* Vitamin B1 (Thiamin):

* Function: Plays a key role in carbohydrate metabolism, converting food into energy. It's also important for nerve function, muscle contraction, and the production of neurotransmitters.

* Deficiency: Beriberi, a condition that can cause fatigue, nerve damage, heart problems, and even death.

* Vitamin C (Ascorbic Acid):

* Function: Acts as an antioxidant, protecting cells from damage caused by free radicals. It's also essential for collagen synthesis (important for skin, bones, tendons, and blood vessels), wound healing, and the absorption of iron.

* Deficiency: Scurvy, a condition that causes fatigue, weakness, gum disease, and poor wound healing.