Possible Clues:

• After starting slim get buxom — it's probably from lack of vegetables
• Condition caused by a deficiency of vitamin C
• Ailment treated with citrus
• Disease caused by vitamin c deficiency
• Disease makes son shapely
• Ascorbic acid is the main cure for this disease
• Son far from straight in making complaint in the main?
• Disease caused by lack of vitamin C
• What sailors caught, close to divers with the bends?
• Condition caused by lack of vitamin C