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Fatty Liver Disease (MASLD): The Metabolic Warning Sign of Insulin Resistance
Metabolic dysfunction–associated steatotic liver disease (MASLD), formerly called fatty liver, is not a liver problem alone—it is a systemic marker of insulin resistance. Often silent for years, MASLD signals elevated cardiometabolic, cognitive, and longevity risk long before abnormal liver enzymes or diabetes appear.

David S. Klein, MD FACA FACPM
7 days ago3 min read


How Does Low Vitamin D Harm Kidney Function?
Creatinine is a late marker of kidney disease and often remains normal while damage is already underway. Low vitamin D contributes to early renal injury through hormonal imbalance, rising parathyroid hormone, RAAS activation, inflammation, and protein loss in the urine. These changes precede declines in GFR and explain why patients with “normal labs” may still be at significant risk for progressive kidney disease.

David Stephen Klein, MD FACA FACPM
Feb 115 min read


Insulin Resistance: The Hidden Precursor to Cardiovascular Disease, Dementia, and Accelerated Aging
Insulin resistance often develops years before diabetes, heart disease, or dementia are diagnosed. During this silent phase, metabolic dysfunction damages blood vessels, the brain, and cellular aging pathways. Understanding insulin resistance early allows for targeted intervention that can meaningfully reduce cardiovascular risk, cognitive decline, and accelerated biological aging.

David S. Klein, MD FACA FACPM
Feb 93 min read


Can Vitamin D Supplementation Cause Kidney Damage?
Vitamin D deficiency is not simply a consequence of kidney disease—it can actively accelerate renal injury. Proper vitamin D signaling suppresses harmful hormonal pathways, protects glomerular structures, and limits fibrosis. Concerns about kidney damage stem from rare cases of vitamin D toxicity, not physiologic replacement. When dosed appropriately and monitored, vitamin D supports kidney health rather than harming it.

David Stephen Klein, MD FACA FACPM
Feb 63 min read


Why Can’t My Doctor Find My Thyroid Problem?
Many patients experience fatigue, weight gain, cold intolerance, and brain fog despite being told their thyroid tests are “normal.” This article explains why thyroid disease is frequently missed, how temperature, genetics, inflammation, diet, and hormone conversion affect symptoms, and why a normal TSH does not rule out clinically meaningful hypothyroidism. Understanding thyroid function beyond basic labs often leads to answers patients have been seeking for years.

David Stephen Klein, MD FACA FACPM
Feb 46 min read


Microplastics and Human Health: What Medicine Is Beginning to Understand.
Microplastics and nanoplastics have emerged as a previously unrecognized but increasingly relevant source of chronic environmental exposure. Once thought to be biologically inert, these particles—derived from degraded consumer plastics and industrial materials—are now routinely detected in human blood, stool, lung tissue, placenta, breast milk, and even atherosclerotic plaques. Their presence in these tissues challenges long-standing assumptions about plastic safety and raise

David S. Klein, MD FACA FACPM
Feb 35 min read


Persistent Fatigue Is Not a Diagnosis
Persistent fatigue is not a diagnosis but a signal of underlying physiologic imbalance. Chronic low energy is often driven by overlooked metabolic dysfunction, hormone signaling abnormalities, sleep disruption, immune activation, or autonomic imbalance—frequently despite “normal” labs. A systematic, physician-led evaluation can uncover reversible causes and restore vitality rather than merely suppress symptoms.

David S. Klein, MD FACA FACPM
Jan 284 min read


Is It Dementia — or Is It Something Else? Medical Conditions That Can Mimic Dementia and Cognitive Decline
Is It Dementia — or Is It Something Else?
Cognitive decline is frequently assumed to represent dementia, yet a wide range of medical conditions can closely mimic neurodegenerative disease and are often treatable when identified early. Acute delirium, commonly triggered by infection, dehydration, metabolic abnormalities, or medication effects, is one of the most frequently missed causes of sudden confusion and cognitive change. Medications themselves, particularly anticholiner

David S. Klein, MD FACA FACPM
Jan 265 min read


Uric Acid and Colorectal Cancer: An Emerging Predictive Biomarker
Elevated uric acid is more than a marker for gout. Growing evidence suggests it reflects metabolic inflammation and oxidative stress linked to increased colorectal cancer risk. This physician-led review explores how uric acid functions as a predictive biomarker, its relationship to insulin resistance and chronic inflammation, and how average-risk screening tools like Cologuard fit into a modern preventive care strategy focused on early detection and risk reduction.

David S. Klein, MD FACA FACPM
Jan 255 min read


Vitamin D is a Hormone
Vitamin D is commonly thought of as a simple nutrient, but medically it functions as a steroid hormone with effects far beyond bone health. Unlike true vitamins, vitamin D is synthesized in the skin, activated through the liver and kidneys, and acts on receptors throughout the body to regulate gene expression. This hormonal role explains its influence on immune function, muscle strength, cardiovascular health, and brain function. Because deficiency is widespread and supplemen

David S. Klein, MD FACA FACPM
Jan 244 min read
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