
Inorganic: Germanium dioxide, germanium-lactate-citrate (Ge-lac-cit)
Organic: Spirogermanium, Bis-2-Carboxyethyl Germanium Sesquioxide (Ge-132, Germanium sesquioxide, CEGS, SK-818)
Germanium is a naturally occurring mineral that is used in the manufacturing of electronics and optical equipments. Whereas trace amounts can be found in some foods, it is not thought to be essential for normal body functions. But inorganic and organic germanium products, which have different biological activities, have been promoted to treat wide range of diseases, including cancer and AIDS.
Germanium compounds have immunomodulating and antioxidant activities (9) (10) (11) (12) (13) (14). Spirogermanium, an azaspiran compound, was investigated as an anticancer drug. However, clinical trials using injectable form reported severe renal, hepatic, myelogenous, and neurologic toxicities (2) (3) (6) (7) (15). Germanium sesquioxide (Ge-132), an organic compound that is supposed to have lower toxicities, has been marketed as a dietary supplement to help fight cancers. In a single case study, tumor remission was reported following oral supplementation (17). However, there is no conclusive evidence showing this compound is an effective cancer treatment. A phase II clinical trial of germanium in reducing radiation-induced fatigue in cancer patients is underway (18).
There are concerns of contamination of germanium products by the toxic inorganic germanium dioxide. The FDA has issued warning letters to marketers of germanium about unsubstantiated anticancer claims. Importation of germanium for human consumption is not allowed (19) (20) (21).
Shiitake mushrooms, garlic, tuna, pan fish, tomato juice
(2)
The atomic structure of germanium allows it to act as a free-radical scavenger (1). Spirogermanium has been shown to inhibit DNA and RNA synthesis in HeLa cells (2). Germanium sesquioxide enhances the activities of macrophage and T-cells (22) and stimulates the production of gamma interferon (23). Inorganic germanium dioxide enhances cellular radiosensitivity (24).
Absorption:
Oral administration of germanium dioxide (GeO2) to rats demonstrates approximately 95% bioavailability. Organic radiolabeled germanium (Ge-132) has repeatedly been shown to have 30% bioavailability in humans and animal models.
Distribution:
Extensive throughout body, but detectable levels in tissue vary based on dose and frequency of administration. Can be detected in blood, lung, and spleen with preferential accumulation in liver and kidneys.
Elimination:
Excreted primarily by the kidneys.
(3)
Germanium supplements should not be consumed because they can cause renal, hepatic, and neurotoxicities. Although studies in animals revealed low potential for toxicity (25), low-dose chronic toxicity has been demonstrated repeatedly. Renal toxicity is characterized by vacuolar degeneration in renal tubular epithelial cells, without proteinuria or hematuria, in the absence of glomerular changes (2) (7).
Theoretically, may have additive toxicity with other drugs known to cause renal (e.g. aminoglycosides), hepato- or neurotoxicity (e.g. taxanes), and myelosuppression.
Many clinical trials evaluating spirogermanium for various cancers were conducted in the early 1980s. A significant incidence of renal, hepatic, and neurological toxicity was documented.
Bottom Line: Germanium shows anticancer properties but it has caused severe side effects and death.
Germanium is a naturally occurring element that can be found in foods such as shiitake mushrooms, garlic, tuna, and tomato juice. It is not an essential nutrient for human health. Germanium acts as an antioxidant, neutralizing free radicals that can damage DNA and cells. In laboratory experiments, a derivative of germanium called spirogermanium has been shown to inhibit replication in certain cancer cells, but human studies show it has adverse effects and is not suitable as an anticancer treatment.