Evidence-Based Research

The question we are asking here is: How does evidence fit in with herbal and dietary supplement research? In many ways, HDS supplement research is very much like prescription medication and pharmaceutical research. Both of them employ the same type of scientific techniques, such as the use of biochemistry, animal studies, observational studies, and clinical trials.

In-vitro and animal studies:

Use objective measurements to isolate tissue or cell cultures as first steps for understanding the physiological or pharmacologic activity of a substance,
Animals are often used in pharmacological studies as they permit control over variables and can help explain possible mechanisms of action,
Are limited in that they may not accurately predict physiological effects in humans.

Observational data:

The history of use of a plant is an important source of information regarding safety and efficacy.

Case Reports:

Provide a snapshot in time of a unique human event,
Are limited by the quality of reported data.

Clinical trials:

Are considered the "gold standard" for pharmaceutical research,
Can greatly reduce bias by using placebos and blinding methods,
Can be sources for measuring efficacy and safety,
and the authors of research articles must clearly provide an adequate description of the product used in the clinical trial.

Despite these similarities, there are indeed differences as well between HDS and pharmaceutical drugs--namely three significant differences--to keep in mind when assessing evidence-based information:

Many dietary supplements have multiple ingredients in a single product.
Due to the natural and complex nature of HDS, there may be variations in research studies between the plant species used in a product, the plant part, and the preparation.
HDS come in numerous forms and preparations. When reading a clinical trial, the author should provide descriptions of the identification of the product (Latin binomial and authority), plant part (root, leaf, seed, etc), and type of preparation (tea, tincture, extract, etc). Precise and clear dosage form should be provided.

For more information and detailed guidelines to reporting RCTs of herbal interventions, please click here for an elaborated CONSORT statement.