H. pylori and Parkinson's disease: what's the link?
A stomach infection you may not know you have could be affecting how reliably your levodopa works. Nutritional therapist Melody Mackeown explains why.
Gut health is increasingly recognised as an important consideration in Parkinson’s disease, particularly because digestive function can influence how consistently Parkinson’s medication is absorbed.
One stomach infection that may be particularly relevant is Helicobacter pylori, usually shortened to H. pylori. So what is the link between H. pylori and Parkinson’s disease, and why does it matter if you take levodopa?
In this article, we'll explore:
What is H. pylori?
H. pylori is a bacterium that lives in the stomach lining. Many people carry it without knowing, because it does not always cause obvious symptoms. In some people, however, it causes chronic inflammation of the stomach lining (gastritis) and is associated with indigestion, stomach discomfort, nausea, bloating, and other upper digestive symptoms.
For people living with Parkinson’s disease, H. pylori matters because research suggests that infection may influence the absorption and effectiveness of levodopa.
Symptoms of an H. pylori infection
Some people experience no noticeable symptoms, while others may develop:
indigestion or upper abdominal discomfort
bloating
nausea
frequent burping
reduced appetite
gastritis or peptic ulcers
In addition, a long-standing infection can alter the stomach environment and, in some people, may contribute to difficulties absorbing nutrients, including vitamin B12 and iron, and lead to other medical conditions.
What is the link between H. pylori and Parkinson's disease?
One of the challenges of Parkinson’s disease is that the response to levodopa can become less predictable over time.
Levodopa is taken orally but is primarily absorbed in the small intestine rather than the stomach. This means the tablet first has to pass through the stomach before it reaches the part of the digestive system where absorption takes place.
Parkinson’s disease itself can affect gastrointestinal motility, including gastric emptying. When stomach emptying is delayed, levodopa may take longer to reach the small intestine, potentially contributing to delayed or unpredictable medication responses.
Inflammation and changes within the stomach associated with H. pylori infection have been proposed as mechanisms that could interfere with levodopa availability and contribute to motor fluctuations in some people with Parkinson’s disease. The research is still small in scale, but it points to levodopa absorption as one area where a treatable stomach infection could make a difference.
Could H. pylori affect nutrient absorption?
Long-standing infection can change the stomach lining and gastric environment, potentially affecting the absorption of certain nutrients, so checking nutrient status is worth considering. Two nutrients are particularly relevant:
Vitamin B12: stomach function plays an important role in releasing Vitamin B12 from food and preparing it for absorption further down the digestive tract. Chronic gastritis associated with H. pylori may therefore contribute to lower Vitamin B12 status in some people.
Iron: H. pylori infection has also been associated with iron deficiency, particularly when there is no obvious alternative explanation.
Both nutrients are important for neurological health, energy production, and general wellbeing, which makes them especially relevant when assessing the nutritional status of someone living with Parkinson’s disease.
How can you get tested for H. pylori?
If you have ongoing upper digestive symptoms, or your response to levodopa has become less predictable, it is worth asking about testing. The usual tests are a stool antigen test or a urea breath test. Testing is not always offered routinely, so the first step is to raise it with your GP or Parkinson’s specialist and explain why you are asking. If they do not put you forward for it, private testing is available through a qualified nutritional therapist.
If H. pylori infection is confirmed, you should discuss treatment options with your GP and healthcare practitioner.
Natural ways to support your body alongside H. pylori treatment
Standard treatment for confirmed H. pylori infection is a course of antibiotics alongside acid-suppressing medication, prescribed and monitored by a GP. This remains the primary evidence-based route to eradication.
That said, a small but growing number of human trials have looked at natural compounds as an adjunct to, or in support of, conventional treatment and can be considered alongside medical treatment under the guidance of a qualified practitioner or to support recovery.
Mastic gum: a resin from the mastic tree, grown mainly on the Greek island of Chios, which has been studied in small trials for its activity against H. pylori.
Broccoli sprouts (sulforaphane): a plant compound that has been examined in human studies for its effect on H. pylori and stomach inflammation.
Zinc-carnosine: a combination of zinc and the amino acid carnosine, used in some trials alongside antibiotic treatment to support the stomach lining.
Probiotics: certain strains have been studied for their role in supporting tolerance of the antibiotic course and rebalancing the gut afterwards.
Supporting recovery after eradication
For those who test positive and complete treatment, what happens nutritionally afterwards matters just as much as the treatment itself:
Rebuilding stomach acid naturally: bitter foods before meals, eating slowly, and managing stress (which suppresses digestive secretions) are all worth considering while stomach acid production recovers.
Replenishing the gut microbiome: eradication therapy is effective but non-selective, so a period of gut-supportive, fibre-rich eating and, where appropriate, targeted probiotic support may play a supporting role in rebalancing the microbiome.
Rechecking nutrient status: B12 and iron levels are worth reviewing again a few months after treatment, since absorption can take time to normalise even once the infection has cleared.
Rebuilding food confidence gradually: many people have unknowingly restricted their diet while trying to manage symptoms before diagnosis, so gently reintroducing variety is often an important part of recovery.
Supporting the stomach lining: nutrients such as zinc, Vitamin A, and L-glutamine are often considered alongside dietary changes to support the stomach lining.
Key takeaways
H. pylori is a common stomach infection that many people carry without symptoms. For someone living with Parkinson’s disease it deserves particular attention, because the research points to a link between H. pylori and Parkinson’s disease medication: the infection may affect how reliably levodopa is absorbed, and it can contribute to lower vitamin B12 and iron status.
Testing is worth asking about if you have ongoing digestive symptoms or a less predictable response to your medication, and if it is not offered, private testing is an option. Treatment sits with your GP, and there is plenty you can do naturally to support your body during treatment and in the months afterwards.
This article is part of Melody's series on nutrition and Parkinson's disease. You may also like to read Rethinking Parkinson's disease: nutrition, lifestyle and the gut-brain connection, What is the link between blood sugar and Parkinson's disease?, and The Mediterranean diet for Parkinson's: what to eat and why.
Work with Melody
Melody Mackeown is a Nutritional Therapist specialising in Parkinson’s disease and digestive health. She holds a BSc in Psychology, an MSc in Personalised Nutrition, and a Dip ION from the Institute for Optimum Nutrition, London. She is registered with BANT and CNHC, and supports individuals living with symptoms of Parkinsonism, an existing diagnosis, or those concerned about their risk.
Melody works through the lens of personalised nutrition, drawing on functional testing where appropriate to build a tailored plan around each individual’s unique biochemistry, symptoms and goals.
"If you'd like to find out more about working with me, visit my profile."
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