During the long sea voyages of the fifteenth and sixteenth centuries, a period known as the age of discoverysailors reported experiencing visions of sublime food and green fields. The discovery that they were nothing more than hallucinations after months at sea was harrowing. Some sailors wept with longing; others threw themselves overboard.
The cure for these harrowing mirages turned out not to be a mixture of complex chemicals, as suspected, but the simple antidote of lemon juice. these sailors suffered from scurvya disease caused by a deficiency of vitamin C, an essential micronutrient that people get from eating fruits and vegetables.
Vitamin C is important for the production and release of neurotransmitters, the brain’s chemical messengers. In its absence, brain cells do not communicate effectively with each other, which can lead to hallucinations.
As this famous example from early explorers illustrates, there is an intimate connection between food and the brain, one that researchers like me are working to unravel. as a scientist who studies the neuroscience of nutrition At the University of Michigan, I am primarily interested in how food components and their breakdown products can alter the genetic instructions that control our physiology.
Beyond that, my research is also focused on understanding how food can influence our thoughts, moods, and behaviors. While we can’t yet prevent or treat brain conditions through diet, researchers like me are learning a lot about the role nutrition plays in the everyday brain processes that make us who we are.
Perhaps not surprisingly, a delicate balance of nutrients is key to brain health: deficiencies or excesses of vitamins, sugars, fats, and amino acids can influence the brain and behavior in negative or positive ways.
Vitamin and mineral deficiencies
As with vitamin C, deficiencies in other vitamins and minerals can also precipitate nutritional diseases that negatively impact the human brain. For example, low dietary levels of vitamin B3/niacin, normally found in meat and fish, causes pellagraa disease in which people develop dementia.
Niacin is essential for converting food into energy and building blocks, protecting the genetic blueprint from environmental damage, and controlling the amount of certain gene products that are produced. In the absence of these critical processes, brain cells, also known as neurons, malfunction and die prematurelywhich leads to dementia.
In animal models, decreased or blocked niacin production in the brain promotes neuronal damage and cell death. Conversely, increasing niacin levels has been shown to mitigate the effects of neurodegenerative diseases such as Alzheimer’s, Huntington’s and Parkinson’s. Observational studies in humans suggest that sufficient levels of niacin can protect against these diseasesbut the results are still inconclusive.
Interestingly, niacin deficiency caused by consuming excessive amounts of alcohol can lead to effects similar to those found with pellagra.
Another example of how a nutrient deficiency affects brain function can be found in the element iodine, which, like niacin, must be obtained from the diet. Iodine, which is present in shellfish and algae, is an essential component of thyroid hormones, signaling molecules that are important to many aspects of human biology, including development, metabolism, appetite, and sleep. Low iodine levels prevent the production of adequate amounts of thyroid hormones, affecting these essential physiological processes.
Iodine is particularly important for the developing human brain; Before table salt was supplemented with this mineral in the 1920s, iodine deficiency was a leading cause of cognitive disability worldwide. The introduction of iodized salt is believed to have contributed to the gradual rise in IQ scores over the last century.
ketogenic diet for epilepsy
Not all dietary deficiencies are bad for the brain. In fact, studies show that people with drug-resistant epilepsy, a condition in which brain cells fire uncontrollably, can reduce the number of seizures by adopting an ultra-low-carbohydrate diet, known as ketogenic dietin which 80% to 90% of calories are obtained from fat.
Carbohydrates are the body’s preferred source of energy. When they’re not available, whether from fasting or a ketogenic diet, cells get fuel by breaking down fats into compounds called ketones. The utilization of ketones for energy leads to profound changes in metabolism and physiologyincluding the levels of hormones circulating in the body, the amount of neurotransmitters produced by the brain, and the types of bacteria that live in the gut.
The researchers think that these diet-dependent changes, especially the increased production of brain chemicals that can calm neurons and lower levels of inflammatory molecules, may play a role in the ketogenic diet’s ability to reduce the number of seizures. These changes may also explain the Benefits of a ketogenic state. – either through diet or fasting – on cognitive function and mood.
Sugar, saturated fats and ultra-processed foods
Excessive levels of some nutrients can also have detrimental effects on the brain. In human and animal models, high intake of refined sugars and saturated fats – a combination commonly found in ultra-processed foods – promotes eating while desensitizing the brain to hormonal signals that regulate satiety.
Interestingly, a diet high in these foods also desensitizes the taste system, causing animals and humans to perceive food as less sweet. These sensory disturbances can affect food choices as well as the reward we get from food. For example, research shows that people’s responses to ice cream in areas of the brain important for taste and reward they get bored when they eat it every day for two weeks. Some researchers believe that this decrease in reward signals from food may improve cravings for even more fatty and sugary foodssimilar to the way smokers crave cigarettes.
Diets high in fat and processed foods are also associated with lower cognitive function and memory. inhumans Y animal models as well as a higher incidence of neurodegenerative diseases. However, researchers do not yet know if these effects are due to these foods or the weight gain and insulin resistance that they cause. develop with long-term consumption of these diets.
time scales
This brings us to a critical aspect of diet’s effect on the brain: timing. Some foods can acutely influence brain function and behavior, such as for hours or days, while others take weeks, months, or even years to have an effect. For example, eating a slice of cake quickly switches a person with drug-resistant epilepsy from a ketogenic fat-burning metabolism to a carbohydrate-burning metabolism, increasing the risk of seizures. By contrast, it takes weeks of sugar consumption to change the brain’s taste and reward pathways, and months of vitamin C deficiency to develop scurvy. Finally, when it comes to diseases like Alzheimer’s and Parkinson’s, the risk is influenced by years of dietary exposure in combination with other genetic or genetic factors. lifestyle factors such as smoking.
In the end, the relationship between food and the brain is a bit like delicate goldilocks: we don’t need too little, not too much, just enough of each nutrient.
