Lithium is a naturally occurring alkali metal present in rocks, soil, water, and various foods. This element is found in trace amounts within the human body. While often associated with its use in higher concentrations as a medication, lithium exists endogenously within biological systems. Its presence in the body is part of a complex physiological landscape, contributing to various bodily functions even at very low levels.
Sources of Lithium in the Body
Lithium enters the human body primarily through dietary intake, absorbed from the gastrointestinal tract; drinking water serves as a significant source, with concentrations varying greatly depending on geographical location and mineral content. For instance, regions with higher natural lithium content in groundwater tend to have more lithium in local produce. Plants absorb lithium from the soil, meaning that vegetables and grains also contribute to dietary intake. The amount of lithium in these food sources can differ widely based on soil composition and farming practices. These natural pathways ensure a continuous, albeit variable, supply of trace lithium to the body.
Physiological Roles of Trace Lithium
Trace amounts of lithium in the body are thought to influence several biological processes, and research suggests that lithium may play a role in supporting brain health by affecting enzymes, neurotransmitters, and signaling molecules involved in neuroplasticity. It has been shown to promote neuronal growth and enhance brain-derived neurotrophic factor (BDNF), which is important for nerve cell function and repair. This element may also contribute to mood and emotional regulation, with some studies indicating an inverse relationship between lithium concentrations in drinking water and rates of suicide or impulsive behavior in populations. Lithium’s influence extends to cellular health, demonstrating antioxidant properties that protect cells from stress and toxins. It may contribute to bone health and immune function, as evidenced by animal studies showing higher mortality and reproductive abnormalities in lithium-deficient diets.
Understanding Lithium Levels
The average daily intake of lithium from diet in the United States, for example, is estimated to range from 0.65 to 3.1 milligrams. This trace intake is far below the levels used in psychiatric medications, which are typically hundreds of times higher. Lithium is absorbed and distributed throughout the body’s water, with varying concentrations in different tissues. For instance, it can be found in bones and muscles, as well as in the kidneys and brain, albeit at lower concentrations in the brain compared to serum. While a “normal range” for trace lithium in human tissues is not precisely defined due to its variability and the ongoing research into its specific roles, its presence is a consistent biological finding.
Dietary Lithium and Health
Cereal grains and vegetables are considered primary dietary sources, providing an estimated 66-90% of daily lithium intake. Specific examples include wheat, rice, oats, potatoes, cabbage, and certain leafy greens. Other food items that contain trace amounts of lithium include legumes such as lentils and beans, some fruits like citrus and grapes, and nuts such as cashews and walnuts. Mineral water, especially from certain springs, can also be a notable source of lithium. For most individuals, a balanced and varied diet, along with drinking water, provides sufficient trace lithium to meet the body’s needs.