How Inhalation of Essential Oils Influence Brain Functioning

Inhalation of essential oils is one of the fastest, direct and most effective ways to shift your health.

Research on Therapeutic Effects and Mechanisms of Essential Oils found that “Inhalation is the fastest and most effective way to induce responses in the central nervous system within a few seconds, altering blood flow in the body by controlling circulation through the autonomous nervous system.”

Your sense of smell, which is part of the olfactory system, is one of the most powerful channels into the body.  In fact, your olfactory system is unique among the sensory systems for having direct anatomical and functional access into the limbic lobe of the brain which is physically located near the olfactory bulb.

This allows inhaled essential oils to easily access areas of the brain that help shift your physical health and your mood.

And it happens quickly!

Research shows that the entire process from the initial inhalation of an essential oil to a corresponding response in the body can happen in a matter of seconds. your sense of smell is thought to be 10,000 times more acute than your other senses. Once registered, scent stimuli travel more quickly to the brain than do either sight or sound.

This is because your sense of smell is key to survival!

Smell is often the first warning of safety or danger.  You smell food and water.  You smell predator odor and fire.

Research elaborates that “intact sense of smell is critical for evaluating the safety of ingestible substances, assessing impending danger, and recognizing social relationships.”

What’s more, your sense of smell bypasses absorption in the gut, where there are usually many roadblocks due to modern terrain issues like inflammation and leaky gut.  Similarly, research reveals that the digestive channel chemically alters the chemical constituents of essential oils, which undergo significant biotransformation after being absorbed in the digestive system which alters bioavailability and has been observed to alter their effects on health.

How Inhalation Allows Access to the Brain

One of the challenges of healing is getting the right remedy into the right area of the body.  For example, it is really hard to get remedies into the brain because the blood brain barrier acts as a highly selective, protective shield that surrounds and protects your brain from potentially dangerous agents that could disturb brain function. The tight gaps between the cells of your blood-brain barrier, known as tight junctions, allow only super small, nano-sized molecules, fat-soluble molecules, and some gases to pass freely through the capillary wall and into brain tissue.

Essential oils are naturally the ideal chemical composition to pass through the blood-brain barrier, as the molecular components that make up essential oils are so small that they’re known as volatile and aromatic. Essential oil molecules are so small – approximately 40 million-trillion molecules in one drop – that they literally circulate in the air where our noses detect them as smell.

When inhaled through the nose, essential oils efficiently pass through the blood brain barrier in the area surrounding the olfactory nerve. A true blood-brain barrier is 8 cells in thickness. The number of cells which constitute the layer around the olfactory nerve is only 4 to 5 cells thick. Hence, it is very easy for the oils to pass straight through to the brain when breathed in through the nose.

Essential oils are also lipophilic (fat-friendly), allowing them to access and bind to cell membranes, which are also comprised primarily of fat.   Research confirms that “the soluble molecules present in essential oil vapor carried with the inhaled air can cross the air–blood barrier. A majority of the essential oil components are lipophilic and hydrophobic in nature (lipid soluble terpene family). Lipophilic EO components can cross the blood–brain barrier and transport healing remedies to the nervous system.”

Your cellular membranes serve as a semi permeable, protective barrier, regulating what enters and leaves your cell.  Surface receptors that line the outside of your cell membranes allow your cells to receive chemical signals from your brain and your body.  When the appropriate chemical messenger binds with these receptors, it initiates a cascade of chemical changes inside your cellular membrane, triggering modifications in the function of the cell.

The selectively permeable nature of your cellular membrane relies on specialized transport mechanisms to help permeate your cell membrane and move into the cell without being limited by the cell’s transport machinery.   This process is known as passive diffusion and only a few substances – including gases like oxygen, nutrients, alcohol, some drugs (like anesthetics) and essential oils — are capable of moving in this way.   For example, the cells of your blood-brain barrier actively transport metabolic products such as glucose across the barrier in response to signals on their receptor sites.

Research demonstrates that when essential oils can interact with the receptor sites on your cellular membranes, influencing the excitatory and inhibitory effects on your brain’s chemical messengers.  It is believed that the compatibility of chemical composition allows essential oils to bind to and modulate cell receptors and transporters. This is because, like your brain cells, your cellular membranes are composed of lipids. Essential oils are lipid soluble and small, allowing them to directly traverse your cellular membrane.

This is one reason that short chain fatty acids help heal inflammation – the fatty acids are composed of lipids so they can actually access the cell membrane.  Essential oils have the same chemical composition and work in the same way! They support the normal electrical functioning of your brain and nervous system.

This makes essential oils especially helpful when your cells are compromised in their ability to efficiently pass substances across its membrane. Your cells can’t repair without the proper exchange of nutrients, but they cannot get the proper nutrients to repair and heal because membrane transport mechanisms are suboptimal. Essential oils have the ability to influence cells even when there is physiologic compromise such as during times of poor nutrition or environmental threats.

When inhaled, essential oils have been found to “stimulate the olfactory, respiratory, and gastrointestinal systems, and release endorphins to initiate a feeling of well-being and an analgesic effect”, according to research on Clinical Aromatherapy.

The Physical Process of Inhalation (Olfaction)

The process of olfaction involves the conversion of a chemical stimulus, an odorant, into an electrical signal sent to the brain for interpretation.

I have been trying to unpack the exact physical process and areas of the brain involved in smell to help explain how, when inhaled, essential oils travel through the nasal passageways into the brain.

Research on the Therapeutic Effect and Mechanisms of Essential Oils in Mood Disorders: Interaction between the Nervous and Respiratory Systems found three potential mechanisms of actions that enable essential oils to travel to the brain and influence brain functioning:

1) Nasal olfactory chemoreceptors (receptor cells found within the nasal cavity) are activated, setting off a cascade of olfactory signals within your brain.  Aromatic molecules contained within essential oils “travel through the interior of the nasal passage where the endothelium in the inner lining is thin and located close to the brain, allowing essential oil molecules to readily enter the local circulation and the brain.

A particular odorant can activate sensors in your nasal cavity, known as olfactory receptor cells, which have specialized cilia extensions. The cilia trap odor molecules as they pass across the epithelial surface. Information about the molecules is then transmitted via electrophysical signals which then stimulate the target regions in the brain.  Each receptor expresses a specific type of odorant reception which is how different odors can be identified and differentiated, according to research on The physiology of taste and smell: how and why we sense flavors.

Here’s how it works:

• The volatile molecules in EOs enter your olfactory system through the nasal cavity which leads to the olfactory lobe located close to the brain. The olfactory lobe is connected to several brain areas, including the amygdala (which processes the emotional response and the controls scent intensity), hypothalamus (which secretes hormones in responds to incoming sensory information) and hippocampus (which plays a role in odor memory formation).
• When you breathe in essential oils, Odorant molecules within the nasal passages signal receptors on the primary cilia of olfactory sensory neurons. Each neuron expresses a single type of protein receptor on these dendritic extensions.
• This activates the sensory neurons present in the olfactory mucosa, which deliver the signals to the limbic system and central nervous system.
• These signals help to modulate specific physiological responses involving mood and behavioral actions (emotion and cognition), hormone production, regulation of body temperature, digestive reactions, memory, stress responses, sedation, sex stimulation, blood pressure, and heart rate.

2) Direct penetration of EO molecules via the olfactory nerve into connected brain areas either by extracellular or by intracellular transport mechanisms. 

• Intracellular mechanism: When essential oils directly pass through the neuronal pathway in the olfactory lobe and are transmitted to the brain. The molecules bind with the olfactory receptor surface of the neurons and initiate receptor-mediated endocytosis (cells take in substances present outside the cell body by engulfing them in a vesicle which reopens inside the cell and the substance becomes a part of the cytoplasm).
• Extracellular transport mechanism: When essential oil molecules pass through the paracellular cleft between the olfactory sensory neuron and supporting cells and enter the connective tissue through fluid and fascia movement.  From the connective tissue, the essential oils are further transported through the blood–brain barrier and blood–cerebrospinal fluid barrier to spread into different regions in the brain where they interact with the neurotransmitter receptors – including GABA, serotonin and dopamine –  and produce anxiolytic and antidepressant effects, according the research on the Therapeutic Effect and Mechanisms of Essential Oils in Mood Disorders: Interaction between the Nervous and Respiratory Systems

3) Absorption into alveolar blood circulation: Post inhalation, essential oils can travel through the respiratory system involving gaseous exchange via diffusion into the blood circulation in the alveoli, also known as the air-containing compartments of the lungs.  Inhaled essential oils travel through the respiratory tract, enter the lungs, and reach the alveolar sacs where the gaseous exchange (of oxygen and carbon dioxide) takes place between the cells of the alveoli and blood cells in the capillaries.  Oxygen passively flows from the air inside the alveoli into the blood in the alveolar capillaries, carrying inhaled essential oils molecules with it, while carbon dioxide passively flows in the opposite direction.  Simultaneously, some essential oil molecules are also absorbed by the inner mucous linings of the respiratory tract, bronchi, and bronchioles.  Deep breathing tends to increase the quantity of any essential oil components absorbed into the body by this route. 

My Favorite Essential Oils to Improve Brain Function

As noted above, inhalation of essential oils can enhance blood flow, including blood flow to the brain with helps support a heathy flow of oxygen to the brain and enhance brain function.

Inhaling Circulation™ blend helps support healthy circulation to deliver oxygen and nutrient rich blood to the body and the brain. The brain is the most vertical tissue in the body with the smallest blood vessels that are furthest from the heart. It is consistently dealing with the forces of gravity due to its vertical position.

Inhalation or topical application of Circulation™ blend may help to increase circulation and blood flow to the brain.

Essential oils may help improve circulation by relaxing the smooth muscles that line the blood vessels and improving the health of the blood vessels.  This helps more blood circulate through them, improving your circulation and increasing brain oxygen levels in the process.

Plant compounds, including the highly concentrated essence of plants found in essential oils,  have been shown to help the veins contract, stimulating blood flow and enhance “brain microcirculation,” which is the flow of blood through the body’s smallest vessels.  

Circulation™ blend in particular contains Black Pepper essential oil, which has been found to enhance circulation, increasing blood flow to your digestive system which helps boost nutrient absorption, so much so that it is often added supplement formulations to enhance the effectiveness of the supplement. 

Apply 2- 3 drops on the sides or back of the neck, over the left clavicle, on the wrists or ankles to promote circulation and greatly accelerate the healing process.

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