Does a lithium deficiency increase the risk of dementia?
People in areas with higher lithium levels in drinking water develop dementia less often, but whether a deficiency actually causes dementia has not been proven. If you are concerned about your dementia risk, discuss it with your doctor rather than taking lithium on your own initiative.
People who receive more than 15 micrograms of lithium per litre through drinking water over a long period appear to develop dementia less often than people in areas with the lowest concentrations (2 to 5 micrograms per litre). This is the finding of a large Danish study involving more than 73,000 dementia cases. Notably, the group exposed to 5 to 10 micrograms per litre actually had a higher incidence. This points to an irregular, non-linear relationship. The researchers explicitly describe it as an association, not a proven cause, and warn of factors at the municipal level that may influence the outcome.
A Japanese study covering 808 cities found the same pattern, but only in women. In men there was no association. Why women appear to be more sensitive to lithium concentrations in water has not been explained. In addition, exposure was measured at the city level for everyone, not individually, which makes this type of study vulnerable to bias.
More is known about the mechanism of action from animal and laboratory research. Lithium inhibits an enzyme that contributes to the accumulation of damaged proteins in the brain (tau and amyloid beta), stimulates the formation of new brain cells, and protects brain cells from damage. A summary of 32 studies, of which 29 were in animal models, confirms these effects, but the step to humans has so far only been taken to a limited extent.
Small clinical studies show tentatively positive signals: lithium treatment slowed cognitive decline in people with Alzheimer's disease after three months and stabilised cognition in people with a mild memory problem (an early precursor to dementia). However, large-scale studies capable of demonstrating cause and effect are still lacking. That same research also highlights the downside: at higher blood levels, lithium can place a burden on the kidneys and thyroid, and can cause involuntary movement disorders or, conversely, cognitive problems. Lithium as a treatment is something to discuss exclusively with a doctor, with blood level monitoring.
Whether a lithium deficiency as such raises the risk of dementia remains uncertain. The 'supplementation theory', which regards lithium as an essential trace element, has yet to receive independent confirmation. The available research shows a consistent pattern in which higher lithium exposure is associated with less dementia, but that is different from evidence that a deficiency causes the disease.
This answer is based on population studies (including one large Danish and one Japanese ecological study), a summary of 32 studies (largely in animals), smaller clinical studies in people with Alzheimer's disease or mild memory problems, and several review articles. The evidence for an association between higher lithium levels in drinking water and less dementia is reasonably consistent, but is nowhere demonstrated to be causal. The researchers behind the meta-analysis themselves emphasise that the human evidence is scarce: only three of the 32 analysed studies had humans as participants. Clinical studies in which people were randomly assigned are still almost entirely absent.
How much lithium do you need each day?
There is no official daily recommendation for lithium; scientists cite 1 mg per day as a cautious guideline, but evidence for benefits in healthy people is largely absent, so supplementation is not yet substantiated.
Does eating low-carb make a difference for belly fat?
Eating low-carb probably helps with belly fat, but the effect depends strongly on how strictly you follow it and whether you are also eating fewer calories at the same time. If you specifically want to target belly fat, a meal time window or a combination of strategies appears more effective than reducing carbohydrates alone.
Is there a link between depression and a higher risk of dementia?
Depression is strongly associated with a higher risk of dementia, though it remains uncertain whether depression causes dementia or is sometimes an early sign of it. Treating depression appears to lower the risk, so if you or someone close to you is experiencing depressive symptoms, it is worth taking them seriously and discussing them with a doctor.
Does type 2 diabetes increase your risk of dementia?
Type 2 diabetes substantially increases the risk of dementia, and the younger you are at diagnosis, the greater that risk. Good blood sugar management and the choice of medication appear to be relevant; discuss this with your doctor if you have diabetes.