by Kathleen Castner
Can you keep your brain healthy and evade deadly diseases by eating crunchy foods?
While a breakfast smoothie may seem enticing, it may not be the best way to start the day. Of course, that’s if you are looking to regenerate your brain cells. Neurogenesis is the process by which new neurons are formed in the brain. It is crucial during embryonic development as stem cells begin to differentiate into various types of neurons. Neurogenesis occurs in mature brains as well. Adult neurogenesis occurs in three main areas: the hippocampus, the amygdala, and the brain’s lateral ventricles. The hippocampus, which is imperative for learning and memory, produces about 700 new neurons per day. It is estimated that the human brain has 86 billion neurons. Interestingly, by the time we turn 50, we will have exchanged all of our original neurons with adult-born neurons.
During adolescence, the hippocampus is maturing which means that neurogenesis is occurring at heightened levels. This is why alterations during this time, such as diet changes or mental health conditions, could be particularly devastating. Furthermore, decreased neurogenesis also occurs in people with depression. Antidepressants are prescribed to stimulate new nerve cells which typically decrease the severity of depression.
The process of neurogenesis was debated until it was confirmed by a 1998 study that looked at postmortem brains and found an abundance of newborn nerve cells. The emergence of newborn neuron cells diminishes with age, however, there is fascinating research about the connection between neurogenesis and neurological diseases. These include Parkinson’s and Alzheimer’s which cause a decrease in memory and cognitive skills. Additionally, a study published in the journal nature medicine found that “the number and maturation of these neurons progressively declined as [Alzheimer’s] advanced” (Moreno-Jiménez et al., 2018). There was a stark contrast between newborn neurons in Alzheimer’s subjects versus healthy subjects. Hence, there is a feature of these neurological diseases that burst newborn neurons throughout adulthood. This explains the early onset of these conditions.
The good news is that we can control neurogenesis. Intuitively, stress and sleep deprivation will decrease neurogenesis, while exercise and learning will increase neurogenesis. Diet matters as well. An increase in nutrients, such as Omega-3 fatty acids—salmon and leafy greens—and flavonoids—blueberries and chocolate—will increase neurogenesis.
Moreover, another way to prevent degeneration is by eating foods that you have to chew. Japanese researchers sickened mice by feeding them a “soft-diet” of powdered foods and found that this decreased neurogenesis. Then, they fed them a “hard-diet” which recovered the impaired effects of the “soft-diet.” This has implications for humans. It suggests that humans should eat crunchy foods such as carrots, whole fruits, chips, and nuts to feed the brain. This hypothesis also explains why elders, who typically require a “soft-diet” due to their lack of teeth, have decreased learning and memory capabilities. So, yes, maybe an apple a day is the way to keep the doctor away.
Sources
1. https://www.ted.com/talks/sandrine_thuret_you_can_grow_new_brain_cells_here_s_how/transcript#t-330078
2. https://www.imi.com.hk/you-can-grow-a-new-brain-every-day
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4016307/
4. https://qbi.uq.edu.au/brain-basics/brain-physiology/adult-neurogenesis
5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5416690/#:~:text=Hippocampal%20neurogenesis%20occurs%20during%20development%20and%20continues%20throughout%20life.&text=During%20the%20adolescent%20period%2C%20maturation,at%20this%20time%20particularly%20consequential
6. https://www.sciencenews.org/article/new-nerve-cells-adult-brains
7. https://www.nature.com/articles/s41591-019-0375-9
8. https://www.the-scientist.com/news-opinion/reduced-adult-neurogenesis-linked-with-alzheimers-disease-68413