The lithium and potassium concentrations engage in a delicate balancing act in the human body. Both are trace elements which perform necessary functions in human physiology. However lithium can cause potassium levels to fall, resulting in serious problems such as hypokalemia (potassium deficiency). When this happens, you may feel weak and your cellular functions may be impaired.

Lithium and potassium are members of the alkali metals which form Group I on the Periodic Table of the Elements. Their properties are similar. Ions of these elements carry a +1 charge, are soluble and very reactive with water. Potassium has an essential function in physiological systems, especially in transporting molecules across the cell membrane. The potassium pump is important in maintaining the equilibrium between the interior of the cells and the surrounding interstitial fluid. This is vital in transferring electrical signals through muscles and sustaining a regular heartbeat. When the lithium ion competes with potassium ion, it interferes with this equilibrium. Lithium may also substitute for potassium in nerve tissues that conduct electrical stimulation to muscles. This results in muscle cramps and pain.

An electrolyte is a substance that breaks down to an ionized form in water and allows the body to conduct electrical stimuli to muscles. An important electrolyte in the human body is potassium. It takes on a positive charge to become K+. We get potassium in our bodies generally from dietary sources such as bananas, Brussels sprouts, yogurt, milk, soy products, beans, peanut butter, chicken, beef, fish, citrus fruits and peaches. Lithium is often a component of medicines and its charged form is Li+ in body fluids. These trace elements have the same valence charge, which allows lithium to actively compete with potassium and often replace it in biochemical reactions in the body.

This substance not only competes with potassium but also with similar trace elements such as sodium, calcium and magnesium which are also alkali metals with a +1 valence charge. When lithium replaces these elements in biochemical reactions, it alters the overall physiology as it affects electrolyte gradients on both sides of the cell membranes. Lithium diffuses into red blood cells which carry it throughout the body in the vascular system. It attaches itself to binding sites on nerve tissues and can change the electrical impulse conduction and the complex electrolyte balance. This eventually causes fatigue and other muscle problems. As lithium replaces potassium, the kidneys remove the potassium ions from the body and further electrolytic imbalance ensues as potassium declines.

Lithium intake depends on diet and the use of medications containing it in some form. A doctor may prescribe it as lithium aspartate as a health or dietary supplement. Doctors prescribe lithium for patients suffering from bipolar disorder or manic-depression as well as clinical depression. It is an effective therapy for reducing aggressive behavior in children. It is also a treatment for dementia and Alzheimer’s disease because it improves memory and has been shown to produce an increase in brain gray matter up to 3 percent in four weeks. Prescribed as lithium orotate or aspartate, it may treat stress, alcoholism, attention deficit hyperactivity disorder (ADHD) and attention deficit disorder (ADD). Under ordinary circumstances there is little lithium present in the body to compete with potassium.

Lithium from medical sources can cause many problems related to low potassium levels. These may include dry mouth, excessive thirst, weak and irregular heartbeat and muscle cramps. Among the symptoms are electrolyte imbalances, kidney problems, dehydration and EKG abnormalities. With possible hypokalemia or potassium deficiency as a side effect, both doctor and patient must monitor the potassium levels constantly while on this type of medication.