According to a recent study in BMJ (formerly the British Medical Journal) the regular consumption of spicy food is associated with a lower risk of death. This study does not prove causation so take the results as exploratory rather than conclusive. This study does however point to potential fruitfulness of further research to establish causation in this area. The study was completed by an international team that looked at the data from almost half a million participants.
From the results:
Spicy food consumption showed highly consistent inverse associations with total mortality among both men and women after adjustment for other known or potential risk factors. … Compared with those who ate spicy foods less than once a week, those who consumed spicy foods 6 or 7 days a week showed a 14% relative risk reduction in total mortality.
You can view this study online: Consumption of spicy foods and total and cause specific mortality: population based cohort study
Many spices are also herbs and spices are generally known for their high levels of beneficial phytochemicals. It’s not a great leap to have a hypothesis that people who consume spices fair better than those who don’t.