In 2025, Jingfeng Chen and a team from Chinese universities reviewed animal and human studies on how vitamin D and exercise together help keep brains healthy as people age. They looked at things like brain growth proteins, blood flow, and swelling in the brain, focusing on older adults with memory problems.

In 2025, Aleksandra Skoczek-Rubińska and a team from Poznan University of Physical Education reviewed 13 studies from 2009-2025 on how vitamin D helps BDNF (a brain protein for nerve growth), mood, and thinking in adults. They looked at human and animal studies from big databases to see how vitamin D levels or supplements affect people’s brains and feelings.

A 2025 study by the University of Bath found that regular indoor exercise helped people keep healthy vitamin D levels during the darker months, even without supplements or weight loss. Staying active supports your bones and immune system year-round.

A 2025 double-blind, placebo-controlled study by Laterza et al. in Nutrients found that taking a multistrain probiotic with vitamin D significantly improved gut barrier function and microbiota balance in people with IBS. Benefits even lasted after treatment stopped.