Yes. The load capacity will decrease, when using rolling bearings in media lubricated or dry running conditions.
The catalog value is calculate for a perfectly lubricated bearing with oil or grease. If the bearing will be lubricated by media like water, liquid plastic, etc., the load capacity is only approx. 5.7%. The load capacity of a dry running bearing will be approx. 1.5%.
This values depend on the viscosity of the fluid and on the bearing material (HNS, ceramic, Inconel, ...)
Bearing manufacturers will calculate and design the bearings for applications with starved or no lubrication.