Dementia and gut health
Dementia and gut health

Dementia and gut health – one a global health concern and the other continues to garner support and evidence for its impact on good health. In Australia, dementia is the second leading cause of death1 and the leading cause of death for women2. In the absence of a medical breakthrough, the number of Australians diagnosed with dementia, is only expected to rise. While dementia research is fairly well funded in Australia, the most common form of dementia – Alzheimer’s disease (first reported in 1906) and it’s prevention, treatment and management is not well understood. More recent research has been looking closely at the gut microbiome and its influence on the brain, in particular, the role the gut’s microbiome plays in the protection or predisposition to dementia.

microbiome: the microorganisms living in our gut that help protect us against germs, break down food to release energy and produce vitamins

Dementia is a general term for a number of progressive neurocognitive diseases, including Alzheimer’s disease, vascular dementia and mixed dementia. Dementia results from the damage and loss of neurons in the brain, leaving sufferers with a reduced ability to think, difficulty communicating and making decisions and poor memory.

neurocognitive: relating to the neural processes and structures involved in cognition

We have trillions of bacteria and viruses coexisting as microbiomes, inside our body and on our skin. Inside the human gut are distinct groups of bacteria known as Firmicutes, Bacteriodetes, Actinobacteria and Proteobacteria, each being critical to good health by supporting resistance to infection, enhancing metabolism and controlling inflammation. When these groups become out of balance, they have the propensity to cause illness and disease, and affect the processes of the central nervous system.

The first signs of an unbalanced gut microbiome are digestive issues such as constipation, diarrhoea, bloating, nausea, inflammation and leaky gut symptoms. The imbalance known as “gut dysbiosis” can promote systemic inflammation and has links to cardiovascular disease, obesity, diabetes, autism, anxiety and depression and many gastrointestinal complaints.

So what causes these complex microbiomes to become unbalanced and disrupted?

There are a number of factors that have the potential to upset the delicate balance of your gut’s flora, however, the ones that we can impact are lifestyle factors – poor diet, stress and illness. High fat, high sugar, low-fibre diets have been linked to changes in the gut microbiota composition, specifically a reduction in the beneficial bacteria, Prevotella and Bacteroides, leading to chronic low-grade inflammation and disease.

How exactly does a change in our gut health affect our brain and risk of dementia?

The gut and brain are closely connected and communicate through the gut-brain axis. This super highway links the cognitive (thinking) and emotional (feeling) centres of the brain with digestive functions and is said to influence appetite, food preference and digestion. Consisting of neurons, hormones and proteins, the gut-brain axis enables the brain to send messages to the gut and vice versa. An unhealthy and unbalanced microbiome further contributes to the development of neurological disorders by  transmitting abnormal proteins and pathogens along the vagal nerve route. This route connects our internal organs like the gut to the brain and through this physical connection, harmful pathogens are exposed to the brain.

[T]he gut microbiomes of dementia patients have an over-representation of pro-inflammatory bacterial strains that may work to increase inflammation in the brain. It is believed that this pro-inflammatory milieu can, in turn, promote the development of amyloid plaques in the brain — a pathophysiological ‘signature’ associated with Alzheimer’s disease

neurologist Dr. Verna R. Porter

How do we improve our gut health and reduce our risk of dementia?

By consuming a healthy Mediterranean style diet including:

  • Proteins from lean meat and fish, which are broken down into amino acids that form the basis of brain cells,
  • Vegetables, fruits, and whole grains to provide important carbohydrates such as the brain’s much-needed fuel – glucose,
  • Healthy fats like omega-3 fatty acids to support the immune system lower inflammation, shielding your brain from damage,
  • Fermented foods to increase the amount of beneficial bacteria in the gut, improving both gut and brain health, and
  • Adequate hydration from water, since brain cells require a balance of water and electrolytes for cells to function properly4.

Try to reduce your stress. In life, some stresses are unavoidable, but there are certainly some that we choose to avoid and that can be addressed. Try to identify what factors are placing stress on you, change them or remove them altogether. Are you overcommitting yourself, under financial stress or about to face a big life change? Whatever you identify as contributing to your stress, work out a plan to confront it and resolve it.

Improving your lifestyle such as exercising more regularly, not smoking and reducing alcohol consumption are all within your power. Regular exercise produces endorphins – the happy hormones, which contribute to a positive mood. It doesn’t have to be a lot. A daily walk around the block is enough to make a start. Smoking is not compatible with good health and we know that drinking in excess puts a lot of stress on our liver and changes the way we digest food. Try and keep alcohol consumption to below the recommended amount.

By eating a diet high in fibre, rich in fruit, vegetables, cereals and low in red meat and sugar, exercising regularly, not smoking, reducing stress and lowering alcohol consumption, you are doing everything in your power to improve your gut’s microbiome and reduce your risk of dementia.

If you would like to know more about how we can help ease the burden of caring for your loved-one, call us today on 1300 331 103 or email


  1. Australian Bureau of Statistics (2020) Causes of Death, Australia, 2019 (cat. No. 3303.0) 
  2. Australian Institute of Health and Welfare, Dementia Snapshot, July 2020
  3. Your gut microbiome may be linked to dementia, Parkinson’s disease and MS The Conversation, November 10, 2020
  4. Researchers Confirm Link Between Alzheimer’s and Gut Microbiota VeryWell Mind, December 02, 2020
Dementia and gut health