How The Body Handles Fear + Anxiety

How The Body Handles Fear + Anxiety

Fear is a universal experience, having shaped our evolution as a means of survival. It's the shiver down our spine, the racing heart, the sudden surge of adrenaline. But what really happens in our body when we're afraid? Learn more about how the body responds to fear, the structures and functions involved when experiencing fear and anxiety, and what nutrients you should consider to offset these responses.

Fear's Origins: The Amygdala

Deep within the temporal lobes of our brain lies the amygdala, an almond-shaped set of nuclei. Part of the limbic system, the amygdala plays a pivotal role in emotional processing, particularly in the modulation and memory of emotional reactions. This organ interacts with other brain regions, like the prefrontal cortex, influencing decision-making, social interactions, and other emotions. It's our fear center, and it's lightning-fast. When we encounter something frightening, the amygdala receives this sensory information and begins to evaluate its threat level.

Step 1: Fight or Flight Response

The immediate response to fear is for the body to go into a "fight or flight" response. Once the amygdala sounds the alarm, a cascade of physiological responses is initiated. The primary response mechanism is the fight or flight reflex, driven by the autonomic nervous system.

  • Adrenaline Rush: The adrenal glands pump adrenaline (epinephrine) into our bloodstream. This hormone increases heart rate, pumping more blood to muscles, and prepares the body for rapid action.
  • Breathing Rate Increases: Our lungs work overtime, delivering oxygen-rich blood to vital organs and muscles.
  • Heightened Senses: Pupils dilate, allowing more light in, sharpening our vision. Our sense of hearing may also become more acute.
  • Muscle Tensing: Muscles receive more blood and brace for action, whether that's to fight the danger or flee from it.

Step 2: The Hypothalamic-Pituitary-Adrenal (HPA) axis

While the immediate response happens in seconds, the body's secondary response is orchestrated by the Hypothalamic-Pituitary-Adrenal (HPA) axis.

  • Immunity + Inflammation: cortisol also modulates the immune system response, suppressing non-essential functions and reducing inflammation.
  • Metabolic Shift: Cortisol ensures that the body has ample energy by increasing blood sugar and enhancing the brain's utilization of glucose.
  • Cortisol Release: The hypothalamus releases corticotropin-releasing hormone (CRH), leading the pituitary gland to secrete adrenocorticotropic hormone (ACTH). ACTH prompts the adrenal glands to release cortisol, a stress hormone.

The DIfference Between Fear + Anxiety

Recognizing the difference between fear and anxiety is essential in understanding our reactions and seeking appropriate interventions or coping mechanisms. Fear, in its essence, is a protector. It kept our ancestors alive, alerting them to predators and other threats. Fear is an immediate, direct response to a known or understood threat. However, in our modern world, where many of our fears are psychological rather than immediate physical threats, it's important to recognize when this protective mechanism becomes maladaptive.

Anxiety is a generalized feeling of unease or worry about a potential future threat or an outcome that is uncertain. It tends to be more chronic and persistent. It may linger and recur over time, especially if the source of worry is not addressed. Worrying about our health, relationships, or future life events can develop into chronic recurring thoughts that affect the body the same as the immediate response of fear, but on a long term basis. Once the threat is gone, the body usually returns to its normal state through the parasympathetic nervous system, often referred to as the "rest and digest" system. However, if the source of fear persists or if we are continually exposed to stressors, the body remains in a heightened state.

This long-term pattern of anxious thoughts and physical responses can exert a profound toll on the body, both physically and mentally. Chronic exposure to stress hormones like cortisol can have detrimental effects on health, including impaired cognitive performance, suppressed thyroid function, and increased abdominal fat.

Nutrients To Support The Fear Response

When faced with a perceived threat, the amygdala interprets this sensory information and initiates a response, often before the conscious brain has had time to process the situation. It does so by communicating with other brain regions and influencing the release of neurotransmitters. Additionally, the amygdala influences the release of stress hormones like cortisol, further amplifying the body's overall fear or stress response. Dysregulation in the amygdala's activity or imbalances in these neurotransmitters can contribute to excessive or inappropriate fear and anxiety reactions, underlying various anxiety disorders. By supporting the amygdala itself, and the neurotransmitters responsible for signaling in different parts of our body, you can help promote better balance in your fear + anxiety response while minimizing the damaging effects of overload on the body.


At the neuronal level, magnesium acts as a natural modulator of the NMDA subtype of glutamate receptors, effectively blocking their activity under typical conditions. Since glutamate is a primary excitatory neurotransmitter that can heighten brain responsiveness, magnesium's modulatory action helps maintain neuronal excitability within a controlled range.

Effects of Deficiency:

When magnesium levels are deficient, there's an increased risk of excessive glutamate receptor activity, which can lead to heightened neural excitability and, in turn, increased susceptibility to fear and anxiety. Furthermore, magnesium influences the release and activity of other neurotransmitters such as serotonin, which plays a significant role in mood regulation. Consequently, adequate magnesium levels are vital in modulating the neurochemical balance, potentially aiding in the reduction of fear and anxiety symptoms.

Vitamin D

Recent studies suggest a deeper connection between vitamin D and brain function, particularly concerning emotional regulation and the body's response to fear and anxiety. Vitamin D receptors are abundantly found throughout the brain, indicating its direct influence on brain activity. Deficiencies in vitamin D have been linked to an increased risk of mood disorders, including depression and anxiety. Some hypotheses suggest that vitamin D helps regulate the synthesis and release of neurotransmitters like serotonin, which play a pivotal role in mood stabilization and emotional well-being.

Effects of Deficiency:

Vitamin D may exert anti-inflammatory effects in the brain, which, when deficient, could predispose individuals to neuroinflammation, a factor recently associated with anxiety and mood disorders.


Emerging evidence is highlighting Zinc's significance in brain function and emotional well-being. Within the central nervous system, zinc is prominently stored in synaptic vesicles of certain neurons and modulates the activity of various neurotransmitters, particularly glutamate and GABA, which are integral to the brain's excitatory and inhibitory balance. Zinc's modulatory effects on glutamate receptors can help prevent excessive neuronal excitation, which has been linked to anxiety and other mood disorders. Additionally, zinc plays a role in the neuronal signaling of BDNF (Brain-Derived Neurotrophic Factor), a protein essential for neuroplasticity, synaptic strength, and resilience against stress.

Effects of Deficiency:

Deficiencies in zinc can disrupt these neurochemical processes, potentially increasing vulnerability to mood disturbances, including fear and anxiety. Therefore, maintaining optimal zinc levels in the body can support a balanced and adaptive neural response to stressors, mitigating the severity of anxiety-related symptoms.


B-vitamins are essential cofactors for enzymes involved in the synthesis of various neurotransmitters that modulate mood and emotional responses. For instance, Vitamin B6 (pyridoxine) is crucial for the synthesis of neurotransmitters like serotonin and dopamine, which are key regulators of mood and emotional well-being. Similarly, Vitamin B9 (folate) and Vitamin B12 (cobalamin) play roles in the synthesis of SAMe (S-adenosyl methionine), a compound involved in neurotransmitter metabolism.

Effects of Deficiency:

Deficiencies in these B-vitamins can lead to imbalances in neurotransmitter levels, potentially heightening vulnerability to mood disorders, including anxiety. Additionally, suboptimal levels of B-vitamins can elevate homocysteine, a compound associated with inflammation and oxidative stress in the brain, further exacerbating anxiety symptoms.

Vitamin C

Vitamin C's role in the central nervous system is gaining increasing attention, particularly concerning emotional well-being and the body's response to fear and anxiety. Vitamin C plays a vital role in the synthesis of neurotransmitters, notably norepinephrine, which affects mood and stress response. Additionally, being an antioxidant, vitamin C combats oxidative stress in the brain, which has been linked to anxiety and depressive disorders. Studies have shown that vitamin C supplementation may have an anxiolytic effect, potentially by modulating the body's physiological response to stress, aiding in neurotransmitter synthesis, and combatting neuroinflammation

Effects of Deficiency:

Chronic stress can deplete the brain's vitamin C levels, potentially exacerbating anxiety symptoms.