Cataracts Produced in Rats by Yogurt

Rats kept on an exclusive diet of yogurt avidly ate the yogurt, grew at a normal rate, were normally active, mated, conceived, and gave birth to normal, healthy litters. However, all of the rats developed cataracts. Cataracts appeared in young rats 2 to 3 months, and in adult rats 4 to 6 months, after initiation of the yogurt diet. Cataracts first manifested themselves in small vacuoles at the periphery of the lens and then in small striae extending toward the center of the lens. These striae progressively became longer, more coarse, and numerous until they coalesced, finally forming a mature white lens. The high content of galactose in commercially available yogurt could account in full for appearance of cataracts in 100 percent of the experimental animals. The cataracts appear to be the same as those produced by diets with a high content of galactose.