Humans and insects evolved on plants. Our bodies are expecting the substances provided by plants grown in healthy soil. Plants live in soil which contains healthy bacteria. When the soil is properly nourished, then plants take these up as they grow and convert them into complex phytonutrients. There are 150,000 to 200,000 edible plant speices on Earth and humans eat only 150 to 200 of these. Over 100,000 phytonutrients have been identified and the bacteria in our intestines break these down into many other substances. While you can survive on a highly processed purified diet, the diversity of plant substances from a diet containing colorful fruits and vegetables cannot be duplicated artificially.
Careful methods are needed to take advantage of a “Seed to Feed” philosophy. It is important to identify and know the farmer producing the plants such as green tea to be sure that only proper agricultural methods are used. Quality control testing must be used to assure that the soil is free of any contaminants. This is accomplished with atomic absorption techniques that can detect the most minute amounts of potential contaminants. Then the phytonutrient profile of the foods harvested is studied to assure that the plant products contain the desired compounds in the proper amounts. All of this is feasible and being done by careful food manufacturers who follow the “Seed to Feed” philosophy.