Can your diet help override the early biological warning signs of Alzheimer’s disease? A new study says yes.
Following more than 1,800 adults for up to 15 years, researchers at the Karolinska Institutet in Sweden discovered that eating a low-inflammation diet can lower dementia risk by 29 per cent – even in people who already test positive for the blood biomarkers that signal the onset of Alzheimer’s years before symptoms appear.
What is more, participants who had a high-risk Alzheimer’s biomarker but strictly followed the anti-inflammatory diet lived nearly one full year longer without dementia (0.89 years) compared to those with low adherence.
How inflammation begins on the plate
We see inflammation in the red swelling around a skin wound, or engorged tonsils in a sore throat. But a wider perspective begins with our plates: the wrong sort of diet can trigger an inflammatory response in our gut, which affects our whole system – including our brains.
An “inflammatory” diet, explained one of the study authors, Anja Mrhar, is an eating pattern linked to higher levels of inflammatory markers such as C-reactive protein (CRP) in the body.
“Inflammation is part of the immune system’s normal response to injury or infection. In the short term, it is useful and protective. But when inflammation is persistent or chronic, it may contribute to damage in different tissues, including blood vessels and possibly the brain,” Mrhar says.
The study was particularly notable because it tracked participants for a median of eight years to observe who developed dementia. The 29 per cent reduction in risk was specifically observed among older adults who already exhibited higher levels of p-tau217 – a blood biomarker that can signal Alzheimer’s-related changes in the brain years before outward symptoms appear.
They also measured two other blood-based indicators: neurofilament light chain (NfL), which reflects general nerve cell injury; and glial fibrillary acidic protein (GFAP), which indicates brain inflammation.
Adhering to a low-inflammation diet reduced dementia risk in people who scored highly on these markers.
Interestingly, the researchers also tracked standard healthy eating regimens, including the traditional Mediterranean diet. They discovered a stark contrast: while general healthy eating protected older adults with low biomarker levels, it was ineffective for those who already exhibited biological signs of risk. For the high-risk group, only a diet specifically tailored to lower inflammatory potential consistently reduced the danger.
Understanding gut-brain communication
The gut-brain link is well established, and that is why the gut-brain axis – the hotline between gut and brain that relays constant messages via nerves, hormones and immune signals – is nicknamed the “second brain”.
What you eat affects your brain not only through its impact on your cardiovascular health, blood sugar and blood pressure levels, but also through the gut’s constant conversation with your brain.
In the context of dementia, inflammation is one of several pathways that may contribute to neurodegeneration, Mrhar says. It is crucial as it influences how disease-related processes develop and progress.
To explain how chronic inflammation might affect the brain in lay terms, Mrhar describes it as acting like low-level “background noise” or a “smouldering fire” in the body. Over time, this may place additional stress on cells and tissues, including nerve cells and supporting cells in the brain.
Systemic inflammation drives many conditions, says Hong Kong-based holistic nutritionist Puja Kumari, including psoriasis, Crohn’s disease, colitis, eczema, rheumatoid arthritis and asthma.
Inflammatory culprits vs brain boosters
Some foods can trigger the formation of excess free radicals. These potentially harmful chemicals are already present in the body – the natural by-products of certain bodily processes such as metabolism – but at normal levels are dealt with before they can cause problems.
Kumari says an excessive amount can lead to cell damage, which increases oxidative stress – or wear and tear at a molecular level, a bit like rust forming on metal left out in the rain – and heightens our body’s inflammatory response.
Among the worst culprits, Kumari notes, are foods fried in repeatedly reused cooking oil – a common practice in Asian night markets and street food stalls – which degrades and turns toxic.
Other major offenders include refined carbohydrates like white bread and pastries because they “create sharp blood sugar spikes that trigger immediate inflammatory responses”. Excess sugar similarly “triggers the body to release inflammatory chemical messengers called cytokines”, while alcohol “stresses the liver, disrupts gut bacteria and floods the system with toxins that spark widespread systemic inflammation”.
Other external factors, such as stress and smoking, can also increase the number of free radicals in the body, Kumari adds.
Dietary antioxidants, on the other hand, are “molecules in food that help remove free radicals from the body”, essentially helping the body clean up its act. While the body makes some of its own antioxidants to clear up this toxic waste, dietary antioxidants also help, Kumari says.
This protective defence was reflected in Mrhar’s study, where a low-inflammation diet generally included combinations of foods and drinks, such as higher intakes of vegetables, tea and coffee, and lower intakes of red and processed meat, refined grains, and soft drinks. An anti-inflammatory lifestyle might also include whole grains and foods high in Omega-3 fatty acids, such as nuts, seeds and oily fish.
Both Kumari and Mrhar stress that an anti-inflammatory diet is not a specific regimen, but a style or pattern of eating. It is not a simple list of “good” and “bad” foods, nor should it be viewed as a rigid prescription. Instead, it is about finding a sustainable way of eating, for which the Mediterranean diet would be a good choice.
While Mrhar’s findings do not indicate that changing to a lower-inflammatory diet will automatically improve a prognosis or prevent dementia entirely, they are deeply hopeful. The data suggests that diet quality – especially that related to inflammation – may still matter even when early biological signs linked to dementia are already detectable.
Ultimately, these findings show that dementia is a brain response to whole-body health over the course of a person’s lifespan, rather than something that just happens at the end of a life.
Source: Written by Anthea Rowan | South China Morning Post
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