Could the Bacteria in your stomach cause Parkinson’s disease?

What is Parkinson’s disease and how does it affect you?

Parkinson’s disease is the second most common neurodegenerative condition (which means the destruction of nerve and brain cells) in the world. It causes your body to shake (the medical community call this tremors) and bradykinesia (which means slow movement). Doctors looking at movement call this ‘motor function’. Parkinson’s affects the brain by decreasing the amount of Dopamine available. Dopamine is one of the chemicals that your brain needs for its cells to communicate with each other. Cells that produce dopamine die in those with Parkinson’s disease. Another problem that Parkinson’s disease can cause, it the creation of ‘Lewy bodies’. These are abnormal protein deposits that can block cells in the brain from communicating with each other

A neuron located in the brain. Parkinson’s Disease can cause Lewy Bodies to deposit in these cells – these are shown in red


The cause of Parkinson’s is thought to be genetic based, however in reality, most cases are caused by something in our environment. The environmental cause of Parkinson’s has been hard to locate, however research has shown that it more than likely begins in the stomach.
Often an early symptom of Parkinson’s begins with stomach issues like over salivating, constipation, feeling sick and incontinence which then develops into motor issues causing problems with walking and tremors.
This study looked into a specific type of pathogenic bacteria called Helicobacter Pylori. This bacteria has chronically infected half of the world population and can lead to stomach ulcers and cancer.

How could H. Pylori cause Parkinson’s disease?

This authors in this study came up with 4 possible ideas for how H. Pylori could cause Parkinson’s:

  1. Toxins produced by the bacteria
  2. Disturbing the delicate balance of bacteria in your gut
  3. Inflammation in the gut that crosses into the brain (via the gut-brain axis – as your brain can influence your gut and your gut can influence your brain)
  4. Manipulation of how drugs move around your body. H. Pylori could affect how Levodopa (a chemical that can be turned into Dopamine) is absorbed by the body

What did they discover?

The key findings were:

  1. People who have Parkinson’s disease are 1.5 to 3 times more likely to be infected with H. Pylori than those who don’t have the disease
  2. Parkinson’s patients who are infected with H. Pylori are show worse motor functions than those who aren’t infected
  3. Removing H. Pylori from infected Parkinson’s patients improved their motor function over those who didn’t get their H. Pylori removed
  4. Removing H. Pylori improved Levodopa absorption in Parkinson’s patients compared to those who didn’t have it removed

This article has shown that there is clearly a link between your stomach and Parkinson’s disease, particularly if you are infected with the stomach dwelling H. Pylori bacteria. The mechanisms that these bacteria take to cause or contribute to Parkinson’s disease is still unclear and more research needs to be done focusing on the H. Pylori toxins, inflammation, Levodopa absorption and the carefully regulated bacterial balance in your gut.



Journal: Journal of Parkinson’s Disease, Volume 8, Issue 3, 14 May 2018

Author: David J. McGeea, Xiao-Hong Lub and Elizabeth A. Disbrowb

Copyright: Open Access


Air pollution’s effect on our blood vessels

Is air pollution that bad? Are cardiovascular diseases a big problem?

It’s long been known that air pollution contributes to global warming and can affect our lungs. This article shows us that air pollution may go one step further and actually affect our cardiovascular system too!


The first graph (A) shows the risk factors for diseases leading to death around the world between 1990 and 2015. You can see that high blood pressure is still the biggest risk factor for death around the globe. The second graph (B) shows the number of deaths due to PM2.5. PM2.5 is basically a complicated way of saying very very small particles (smaller than dust or pollen) – take a look at the picture below. Some definitions for graph A: Tracheal and Bronchial refer to the breathing tubes of the lungs (dark blue), Ischaemic means a restriction of blood flow causing less oxygen to be able to get where it’s supposed to go (light blue), Cerebrovascular refers to the blood vessels of the brain (red), Chronic Obstructive Pulmonary Disease, also known as COPD refers to a group of lung conditions that cause trouble breathing (purple) and lower respiratory tract infections are lung infections like Pneumonia (green).

So what we can see here is that clearly deaths due to an increase in PM2.5 pollution are increasing. PM2.5 particles are particularly bad as they can penetrate deep into your lungs when you breathe them in as they’re so small.



What has air pollution got to do with our blood vessels?

This study looked into endothelial cells (or the endothelium part of a blood vessel). These are a thin layer of cells on the inside of our blood vessels that have direct contact with our blood. Whilst pollution has been shown to affect our cardiovascular system in many different ways, one of the critical steps that leads to the risk factors described above are changes to the endothelium. These cells are involved in the constriction or relaxation of our blood vessels (scientists call this vascular tone). They are also important in injury repair.


How do our endothelial cells go wrong?

So now we know that air pollution containing very small particles of pollutants (carbon monoxide, nitrogen dioxide and many others) are increasing the number of PM2.5 related deaths – how does it actually affect our cardiovascular system?

One of the main causes of damage to our blood vessels is through a process called oxidative stress. This process happens when reactive oxygen species are present in our lungs and blood stream. These are highly reactive chemicals (they are also found in bleach and in our own immune system to kill pathogens). These reactive chemicals can damage our blood vessels and mutate our DNA.

This article explains that we have evidence of air pollution causing the production of reactive oxygen species in in vitro cell culture (testing cells in the lab), animal and human studies. Animal studies have also shown that if you remove the mechanism that causes reactive oxygen species (in this case pollution), endothelial and blood vessel health starts to get better. Other studies showed that certain air pollutants can get into the central nervous system (the brain and spinal cord) and affect your blood pressure and metabolism. Our body’s immune system can also become affected as it attempts to clear the pollutants and reactive oxygen species from our body, meaning less availability to fight off infections.

What does this all mean?

Whilst it is widely known that pollution affects our lungs and contributes to global warming, this article has shown that pollution could also affect our blood vessels, metabolism, blood pressure and immune system. This article argues that with the increasing population and life expectancy causing an increase in energy and transportation requirements, more research should be done to protect millions of at risk people from cardiovascular diseases caused by pollution. Pollution’s direct influence on global warming will also have an impact on health as temperatures rise and carbon dioxide levels increase.



Journal: European Heart Journal, Volume 39, Issue 38

Authors: Thomas Münzel, Tommaso Gori, Sadeer Al-Kindi, John Deanfield, Jos Lelieveld, Andreas Daiber and Sanjay Rajagopalan

Copyright: Open Access


Female Male symbols

Sex Hormones and their effect on your immune system

What is a hormone?

A hormone is a chemical produced by the body that can control and regulate the activity of certain cells or organs. An example of a non-sex specific hormone is vasopressin. This hormone is released by the pituitary gland (which is found on the underside of your brain) when we are dehydrated in order to preserve water. This hormone travels in the blood from your head to your kidneys where it acts on kidney cells to instruct them to hold onto more water.

What are sex hormones?

Sex hormones are chemicals that tend to affect sexual development and reproduction. Most people think that men produce testosterone and women produce oestrogen and progesterone. However, both sexes actually produce all 3, but in varying amounts.

Oestrogen (or Estrogen) is typically associated with women and Testosterone with men, although both sexes have both hormones.


Do sex hormones affect our immune systems?

Studies that go back as early as the 1940’s have shown that women tend to have better immune systems as they are better at producing antibodies. This can actually work against them as there may be a greater chance that their immune system could become overactive and start to attack healthy cells instead of the pathogens in our blood (this is called autoimmunity). If you want to know more about what an antibody is, what a pathogen is and some more information on autoimmunity, take a look at this article.

The difference between men and women’s immune responses can be directly related to the sex hormones that each gender has. This article suggests that sex hormones have an impact on the amount and type of bacteria found in the body.

How do these sex hormones affect our immune systems?

Testosterone (which is generally higher in men) has been shown to lower your immune system (also known as immunosuppression). Oestrogen on the other hand, has been shown to boost your immune system (also known as immunoenhancing).

A model of these immune system differences were put to test in mice. Scientists tested the amount of inflammation in male mice by injecting them with oestrogen and decreasing their testosterone through castration (removal of the testicles). They discovered that these mice were at greater risk of developing autoimmunity, much like what is seen in autoimmune women.

As mentioned earlier, women have a more active immune system and are more at risk of autoimmune disorders like rheumatoid arthritis or lupus. Whilst men, (who have a less active immune system) are more at risk of developing cancer as they cannot get rid of faulty cells as quickly as women can.

Why do men and women have different immune systems?

One of the reasons men and women may have different immune systems could be due to the evolution and preservation of humankind. In order for women to reproduce, it makes sense for their immune systems to be stronger so that they are healthy enough to have children.

What does this research mean for the future?

Currently there are no disease treatments that are based on the sex of a patient (unless specific to their reproductive organs). This research has highlighted that more research should be undertaken on the role of sex-specific immune responses, as one day we may be able to treat men and women differently to match their immune systems.



Journal: Frontiers in Immunology, Volume 9, August 2018

Author: Veena Taneja

Copyright: Open Access