It is one food colouring that you won't mind giving to the family. Research has shown that saffron, which gives chicken korma and paella their yellow colour, helps keep vision sharp.
Test findings suggest the spice reverses age-related macular degeneration, or AMD, the most common cause of blindness in old people, the Daily mail reported on its website.
"Patients' vision improved after taking the saffron pill," said professor Silvia Bisti, of the University of Sydney, who carried out the research. "When they were tested with traditional eye charts, a number of them could read one or two lines smaller than before, while others reported they could read newspapers and books again."
The finding is timely as it is thought the number of AMD sufferers will treble in the next 25 years as the population ages. It currently affects a quarter of over-60s in Britain and more than half of over-75s. There are few treatments for the condition and no cure.
While peripheral vision is not affected, the damage to central vision leads to many sufferers being registered as blind or partially sighted.
Saffron has actually been used in traditional medicine for centuries to treat a range of ailments, though Professor Bisti is the first to look at its effects on eyesight.
In tests carried out in Italy - where saffron is widely cultivated - pensioners with AMD were given a daily saffron pill for three months followed by a dummy drug for a further three months.
A second group took the supplements in the reverse order. Twenty-five took part in all.
"All patients experienced improvements in their vision while taking the saffron pill," Bisti said. "But when they stopped taking it, the effect quickly disappeared."
She added: "The chemistry of saffron is quite complex. It is well-known as an anti-oxidant but no one has explored its effects on eyesight before."
She believes saffron, which is widely used in Spanish and Indian cooking, affects the amount of fat stored by the eye, making vision cells "tougher and more resilient".
Saffron is used in traditional medicine for treating conditions including cancerous tumours and depression. The spice also has properties which encourage oxygen flow and prevents cell death.
Researchers are now hoping to discover the ideal dosage. They will also look at saffron's ability to treat genetic eye diseases that can cause life-long blindness.