<prompt> tafsiri zifuatazo kutoka kwa swahili hadi kiingereza.vitamini d kuongeza ni bora katika kuboresha ugumu, maumivu na kazi ya wale wenye osteoarthritis katika goti, kulingana na watafiti wa kichina kuchunguza masomo ya wagonjwa 1136 na hali 25.  <response>: vitamin d supplementation is effective in improving the stiffness, pain, and function of those with osteoarthritis in the knee, according to chinese researchers analyzing studies totaling 1136 patients with the condition 25. 