From Memory to Mood: BDNF's Wide-Ranging Impact on the Brain*

Have you ever wondered why some people seem more susceptible to stress than others, even under very similar circumstances?

Recent events (hello, pandemic) have consistently caused many of us to experience high-stress levels. Don't get us wrong. Feeling stressed, given these challenging times, is completely natural.

However, it was interesting to see how some individuals appeared more resilient, somehow handling the events better than others.

It's a conundrum with no simple answer.

According to science, our varying levels of vulnerability to stress result from a complex interplay of factors.^1,2,3 Both environmental influences and genetic predispositions significantly shape our responses to stressful and high-pressure situations.

So, what exactly did the scientists learn? Luckily, we now know a bit more about how stress and resilience are processed in our brains.

Many tiny-but-important molecular mechanisms may play a role in our ability to adapt to stress. One of them is the brain-derived neurotrophic factor (BDNF).

Yves Barde and Hans Thoenen first identified this particular process in the 1980s. Later, their work built on Nobel laureate Rita Levi Montalcini's groundbreaking discovery of the nerve growth factor.

Did you know that...

...your brain is made of billions of neurons? About 86 billion. These neurons communicate through electrical impulses sent along nerve fibers (known as axons) or through neurochemical signals transmitted via synapses. Pretty cool, right?

But here's the thing: the connections between neurons—synaptic connections—are constantly changing. New connections form while old ones (that are no longer needed) are pared away.

This dynamic means the number of synaptic connections is always in flux. However, an adult brain might have upwards of 100 trillion at any given time.

Similarly, the number of neurons in your brain is not fixed. While there's still some debate, scientists believe that new neurons are always created in certain brain areas through a process known as neurogenesis.^4,5

At the same time, specific enzymes trigger the controlled death of other neurons, a process known as apoptosis.

Is this a bit overwhelming? Let's tie everything together: specific proteins in your brain (called neurotrophic factors, or neurotrophins) help regulate these vital processes of cell birth and cell death.⁶ One key neurotrophin involved in these processes is the brain-derived neurotrophic factor.

Pretty interesting, but what exactly does that have to do with being more or less susceptible to stress?

BDNF is highly sensitive to stress. And it can play an important role in how certain substances affect the brain to enhance our mood.*⁷

Counterintuitively, despite its benefits, BDNF can also interact with environmental stressors and negative experiences to amplify feelings of anxiousness, fear, and sadness.*⁸

However, BDNF seems to help more than it hurts in many instances. It can be important to the neuroplasticity processes essential for adapting to our fast-evolving world. These processes enable our brains to change structurally and functionally, helping us adjust to new experiences and environments.*

Notably, BDNF may support these (for the most part, fantastic) plastic changes by sustaining the differentiation, growth, and survival of neurons in both the brain and the peripheral nervous system.*⁹

And, finally, BDNF is active in many brain regions that may be crucial for cognitive functions, such as the hippocampus, basal forebrain, and cortex. These areas are instrumental in learning, memory, and analytical thinking—skills we rely on every day.*

So, that means I can improve my wellbeing with BDNF?

Not directly. BDNF isn't (for now) available in nootropic form, so you can't buy it from your local store or pharmacy to improve your ability to roll with the punches when it comes to stress.*

But there is some good news, too. There are some easy, practical things you can do to help maintain (and potentially) increase your BDNF levels.*

Get your daily dose of antioxidants.*

Many studies have looked into how a diet rich in antioxidants—including green leafy vegetables, broccoli, berries, and even dark chocolate—can help maintain healthy brain levels of BDNF.*¹⁰

Or, if you'd rather, you can consider sipping on green tea or adding turmeric and black pepper to your favorite dishes to boost your antioxidant intake.*

Plus, ongoing research also suggests that a well-balanced diet may not only help your body combat stress but also offer significant cognitive health benefits—and that's nothing to sniff at, either.*

Exercise more.*

It's no secret that physical activity can be important for maintaining good health (both physical and mental).

Research shows that various forms of exercise can significantly boost brain-derived neurotrophic factor (BDNF) levels:*^11,12

• Pilates
• Strength (or cardio) training
• Mindful walking
• Aerobic
• High-intensity interval training (HIIT) at home
• Mixed-modality workouts, outdoor activities
• Enjoying long walks with friends

Discover new interests.*

Introducing your brain to diverse forms of information, aka learning new languages, musical instruments, or mathematical concepts, can enhance neuroplasticity and boost levels of brain-derived neurotrophic factor.*^13,14 These benefits may be especially notable in seniors.

If you're unsure where to start, a quick online search may yield many low-cost (or even free) resources tailored to your interests.

Embrace more sunlight.*

Many are not huge fans of winter months. And it's not just because of the cold weather. Winter can oftentimes affect one's mood and dampen our spirits. Yet, the exact neurobiological reasons remain somewhat mysterious.

One theory talks about a potential link between BDNF and Vitamin D levels. Since our skin produces Vitamin D from cholesterol when exposed to sunlight, more sunlight could potentially increase BDNF levels.*

→ A 2012 study in PLoS One with 2,851 participants observed notable seasonal variations in BDNF levels—higher in spring and summer, lower in autumn and winter.¹⁵ This may suggest that Vitamin D, boosted by sunlight exposure, might help regulate BDNF concentrations, influencing our mood throughout the year.*

Go out and socialize.*

Social engagement may be another contributing factor to BDNF levels, particularly in developing brains.*

In fact, research consistently shows that a positive and engaging social environment in early life can yield beneficial behavioral outcomes later on.

→ One good example is the 2006 comparative study published in Biol Psychiatry. The study found that mice raised in communal nests exhibited significantly higher levels of neurotrophins, especially in brain areas like the hippocampus and hypothalamus, even later in life.¹⁶ This may suggest that similar effects could be observed in humans.*