When I started formulating my ideas for this article back in May, I’d have never thought how personal these topics will become to me after losing a close friend of mine to depression a couple of weeks later.
More than ever, it showed me how important mental health awareness really is. At first, I combined both topics in one giant article, but finally decided to split it up in two separate ones.
Initially, I just wanted to write an article about the relationship between food and neurogenesis, but had to take a break after everything that has happened. Nevertheless, I reevaluated the content as soon as I got back into it.
As the weeks passed and life went on, I just wasn’t able to get one specific thought out of my head.
What if there’s a way to battle and prevent depression and even mental decline through your diet and lifestyle alone? Is it possible to influence the growth of new neurons in our brain by what we eat?
It kept me awake at night and I decided to dig deeper into the current state of research behind this specific question. I know that depression is way more complex than that and consists not only of chemical imbalances in your brain, but has deep psychological roots, too.
Even though I’m not a neuroscientist myself, I wanted to at least try to do the research and find ways to help answer my own question.
Above all, imagine if knowledge and the application of it could even act as a preventive measure — that would be equally important.
The hippocampus is a part of the brain located in the medial temporal lobe. It’s quite well-researched and, for example, one of the first, if not the first region that’s, for example, affected in Alzheimer’s disease in older people.
When talking about depression, it’s interesting to see that one of the things SSRI drugs, more commonly known as antidepressants, actually do is augmenting the growth of new brain cells in the brain’s memory center.
Neurogenesis (the process of growing new neurons in the brain) is a fundamental player in helping against a decline in memory function and plays a significant role in mood regulation as well.
Keep in mind that science is actually not exactly sure to what extent we can really influence the rate of neurogenesis in a meaningful way. Direct causal evidence linking adult neurogenesis to depression still needs to be thoroughly examined.
BDNF (brain-derived neurotrophic factor) is a protein produced inside your nerve cells that improves the function of neurons, encourages their growth and protects them against premature cell death. It has actually been shown to be low in people with schizophrenia and depression. This could have major clinical potential, even if it doesn’t sound like much at first.
We also know that if there’s decreased BDNF circulating in the brain, it strongly correlates with depression as well.
You might start realizing now why higher BDNF levels are so helpful — not only for depression, but also when talking about mental decline — it regenerates the hippocampus! That’s definitely something good if we want to maintain our brain health and prevent cognitive disorders or depression.
I had to go deeper, though, and spent literally some days just with research to gather an objective and unbiased perspective on all of these topics.
As someone with a deep interest in optimizing cognitive health and brain function, I’m often faced with contradicting evidence when going through scientific papers.
Especially in times of pseudoscience and self-claimed experts, it gets more and more difficult to differentiate between all the superficial and easily misinterpreted data out there.
You quickly notice that each variable could have different effects depending on the specific context you’re analyzing it for.
Let’s take coffee for example. I used to drink some cups of it before each heavy lifting session in the gym. My actual goal was it to improve not only my focus, but also my performance during these workouts.
According to the most recent research, around 5–6mg of caffeine per kg of bodyweight in general seem to be the peak for enhancing exercise performance.
If you look closely, this makes for a hefty dose in and of itself. It definitely has its place for performance athletes, but might not be necessary for the average joe who is just looking to get fit and doesn’t bother to compete.
According to my 23andMe data of my genome, a polymorphism of my CYP1A2 gene (encodes for an enzyme which, among others, controls caffeine metabolism) even makes the absorption of caffeine extremely efficient for me.
Coffee also plays a role in regulating Nrf2, a pathway in the body being proven to amplify the production of antioxidants and reduce inflammation. Don’t even let me start raving about how good it tastes.
Putting everything together, these are all legit reasons to love you some coffee. Especially it you briefly forget about coffee stain on teeth, occasional caffeine jitters, elevated blood pressure and a couple of other things that are negatively associated with coffee.
Is caffeine, in our case, beneficial for neurogenesis though?
Higher caffeine intake may increase focus and concentration in the short-term, but it definitely influences our brain’s function in the long-term by decreasing neurogenesis in the brain. I’ll talk about it in more detail later on.
The consensus is that every human has different goals, therefore, the optimal diet and lifestyle is the one that works for you.
Don’t get me wrong, by no means I’m saying people should or should not drink coffee. It depends on so much more and, in the end, is completely up to your own preferences.
I just wanted to show you that there are always two sides to an issue and how it helps to be clear about your own intentions of doing something. Talking about opportunity cost and stuff. I evaluated my own reasons back then and made a conscious decision with my caffeine intake which is what is most important.
Without further ado, I want to present you with some scientifically proven factors that influence the rate of neurogenesis, increase BDNF or modulate learning, memory and depressive behavior.
Occasionally decreasing your calorie intake by 20–30% might be one of these things that don’t particularly sound attractive at first, but might positively influence the rate of neurogenesis in the long run.
It gets even more interesting when researchers started looking at how it influenced cognitive abilities when mice and rats were faced with certain tasks. Limiting calorie intake was, for example, associated with enhanced spatial learning in rats and increased learning in mice.
Intermittent fasting, also known as time-restricted feeding, actually shows similar benefits — increased time between meals raises BDNF levels and the rate of neurogenesis, too.
If you want to learn more about fasting per se, you can have a look at one of my other articles where I get more detailed with the topic.
If there’s only one dietary choice you could make to help your brain make new neurons, it would definitely be to get more omega-3s into your diet.
Your brain is constituted of 60% by fat, of which 30% are made of the important omega-3 fatty acid DHA (docosahexaenoic acid) and around 25% of cholesterol. DHA has been proven to increase neurogenesis in rats.
There’s actually a strong correlation with omega-3 intakes and delayed onset of depressive periods in studies being done with people suffering from bipolar disorder.
Moreover, higher doses of EPA (eicosapentaenoic acid) have also shown a therapeutic effect on depressive behavior, and around 1g of EPA per day were sufficient enough to intervene with bipolar depression.
Fatty fish like wild salmon, sardines or mackerel are king when talking about high omega-3 concentrations. If you don’t like eating fish, you can always supplement with a high quality fish or krill oil.
Salmon roe is also another great source, even though it’s a little more pricey. The DHA in salmon roe is actually in its phospholipid form, making it way more bioavailable to your body.
A good start would be to get at least 1–2g of combined EPA and DHA (not just the total amount of fish oil) per day.
For you vegetarians and vegans out there, you should definitely opt for microalgae oil which is a great source of EPA and DHA, too. That’s actually where all the fish get it from as a matter of fact — by eating algaes.
Many people still tend to recommend ALA (alpha-linolenic acid) — which is being found in plant food — as a good source for omega-3 fatty acids. However, the human body is incredibly inefficient in transforming these into the more important EPA and DHA.
According to the Pauling Institute at Oregon State University, for example, only 8% is converted to EPA and 0–4% to DHA in healthy young men. You’d have to eat lots of calorie-rich foods to gather meaningful doses from it which is just not realistic at all.
The skin of blueberries is high in phytonutrients called anthocyanins which act as antioxidants in the human body. They are linked with increased neurogenesis, seem to protect against cognitive decline and inflammation and produce more BDNF, too.
Blueberries are also high in tryptophan, which can raise serotonin levels. Serotonin itself affects concentration and mood to a significant degree.
A daily cup of blueberries is usually a good minimum effective dose to implement into your diet.
We all know that exercise is good for your brain, there’s nothing to argue about. It can be extra motivating though to learn the scientific benefits behind it.
In one Harvard study with rats, researchers compared resistance training, high intensity exercise training and aerobic training to their corresponding relationship with neurogenesis.
The results were that resistance training had virtually zero influence on neurogenesis, HIIT just a little and aerobic training by far the most profound effect on neurogenesis.
Another interesting study done on men between the ages of 18–25 showed that 20–40 minutes of aerobic exercise triggered a 32% increase in BDNF. Thus, we have a natural tool we can use to trigger neuronal upkeep and renewal.
But, as we all know — perfect is the enemy of the good. It’s important to not lose sight of the bigger picture. Although aerobic exercise seems to be a little more beneficial when exclusively talking about brain health, HIIT simultaneously boosts the production of BDNF.
It’s always a good idea to combine several types of exercise when your goal is to optimize your brain’s function and generally keep your body healthy. In the end, lifting weights is as good as running or yoga are for different aspects of your health, so just keep your exercise routine varied and balanced!
Curcumin is a powerful anti-inflammatory and antioxidant compound found in turmeric, actually giving curry the yellow color.
On the other hand, more is not always best — high doses seem to impair cognitive abilities. A lot of studies use dosages of curcumin around the 500mg mark, assuming it’s combined with something like piperine (can be found in black pepper) and a fat source to enhance absorption.
From my experience — whenever I use a higher dosage of turmeric when cooking, it immediately relieves any feeling of a brain fog shortly after consuming my meal.
Curcumin itself amounts around 3% per weight of turmeric, so if you want to use a scientific dosage, 3–4 teaspoons per day should be a good start. You can easily use turmeric for cooking.
Stress negatively influences the rate of neurogenesis, as this stress hormone is meant to make your body redirect all resources towards immediate energy expenditure (fight or flight) as opposed to regeneration and maintenance.
In a nutshell, caffeine seems to decrease neurogenesis.
Interestingly enough, at supraphysiological (extremely high) doses, there is actually an increase in the amount of blast cells, basically being the most immature form of a cell. However, it doesn’t yield an increase in neurogenesis because, in response to caffeine, these neurons tend to have a lower survival rate anyway.
There are some unknowns on why caffeine (important: long-term caffeine intake) could be a detriment to adult hippocampal neurogenesis.
Researchers actually insinuate that you should be very careful to not put caffeine on the same level as coffee.
The reality is that consuming coffee in comparison to consuming caffeine in its isolated form is very different. It might be much wiser to consume caffeine from natural sources like coffee, tea or raw cacao than in isolation.
For example, pure caffeine consumption is associated with shorter telomeres in the human body, while coffee consumption is associated with longer ones.
On the other hand, chlorogenic acid in coffee is known to boost neurogenesis, and there are some studies showing that coffee boosts Nrf2 levels in the brains of rats and might also be neuroprotective in multiple models of dementia in the short term — through mechanisms which are different than just increasing neurogenesis or BDNF.
The compounds in coffee, more precisely the polyphenols, likely offset a majority of the negative effects of caffeine.
Although two studies concluded that caffeine decreased neurogenesis, however, those were only a few. There are still many brain benefits of tea and coffee, such as reducing the risk of Parkinson’s and Alzheimer’s disease — precisely due to their high polyphenol content.
You could even switch to decaf coffee which might resolve a majority of caffeine-related problems, while still giving you most of the benefits of regular coffee.
You might also want to include green tea in your diet to benefit from the effects of EGCG and l-theanine, both of which also promote neurogenesis and increase BDNF levels — even if it comes with a standardly low dose of caffeine.
L-theanine probably has some efficacy in preserving BDNF when administered with caffeine together, too.
Matcha tea is a great option because you’re consuming the whole leaves with your tea. If you’re simply looking for EGCG, the highest amount can actually be found in gyokuro tea.
What matters is the EGCG in the green tea extract and recommendations are to not exceed 300mg of total EGCG per day.
If you don’t like drinking tea or are extremely sensitive to caffeine, you can also switch to caffeine-free green tea extract pills which should contain at least 45% EGCG though.
Resveratrol is a polyphenol positively correlating with neural plasticity by promoting hippocampal neurogenesis in your brain. Sources of resveratrol in food include the skin of grapes, blueberries, raspberries, mulberries, peanuts and red wine.
Now, red wine makes for an interesting one. There seems to happen a natural neutralization between resveratrol and ethanol when consuming both of them.
Even though alcohol is certainly detrimental to the growth of new neurons, red wine in moderation seems to be a bit of an exception because of its contents of resveratrol, making it a “neurogenesis-neutral” drink. Take this one with a grain of salt though because alcohol still remains extremely unhealthy.
Reaching the end of this little journey full of scientific gibberish, I really hope that you were able to get at least a small nugget of knowledge out of it. If you have any more questions or remarks, feel free to leave me an email.