Rubidium is a relatively benign element that typically parallels the potassium level. It varies according to levels found in water supplies.
Rubidium is a non-toxic element and is known to be associated with lithium. It is also frequently found to be elevated with potassium.
Rubidium and its salts have few commercial uses. The metal is used in the manufacture of photocells. Rubidium salts are used in glass and ceramics and in fireworks to give them a
purple color. Potential uses are in ion engines, vapor turbines, and as a “getter” in vacuum tubes. Rubidium isotopes have been used as tracers in medical tests to observe blood flow in
the heart, brain, and kidney.
Foods found to contain up to 200 ppm rubidium include:
- tomatoes,
- beef,
- soybean,
- and coffee.
Rubidium has no known biological role but has a slight stimulatory effect on metabolism, probably because of its similarity to potassium. The two elements are found together
in minerals and soils, although potassium is much more abundant than rubidium. Rubidium enters the food chain and so contributes to a daily intake of between 1 and 5 mg. It is
moderately toxic by ingestion. Rubidium reacts readily with moisture on the skin and forms rubidium hydroxide which can cause chemical burns of the eyes and skin.
Overexposure to rubidium can cause failure to gain weight, ataxia, skin ulcers, and extreme nervousness. Since rubidium and potassium have similar properties, potassium imbalance can occur when replaced with rubidium in the body.
Rubidium can be tested in human erythrocytes, plasma, or urine. Hair levels are thought to indicate rubidium exposure.
Rubidium has been used in alternative cancer treatments to raise pH.
Toxicity studies in rats showed that rubidium chloride resulted in decreased growth, anemia, and changes to liver cells, kidney cells, brain enzymes, and hepatic lipid composition. Ascorbic acid supplementation appeared to prevent the rubidiuminduced liver and kidney effects. Studies on experimental animals suggested that rubidium would pose an acute health hazard only when it is ingested in large quantities.
References:
Tamburo E, Varrica D, Dongarrà G, Grimaldi LM. Trace elements in scalp hair samples from patients with relapsing-remitting multiple sclerosis. PLoS One. 2015 Apr 9;10(4):e0122142. doi: 10.1371/journal.pone.0122142. PMID: 25856388; PMCID: PMC4391939.
Biological properties of extracellular vesicles and their physiological functions. J Extracell Vesicles. 2015 May 14;4:27066. doi: 10.3402/jev.v4.27066. PMID: 25979354; PMCID: PMC4433489.
Rubidium
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