Now that I have written a couple of blogs about how our brain influences what we eat I was attracted to the idea of, how does food affect the human brain? In this blog I will explore this idea in depth in an attempt to gain an understanding about the reciprocal relationship between food and the human brain.
I want to start off by providing information on the effects of feeding on cognition and its importance in the human body. “The effects of food on cognition and emotions can start before the act of feeding itself, as the recollection of foods through olfactory and visual sensory inputs alters the emotional status of the brain” (ncbi.nlm.nih.gov). When the body start to ingest food it releases hormones, like insulin, that proceed to the hypothalamus and hippocampus, which in return activate the synapses in the brain increasing learning and memory. Interestingly enough a lack of food in the human body can elicit a similar response. An empty stomach promotes the release of a chemical, ghrelin, supporting synaptic plasticity and cognitive function. It is understood that a balanced diet as well as an empty stomach can lead to an increase in synaptic plasticity, learning, and memory; therefore, lets begin by examining how a balanced diet initiates this process.
A University of California Los Angeles professor of neurosurgery and physiological science by the name of Fernando Gmez- Pinilla has spent numerous years studying how food, as well as exercise and sleep, affects the brain. He has found that a balanced diet is very beneficial to the human brain as well as overall health. For example, by maintaining a balanced diet an individual is at a decreased risk for heart disease, cancer, and mental disorders. An important finding about the brain was that omega three fatty acids are extremely important to the brain. Omega three fatty acids have multiple benefits such as: improved learning and memory, helps fight mental disorders such as depression, and also helps fight mood disorders such as schizophrenia and dementia. According to professor Fernando Gmez- Pinilla, “Omega three fatty acids support synaptic plasticity and seem to positively affect the expression of several molecules related to learning and memory that are found on synapses.” Professor Gmez- Pinilla goes on to further state that, “Omega three fatty acids are essential for normal brain function.” There are many fantastic benefits from the consumption of omega three fatty acids; however, have a deficient amount of this fatty acid can have detrimental affects to the human brain. Not having a normal amount of omega three fatty acids can increase an individual’s risk of mental disorder. The common mental disorders are: attention- deficit disorder, depression, dyslexia, bipolar disorder, dementia, and schizophrenia. Another important note that professor Fernando Gmez- Pinilla makes is that, “getting omega three fatty acids from foods rather than from capsule supplements can be more beneficial, providing additional nutrients” (newsroom.ucla.edu). A few examples of foods that are rich in omega three fatty acids are: salmon, walnuts, and kiwi fruit.
http://www.healthyfoodhouse.com/kiwi-natural-remedy-for-many-diseases/
An important omega three fatty acid is docosahexaenoic acid, or DHA, which is an important omega three fatty acid that enhances synaptic plasticity, learning, and memory. DHA is also “the most abundant omega three fatty acid in cell membranes in the brain” (newsroom.ecla.edu). There is “abundant paleontological evidence [that] suggests that there is a direct relationship between access to food and brain size, and that even small differences in diet can have large effects on survival and reproductive success” (ncbi.nlm.nih.gov). If we look back in history to the beginning of humans we can detect ways in which the diet of early hominids increased the brain to body mass ratio (encephalization). Hominids diet was heavily reliant on shore- based foods such as fish. “Archeological evidence shows that early hominids adapted to consuming fish and thus gained access to DHA, [docosahexaenoic acid], before extensive encephalization occurred” (ncbi.nlm.nih.gov).
In addition to increasing synaptic plasticity, learning, and memory lets explore how a balanced diet influences diet and temperament. There has been an abundant amount of research done in the last 80 years and “these studies suggest that foods directly influencing brain neurotransmitter systems have the greatest effects on mood, at least temporarily” (dujs.dartmouth.edu). Serotonin is an important neurotransmitter produced by the brain and is responsible for regulating sleep, appetite, and impulse control. Serotonin is found in foods such as: oysters, clams, bananas, pineapples, nuts, milk, turkey, and many more. It is theorized by Wurtnman and Wurtman (1989) that a protein rich diet decreased serotonin levels in the brain. Protein rich foods are full of amino acids and low in tryptophan. The synthesis of serotonin relies on the binding of tryptophan to the transporters in the brain. The receptors that bind with tryptophan also bind with amino acids meaning if there is a plethora of amino acids and low count of tryptophan, the amino acids will occupy the receptors decreasing the production of serotonin. They also theorized “a diet rich in carbohydrates can relieve depression and elevate mood in disorders such as carbohydrate craving obesity, pre- menstrual syndrome and seasonal affective disorder (SAD)” (dujs.dartmouth.edu). Consuming a carbohydrate rich meal increases the production of glucose. This is important due to the fact that it increases the release of insulin allowing muscles to break up the amino acids and “enabling tryptophan to bind to transporters, enter the brain in large amounts, and stimulate serotonin synthesis” (dujs.dartmouth.edu).
https://www.organicfacts.net/health-benefits/animal-product/oysters.html
The most well- known foods people think of, when talking about mood altering foods, are chocolate and caffeine. Chocolate generally increases pleasant feelings and reduces tension; therefore, many people eat chocolate when they are in a bored, depressed, and stressed. “Chocolate contains a number of potentially psychoactive chemicals such as anandamines which stimulate the brain in the same way as cannabis” (dujs.dartmouth.edu) but they are in very low doses. In a 1994 experiment by Michener and Rozin it was found that it is actually the “taste and feel of chocolate in the mouth [that] is responsible for the chocolate craving.” From this experiment it can be concluded that chocolate can serve as a powerful mood enhancer. Next is caffeine, the most commonly used psychoactive substance in the world. Caffeine is attractive because it relieves headaches and drowsiness by blocking adenosine receptors in the brain. It can improve alertness and energy levels; however, it can also cause unpleasant effects for individuals with high anxiety.
http://kidswithoutgod.com/teens/forbidden-fruit/deadly-caffeine/
http://weknowyourdreams.com/chocolate.html
Although it is shown that food has many benefits for the brain and body, not all foods are beneficial. Poor diets full of sugars and high- fats can lead to serious health issues such as: obesity, cardiovascular disease, diabetes, and some forms of cancer. It has been shown that food preferences start in the womb. To see if this theory was true researchers turned to monkeys. “While pregnant, monkey mothers ate either a healthy, low- fat diet or a high- fat one. When their offspring were young- equivalent to human toddlers- they were given access to a junk food diet, high in fat and sugar. Compared to monkeys whose mothers ate healthy diets during pregnancy, monkeys whose mothers ate high- fat diets consume more of the junk food” (brainfacts.org). The researchers also tracked the expression of dopamine in order to see if their brains were permanently shaped to these food preferences. Due to the fact that dopamine levels decrease the more “treats” that an individual consumes because the brain is trying to turn down the dopamine signals and this is why it takes more of the same treat to experience the same feeling. A postdoctoral researcher at the Oregon National Primate Research Center by the name of Heidi Rivera pointed out that the high- fat diet is “similar to our western- style diet.” Going off of Rivera’s research Constance Harrell at Emory University sought out to answer the question of, “Can what you eat affect how you feel?” In order to test this question Harrell put adolescent rats on either a healthy rodent diet or a diet full of fructose. It was found that rats that had the high fructose diet exuded higher levels of stress hormones. This led to her next experiment of whether sugar- fed rats were more anxious or depressed. The two sets of rats were put in a maze and given the option of staying in the light or choosing the dark. The rats filled with sugar chose the dark hinting increased anxiety. Next they were put in a tank of water and again the rats full of sugar gave up earlier than those with a healthy diet, a sign of depression. Constance Harrell then stated, “I think it’s important to recognize there are potential impacts for a high fructose diet not only on metabolism, but also on the mind.”
Now that we understand how food affects the body and mind lets explore the affects of the lack of food on the human body and brain. “Based on our observations in animal models, a practical recommendation could be that children may benefit from not overeating at breakfast in order to make the most out of their morning hours at school,” said Horvath a chair and associate professor of the Section of Comparative Medicine at Yale School of Medicine, and associate professor in the Department of Obstetrics, Gynecology and Reproductive Sciences, and Neurobiology. The main hormone that is responsible for regulating hunger is Ghrelin, growth hormone- releasing peptide. In addition to regulating hunger Ghrelin “ghrelin enters the hippocampus of the brain from the blood and alters the connections between nerves and cells to enhance learning and memory” (news-medical.net). It is found that learning is most effective throughout the middle of the day when the stomach is empty due to the fact that the levels of ghrelin are higher when the stomach is empty. Ghrelin is also important for neurotrophy, which is the brain’s ability to adapt to new environments and learn new processes.
Work Cited
Gómez-Pinilla, F. (2008, July 1). Brain foods: The effects of nutrients on brain function. Retrieved December 11, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2805706/
Hopf, S. (2011, February 3). You Are What You Eat: How Food Affects Your Mood. Retrieved December 11, 2015, from http://dujs.dartmouth.edu/fall- 2010/you-are-what-you-eat-how-food-affects-your-mood#.VmxRQkJVg5M
Interpretation of a dream in which you saw «Chocolate». (n.d.). Retrieved December 11, 2015, from http://weknowyourdreams.com/chocolate.html
Kids Without God : Deadly Caffeine? (2012). Retrieved December 11, 2015, from http://kidswithoutgod.com/teens/forbidden-fruit/deadly-caffeine/
Klosowski, T. (2012, April 5). What ‘Brain Food’ Actually Does for Your Brain. Retrieved December 11, 2015, from http://lifehacker.com/5899379/what- brain-food-actually-does-for-your-brain
Let’s Eat: How Diet Influences the Brain. (2015, May 15). Retrieved December 11, 2015, from http://www.brainfacts.org/across-the-lifespan/diet-and- exercise/articles/2015/lets-eat-how-diet-influences-the-brain/
Mandal, A. (2010, May 17). What Does Ghrelin Do? Retrieved December 11, 2015, from http://www.news-medical.net/health/What-Does-Ghrelin-Do.aspx
Shaw, G. (2010, December 19). We Eat With Our Eyes First. Retrieved December 11, 2015, from http://glennashaw.com/2010/12/we-eat-with-our-eyes-first/
We may learn best on an empty stomach! (2006, February 23). Retrieved December 11, 2015, from http://www.news- medical.net/news/2006/02/23/16154.aspx
Wenk, G. (2010, October 25). How does food affect our brain? Retrieved December 11, 2015, from https://www.psychologytoday.com/blog/your-brain- food/201010/how-does-food-affect-our-brain
Wolpert, S. (2008, July 9). Scientists learn how what you eat affects your brain – and those of your kids. Retrieved December 11, 2015, from http://newsroom.ucla.edu/releases/scientists-learn-how-food-affects- 52668