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Exercise offers many benefits through the production and release of a complex mix of molecules from the muscles that affect a variety of brain functions. Daily moderate exercise can also slow cognitive functional decline associated with normal aging and many common neurodegenerative diseases that depend on neurogenesis, or the daily birth of new neurons. Although the neurogenesis-enhancing effects of exercise have been known for more than twenty years, the mechanisms underlying this response have remained unclear. Initial studies reported that levels of hormone BDNF increased in the blood after exercise. However, systemic BDNF cannot cross the blood-brain barrier and therefore does not appear to play a direct role in the effects of exercise on the brain.
Many other molecules also enable communication between exercising muscles and the brain, including beta-hydroxybutyrate, lactate, cathepsin B, lipocalin-2, VEGF, irisin, and PGC-1alpha. For a detailed discussion of the role of these molecules in the effects of exercise on the brain, see the reference below.
A recent study reported that the neurogenesis-enhancing effects of exercise are mediated by the systemic release of selenium as the antioxidant selenium transporter protein, called selenoprotein P (SEPP1) in mice. The authors confirmed that the actions of SEPP1 at its receptor are required for the exercise-induced increase in adult hippocampal neurogenesis.
When mice were forced to exercise, SEPP1 levels were significantly elevated in plasma. More importantly, exercise increased the transport of SEPP1 and selenium from plasma to the brain. SEPP1 is responsible for maintaining selenium levels in the brain. Selenium and selenium-containing proteins are well-known antioxidants that the brain relies on for defense. oxidative stress. Many studies have identified an age-related decline in plasma selenium levels in humans that correlates positively with cognitive impairment.
The current study demonstrated that mimicking the effect of exercise through dietary selenium supplementation in mice effectively restored neurogenesis and reversed cognitive decline associated with aging and hippocampal injury. These results provide, for the first time, a molecular mechanism linking exercise-induced changes in plasma selenium levels and hippocampal stem cell activation.
So on those days when you can’t make it to the gym, you might consider adding these selenium-rich foods to your diet. diet: Brazil nuts, salmon, tuna, halibut, eggs, turkey, cottage cheese, mushrooms, and navy beans.
Selenium is considered a trace mineral, so very low concentrations of selenium are required in the diet. If you are considering taking supplements, be aware that high doses (>900 mcg/day) of selenium are toxic and can cause hair loss, abnormal nails, dermatitis, peripheral neuropathy, nausea, diarrhea, tremor, blood clotting problems, blood, fatigue, irritability, and a garlicky breath odor.
This discovery could lead to the use of selenium dietary supplements to mimic the beneficial effects of exercise on the brain and raises the question of whether other dietary modifications could replicate the benefits of exercise on the brain.
