Lithium is a naturally occurring element found in trace amounts throughout the earth’s crust, soil, and water. This alkali metal is considered a trace mineral that is part of the human diet. Average daily intake in the United States is estimated to range between 0.65 and 3.1 milligrams of elemental lithium per day. This low-level intake is distinct from the much higher doses of prescription-strength lithium, such as lithium carbonate, which is a strictly regulated medication used to manage mood disorders like bipolar disorder. Therapeutic doses for mood stabilization are typically hundreds of times greater than the trace amounts consumed naturally.
Dietary Sources of Trace Lithium
Lithium enters the human food chain through soil-to-plant transfer, making solid foods a primary source of the trace mineral. The mineral’s concentration in any food depends heavily on the geographical location and the specific mineral content of the soil where the crop was cultivated. For instance, lithium uptake by plants is generally greater in acidic soils compared to alkaline soils, influencing the final amount found in the food.
Cereal grains and vegetables are estimated to contribute the majority, about 66% to 90%, of the total dietary lithium intake. Whole grains, root crops, and leafy greens tend to accumulate measurable amounts of the mineral. Specific examples of foods with detectable levels include tomatoes, cabbage, and spinach, though concentrations vary widely depending on growing conditions.
Nuts and legumes also serve as notable sources of trace lithium, with certain nuts like walnuts and cashews containing higher concentrations. Animal products, such as meat and dairy, generally contain lower levels of the mineral compared to plant-based sources. Because of this variability, vegetarians who consume a high volume of grains and vegetables may ingest higher levels of lithium.
Lithium Content in Drinking Water and Geography
For many individuals, drinking water is a consistent and sometimes substantial source of natural lithium intake, directly influenced by local geology. Lithium is leached from rocks, particularly igneous rocks and mineral-rich deposits, and dissolves into groundwater and surface water. The concentration can vary dramatically, ranging from less than one microgram per liter (µg/L) to well over 100 µg/L, depending on the region.
In the United States, higher concentrations of 30 µg/L or more are often found in the groundwater of arid western and southwestern states. In these areas, low precipitation and deep wells contribute to higher mineral content. Conversely, areas with different rock types, such as carbonate-rock aquifers, often exhibit much lower lithium levels. These geographical differences mean tap water can be a significant source of daily intake in some locations but negligible in others.
Common water processing methods can affect the final lithium concentration reaching the consumer. While the mineral is not currently regulated by the U.S. Environmental Protection Agency, public water systems must monitor it as a contaminant. Filtration methods or the choice of bottled water can alter an individual’s intake from local water supplies. Certain mineral waters are naturally high in lithium, offering a concentrated source.
Low-Dose Supplemental Forms and Safety Considerations
When seeking concentrated intake, some consumers turn to over-the-counter low-dose supplements, commonly lithium orotate or lithium aspartate. These compounds deliver elemental lithium bound to a carrier molecule, such as orotic acid. The use of these supplements is often referred to as micro-dosing, with typical capsules providing small amounts, often translating to a few milligrams of elemental lithium.
This micro-dosing approach is vastly different from the prescription use of lithium carbonate for psychiatric treatment. Prescription lithium has a narrow therapeutic window, meaning the effective dose is close to the toxic dose. This necessitates frequent blood monitoring to ensure safety and prevent potential side effects like kidney or thyroid issues.
Unlike prescription lithium, dietary supplements are not approved by the Food and Drug Administration (FDA) for treating any medical condition. The research supporting their efficacy for mood or cognitive support is also limited.
Self-medicating with any form of lithium is strongly advised against, especially for individuals with existing health issues. Anyone considering low-dose lithium supplementation should consult a physician first. This is particularly important if they take other medications or have pre-existing kidney conditions, as even small amounts can interact with other drugs and impact renal function.