I recently received free samples of some oils that are made with walnut oil instead of linseed oil. They also make a walnut oil that replaces all other solvents. This is NOT a solvent and truly safe. No citrus or solvents of any kind. I have done two paintings with it so far and LOVE it. But I work wet into wet so the longer drying time is in my favor. It cleans my brushes as well as the natural turpenoid that I have been using, too.
If you would like to find out more they have a website you can check out. I am sure they would send you a free sample to try if you have questions. They are a small company and only work with mom and pop type art stores so you can't find the stuff online with the bigger stores.
Winsor and Newton has recently decided to pick on them and try to crush them by telling people that walnut oil will go rancid quicker than linseed. Tests performed prove the opposite, though. Besides, that is a non-issue anyway, unless you are going to drink it.
Try it for yourself if your are concerned about your health.
http://www.mgraham.com/
morgan