Skip to main content

Fundamentals

Many individuals recognize a subtle shift in their internal rhythm, a feeling of being out of sync with their own body’s once-predictable patterns. This often manifests as persistent fatigue, unexpected weight fluctuations, or a recalcitrant mood. These sensations are not merely subjective experiences; they signal a deeper, biological dialogue unfolding within your cells. Our understanding of this internal communication has advanced significantly, moving beyond a static view of inherited predispositions to acknowledge the profound plasticity of our biological systems.

The blueprint for our physical existence, the genome, holds a remarkable capacity for dynamic adjustment. This adaptability is governed by a sophisticated regulatory layer known as the epigenome. Epigenetics, in essence, represents the intricate software dictating how our genetic hardware operates.

It comprises a collection of chemical modifications to DNA and its associated proteins, which determine which genes are active or quiescent without altering the underlying genetic code itself. These modifications act as molecular switches, influencing the production of everything from enzymes to the very hormones that orchestrate our well-being.

Your body’s internal sensations are signals of a dynamic biological conversation, revealing the profound adaptability of your genetic blueprint.

A patient on a subway platform engages a device, signifying digital health integration for hormone optimization via personalized care. This supports metabolic health and cellular function by aiding treatment adherence within advanced wellness protocols

How Does the Epigenome Function?

Two primary mechanisms illustrate the epigenome’s operational prowess ∞ DNA methylation and histone modification. DNA methylation involves the addition of a methyl group to specific cytosine bases within the DNA sequence. This chemical tag typically silences gene expression, much like a dimmer switch reducing the output of a light. Conversely, the removal of these methyl groups often reactivates gene transcription. This process is highly responsive to environmental cues, acting as a direct interface between external stimuli and internal genetic activity.

Histone modifications represent another layer of epigenetic control. Our DNA wraps around proteins called histones, forming a compact structure within the cell nucleus. The tightness of this wrapping determines gene accessibility. Chemical tags, such as acetyl groups, attach to these histones, altering how tightly the DNA is coiled.

Acetylation, for example, typically loosens the DNA-histone interaction, making genes more accessible for transcription, thereby increasing gene expression. Deacetylation, conversely, condenses the DNA, restricting gene access. These modifications are not random occurrences; they respond with precision to signals derived from our daily choices, translating them into instructions for our endocrine system.

A woman releases dandelion seeds, symbolizing the diffusion of hormone optimization and metabolic health. Background figures portray a thriving patient community benefiting from clinical protocols, promoting cellular function, patient well-being, health longevity, and optimal health outcomes on their wellness journey

Epigenetic Influence on Hormonal Systems

The endocrine system, a complex network of glands and hormones, serves as the body’s internal messaging service, regulating virtually every physiological process. Epigenetic modifications directly influence the genes responsible for hormone synthesis, receptor sensitivity, and metabolic breakdown.

For instance, epigenetic changes can dictate the efficiency of testosterone production in the testes or ovaries, modulate the sensitivity of cells to insulin, or alter the feedback loops governing thyroid hormone release. Understanding these mechanisms provides a clear framework for comprehending how our actions can recalibrate our hormonal landscape.

Consider the hypothalamic-pituitary-gonadal (HPG) axis, a central regulator of reproductive and stress hormones. Epigenetic marks can fine-tune the expression of genes for gonadotropin-releasing hormone (GnRH) in the hypothalamus, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the pituitary, and steroidogenic enzymes in the gonads. These molecular adjustments mean that lifestyle factors possess the power to influence the very command centers of our hormonal health, offering a pathway toward restoring balance and function.

Intermediate

Moving beyond the foundational understanding of epigenetics, we consider how specific lifestyle domains engage in this intricate molecular dialogue, shaping our hormonal health. The body continuously interprets environmental inputs, translating them into epigenetic instructions that either support or challenge endocrine equilibrium. This continuous feedback loop underscores the profound impact of daily habits on our long-term vitality.

Gentle patient interaction with nature reflects comprehensive hormone optimization. This illustrates endocrine balance, stress modulation, and cellular rejuvenation outcomes, promoting vitality enhancement, metabolic health, and holistic well-being through clinical wellness protocols

Nutrition and Epigenetic Programming

Dietary choices serve as a powerful epigenetic modulator, supplying the necessary building blocks and signals for enzymatic activity. Micronutrients, often overlooked, play indispensable roles. For instance, B vitamins, particularly folate and B12, act as methyl donors, providing the raw material for DNA methylation processes. A deficiency in these essential cofactors can disrupt the precise balance of methylation, potentially altering the expression of genes involved in hormone metabolism or receptor function.

The composition of macronutrients also influences the epigenome. High-fat diets, for example, can induce epigenetic changes that promote insulin resistance, thereby affecting metabolic and hormonal pathways. Conversely, diets rich in polyphenols, found in fruits and vegetables, can activate enzymes that remove acetyl groups from histones, influencing gene expression in a manner beneficial to metabolic health. The gut microbiome, itself shaped by diet, also produces metabolites that directly interact with epigenetic machinery, demonstrating a complex, multi-layered influence.

Dietary components provide the molecular signals and substrates that guide epigenetic modifications, directly influencing hormonal balance.

A woman's serene expression embodies optimal health and vitality, reflecting patient satisfaction from personalized care. Her appearance suggests successful hormone optimization and improved metabolic health via clinical protocols, enhancing cellular function and clinical wellness

Sleep Rhythms and Endocrine Regulation

The modern world often disregards the profound importance of adequate sleep, yet it represents a cornerstone of hormonal health. Circadian rhythms, our internal 24-hour clocks, are themselves under epigenetic control and, in turn, regulate the rhythmic release of many hormones.

Chronic sleep deprivation or irregular sleep patterns can induce epigenetic modifications that disrupt the hypothalamic-pituitary-adrenal (HPA) axis, leading to sustained elevations in cortisol. This sustained cortisol can, through epigenetic mechanisms, suppress the HPG axis, impacting testosterone and estrogen production.

Disruptions to sleep also affect growth hormone release, which typically peaks during deep sleep cycles. Epigenetic alterations influencing growth hormone-releasing hormone (GHRH) or its receptors can attenuate this crucial nocturnal surge, affecting cellular repair, muscle synthesis, and fat metabolism. Optimizing sleep hygiene becomes a potent intervention for recalibrating these vital hormonal rhythms.

Group preparing fresh food exemplifies proactive health management via nutritional therapy. This lifestyle intervention supports metabolic health and endocrine function, central to hormone optimization, cellular regeneration, and patient empowerment in clinical wellness

Stress Management and Hormonal Resilience

Chronic psychological stress represents another significant epigenetic driver. The sustained activation of the HPA axis in response to persistent stressors leads to a continuous deluge of cortisol. Over time, this can epigenetically reprogram genes within the brain’s stress response circuitry, leading to heightened sensitivity to stress and impaired feedback inhibition. Such changes can perpetuate a state of hypercortisolemia, which profoundly impacts other endocrine systems, including thyroid function and gonadal hormone production.

Protocols centered on stress reduction, such as mindfulness practices or targeted peptide therapies like Sermorelin, which can support pituitary function, may influence these epigenetic adaptations. By modulating the HPA axis’s epigenetic landscape, individuals can enhance their hormonal resilience, fostering a more balanced stress response.

A focused individual executes dynamic strength training, demonstrating commitment to robust hormone optimization and metabolic health. This embodies enhanced cellular function and patient empowerment through clinical wellness protocols, fostering endocrine balance and vitality

Physical Activity and Metabolic Hormones

Regular physical activity initiates a cascade of beneficial epigenetic changes, particularly those affecting metabolic function and hormonal signaling. Exercise induces alterations in DNA methylation patterns and histone modifications in muscle and adipose tissue, enhancing insulin sensitivity and mitochondrial biogenesis. These epigenetic adaptations optimize glucose uptake and energy expenditure, directly influencing hormones like insulin, glucagon, and adipokines.

For men, consistent exercise supports healthy testosterone levels, with epigenetic mechanisms potentially influencing steroidogenic enzyme expression. For women, appropriate physical activity can contribute to more stable menstrual cycles and improved symptom management during perimenopause by supporting overall endocrine balance. Tailored exercise regimens, therefore, constitute a powerful tool for sculpting a more favorable epigenetic and hormonal profile.

The table below outlines how various lifestyle interventions can specifically influence epigenetic markers relevant to hormonal and metabolic health.

Lifestyle Intervention Primary Epigenetic Mechanism Hormonal/Metabolic Impact
Balanced Nutrition DNA Methylation, Histone Acetylation Optimized hormone synthesis, improved insulin sensitivity
Adequate Sleep Circadian Gene Expression, HPA Axis Regulation Balanced cortisol rhythms, optimized growth hormone release
Stress Reduction HPA Axis Gene Reprogramming Enhanced stress resilience, reduced cortisol-induced hormonal suppression
Regular Exercise Mitochondrial Gene Expression, Insulin Signaling Pathways Improved insulin sensitivity, supported gonadal hormone production

The integration of these elements creates a synergistic effect, where each choice reinforces the body’s capacity for self-regulation.

A personalized approach to wellness considers the individual’s unique epigenetic landscape and how targeted lifestyle adjustments can optimize their hormonal milieu. This is a continuous process of observation, adjustment, and refinement, moving toward a state of optimal function.

Academic

The exploration of lifestyle’s influence on epigenetic markers related to hormonal health necessitates a deep dive into the molecular intricacies governing gene expression. This academic perspective moves beyond correlational observations to examine the specific enzymatic machinery and non-coding RNA species that mediate these dynamic interactions. Our focus here centers on the precise mechanisms by which environmental cues translate into lasting changes in endocrine function.

A woman's healthy glow reflects optimal hormone balance and metabolic health. Her poised expression signifies successful cellular function, patient well-being, and personalized clinical wellness outcomes for endocrine health

Molecular Regulators of the Epigenome

At the heart of epigenetic regulation lie specific enzymatic families. DNA methyltransferases (DNMTs), for instance, catalyze the addition of methyl groups to cytosine residues, typically leading to gene silencing. Conversely, ten-eleven translocation (TET) enzymes facilitate DNA demethylation, promoting gene activation.

The precise balance of DNMT and TET activity, itself influenced by cellular metabolism and nutrient availability, dictates the methylation landscape across the genome. Lifestyle factors such as dietary intake of methyl donors (e.g. betaine, methionine) directly impact the availability of S-adenosylmethionine (SAM), the universal methyl donor for DNMTs.

Histone modifications involve a diverse array of enzymes, including histone acetyltransferases (HATs) and histone deacetylases (HDACs). HATs add acetyl groups to histones, opening chromatin structure and promoting gene transcription, while HDACs remove them, leading to gene silencing. The activity of these enzymes is highly sensitive to metabolic intermediates.

For example, butyrate, a short-chain fatty acid produced by gut bacteria from dietary fiber, acts as an HDAC inhibitor, potentially promoting beneficial gene expression patterns in various tissues, including those involved in insulin signaling. This highlights the profound interconnectedness of nutrition, the microbiome, and epigenetic control over metabolic and hormonal pathways.

Epigenetic regulation relies on precise enzymatic balance, which is highly responsive to cellular metabolism and nutrient availability.

Two females, showcasing vibrant metabolic health and endocrine balance, reflect successful hormone optimization. Their healthy appearance signifies optimal cellular function and positive clinical outcomes from personalized wellness and peptide therapy protocols

Non-Coding RNAs as Epigenetic Mediators

Beyond DNA methylation and histone modifications, non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs), play a significant role in modulating gene expression at a post-transcriptional level. miRNAs are small RNA molecules that bind to messenger RNA (mRNA) molecules, leading to their degradation or translational repression. This effectively silences gene expression without altering the DNA sequence.

Research indicates that lifestyle factors can alter miRNA expression profiles, which in turn affect hormonal pathways. For example, certain dietary patterns can influence the expression of miRNAs that target genes involved in cholesterol synthesis or steroid hormone production.

Chronic stress can also induce changes in specific miRNAs that regulate components of the HPA axis, potentially contributing to long-term alterations in cortisol dynamics. Understanding these miRNA-mediated regulatory networks provides a deeper appreciation for the nuanced ways lifestyle sculpts our endocrine landscape.

A patient consultation focuses on hormone optimization and metabolic health. The patient demonstrates commitment through wellness protocol adherence, while clinicians provide personalized care, building therapeutic alliance for optimal endocrine health and patient engagement

Epigenetic Memory and Intergenerational Effects

A compelling aspect of epigenetic research involves the concept of epigenetic memory, where environmental exposures can leave lasting marks on the epigenome, influencing health outcomes across an individual’s lifespan. Furthermore, evidence suggests the possibility of intergenerational epigenetic inheritance, where these lifestyle-induced epigenetic changes can be transmitted to subsequent generations, impacting their predisposition to metabolic and hormonal dysregulation. While the mechanisms for such inheritance are still under active investigation, they underscore the far-reaching consequences of our lifestyle choices.

This phenomenon holds significant implications for public health and personalized wellness protocols. Recognizing that early life nutrition or parental stress exposures can epigenetically prime an individual’s hormonal systems provides a powerful impetus for proactive interventions.

Two individuals portray radiant hormonal balance and metabolic health, reflecting optimal cellular function. Their expressions convey patient empowerment from personalized care via clinical protocols, showcasing wellness outcomes in integrative health

Peptide Modulators and Epigenetic Crosstalk

The clinical application of specific peptides offers a fascinating avenue for modulating cellular pathways that intersect with epigenetic machinery. Peptides like Sermorelin and Ipamorelin, which stimulate growth hormone release, operate through receptor-mediated signaling cascades. These cascades can ultimately influence the activity of transcription factors that, in turn, regulate the expression of DNMTs, HATs, or HDACs. By optimizing growth hormone pulsatility, these peptides may indirectly support a more favorable epigenetic environment for cellular repair and metabolic efficiency.

Similarly, peptides such as Pentadeca Arginate (PDA), known for its tissue repair and anti-inflammatory properties, may exert their effects by influencing cellular signaling pathways that have downstream impacts on epigenetic regulators. For instance, reducing inflammation through PDA could mitigate inflammatory signals that often lead to adverse epigenetic changes in metabolic tissues. The interplay between these exogenous peptides and endogenous epigenetic processes represents a frontier in personalized wellness, offering sophisticated tools for biochemical recalibration.

The table below details specific epigenetic targets and their potential modulation by lifestyle and therapeutic peptides.

Epigenetic Target/Pathway Mechanism of Action Lifestyle/Peptide Influence
DNA Methylation (DNMTs, TETs) Gene silencing/activation via methyl group addition/removal Dietary methyl donors, B vitamins, stress, Sermorelin (indirectly via GH signaling)
Histone Acetylation (HATs, HDACs) Chromatin opening/closing, gene accessibility Polyphenols, short-chain fatty acids, exercise, PDA (via inflammation reduction)
MicroRNA Expression Post-transcriptional gene silencing Specific dietary components, chronic stress, sleep disruption
HPA Axis Genes Stress response modulation Mindfulness, adequate sleep, Sermorelin (stabilizing cortisol feedback)

This intricate network reveals that a comprehensive wellness protocol extends beyond simple supplementation, embracing a systems-biology perspective where lifestyle choices, supported by targeted interventions, can fundamentally reshape our biological destiny.

The ongoing research into these molecular mechanisms promises increasingly precise strategies for optimizing hormonal health and promoting longevity.

A focused woman with vital appearance signifies achieved physiological balance and optimal metabolic health from hormone optimization. This exemplifies enhanced cellular function through a structured clinical protocol for wellness outcomes in the patient journey

References

  • Dolinoy, Dana C. Randy L. Jirtle, and Robert A. Waterland. “The Agouti viable yellow allele ∞ a model for prenatal nutritional effects on the epigenome and adult health.” Nutrition Reviews 64.Suppl_1 (2006) ∞ S7-S12.
  • Holliday, Robin. “DNA methylation and epigenetics.” Science 238.4823 (1987) ∞ 102-104.
  • Feinberg, Andrew P. “Epigenetics at the epicenter of modern medicine.” JAMA 313.21 (2015) ∞ 2119-2120.
  • Waterland, Robert A. and Randy L. Jirtle. “Transposable elements ∞ targets for early nutritional effects on epigenetic gene regulation.” Molecular and Cellular Biology 23.15 (2003) ∞ 5293-5300.
  • Szyf, Moshe. “DNA methylation and cancer ∞ an epigenetic paradigm.” Seminars in Cancer Biology 15.4 (2005) ∞ 329-333.
  • Nestler, Eric J. “Epigenetic mechanisms in depression.” Dialogues in Clinical Neuroscience 13.3 (2011) ∞ 327.
  • Deldicque, Louise. “Epigenetic regulation in skeletal muscle with exercise.” Current Opinion in Clinical Nutrition and Metabolic Care 18.2 (2015) ∞ 159-165.
  • Kovats, Eszter, and George P. Chrousos. “Stress, hormones, and immunity.” Annals of the New York Academy of Sciences 840.1 (1998) ∞ 641-647.
  • Chrousos, George P. and Philip W. Gold. “The concept of stress and stress system disorders.” JAMA 267.10 (1992) ∞ 1244-1252.
  • Lim, Aaron S. et al. “Epigenetic drift in the human prefrontal cortex ∞ the impact of aging and common neuropathology.” Brain 138.10 (2015) ∞ 3008-3022.
A focused woman, embodying cellular vitality, reflective of hormone optimization. Her patient journey toward endocrine balance in clinical wellness through individualized protocols delivers metabolic health and therapeutic outcomes

Reflection

As we conclude this exploration, consider the profound agency you possess in shaping your biological destiny. The knowledge that lifestyle choices orchestrate epigenetic modifications, thereby influencing your hormonal health, shifts the perspective from passive inheritance to active participation. This understanding is not an endpoint; it marks the genesis of a deeply personal inquiry into your own physiological landscape.

Each dietary decision, every moment of restorative sleep, and every conscious effort to manage stress becomes a deliberate input into a complex system designed for adaptation. The path toward reclaiming vitality and optimal function unfolds through consistent, informed engagement with these biological realities. Your unique journey warrants a personalized approach, one that respects your lived experience while leveraging the most current scientific insights to guide your way.

A patient's tranquil posture conveys physiological well-being, reflecting successful hormone optimization and metabolic health improvements. This image captures a positive patient journey via personalized therapeutic protocols, achieving endocrine balance and optimized cellular function for clinical wellness

Glossary

Individuals reflect optimal endocrine balance and enhanced metabolic health. Their vitality signifies successful hormone optimization, validating clinical protocols for cellular regeneration, fostering a comprehensive patient wellness journey

histone modification

Meaning ∞ Histone modification refers to reversible chemical alterations applied to histone proteins, fundamental components of chromatin, the DNA-protein complex within the cell nucleus.
Guitar playing illustrates achieved endocrine balance and metabolic health. This reflects profound patient well-being from precise hormone optimization, enhancing cellular function

dna methylation

Meaning ∞ DNA methylation is a biochemical process involving the addition of a methyl group, typically to the cytosine base within a DNA molecule.
A woman embodies hormone optimization and metabolic health. Her vitality reflects positive therapeutic outcomes of a patient journey, emphasizing holistic wellness, cellular function, and proactive health management

histone modifications

Lifestyle choices create the optimal cellular environment, amplifying the precision and power of peptide signals for enhanced therapeutic outcomes.
Two men, different ages, embody the hormone optimization journey. Their focused gaze signifies metabolic health, endocrine balance, and cellular function, reflecting personalized treatment and clinical evidence for longevity protocols

endocrine system

Meaning ∞ The endocrine system is a network of specialized glands that produce and secrete hormones directly into the bloodstream.
An emergent fern symbolizes profound cellular regeneration and physiological restoration, representing the journey toward optimal hormonal balance and metabolic health. Expert peptide therapy and precise clinical protocols enable comprehensive patient well-being and health optimization

gene expression

Meaning ∞ Gene expression defines the fundamental biological process where genetic information is converted into a functional product, typically a protein or functional RNA.
Two women, representing the patient journey in hormone optimization, symbolize personalized care. This depicts clinical assessment for endocrine balance, fostering metabolic health, cellular function, and positive wellness outcomes

epigenetic modifications

Lifestyle-driven epigenetic changes in PCOS can be heritable, offering a potential pathway to influence the health of future generations.
A serene woman embodies optimal metabolic health and hormonal balance, reflecting successful clinical outcomes. Her vibrant appearance suggests enhanced cellular function and overall physiological well-being from personalized patient care

epigenetic changes

Targeted lifestyle and clinical protocols can influence the body's gene expression, promoting a functional reset of cellular health.
Two people on a balcony symbolize their wellness journey, representing successful hormone optimization and metabolic health. This illustrates patient-centered care leading to endocrine balance, therapeutic efficacy, proactive health, and lifestyle integration

hormone release

Strategic meal timing and targeted amino acids can amplify your body's natural release of growth hormone for repair and vitality.
A woman with glasses represents a patient engaged in personalized hormone optimization. Her calm expression reflects successful metabolic health management and a positive clinical wellness journey, emphasizing patient consultation for endocrine balance and cellular regeneration

hormonal health

Meaning ∞ Hormonal Health denotes the state where the endocrine system operates with optimal efficiency, ensuring appropriate synthesis, secretion, transport, and receptor interaction of hormones for physiological equilibrium and cellular function.
A confident woman with radiant skin and healthy hair embodies positive therapeutic outcomes of hormone optimization. Her expression reflects optimal metabolic health and cellular function, showcasing successful patient-centric clinical wellness

methyl donors

Meaning ∞ Methyl donors are compounds that provide a methyl group, a single carbon unit (CH3), essential for various biochemical reactions throughout the body.
A vibrant young man exemplifies comprehensive hormone optimization and excellent metabolic health. His relaxed smile highlights profound patient well-being, demonstrating successful clinical wellness and the therapeutic efficacy of tailored regenerative protocols for endocrine balance and optimal cellular function

circadian rhythms

Meaning ∞ Circadian rhythms are intrinsic biological processes oscillating approximately every 24 hours, regulating numerous physiological and behavioral functions.
A glowing citrus cross-section reveals intricate cellular structures and essential bioavailable nutrients, symbolizing profound physiological vitality and metabolic health foundational to effective hormone optimization and advanced therapeutic intervention protocols.

growth hormone release

Strategic meal timing and targeted amino acids can amplify your body's natural release of growth hormone for repair and vitality.
A woman's vibrant appearance embodies hormone optimization and metabolic health. This reflects positive therapeutic outcomes from a clinical protocol, highlighting optimal cellular function and physiological balance achieved through personalized care and patient education

growth hormone

Peptides stimulate your body’s own rhythmic GH production, while direct GH provides a constant external supply that bypasses this natural system.
A woman in glasses embodies hormone optimization through personalized wellness protocols. Her direct gaze reflects a patient consultation for endocrine balance, metabolic health, cellular function, and longevity medicine, supported by clinical evidence

hpa axis

Meaning ∞ The HPA Axis, or Hypothalamic-Pituitary-Adrenal Axis, is a fundamental neuroendocrine system orchestrating the body's adaptive responses to stressors.
Individuals exhibit profound patient well-being and therapeutic outcomes, embodying clinical wellness from personalized protocols, promoting hormone optimization, metabolic health, endocrine balance, and cellular function.

hormonal resilience

Meaning ∞ Hormonal resilience denotes the physiological capacity of the endocrine system to maintain optimal function and equilibrium amidst various internal and external stressors.
Serene individuals radiate vitality, showcasing optimal hormone optimization for metabolic health. This image captures patient outcomes from personalized medicine supporting cellular function, endocrine balance, and proactive health

metabolic function

Meaning ∞ Metabolic function refers to the sum of biochemical processes occurring within an organism to maintain life, encompassing the conversion of food into energy, the synthesis of proteins, lipids, nucleic acids, and the elimination of waste products.
Radiant woman embodies hormone optimization, metabolic health, physiological well-being. This reflects enhanced cellular function, endocrine balance via personalized wellness protocols from patient consultation, demonstrating restorative health

gene silencing

Meaning ∞ Gene silencing refers to the cellular process controlling gene expression by preventing a specific gene from producing its corresponding protein.
Patient on coastal rock represents hormone optimization, metabolic health, and endocrine balance. This reflects personalized treatment success for optimal cellular function, a pivotal patient journey towards holistic wellness and longevity strategies

personalized wellness protocols

Meaning ∞ Personalized Wellness Protocols represent bespoke health strategies developed for an individual, accounting for their unique physiological profile, genetic predispositions, lifestyle factors, and specific health objectives.
A mature male's confident gaze conveys optimal endocrine balance and enhanced cellular function. This portrays successful hormone optimization, showcasing improved metabolic health and positive outcomes from a tailored clinical protocol, marking a holistic wellness journey

biochemical recalibration

Meaning ∞ Biochemical recalibration refers to the adaptive processes by which the body's internal chemical environment is adjusted to restore or maintain optimal physiological function.