Authored by Theresa Sam Houghton via The Epoch Times (emphasis ours),
Cognitive health depends on impulses that constantly pass between the 100 million brain cells (neurons) in your brain. One particular protein, brain-derived neurotrophic factor (BDNF), is instrumental in maintaining the connections that make the symphony of brain communication possible.
BDNF is just one player among many, but its role is essential for lifelong cognitive health. Optimizing BDNF with diet and lifestyle changes could help support brain volume, function, and adaptation, especially as you age.
BDNF is a neurotrophin, a type of protein called a growth factor that supports the survival of the neurons in your brain's communication network. As the most abundant neurotrophin in the brain, BDNF is found in high concentrations in the hippocampus, amygdala, cerebellum, and cerebral cortex. These areas are responsible for memory, emotions, spatial recognition, language processing, and movement.
For your brain to work properly, the functions of each region must remain separate from each other. According to J. Carson Smith, professor of kinesiology at the University of Maryland at College Park, the distinctions between regions start to break down as you age, causing interference that can distract you when you're trying to pay attention to or remember something.
"As we lose function in our brains, all of our brain regions tend to become activated all at once because we're trying to compensate for this loss of neural function that we have as we get older," Smith told The Epoch Times in an interview.
BDNF is key in maintaining this neural function, and its role begins during development as it helps brain cells mature and survive. The protein continues to be active in brain cell growth, maturation, and maintenance throughout life. BDNF is also essential for plasticity, the adaptive process that allows your brain to form fresh connections in response to new information and challenges.
However, Smith said that, rather than helping the brain create new connections, BDNF's primary function may be related more to maintaining structures called dendrites, projections at the ends of neurons that enable information to pass between cells in your brain's network.
"BDNF is like a fertilizer," he said. "So it's going to help stimulate connectivity and make sure that dendritic branching is intact instead of deteriorating and falling away and losing connections in the brain."
BDNF levels decrease with age, leaving less "fertilizer" to support brain cells and the connections between them. Research suggests a correlation between lower BDNF levels and age-related changes in the brain, including lower cognitive test scores, a reduction in hippocampal volume, and mild cognitive impairment (MCI). In this condition, difficulties with memory, judgment, and decision-making are more significantly pronounced but don't reach the level of dementia or Alzheimer's. Other changes like decreased neurogenesis and the beta-amyloid buildup seen in Alzheimer's disease may also be related to BDNF decline.
However, the picture is more complex, and there may not be clear associations between BDNF levels and cognitive decline. A 2023 study published in Biomolecules showed that BDNF levels are higher in people with Alzheimer's than those with MCI but cited other research showing that Alzheimer's and MCI patients have lower BDNF levels than healthy people.
According to the study's authors, "It has been suggested that BDNF levels vary with disease severity, with higher levels associated with MCI and early stages of AD and lower levels reported in patients with severe AD symptoms." While the reasons for this are unknown, researchers hypothesize that the body may produce more BDNF in the early stages of cognitive decline in an attempt to repair brain cells or protect against disease progression.
How BDNF is measured can influence study results. Smith told The Epoch Times that measuring BDNF in human brains can be difficult and invasive, so researchers often rely on levels of circulating BDNF. These levels may not accurately reflect the amount of BDNF in the brain because the protein is also present in other tissues like muscle.
Despite these complexities, patterns across studies point to modifiable factors that may promote or interfere with BDNF. According to Gina Nick, a leading naturopathic physician and formulator of glutathione-based health products, including Best Daily Ever Pixie Sticks, inflammation is one of the most important.
She told The Epoch Times in an interview that exposure to potential toxins in food and the environment can cause inflammation to increase with age. These exposures create unstable molecules called reactive oxygen species (ROS). As a type of free radical, ROS stabilize themselves by taking electrons from molecules in healthy tissues, which sets off chain reactions that produce more free radicals.
The resulting tissue damage, known as oxidative stress, appears to promote inflammation throughout the body, including in the brain. As oxidative stress increases, Nick said, BDNF levels go down. The effects may be more pronounced in the brains of older people due to a decrease in the body's ability to repair damage to cells and DNA.
Inflammation may be driven by dietary factors like salt, fat, and additives in ultra-processed foods. Nick said that such foods can deplete glutathione, the body's most abundant protective antioxidant, and start a cycle that promotes chronic neuroinflammation.
"Glutathione, when it's manufactured in the body, it's naturally occurring in the body, it eats up a lot of other antioxidants when it's making it," she told The Epoch Times. "And when you're exposed to a bunch of toxins in the environment, that triggers neuroinflammation -- it reduces the amount of glutathione in your brain."
She said it's important to replace the stores of antioxidants you need to make glutathione so your body can continue to protect brain cells from damage.
Research suggests that other antioxidants may also increase or maintain BDNF levels. In a 2021 study published in Nutritional Neuroscience, researchers found that foods and supplements containing plant-based nutrients called polyphenols were associated with increased BDNF. There may also be a potential connection between higher BDNF levels and anti-inflammatory compounds like flavonoids and the omega-3 fatty acid DHA.
Staying active may provide additional benefits for BDNF and overall brain health. According to a 2023 review, BDNF appears to be one of the major factors responsible for the cognitive benefits observed in many exercise trials. The researchers concluded that exercise, particularly aerobic activity commonly known as cardio, is associated with better cognition in cases of MCI and dementia.
The review linked several effects of exercise to better cognitive outcomes, including the release of lactate and proteins from muscle and the stimulation of osteocalcin. This protein promotes bone growth and helps muscles adapt to exercise. These molecules promote the production of BDNF and appear to be the factor that connects these processes to improvements in mood, cognition, learning, and memory.
As with diet, the process is complex. Factors like intensity and duration may influence the extent to which exercise affects BDNF and brain health, and long-term exercise may decrease blood levels of BDNF without causing changes in cognitive function or memory.
Following diet and lifestyle patterns consistently shown to promote cognitive well-being may support BDNF production and help keep the symphony of interactions in the brain playing in harmony.
The popular Mediterranean diet, for example, focuses on whole and minimally processed plant foods, lean proteins, and unsaturated fats. This combination increases antioxidant intake while reducing or eliminating pro-inflammatory factors like saturated fats and refined carbohydrates, which may increase the risk of oxidative stress.
Nick recommends incorporating foods that contain glutathione or promote its production, including cruciferous vegetables like broccoli, fruits like peaches, cherries, and strawberries, and unprocessed grass-fed red meat. She's also a fan of walnuts for their omega-3 content.
"A handful of walnuts a day will provide you with sufficient omega 3 fatty acids for helping to maintain BDNF levels," she told The Epoch Times.
As for exercise, research shows that single sessions and consistent habits may boost BDNF levels. To build a habit for healthy brain function, Smith recommends that people do whatever type of exercise is most accessible and enjoyable for them.
Even simple activities like climbing stairs or gardening can improve BDNF, so be on the lookout for opportunities to skip the elevator or take a quick walk after dinner. If weather or safety is an issue, try free online resources like indoor walking videos or follow-along bodyweight workouts.
Making these changes with help from family and friends may provide additional cognitive support.
As Nick said, "There are always things that you can do to impact BDNF."