Zinc provides a wide variety of general health benefits and it may positively influence cognition, mood, and well-being. Interestingly, both a deficiency and a surplus of zinc in the brain have been correlated with memory impairment [1, 2].
Effects On Cognition
Zinc supplementation has been shown to improve cognitive performance and taste acuity in a study of adolescent girls .
Additionally, correcting for zinc deficiencies has been shown to restore memory and cognition in stroke patients .
Effects On Memory and Learning
Zinc is highly concentrated in the hippocampus region of the brain, and deficiency of this mineral is associated with both mood disorders and impaired memory formation [5, 6, 7]. Specifically, zinc deficiency is highly correlated with decrements in spatial memory, thought to result from impaired BDNF signaling (a pathway associated with neuronal growth and plasticity) [8, 9, 10].
In a mouse model, zinc-fortified water given throughout the lifespan had neuroprotective effects compared to control, indicating that zinc may aid in preventing decline in memory over time .
It is theorized that zinc may reduce the accumulation of the protein beta-amyloid (which is linked to the onset of neurodegenerative diseases) in the brain as well as improve mitochondrial function and BDNF levels .
Effects On Mood
Depressed patients appear to have reduced levels of serum zinc, and the magnitude of the deficiency is related to the severity of the depression [13, 14, 15].
Zinc supplementation is effective as an adjunct therapy alongside traditional antidepressants, but it may also reduce depressive symptoms in otherwise healthy individuals via increased BDNF .
The results of a 6-month trial showed improvements in mood in a population of young, healthy women after supplementing with 7 mg elemental zinc . Another study showed that 30 mg elemental zinc taken daily for 12 weeks was associated with improvements in depressive symptoms compared to placebo .
Studies involving rats have shown that depressive and behavioral symptoms were improved upon normalizing zinc levels after a period of two weeks of zinc deprivation [19, 20].
Zinc is thought to inhibit the enzyme glycogen synthase kinase-3B (BSK3B) which is a molecular target for mood disorders [21, 22, 23].
Cases of nausea have been reported when zinc is taken on an empty stomach and at high doses.