Can we, as adults, grow new neurons? Neuroscientist Sandrine Thuret says that we can, and she offers research and practical advice on how we can help our brains better perform neurogenesis—improving mood, increasing memory formation and preventing the decline associated with aging along the way.
If you are not deeply ensconced in the scientific literature, particularly the field of neurology, the title to this article may seem preposterous, far-fetched, and straight out of a 1950s scientific fiction novel. But the startling fact is adults are FULLY CAPABLE of growing new brain cells, no matter how old they may be. As researchers somewhat understated in 2005: “the discovery that the adult mammalian brain creates new neurons from pools of stemlike cells was a breakthrough in neuroscience”.
As was once traditionally taught in neurology, the human brain was thought to be “fixed,” meaning of course that once brain cells were lost, they couldn’t be re-grown, and/or new cells couldn’t be manifested. Since this has been proven to be untrue, one first must wrap their head around this development before we can proceed further.
To give a brief overview, there are many different regions of the human brain. Neurogenesis is what the process of new brain cell development is called. It is most active during pre-natal development but there are two parts of the human brain, so far, where this process has been shown to continue into adulthood. These two regions are named the hippocampus and the sub ventricular zone. While further research may show other regions demonstrate neurogenesis, the science has yet to articulate any such developments.
Joseph Altman must be given credit for his groundbreaking work in the field of neurogenesis, with important discoveries happening in both 1962 and 1963.Altman’s work was largely and uniformly ignored, which was preposterous. It took until the 1990s for mainstream research to finally start to regard neurogenesis as a priority and possibility. Obviously, there is the likely possibility that learning and memory would be important related brain functions that may be affected by neurogenesis.
Besides learning and memory, some supposed and likely neuronal effects are found in the regulation of stress and also in the beneficial mechanisms of some antidepressants. Besides these functions, neurogenesis shows promise in the areas of depression, as well as Alzheimer’s.
So you may find this briefest history of neurogenesis interesting, but you are probably getting restless in hopes that I will soon communicate how you can grow new brain cells yourself. Well, you won’t have to wait any longer. You will likely be interested to know that none of these measures will take much money, and they don’t require any surgical procedures. They are methods that anyone and everyone can, and I would argue, SHOULD use, in order to maximize their cognitive potential.
Firstly, exercise, even simply walking, has shown a direct link to neurogenesis. The below chart, from a study which showed walking for just 45 minutes per day lead to new hippocampal tissue growth, shows – in striking simplicity – how moving can cause your brain to grow.
Besides the obvious positive physical, mental and emotional benefits of exercise, it is striking to see the intellectual and neuronal effects. There are multitudes of other studies, all of which show that exercise is beneficial to neurogenesis. This extends to protecting against Alzheimer’s as well.
Besides exercise, there are many dietary measures that can help boost brain growth. The first would be curcumin, which is an element of the spice turmeric. As studies have indicated, curcumin has been directly linked to neurogenesis, at least in rats. Other studies have shown that curcumin also increases brain derived neurotrophic factor expression. This is important because BDNF is vital to many neurologic functions.
Survival of brain cells in situations where they would normally die has also been shown to happen by caloric restriction, and/or intermittent fasting. So to put the methods laid out so far, in a working context, it is a good idea to include turmeric in your diet, and then either calorically restrict, or intermittent fast, from time to time.
Besides neurogenesis, there is also a process called autophagy which gets turned on when human beings fast. Autophagy is loosely described as the process of cells cleaning house, and getting rid of junk. Theoretically, you can see how this may be beneficial to improved cellular and neuronal firing. But besides exercise and fasting, there are a few other elements that can help to grow new brain cells.
It should come as no surprise to the Paleo community that there are benefits to omega-3 fatty acids. As I’ve written about many times, docosahexaenoic acid is preferable over all other forms of omega-3s. Unsurprisingly, the scientific literature shows that DHA helps to support neurogenesis. There are many other reasons why you may want to supplement with DHA, or obtain large amounts from daily intake of wild-caught fish, but the specific neurological effects of DHA are intriguing.
Blueberries are another beneficial food that can be linked to neurogenesis. As this study on diet’s impact on neurogenesis indicates, the flavonoids in blueberries are advantageous. Since the link between increased neurogenesis and increased mood and cognition is obvious, it makes sense to regularly include blueberries in your diet. Not only will you be enjoying the cognitive effects of the food, but you will be indulging your taste buds and getting the inherent antioxidant effects as well.
While it is generally a good idea to keep your diet low in sugar, especially when looking to increase neurogenesis, blueberries are a rare exception because they offer so many other benefits. And it must be pointed out that they are low in sugar when compared to many other fruits. In fact, the below figure shows the multitude of factors involved in influencing neurogenesis, where both blueberries and flavonoids are shown individually.
Besides the above-listed methods, green tea is another method of increasing neurogenesis. Specifically, the compound epigallocatechin gallate (EGCG) is the element which has been linked to the growth of new brain cells. Researchers have shown that “EGCG treatment significantly increased the number of 5-bromo-2′-deoxyuridine (BrdU)-labeled cells in adult hippocampal neural progenitor cell (NPC) cultures and in the dentate gyrus of adult mice.” What does this mean to the layman? It means that drinking green tea, or supplementing with EGCG in isolated form, will increase your rate of new neuronal growth.
Initially neurogenesis was studied in rats before moving to humans. Unsurprisingly, EGCG was found to be beneficial for neurogenesis in rats as well. When comparing rat to human studies, we must always make sure the data is physiologically relevant. What does this mean? It means we must use dose-relevant amounts. The amount of EGCG that has been studied to be beneficial is obtainable by normal means in humans. A few cups of green tea, or a standardized extract of EGCG, will do the trick. This is not always the same, as is seen in the case for resveratrol.
Now before you get too excited about the process of becoming a genius via neurogenesis, it is vital to note the downsides and realistic outcomes of growing these new neurons. Though an exciting prospect, neurogenesis is subject to the rest of the diet, human bodily processes, and other activities and stresses going on in your brain. As researchers have also noted, too much neurogenesis could be just as bad as too little.
It is also important to note that many new neurons borne via the process of neurogenesis die within 2 weeks. So, it is not a way to replace a barely-functioning brain with Einstein’s brain. But, many of the new neurons do migrate into the molecular layer.
It is easy to overstate the importance of neurogenesis but the science is still emerging on just how much control we have over our own adult brain’s growth. There are, of course, other theories out there on how to increase your intelligence. And, it must be pointed out, that there are other factors influencing neurogenesis, both in a positive and negative fashion, as illustrated in the figure below.
In closing, it is important to think of neurogenesis as being similar to taking a supplement. Yes, it may be slightly beneficial to increase your intake of foods and supplements to help stimulate neurogenesis. But if your overall diet and lifestyle is poor, highly stressed and generally unhealthy, these methods will do little-to-no benefit. You must always remember the whole picture, the whole human body, and the whole psyche.