Table 1.

Table of included studies.

Study	Year	Vitamin deficiency	Key findings	Therapeutic implications
Tabel et al.	2020	B12, Folate	Increased ulcer frequency; mucosal sensitivity	Importance of vitamin testing
Padayatty et al.	2021	C	Delayed healing; gingival bleeding	Supplementation recommended
Hugar et al.	2017	Folate	Severe RAS linked to folate deficiency	Folate therapy for severe cases
Freitas et al.	2019	B12, C, Folate	Reduction in ulcer frequency with supplementation	Multivitamin approach