Pure gold, in its elemental form, is generally not considered poisonous to humans. The way gold interacts with the body varies significantly depending on its form, purity, and how it is encountered. This article explores these different forms and their specific interactions, distinguishing between inert forms and those that can elicit a physiological response.
Pure Gold: An Inert Element
Pure gold, specifically 24-karat gold, is known for its chemical stability and non-reactivity. It is considered biologically inert, meaning it does not readily interact with the chemical processes within the human body. This inertness is due to gold’s noble metal status, which makes it highly resistant to oxidation and corrosion.
When ingested, pure elemental gold passes through the digestive system largely unchanged, without being absorbed into the bloodstream or causing any chemical reactions. It exits the body as waste, posing no significant toxicological threat to humans.
Gold in Daily Life: Jewelry and Edible Forms
Gold commonly encountered in daily life, such as in jewelry, is often not pure gold. Jewelry is typically made from gold alloys, which are mixtures of gold with other metals like copper, silver, nickel, or zinc to enhance durability and alter color. While pure gold itself is unlikely to cause a reaction, any skin irritation or allergic response to gold jewelry is almost always attributed to these other metals, especially nickel, which is a common allergen. Symptoms of such allergies can include redness, itching, swelling, or rashes at the site of contact.
Edible gold, used as a decorative element in food and beverages, is typically 22 to 24 karats, indicating a high level of purity. This form of gold is biologically inert and passes through the digestive system without absorption. It offers no nutritional value but is considered safe for consumption in decorative quantities due to its non-reactive nature.
Specialized Gold: Medical Uses and Nanoparticles
Beyond its inert forms, certain gold compounds and nanoparticles are designed to interact with the body and can have distinct effects. Historically, gold compounds, often referred to as “gold salts,” were used in a treatment called chrysotherapy for conditions like rheumatoid arthritis. These are not elemental gold but specific chemical formulations that exert pharmacological effects, including anti-inflammatory properties. However, their use has declined due to a slow onset of action and significant side effects, which could include skin rashes, mouth ulcers, kidney problems, and blood disorders.
Gold nanoparticles (GNPs) are microscopic particles of gold, typically ranging from 1 to 100 nanometers, used in emerging medical applications like diagnostics and drug delivery. Their small size allows them to interact with biological systems in ways bulk gold cannot, potentially entering cells and tissues. While research is ongoing, initial clinical trials suggest a good safety profile for GNPs. However, factors like particle size, shape, surface chemistry, and dosage can influence their biological interactions and potential for accumulation, particularly in organs like the liver and spleen.
Potential Health Reactions and Misconceptions About Gold
While elemental gold is largely non-toxic, some individuals can develop allergic contact dermatitis. This reaction is typically a delayed hypersensitivity to gold or its alloys, often triggered by other metals mixed with gold in jewelry, particularly nickel. The symptoms are an immune response, not a direct poisoning from gold itself.
It is important to distinguish between the intentional pharmacological effects and side effects of medically administered gold compounds, which are known and monitored, and the concept of “toxicity” from elemental gold. Gold in its common forms, such as high-purity edible gold or gold jewelry, presents no significant health risk. The idea of gold being inherently toxic is largely a misconception, as its chemical inertness prevents it from reacting harmfully with the human body in most typical exposures.