulate mercury… crazy!

Signs and Symptoms

Like I said earlier, mercury = not good for you. But what exactly does that mean practically? How do you know if you might have increased levels of methylmercury in your body. Well, according to the EPA, there are a few telltale signs that let you know you made need to go see your doctor. The neurotoxic effects of methylmercury include lack of coordination, impaired speech, pins and needles feelings, and more, yikes! Most people do NOT have high enough levels to be concerned, but if you fear that you may have eaten a little too much tuna regularly, or maybe are exposed in other ways, definitely get checked out if you experience these.

While it’s great to know what to look out for, it is hard to know at what point you should be concerned about methylmercury consumption. Exactly how much tuna is too much tuna? While this varies for different populations, I can give you a quick rundown. According to the FDA, a serving of tuna is 4 oz. before cooking. While the FDA does recommend that adults, pregnant women, and children eat 2-3 servings of fish per week, it also highly recommends that pregnant women and children eat within the “Best Choices” category of fish which does not include any variety of tuna. For college students, tuna is alright, but the FDA recommends sticking to light tuna to avoid overconsumption of methylmercury. Additionally, it is recommended that if a serving of albacore tuna is consumed, no other fish should be eaten that week to keep methylmercury levels in check.

Thimerosal

While we’re on the topic of mercury, it is important to take a look at thimerosal. Thimerosal is an organomercury that gets used in vaccines to help with preservation. You might be thinking, wait a minute… mercury… in vaccines?! So vaccines are toxic? In short, no. But let me show you why. In the body, thimerosal is broken down into ethylmercury not methylmercury. Studies have demonstrated that this ethylmercury can be excreted from the body in a week or less, while methylmercury sticks with us for way longer. This University of Rochester study, tested mercury levels in infants after receiving vaccines and showed that there was no increase above safe levels and the mercury did not linger.

If that’s not convincing enough for you, take a look at some other studies, there are plenty out there! For example, this Danish study showed that even after removing thimerosal from vaccines there was still an increase in autism incidences over the decades. The data analysis demonstrated that there is no correlation between autism and thimerosal concentrations in vaccines. Most likely, there is an incorrect relationship being drawn by culture because as our diagnosis tools improve, the ability to correctly diagnose autism increases. But it has nothing to do with vaccines and thimerosal as far as we can tell!

A Personal Note 🙂

Personally, I pretty much only eat tuna when I go out for sushi, which is probably only about 2 times per month. And sometimes, I don’t even eat sushi with tuna, opting for a roll that has shrimp or whitefish. So I think that I should consider my mercury levels to be pretty safe. If anything, this dive into learning more about mercury has shown me that fish, while good, has some concerns to consider. Methylmercury is by far more dangerous than ethylmercury, due to it staying in the body longer and accumulating. So go eat fish for all the benefits, but mind your mercury!!