Adopting a lower-inflammatory diet may help delay or reduce the risk of dementia, even in older individuals who exhibit biological signs associated with Alzheimer's disease, according to new research. The study suggests that it is never too late to improve dietary habits to potentially mitigate the risk of cognitive decline.
The research, a collaboration between teams from the Karolinska Institutet in Sweden and the University of Ljubljana in Slovenia, observed 1,865 participants aged 60 and older in Sweden for an average of 8.4 years. Published in JAMA Network Open, the study sought to establish a connection between diet quality and the incidence of dementia later in life.
Participants completed detailed food questionnaires and were assessed on their adherence to three distinct healthy eating patterns: a Mediterranean-style diet, the Alternative Healthy Eating Index, and the reversed Empirical Dietary Inflammatory Index, which measures the anti-inflammatory properties of a diet. The Mediterranean diet, characterized by whole grains, fish, healthy oils, and fresh vegetables, is widely recognized for its health benefits. The other two dietary patterns emphasize similar principles, focusing on fruits, vegetables, legumes, and nuts.
Scientists also analyzed blood samples to identify three key markers associated with dementia risk: p-tau217, strongly linked to Alzheimer's disease; neurofilament light chain, a marker of nerve cell damage; and glial fibrillary acidic protein, associated with brain inflammation or injury.
Over the study period, 240 participants were diagnosed with dementia. After adjusting for various factors including age, sex, education, smoking status, exercise, weight, calorie intake, and pre-existing health conditions, researchers found that higher diet quality correlated with a reduced risk of developing dementia. The most pronounced effects were observed in relation to the lower-inflammatory diet. Notably, among individuals with elevated levels of Alzheimer's markers and indicators of brain damage, a greater adherence to this diet was consistently associated with a lower dementia risk. Even participants showing early biological red flags for dementia appeared to experience a longer delay in disease onset when following a healthier diet.
It is important to note that, as an observational study, these findings can only demonstrate an association and cannot definitively prove that a healthier diet directly prevents dementia or its progression. Inflammation, a natural defense mechanism of the body's immune system, can become chronic due to factors such as obesity, poor diet, and long-term health issues. This persistent, low-level inflammation is believed to contribute to brain cell damage, the accumulation of Alzheimer's-related proteins, and an accelerated development of dementia.
The study's authors suggest that these findings warrant further investigation into personalized dietary recommendations for individuals at higher risk of dementia. Globally, dementia affects millions, with projections indicating a significant rise in cases. While research for a cure continues, evidence increasingly points to prevention as a key strategy. A significant consensus among experts suggests that a substantial portion of dementia cases could be prevented or delayed by addressing modifiable risk factors, which include lifestyle elements such as smoking, alcohol consumption, social isolation, and physical inactivity.