Gold is present within the human body in extremely minute, trace amounts. These quantities have no known biological function, reflecting environmental exposure rather than a health requirement.
Trace Amounts and Origin
The human body typically contains around 0.2 milligrams of gold for an average 70-kilogram person, equating to approximately 140 parts per billion. This minuscule quantity enters primarily through diet, as plants absorb gold from soil, and it may also be found in drinking water. Environmental exposure, such as inhaling dust or contact with gold jewelry, can also contribute. Once inside the body, gold is detectable in various tissues and fluids, including blood, liver, kidneys, hair, and nails. Despite its widespread presence at these low concentrations, gold has no established biological role or essential function in human physiology.
Gold in Medicine
Gold compounds and nanoparticles have found applications in medicine. Historically, gold salts, such as auranofin and sodium aurothiomalate, treated rheumatoid arthritis due to their anti-inflammatory properties. These compounds modulated immune functions, inhibited enzymes, and reduced oxidative stress, though their precise mechanisms are not fully understood. Their use has declined with newer, more effective medications.
In contemporary medicine, gold nanoparticles (AuNPs) are extensively researched for targeted drug delivery, diagnostics, and cancer therapies. Due to their unique properties, AuNPs can deliver drugs directly to cancer cells, minimizing harm to healthy tissues and enhancing efficacy. They are also explored in photothermal therapy, absorbing light and generating heat to destroy tumor cells, and in radiosensitization to enhance radiation therapy effects. Furthermore, gold nanoparticles are being developed as contrast agents for medical imaging and tools for molecular diagnostics.
Gold and Health Concerns
While metallic gold is largely inert and generally safe, exposure to certain gold compounds or excessive concentrations can lead to health concerns. Gold poisoning, also known as chrysiasis or chrysotherapy toxicity, is rare but can occur, particularly from medically administered gold compounds. Symptoms may include skin inflammation, kidney damage, blood disorders, gastrointestinal issues, and in chronic cases, bluish-grey skin discoloration.
Allergic reactions to gold are also possible, most commonly manifesting as contact dermatitis from jewelry. These reactions are often attributed to other metals alloyed with gold, like nickel, but pure gold can also trigger an allergic response. Symptoms typically involve redness, itching, swelling, and rashes. The key difference in health impact lies between inert metallic gold, which generally passes through the body without reaction, and reactive gold compounds or ions, which can interact with biological systems and potentially cause adverse effects.