Novel lactopeptides in fermented dairy products improve memory function and cognitive decline

Abstract

Alongside the rapid growth in aging populations, prevention of age-related memory decline and dementia has become a high priority. Several epidemiological and clinical studies have concluded that fermented dairy products can help to prevent cognitive decline; furthermore, intake of Camembert cheese prevents Alzheimer's pathology in model mice. To elucidate molecular mechanisms underlying the preventive effects of fermented dairy products, here we screened peptides from digested fermented dairy products for ability to improve memory function in a scopolamine-induced amnesia mouse model. We found that Trp-Tyr (WY)-containing peptides from whey protein improved memory function in the mice, and the effects were confirmed in aged mice. The WY-containing peptides directly inhibited monoamine oxidase-B activity and increased dopamine levels in brain tissue. Pretreatment with dopamine receptor antagonist abolished the improvement in memory function due to WY-containing peptides. These results suggest that WY-containing peptides in fermented dairy products increase monoamine levels by inhibiting monoamine oxidase-B activity, helping to prevent age-related cognitive decline.

β-Lactolin, a Whey-Derived Lacto-Tetrapeptide, Prevents Alzheimer’s Disease Pathologies and Cognitive Decline

“…Accumulating studies indicate that fermented dairy products rich in ␤-lactolin improve cogni- tive performance and dementia [15,17]. However, the effects of ␤-lactolin on AD pathologies and cognitive decline have not been investigated.…”

“…Our previous studies have demonstrated that ␤lactolin orally administered can enter the brain and inhibit the activity of monoamine oxidase B (MAO-B), thereby resulting in increased dopamine levels in the brain in normal ICR mice [15,21], and dopamine D1-like receptor is involved in the memory improvement induced by ␤-lactolin in scopolamine-induced amnesia model mice [15]. In the present study, the levels of dopamine in the frontal cortex increased in 5 × FAD mice fed with the diet containing ␤-lactolin and whey digestion rich in ␤-lactolin.…”

“…␤-Lactolin is rich in Camembert cheese and other cheeses fermented by Penicillium [15]. ␤-Lactolin has been shown to increase monoamine levels in the frontal cortex and hippocampus and improve spatial working memory and attention in pharmacologically induced amnesia mice.…”

Emerging roles of bioactive peptides on brain health promotion

“…Furthermore, MKP, a tripeptide with greater blood-brain barrier (BBB) penetration, was one of the primary players in the prevention of cognitive impairment (Table 1). On the other hand, from milk whey digestion products, GTWY peptides in the b-lactoglobulin sequence were identified as the components responsible for improving memory function in a scopolamine-induced amnesia mouse model (Ano et al, 2018; Table 1). The underlying mechanism was probably inhibition of the monoamine oxidase-B activity and subsequent increment in dopamine levels in the brain.…”

Antidepressant-Like Effect of β-Lactolin, a Glycine-Threonine-Tryptophan-Tyrosine Peptide

“…Previous studies indicate that some dipeptides improve memory, ameliorate depression, and relieve anxiety. For example, a pyroglutamyl-leucine dipeptide exerts antidepressant effects (7), a tyrosine-leucine dipeptide acts as an anxiolytic agent with activity comparable with that of diazepam (8), and a tryptophan-tyrosine dipeptide ameliorates deficiencies in memory (9,10). Further, an epidemiological study found that consumption of low-fat dairy products, including fermented products, is inversely associated with the symptoms of depression (11,12).…”