Summary: Researchers assess how our choice of diet can affect our mood and behavior, and explain how certain diets can help manage certain neurological conditions.
During the long sea voyages of the fifteenth and sixteenth centuries, the period was known as era of discoveryThe sailors reported that they were suffering Visions of sublime foods and green fields. The discovery that these were nothing more than hallucinations after months at sea was heart-wrenching. Some sailors cried in longing. Others threw themselves into the sea.
The cure for this horrific mirage turned out not to be a mixture of complex chemicals, as previously suspected, but a simple antidote to lemon juice. These sailors Suffered from scurvyIt is a disease caused by a deficiency of vitamin C, an essential micronutrient that people gain from eating fruits and vegetables.
Vitamin C is important To produce and release neurotransmitters, Chemical messengers of the brain. In the absence of it, brain cells do not communicate effectively with each other, which can lead to hallucinations.
As this famous example of early explorers demonstrates, there is an intimate relationship between food and the brain, which researchers like myself are working to unravel. as a scientist who studies nutritional neuroscience At the University of Michigan, I’m primarily interested in how food ingredients and their decomposition products can change Genetic instructions that control our physiology.
Beyond that, my research also focuses on understanding how food can It affects our thoughts, moods, and behaviors. While we can’t yet prevent or treat brain conditions through diet, researchers like myself are learning a lot about the role that 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: A deficiency or excess of vitamins, sugars, fats, and amino acids can affect the brain and behavior in negative or positive ways.
Vitamin and mineral deficiency
As with vitamin C, deficiencies in other vitamins and minerals can lead to nutritional diseases that negatively affect the brain in humans. For example, low dietary levels of vitamin B3/niacin – commonly found in meat and fish – cause pellagraIt is a disease in which people become demented.
Niacin is necessary for converting food into energy and building blocks, protecting the genetic blueprint from environmental damage and controlling the amount of certain genetic products. In the absence of these critical processes, brain cells, also known as neurons, Malfunction and die prematurelyleading to dementia.
In animal models, reducing or blocking niacin production in the brain leads to neuronal damage and cell death. Conversely, improving niacin levels has been shown to mitigate the effects of neurodegenerative diseases such as Alzheimer’s, Huntington, and Parkinson’s. Observational studies in humans indicate adequate levels of niacin It may prevent these diseasesbut the results are still inconclusive.
Interestingly, niacin deficiency caused by consuming large amounts of alcohol can lead to effects similar to those of pellagra.
Another example of how nutrient deficiencies affect brain function can be found in iodine, which, like niacin, must be obtained from an individual’s diet. Iodine, found in seafood and seaweed, is an essential building block of thyroid hormones — signaling molecules important to many aspects of human biology, including growth, metabolism, appetite and sleep. Low iodine levels prevent the production of adequate amounts of thyroid hormones, impairing these basic physiological processes.
Iodine is especially important for human brain development. Before supplementing table salt with this mineral in the 1920s, iodine deficiency was a The leading cause of cognitive impairment worldwide. The introduction of iodized salt is believed to have contributed to The gradual rise in IQ scores in the last century.
Ketogenic diet for epilepsy
Not all nutritional deficiencies are harmful to 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 a low-carb diet known as a Ketogenic diet80% to 90% of calories come from fat.
Carbohydrates are the body’s preferred source of energy. When it’s not available — either because of fasting or because of a ketogenic diet — cells get fuel by breaking down fats into compounds called ketones. Using ketones for energy leads to depth Shifts in metabolism and physiologyThis includes the levels of hormones circulating in the body, the amount of neurotransmitters the brain produces and the types of bacteria that live in the gut.
Researchers think so These changes are based on dietIt may play a role in the ketogenic diet’s ability to reduce the number of seizures, particularly the higher production of chemicals in the brain that can calm nerve cells and reduce levels of inflammatory molecules. These changes may also explain Benefits of ketosis – Whether through diet or fasting – on cognitive function and mood.
Sugar, saturated fat, and ultra-processed foods
Excess levels of some nutrients can have harmful effects on the brain. In human and animal models, high refined consumption Sugars and saturated fats – A common blend in ultra-processed foods – encourages eating by sensitization the brain to hormonal signals known to regulate satiety.
Interestingly enough, a diet rich in these foods also Desensitizes the taste systemThis causes animals and humans to perceive food as less sweet. These sensory changes may affect food choice as well as the reward we get from food.
For example, research shows that people’s responses to ice cream are in areas of the brain Important for taste and reward Dull when they eat it every day for two weeks. Some researchers believe that this decrease in food reward signals may occur Increased cravings for more fatty and sugary foodssimilar to the way smokers crave cigarettes.
Diets high in fat and processed foods are also associated with lowered cognitive function and memory in humans And the animal models As well as the high incidence of neurodegenerative diseases. However, researchers still do not know whether these effects are due to these foods or to weight gain and insulin resistance Develop with long-term consumption of these diets.
This brings us to an important aspect of diet’s effect on the brain: time. Some foods can affect brain function and behavior acutely – for example over hours or days – while others take weeks, months or even years to have an effect.
For example, eating a slice of cake quickly changes the fat-burning ketogenic metabolism of an individual with drug-resistant epilepsy to a carbohydrate-burning metabolism, increasing the risk of seizures.
In contrast, it takes weeks of sugar consumption for tasting and altering reward pathways in the brain, 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 exposure to food as well as other genetic factors. Lifestyle factors such as smoking.
In the end, the relationship between food and the brain is a bit like a thin moderate: we don’t need too little, not too much, but just enough of each nutrient.
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