Isolated are just what they sound like, they are totally isolated from there original form in food to form things like ascorbic acid (vit C)  and will usually appear in much higher doses than the RDA (recommended daily allowance) determined by the FDA.  Isolates are not bad, they are simply different and are best used for a specific health challenge and with the input of a professional and you may need blood tests to check for levels.

Food grown supplements are when isolated vitamins discussed above are fed to food so that it may be transformed into a form your body recognizes....that would be food!  It is not important to understand this process, except to know that we were designed to eat food for nutrition and that is still the best way to get our nutrients.  However, because of the pace of our lives and the quality of our food, most of us could benefit from a  multivitamin and mineral supplement.  My bias is that food grown is best.  

Food Grown supplements are MORE EXPENSIVE.  The rule in the natural products industry is that you get what you pay for, so don't think you are saving money on that drugstore brand, you are really wasting money and may even be costing yourself money because who really knows what the long-term consequences are to taking junk.

Over the years, I have tried many, many products, both for my own personal use and with my family and clients.  Please beware that the Natural Products Industry is a multimillion dollar industry and though they really like to set themselves as superior to the pharmaceutical industry the goal is the same...to make greater profits for the company and that health and truth are secondary.  Unlike the pharmaceutical industry, the nature products industry has very little regulation and so a product will not be noticed until someone has a bad reaction.  Having said that there are very few bad reactions that people have with natural products (I said few, not none).  However, you are a unique biochemical, emotional being, no product has been tested on you until you try it, so be aware.  Pay attention to your body, mind, spirit and heeds its wisdom.  Stop any product that does not set well with your constitution and seek professional advise on how to proceed.