The brain comprises billions of neurons that communicate with one another through electrical impulses or by sending neurochemical signals to one another via synapses. New connections are constantly being made, while old, no longer useful connections are continually being pared. Thus, the number of neurons in the brain is constantly changing. Though there is still some debate on the matter, it appears that new neurons are continually being formed (via a process called neurogenesis) in certain parts of the brain. Meanwhile, it has been established that degrative enzymes lead to the controlled death (apoptosis) of other neurons. The proteins responsible for regulating these processes of cell birth and cell death in the brain are known as neurotrophic factors (or neurotrophins), one of which is a brain-derived neurotrophic factor (BDNF).
What Is BDNF?
Neurotrophic factors are produced in the brain and the gut. BDNF is regarded as the most active neurotrophin, and it is also essential to energy homeostasis and neuronal plasticity, which is crucial to learning and memory. Decreased levels of BDNF have been associated with neurodegenerative disorders such as Parkinson’s disease and Alzheimer’s disease. In addition, reduced BDNF levels may also be associated with type-2 diabetes.
Conversely, higher protein levels are associated with improved cognitive functioning, mental health, and short- and long-term memory. Thus, while it is not clear at this time if increasing BDNF levels can reverse or prevent neurodegenerative conditions, normal levels of BDNF are typically associated with better cognitive performances and overall brain function.
Can I Increase My BDNF Levels?
The short answer is yes. Research has found that several factors, particularly obesity, may influence BDNF levels—obese individuals have lower BDNF levels while non-obese individuals have higher BDNF levels. Additionally, research indicates that other lifestyle changes (explored below) may positively impact BDNF levels.
Rigorous exercise has been shown to increase BDNF levels. For example, a study published in 2011 found that three weeks of high-intensity cycling and five weeks of aerobic exercise improved cognitive functioning and increased levels of BDNF. Yet another study found that BDNF levels increased with aerobic exercise and that this corresponded with an increase in hippocampal volume by 2 percent. (The hippocampus plays a significant role in creating and storing memories and decreasing in volume with age.) Thus, on top of helping to combat obesity and increase BDNF, thereby improving overall brain function, these studies suggest that exercise can be especially beneficial to memory.
Several studies have found that intermittent fasting and caloric restriction is associated with increased BDNF levels. Additionally, diets high in processed sugars and saturated fats can affect neurotrophin levels, including BDNF levels, leading to reduced neuroplasticity. To avoid these detrimental effects, individuals should stay away from processed sugars and saturated fats and switch to a diet based mainly on leafy vegetables, fruits, lean proteins, and whole grains.
Drugs and Supplements
In addition to making dietary changes, some supplements have been shown to increase BDNF levels. They include:
While it is well known that the winter months can often affect one’s mood, the precise neurobiological mechanism behind this change is not entirely known. One possible mechanism could be decreased levels of BDNF, which is correlated positively with levels of Vitamin D, a vitamin our skin makes from cholesterol when exposed to sunlight. In other words, more sunlight appears to lead to increases in BDNF levels.
Social engagement appears to also affect BDNF levels, particularly in developing brains.
Ultimately, the best way to increase BDNF levels is to adopt a healthier overall lifestyle that can also contribute positively to one’s mental health and cardiovascular health while also reducing one’s level of body fat. These changes include exercising, being social, getting outside, eating a diet rich in nutrient-dense foods and devoid of processed sugars and saturated fats.