Functional hypoglycemia has not yet been clearly defined, however, it is generally understood as a condition in which hypoglycemic symptoms occur, predominantly postprandially, in the absence of glucose-related diseases or identifiable organic causes, such as diabetes mellitus, alcoholism, insulinoma, or insulin autoantibodies. The management for functional hypoglycemia is also not well established. Dietary modification, such as eating small, frequent meals, reducing carbohydrate intake, and increasing dietary fiber, is important, and regular physical activity is also useful. But other treatment options are limited and well not established. From a functional medicine perspective, functional hypoglycemia is thought to be associated with impaired insulin counter-regulatory response, particularly involving adrenal hormone function. A functional medical approach may be beneficial in managing patients with diminished adrenal capacity. In this context, we aim to explore the functional medicine-based diagnostic and therapeutic approach to functional hypoglycemia by presenting a case in which a suspected functional hypoglycemia was evaluated using continuous glucose monitoring and showed clinical improvement following dietary interventions and adrenal support therapy.

Functional digestive diseases are common conditions in primary care and chronic diseases that are not easily treated with traditional medicine approaches. This is because the one of fundamental causes of functional digestive diseases is gut dysbiosis, and therefore the 5R program as a functional medicine approach, is very effective in patient management. The 5R program has five steps: an elimination step (remove) to eradicate the overgrowth of harmful bacteria in the intestines, a digestive enzyme supplement step (replace) to help with food digestion, a reinoculation step to supplement beneficial bacteria following the elimination of harmful bacteria, a repair step to supplement nutrients to help restore damaged intestinal mucosal cells broken by inflammation caused by gut dysbiosis, and finally an education stage (rebalance) to improve bad lifestyle habits that may cause altered gut microbiota. These case studies demonstrate how the 5R program can be applied to patients with functional gastrointestinal disorders using non-absorbable antibiotics, digestive enzymes, probiotics, and nutritional supplements.

As awareness of the public health significance of particulate matter (PM) continues to spread, various epidemiological studies have revealed associations between PM exposure and respiratory diseases, cardiovascular complications, neurological disorders, systemic inflammatory responses, some cancer incidence, and mortality. Climate changes alter the composition and concentration of air pollutants and can increase morbidity rates for various diseases through interactions with PM. The importance of understanding how PM and climate changes affect energy metabolism lies in their potential to act as catalysts that exacerbate unnoticed or unrecognized health vulnerabilities. From a functional medicine perspective, it is important to understand these interactions regarding particle aging, accumulation in the mitochondrial matrix, and damage to the blood-brain barrier. Furthermore, it is important to keep in mind that the environment, PM, and viral infections can interact to affect the human health. The clinical implications of how PM and climate changes impact energy metabolism can become an important aspect of functional medicine healthcare to improve quality of life and prevent disease in daily life.

Chronic fatigue syndrome is a long-term condition that can affect different parts of the body which includes symptoms of extreme tiredness which can make daily activities difficult, sleep problems, brain fog. The symptom “chronic fatigue” might seem like a simple physical status; however, it might be a crucial sign of mitochondria dysfunction, problematic neurotransmitter synthesis, increased micro-inflammation and/or increased gut permeability. These metabolic conditions are likely to cause lethal vascular diseases, neurological deficits, psychological disorders or serious immune reactions if patients do not receive proper care. Thorough clinical approaches and individualized treatments should be achieved not only to resolve symptoms but also to maintain healthy status. Functional medicine approach from simple blood analysis to urine organic acid analysis and food IgG4 antibody test and treatment methods which help to recover mitochondrial function could be proper options.

Hypochlorhydria and achlorhydria, a condition of abnormally low and no gastric acid secretion, are often underdiagnosed due to its nonspecific symptoms and limited clinical awareness. Gastric acid plays a critical role in protein digestion, micronutrient absorption, and microbial defense. Functional medicine approaches emphasize the upstream causes and systemic impacts of hypochlorhydria, identifying its contribution to nutritional deficiencies, small intestinal bacterial overgrowth, and chronic gastrointestinal symptoms. This review explores the pathophysiology, diagnostic strategies—including serologic, endoscopic, and microbiome-based assessments—and root causes such as Helicobacter pylori infection, autoimmune gastritis, and medication-induced hypochlorhydria. Functional medicine interventions such as the 5R framework (remove, replace, reinoculate, repair, rebalance) offer a holistic model to restore gastric function and systemic health. Particular attention is given to the role of nutrient supplementation, targeted microbial therapies, and acid replacement strategies like betaine HCl. In addition to diagnostic accuracy, therapeutic timing is crucial to prevent irreversible mucosal atrophy and micronutrient depletion. Clinical implications extend to anemia, osteoporosis, vitamin B12 deficiency, and impaired methylation pathways. Functional medicine offers a unique paradigm to address these interconnected systems, presenting opportunities for both disease management and prevention.

Mastication and salivation play vital roles in digestion, oral health, and systemic well-being. Proper chewing enhances nutrient absorption, regulates metabolism, supports immune function, and maintains cognitive health, while saliva facilitates digestion, protects oral tissues, and maintains microbial balance. The oral microbiome interacts with gut microbiota, influencing systemic diseases such as metabolic disorders and neurodegenerative conditions. Impaired mastication and reduced salivation can lead to nutritional deficiencies, weight fluctuations, and increased disease risk, particularly in aging populations. Xerostomia contributes to dental and digestive issues, while halitosis may stem from oral bacteria or gastrointestinal conditions. Maintaining optimal oral health through proper hygiene, hydration, and dietary habits is essential for overall well-being. Further research into oral-gut microbiome interactions could provide insights into disease prevention and management.

Advanced glycation end products (AGEs), which are formed through nonenzymatic glycation, accumulate in the body and play a very important role in causing chronic, degenerative diseases and related complications, especially diabetic complications, chronic kidney disease, nonalcoholic fatty liver disease, and neurodegenerative disease such as Alzheimer's disease and Parkinson's disease. AGEs can modify proteins and change their physical and chemical properties and can act also via specific receptors, among them receptors for advanced glycation end products (RAGE) is the best known. RAGE, a starting point of toxic signals from AGEs, is also an important factor for the prevention and treatment of each disease. From a functional medicine perspective, understanding the relationship between AGEs, which are closely related to diet and dietary habits, and each disease and strategies to control the interaction and formation of AGEs-RAGE can be helpful in the prevention and treatment of chronic diseases and neurodegenerative diseases.

Chronic pain is not merely a symptom but a complex pathophysiological condition closely associated with nociceptor activation and sensitization, central nervous system reorganization, neuroimmune interactions, and gut microbiota dysbiosis. The limited efficacy of traditional treatments such as medications, surgeries, nerve blocks, and neuroplasticity in many patients can be attributed to their failure to adequately address these molecular, neurological, and immunological pathological mechanisms. This review article thoroughly analyzes the molecular mechanisms underlying the persistence and exacerbation of chronic pain. It particularly focuses on the effects of nociceptor sensitization, central nervous system sensitization, neurogenic inflammation, and gut microbiota dysbiosis on pain chronification. The paper also details how adrenal insufficiency and the weakening of the cholinergic anti- inflammatory pathway contribute to the aggravation of chronic pain. A notable finding is that gut microbiota dysbiosis extends beyond gastrointestinal issues, potentially triggering systemic inflammatory responses and pain sensitization. This occurs through visceral-somatic neural connections and neuroimmune interactions, suggesting new therapeutic targets for chronic pain.

Fibromyalgia is characterized by chronic widespread musculoskeletal pain and accompanied by various somatic and psychological symptoms such as sleep problems, fatigue, cognitive dysfunction, depression and anxiety. Fibromyalgia, as a representative condition of nociplastic pain and classified as chronic primary pain, is recognized as an independent disorder. However, its pathogenesis and treatment remain incompletely established to date. The pathogenesis of fibromyalgia involves a complex interplay of factors, including neurotransmitter imbalances, dysregulation of the neuro-endocrine-hormonal axis mediated by the autonomic nervous system gut microbiota imbalances, mitochondrial dysfunction, impaired antioxidant capacity, as well as genetic and psycho-social factors. The management of fibromyalgia requires an integrated approach combining pharmacological and non-pharmacological therapies tailored to individual patients. Pharmacological treatment includes FDA-approved medications such as pregabalin, duloxetine, and milnacipran, as well as the use of tricyclic antidepressants, gabapentin, and tramadol. Generally, using more than one medication tailored to symptoms is effective, and a multidisciplinary approach that prioritizes non-pharmacological treatments is necessary. Nonsteroidal anti-inflammatory drugs and strong opioids have not demonstrated benefits for fibromyalgia and have significant limitations. Lifestyle modification, such as low-intensity exercise, mind-body relaxation, an anti-inflammatory and antioxidant diet and maintaining a nutritional status that supports gut microbiota balance, are key factors in fibromyalgia management. This study aims to review the latest insights on fibromyalgia and enhance the understanding of this condition to ultimately aid in patient treatment.