Are there good supplements for rosacea treatment?

No. There are on specific supplements for rosacea, but zinc is helpful for acne and may help rosacea.
Rosacea, fatty acids. Rosacea is a chronic skin disorder usually confused with acne. As far as supplements I recommend that my patients follow an anti-inflammatory diet rich in essential fatty acids (olive oil, nuts) supplemented with flax and borage oils. Topically preparations with Alpha lipoic acid reduce the redness.