Titanium Dioxide is used as an opaquing agent in the shell of Longevinex capsules to protect contents from light exposure. Unfiltered light may degrade a key ingredient (resveratrol) in Longevinex.
The Food & Agriculture Organization (FAO) of the United Nations says this about titanium dioxide.
Given its insolubility in water, hydrochloric acid, dilute sulfuric acid, and organic solvents, titanium dioxide is not expected to react with components of food. Its functionality depends upon its inertness within a food matrix. In fact, in 1969 JECFA (JECFA, 1970) “decided not to establish a limit on intake of titanium dioxide since the evidence indicates that it is free from toxic effects on account of its insolubility and inertness. The intake in food would be limited by good manufacturing practice.” ftp://ftp.fao.org/ag/agn/jecfa/cta_tio2.pdf