This is a question that I always make to myself when I take vitamin C in pills, or when I have the chance to squeeze a bunch of oranges. It is an interesting question.

First of all, let me tell you that the vitamins in their natural source like fruit are those that occur in nature while synthetic vitamins are manufactured in a laboratory. The benefit of synthetic vitamins is that they are cheaper to make, therefore less expensive for the consumer.

Synthetic vitamins are produced with the same molecular and chemical structure as their natural vitamin counterparts, then the body treats most natural vitamins the same as synthetic vitamins when it absorbs them. The body absorbs the vitamins in a process by which they enter the circulatory system from the gastrointestinal tract. In order for vitamins to reach the bloodstream, they must dissolve in the stomach or intestines and diffuse across the membranes lining the digestive tract. In spite of the fact that there is no difference in absorption between natural and synthetic vitamins, still food is the preferable way to get all the healthy stuff you need because in eating it, you are also getting a ton of other good-for-you things such as antioxidants (which have been rumored to prevent the aging of cells).

Vitamins in nature occur within a family of micro-nutrients (things like trace elements, enzymes, co-factors and other unknown factors) that help them absorb into the human body and function to their full potential. A few synthetic vitamins differ from the natural forms. For example, synthetic vitamin E, called d,l-alpha-tocopherol, is a mixture of both left- and right-handed molecules, while the natural alpha tocopherol is a single form called d-tocopherol. The synthetic product is adjusted to provide the same biological activity as the natural form.

Certain vitamins like vitamin B12 possess structures that are too complex for a convenient lab synthesis, but microbial sources have been selected to produce large amounts of this vitamin.

I thing that it might not be easy for you to test the efficiency of the vitamins in their natural and synthetic form, because you would have to take samples from fluids of the human body, and work with some volunteer persons who want to do that.

You can do a simple absorption experiment to estimate the absorbability of calcium tablets or multivitamins that contain calcium, by placing the tablet in 6 ounces of vinegar for 30 minutes. If it disintegrates, the calcium in the pill can be effectively absorbed by your body. In this experiment, we are trying to simulate the stomach acidity with the vinegar. However, the calcium from food is better absorbed and used than calcium from pills.