Brain derived neurotrophic factor
The brain derived neurotrophic factor (BDNF) belongs to the class of neurotrophins – a group of proteins that induces development, survival and function of nerve cells. The neurotrophins are growth factors, which means they promote the formation of new nerve cells and prevent programmed cell death.
Although most human neurons are formed before birth, special parts of the adult brain (for example the hippocampus) keep the ability to grow new cells from neural stem cells. And this is exactly the function of BDNF: to stimulate the development of new cells. So, the more BDNF we have, the more we are able to form new nerve cells and to prevent our original cells from death.
Because of its ability to promote the growth and adequate function of nerve cells, BDNF has been postulated to be an essential part of the cellular mechanism supporting memory formation and maintenance. And indeed it has been shown that BDNF is essential for persistence of long-term memory storage (1).
BDNF secretion is controlled and modulated by several factors such as:
- Neuronal activity
- Physical exercise
- Hormones such as estrogens
- Caloric restriction and intermittent fasting
BDNF and Alzheimer’s disease
The relationship between BDNF and cognitive function has been documented in many previous studies. It has been suggested that higher BDNF gene expression may have a role in slowing cognitive decline. Other studies have demonstrated that aerobic exercise resulted in higher BDNF level and in increased hippocampal volume.
One very interesting study published in 2014 in JAMA neurology (2) showed the correlation between BDNF and risk for developing dementia. Using a database of the Framingham Heart Study (the largest and the most well respected epidemiological study ever conducted), they evaluated more than 2000 individuals who had no signs of dementia (60 years old or older), measured their serum levels of BDNF and followed them in order to determine who developed dementia after a period of time. They found that the highest levels of BDNF were associated with a dramatic reduction in risk for developing dementia.
The authors conclude that BDNF may play a role in the development of AD. They also suggest that the serum BDNF level can be used as a predictor of dementia in healthy adults and as a biomarker of dementia risk and prognosis.
These findings are of particular interest because serum BDNF levels can be elevated through simple lifestyle measures (such as increased physical activity, fasting or ketogenic diet).
In this way, physical activity has been especially studied and related to improvement in BDNF levels and hence in the prevention of dementia. Both aerobic exercise and strength/stretching activities seem to be beneficial in preventing dementia. However aerobic exercises seem to have other benefits like cardiovascular fitness, heart disease and stroke prevention.
The BDNF is a key element in promoting new nerve cells formation and preventing cognitive decline. The levels of BDNF can be improved by many different lifestyle measures, among which, physical exercise has been shown to be very effective and easy to implement. So, if you want to prevent dementia buy a new pair of tennis shoes and let’s go!
- Bekinschtein P, Cammarota M, Katche C, et al. BDNF is essential to promote persistence of long-term memory storage. Proc Natl Acad Sci U S A. 2008 Feb 19;105(7):2711-6. Pubmed
- Weinstein G, Beiser AS, Choi SH, et al. Serum brain-derived neurotrophic factor and the risk for dementia: the Framingham Heart Study. JAMA Neurol. 2014 Jan;71(1):55-61. Pubmed
- Buchman AS, Yu L, Boyle PA, et al. Higher brain BDNF gene expression is associated with slower cognitive decline in older adults. Neurology. 2016 Feb 23;86(8):735-41. Pubmed
- Ismail NA, Leong Abdullah MFI, Hami R, Ahmad Yusof H. A narrative review of brain-derived neurotrophic factor (BDNF) on cognitive performance in Alzheimer’s disease. Growth Factors. 2021. Pubmed