However, this empiric usage has not been tested in a prospective controlled trial.

The main difficulty is that there have been no controlled prospective clinical trials.

"But we need long-term, large-scale prospective trials to actually prove that."

Several current publications have begun to remedy this lack of prospective, randomized trials.

But the only way to prove any treatment effective is with the results of a randomized, controlled prospective clinical trial, and none are yet available.

However, a prospective, randomized trial has not been performed.

No prospective or randomized trials document the value of this approach.

This approach may become a treatment for some people with type 2 diabetes, but has not yet been studied in prospective clinical trials.

A prospective, random trial is a good example of an experiment: the study is designed first, then the data are collected.

All the studies, researchers say, need to be followed by large prospective clinical trials.