Tomato British researchers have produced genetically modified tomatoes that have high levels of beta-carotene in order to prevent blindness, heart disease and cancer. Beta-carotene is converted to vitamin A in the body and this, as an antioxidant, may help stave off chronic diseases. The deficiency of vitamin A, which is common in developing nations, can increase the risk of blindness and premature deaths. UNICEF says that between one and two million deaths a year could be prevented by increasing the intake of this vitamin among children aged between one to four years.