As we grow older, many changes take place in the body. One of them is a slow rise in inflammation.
This ongoing, low-level inflammation—sometimes called “inflammaging”—may be a key reason why aging and obesity are linked to memory problems and dementia.
A new study from Baycrest suggests that inflammation in the body could play an important role in cognitive decline.
The research, published in the Journal of Alzheimer’s Disease, found that about two-thirds of people with cognitive impairment had high levels of inflammation. In contrast, only about one-third of cognitively healthy older adults showed similar levels.
Inflammation is the body’s natural defense system. It helps fight infections and heal injuries. But when inflammation becomes chronic—lasting for months or years—it can start to harm healthy tissues.
Scientists believe that this long-term inflammation may gradually affect the brain, even if it begins elsewhere in the body.
The study looked at 514 older adults who were part of the Canadian Consortium on Neurodegeneration in Aging through its COMPASS-ND project. This large Canadian study includes people aged 50 to 90 who are living with dementia, mild cognitive impairment, or no cognitive problems at all. Because the group includes people with different health conditions and backgrounds, it reflects real-world aging more closely than many smaller studies.
Researchers measured inflammation levels in the blood and examined many possible contributing factors. These included age, sex, body weight, heart and vascular health, smoking, diet, sleep habits, and medical history. Participants also completed cognitive testing, and many underwent brain scans to look at changes in white matter.
The results showed that obesity was the strongest lifestyle-related factor linked to higher inflammation levels. Although poor diet and sleep also played a role, excess body weight stood out as the most powerful contributor. Among participants who already had dementia, those with vascular conditions such as heart disease or stroke tended to have even higher levels of inflammation.
Importantly, many of the factors connected to inflammation are modifiable. Body weight, physical activity, diet quality, smoking, and cardiovascular health can all be improved with lifestyle changes. This means there may be opportunities to reduce risk earlier in life by focusing on overall physical health.
The researchers caution that it is still unclear whether directly treating inflammation can prevent dementia. However, the findings highlight inflammation as a possible bridge between physical health and brain health. By better understanding how obesity and other lifestyle factors drive inflammation, scientists hope to develop earlier and more effective prevention strategies.
In short, taking care of the body may be one of the best ways to protect the brain.
