How Smell, Taste & Pheromone-Like Chemicals Control You | Huberman Lab Podcast #25

Summary

• Smell, taste, and pheromone-like chemicals play a role in controlling human behavior and emotions
• Roka makes high-quality, aesthetically pleasing eyewear with excellent optical clarity
• InsideTracker is a personalized nutrition platform that analyzes data from blood and DNA to help individuals understand their body and reach health goals
• The human visual system has a high degree of plasticity and can adapt to different environments
• The human brain is able to perceive and interpret smells and tastes in a complex manner
• Pheromones, chemical signals released by animals, can influence behavior and physiology in other animals
• Human pheromones may also play a role in social communication and attraction
• The olfactory system, responsible for the sense of smell, is closely linked to the brain's emotional centers
• Disruptions in the sense of smell can have negative impacts on mental health and overall well-being
• Pheromonal effects in humans are controversial and have not been clearly demonstrated
• Humans release chemicals in sweat, tears, and breath that can affect the biology of others
• Sensing and smelling chemicals can enhance sense of smell, taste, cognition, and learning
• Protocols for improving vision include near-far viewing exercises and spending 2 hours outside per day
• Correction: blue light from sunlight is beneficial, but bright blue light close to the eyes is not
• Chemical sensing protocols include smelling coffee beans, using essential oils, and practicing "smelling meditation"
• Nutrients and supplements that may improve sense of smell include zinc, magnesium, and vitamin A
• Dehydration can affect sense of smell, so it is important to drink enough water
• Exposure to pollutants can also impair sense of smell
• Techniques for improving memory include spacing out learning sessions, using mnemonic devices, and testing yourself on the material
• Memory can also be improved by getting enough sleep, staying physically and mentally active, and reducing stress.
• Chemicals that we smell and taste enter our body through the nose, mouth, and eyes
• Sometimes we intentionally bring chemicals into our body through food and drink, while other times we are exposed to chemicals through our environment
• People can also produce chemicals with their body, such as through breath, tears, or possibly pheromones, which can alter our biology
• A study found that men who smelled women's tears had a reduction in testosterone levels and brain activity associated with sexual arousal
• Pheromones may be responsible for the effect of tears on testosterone, but more research is needed to confirm this
• Other research has shown that pheromones may affect behavior and physiological processes in animals, but the evidence for their effects in humans is limited
• More research is needed to fully understand the role of pheromones in human biology and behavior
• Inhaling has a significant effect on alertness, focus, and memory
• Nasal breathing is better for learning than mouth breathing
• Sniffing nothing 10-15 times can enhance one's sense of smell and taste
• Smelling salts, ammonia, and adrenaline can increase brain activity and alertness
• The olfactory system is closely connected to the emotional and memory centers of the brain
• Aromatherapy may have some benefits, but more research is needed
• The act of smelling itself can have psychological effects on the brain, regardless of the smell itself
• People can learn to enhance their sense of smell by eliminating all other sensory input and focusing on their sense of smell
• Doing this can increase pleasure from food and increase sensitivity to different odors
• This can be achieved through practicing sniffing and interacting with different smells
• The effects of this training can be long-term
• The olfactory system is more receptive to these changes than other sensory systems
• Smelling food before eating it can improve the taste experience
• Strong smells can overwhelm the olfactory system, leading to a decrease in sensitivity
• The olfactory system can be trained to become more sensitive to certain smells while ignoring others
• This can be useful for people who have a strong sense of smell that picks up bad odors easily
• Olfactory (sense of smell) dysfunction is common in traumatic brain injury due to the location of olfactory neurons and the impact of head injuries on them
• Dopamine is associated with motivation, drive, and the establishment of new neurons in the olfactory system
• New relationships and taking certain antidepressants can impact the sense of smell
• Aging can lead to a loss of sense of smell and other senses, and interacting with odors can help maintain and improve the sense of smell
• Traumatic brain injury can be partially gauged and tracked by changes in the sense of smell
• Using smell to track recovery from brain injury and other conditions, and using pleasant odors to improve mood and motivation, are areas of ongoing research.
• People can smell things in their dreams and sniff in their sleep, but this ability is diminished during rapid eye movement (REM) sleep.
• Sniffing in response to an odor can be used to assess brain activity in people in coma or other states of unconsciousness.
• The smell of peppermint can increase attention and arousal, and smelling salts (ammonia salts) can also increase arousal but can be dangerous if used improperly.
• The sense of smell is closely tied to the emotional centers of the brain and can evoke strong emotional responses.
• The sense of smell can be impaired by alcohol, tobacco smoke, and some medications, and can also decline with age.
• The sense of smell can be improved through certain activities, such as regularly smelling a variety of odors and trying to identify them.
• Skunks, ferrets, and other animals can spray in response to fear or to mark their territory
• Some people find the smell of skunks to be pleasant, while others find it noxious
• There are five main tastes that humans can detect: sweet, salty, bitter, sour, and umami
• The myth that different parts of the tongue are responsible for detecting different tastes is false
• The taste receptors in the tongue are intermixed and respond to specific chemical structures in food and drink
• The gustatory nerve and the NST (nucleus of the solitary tract) are responsible for transmitting taste information to the brain
• The gustatory cortex processes and interprets taste information in the brain
• There are five main senses of taste: sweet, sour, salty, bitter, and umami
• Umami receptors detect amino acids and savory flavors, which may signal the presence of essential nutrients
• Sour receptors may help detect spoiled or fermented food
• There may be a potential sixth sense of taste for sensing fat in food
• Fat is important for brain function and the function of other organs
• Texture and flavor of fat can be enjoyable, but it is also important to have a balance in the types and amounts of fat consumed
• Carbohydrates and sugars are not essential nutrients, but amino acids and fatty acids are essential
• Individuals may need to determine the best diet for themselves, including potentially trying a ketogenic diet
• Fermented foods can be healthy and reduce inflammation, but fermented fruit can also be poisonous
• Taste receptors communicate with the brain to elicit responses such as closing the eyes and mouth to potentially harmful substances