Do ProLon® 5-day Menus 1 and 2 contain nickel? 21 February 2023 08:02 Updated Yes, both menus include components that may contain nickel. Related articles Do the Longevity Guidelines represent a personalized diet? Can I do ProLon® 5-day if during menstrual cycle? Can I chew a gum during ProLon® 5-day? Can I do ProLon® 5-day if I have COVID-19 (even in the case of asymptomatic subjects)?