The fate of ingested gold within the human body depends entirely on its chemical form. Gold exists either as the pure metal (elemental gold) or as a chemical compound (often called a gold salt). These two forms behave differently in a biological system. Elemental gold is famously non-reactive, while gold compounds are chemically active and designed to interact with the body’s biology. This distinction determines if gold acts as a decorative additive or a biologically potent substance.
The Fate of Metallic Gold
When people ingest gold as a decorative element, such as in gold leaf, dust, or flakes used in culinary arts, they are consuming metallic or elemental gold. This form of gold is chemically inert, meaning it does not readily react with other substances, including the powerful acids and enzymes in the digestive tract. The inability to break down the dense, pure metal results from gold’s noble characteristics.
Since metallic gold does not dissolve or react, it is not absorbed into the bloodstream or body tissues. The physical structure, typically applied in thin sheets or fine particles, remains largely intact as it travels through the stomach and intestines. This ingested gold simply passes through the entire gastrointestinal system and is eventually eliminated from the body as waste, unchanged.
While most elemental gold is excreted, a small amount, particularly in nanoparticle form, may be partially absorbed and distributed to organs like the liver and kidneys. However, the acute toxicity of orally ingested elemental gold is considered low. The primary concern for metallic gold is its purity; edible gold must be at least 23 to 24 karats to ensure the absence of potentially harmful metal alloys found in lower-carat jewelry.
Gold Compounds in Medical Treatment
A completely different biological scenario occurs with the ingestion or injection of gold compounds. These compounds, often incorrectly called “gold salts,” are chemically reactive molecules where gold is bonded to other elements, such as sulfur or phosphorus. These gold drugs were once a standard treatment for severe inflammatory conditions, primarily rheumatoid arthritis. The goal of administering these compounds is to achieve a pharmacological effect by allowing the gold to interact with biological processes.
Once in the body, these compounds interact with immune cells, potentially inhibiting inflammatory processes and altering the expression of certain proteins involved in the disease. Unlike metallic gold, these gold compounds are processed and absorbed into the system. They are typically administered via intramuscular injection, though oral forms exist. This therapeutic application demonstrates that chemically bonded gold can be biologically potent and affect the immune system.
Distinguishing Toxicity from Inertness
The primary factor distinguishing safe ingestion from potential harm is the gold’s chemical state. Elemental gold is biologically inert because its atoms are tightly bound, preventing interaction with biological molecules. In contrast, gold compounds are chemically active, which makes them effective as a drug but also the source of potential toxicity. The chemical bond allows the gold to be metabolized, leading to potential side effects such as skin rashes, kidney problems, or gastrointestinal distress. Toxicity is linked to the gold ion’s ability to react with various proteins and enzymes.