Intoxication with which heavy metal leads to loss of smell?

Lead intoxication can lead to loss of smell, and this effect is due to its neurotoxic action. Lead — one of the most dangerous heavy metals, which easily accumulates in the body and has a destructive impact on the central and peripheral nervous systems.

Here’s how this happens:

Neurotoxicity of lead and the olfactory tract. Lead can penetrate the blood-brain barrier and directly damage olfactory neurons as well as brain structures, including the olfactory bulbs and hippocampus. This leads to disruption of nerve impulse transmission related to the perception of smells. Additionally, glial cells that support neuronal function are also damaged.

Accumulation in the nasal mucosa and epithelium. Lead can deposit in the tissues of the nasal mucosa, where it destroys olfactory receptor cells. These cells are regularly renewed, but chronic intoxication disrupts this regeneration process, ultimately leading to a persistent decrease or loss of smell — anosmia.

Disruption of neurotransmitter metabolism. Lead disrupts the functioning of calcium channels, which affects signal transmission between neurons. It also reduces the synthesis and release of important neurotransmitters (such as acetylcholine and glutamate), which play a role in sensory function, including the perception of smells.

Oxidative stress and inflammation. Chronic exposure to lead causes significant oxidative stress — the formation of a large number of free radicals. This leads to damage to lipids, proteins, and DNA in the olfactory system. Inflammatory cytokines are also activated, exacerbating the damage.

Other neurological and cognitive symptoms. Loss of smell is often accompanied by other neurological manifestations of lead intoxication: headaches, memory impairment, decreased concentration, and changes in behavior. Loss of smell can be one of the early signs of toxic effects on the CNS.

Conclusion

The loss of smell in lead intoxication is the result of both direct damage to olfactory receptors and systemic neurotoxic effects.

Chronic exposure, even at low doses, is particularly dangerous as lead is cumulative and can cause lasting changes, including irreversible ones.