How Inflammation Ages Your Brain

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As we age, we tend to experience an increase in low-grade inflammation throughout our bodies. This process is referred to as “inflammaging,” and it is thought to represent a significant risk factor for conditions like heart disease, cancers, diabetes, muscle loss as well as brain disorders like dementia and depression.

There are a number of potential ways in which inflammaging may develop in the body, ranging from chronic viral infection to poor quality of diet. In people who live to be over 100, it has been noted that inflammaging may be offset by anti-inflammatory processes. Notably, this ability to balance inflammatory changes as we age is also proposed to impact the risk for Alzheimer’s disease.

As it relates to the specifics of how inflammaging impacts the brain, one key area of focus is brain immune cells called microglia. Microglia are tasked with responding to a wide range of threats across our brains. Inflammation existing outside the brain may be detected inside the brain by microglial cells that then amplify this signal, producing brain inflammation. It’s important to note that microglial cells play a number of roles in the brain, and can produce both pro or anti-inflammatory molecules depending on the signals they receive. However, some data suggest that microglia in the aged brain may preferentially produce signals that are more pro-inflammatory, leading to brain-damaging effects.

With a larger percentage of the population entering older ages accompanied by a higher risk of age-related health conditions, inflammaging becomes increasingly relevant. This seems especially true as we look at increasing rates of age-related brain diseases like Alzheimer’s that may have roots in inflammation. From a lifestyle perspective, what can we do that might help offset this risk?

1. Avoid the standard American diet, and prioritize whole-food sources of fiber and plant nutrients

A number of dietary strategies have been proposed to help dampen the potential effects of chronic inflammation on the body and brain. One consensus seems to be that the constant supply of ultra-processed calories that characterizes the standard American diet (or Western pattern diet) is worth avoiding. In its place, some recommend calorie restriction, although in practice this can be difficult to implement. Other research suggests that plant foods rich in phytonutrients (like curcumin, anthocyanins, flavanols, and olive-oil polyphenols) may have beneficial effects on inflammatory pathways. Additionally, eating adequate dietary fiber may help mitigate certain aspects of age-related inflammation. Finally, the Mediterranean diet, which is rich in phytonutrients, fiber, and as well as healthy fats, is noted to provide a potential offset to inflammaging pathways.

2. Prioritize daily movement

Exercise is perhaps the most well-established brain-boosting intervention, with preclinical and clinical evidence converging on key mechanisms and outcomes. By enhancing levels of neuroplasticity-promoting molecules like BDNF, helping balance immune responses, enhancing metabolic health and more, physical activity may represent an important interventional tool for those seeking to offset the effects of age-related brain inflammation. Recent work proposes that exercise may represent a way to inhibit excess brain activation by way of effects on microglial cells, and in animal research, exercise prevented age-related activation of microglial cells.