Age-related changes in the brain drive cognitive impairment, which in turn alters memory formation and promotes mitochondrial dysfunction. A recent study demonstrates that spermidine improves cognitive function in humans.

Spermidine is a dietary compound found in a number of foods, including wheat germ, cauliflower, broccoli, mushrooms, amaranth, a variety of cheeses (especially aged cheeses), and soybean products, such as natto. First identified in semen, spermidine demonstrates anti-aging properties in animal studies, likely due to its capacity to induce autophagy – the process by which the body clears dead and damaged cells. Human studies have demonstrated an association between dietary spermidine intake and increased survival..

The authors of the study investigated the effects of spermidine supplementation in various models of aging. They fed aged mice spermidine in their drinking water and measured the compound’s appearance in the animals' brains. The compound appeared in brain tissue within one week of administration and continued to accrue to roughly one-third of bloodstream levels. Spermidine altered protein synthesis in the animals' brains via its actions on hypusine, an amino acid that is essential for the function of ELF5A, a protein that plays roles in mammalian protein production. Mice that received spermidine exhibited improvements in spontaneous behavior, exploration, maze completion, and other measures of cognitive function.

The authors also fed fruit flies spermidine and found that the compound improved mitochondrial function and reduced age-induced memory impairments. These improvements were mediated by Atg7, PINK, and parkin – proteins that play key roles in autophagy and mitophagy.

Then the authors reviewed epidemiological data from food frequency questionnaires and cognitive tests completed by participants in the Bruneck Study, a prospective cohort study of adults living in Bruneck, Italy. They found that higher intake of spermidine-rich foods was associated with greater cognitive function in aging.

These findings suggest that dietary spermidine exerts neuroprotective effects in several model of aging, likely due to the compound’s effects on mitochondrial health. Dietary interventions that promote spermidine-rich foods may be useful in slowing cognitive decline in humans.

• Link to full study.
• Learn more about dietary spermidine and autophagy from Dr. Guido Kroemer in this clip.