It is said in the sastras that the head of the body represents the brahmanas, the arms represent the ksatriyas, the abdomen represents the vaisyas, and the legs, beginning with the thighs, represent the sudras. The sudras are sometimes called black, or krsna. The brahmanas are called sukla, or white, and the ksatriyas and the vaisyas are a mixture of black and white. However, those who are extraordinarily white are said to have skin produced out of white leprosy. It may be concluded that white or a golden hue is the color of the higher caste, and black is the complexion of the sudras.
Srimad Bhagavatam, Bhaktivedanta Book Trust, 1999. Canto 4, chapter 14, verse 45, purport. Vedabase - Quotes from Books - Quotes from Books: Racism and Homophobia