It is known that a clear relationship exists between the food we eat and our health. Thus, the functional components of food, besides being fundamental to the good and normal functioning of the human body, can also be applied effectively in the treatment and prevention of some diseases.
More than 5,000 bioactive components have been identified in plant foods, but there are believed to be more than 25,000, and most are metabolized to different compounds during and after digestion. Considering this huge variety of compounds, it can be assumed that it is the combination of many food compounds consumed from a variety of whole foods that probably brings the greatest health benefits and not just a specific one.
Thus, there is still much research required to better understand the role of bioactive dietary compounds and their metabolites in human health. In this sense, in vitro methods can be used to understand and study:
- the identity and quantity of bioactive components in food and its metabolites.
- mechanisms of action, absorption, bioavailability, metabolism and biological activity.
This allows an assessment of the performance, toxicity, efficacy and side effects of bioactive compounds.
In vitro is an expression of Latin which means "in the glass" and refers to the technique of performing a certain procedure in a controlled environment outside a living organism. It can be performed on a wide range of cells, and the biological material that best suits the purpose of the test must be selected.
Laboratories preferentially use in vitro tests due to the following advantages:
- Does not require animals or humans
- Absence of ethical restrictions
- Avoid the need to submit animal protocols
- Avoid/reduce the need for laboratory personnel with experience in handling animals
- Less security concerns
- Lower cost
- Faster
The problem with the in vitro study is that it is not a complete representation of the response of a human being to a compound.
The human body is much more complex than a simple cell culture, so there is a big difference between an active compound are administrated to the cells and the same compound administered to a human being.
It is important to consider the relationship between the compound applied directly to the in vitro system and the identity and concentration of the compound that reaches the target (e.g., tissue, receptor, subcellular component) following human ingestion of the specific ingredient. After a substance is ingested, the metabolic fate of the compound and the amount of the biologically active compound that actually reaches the target site is dependent on a multitude of processes, including absorption, distribution, metabolism, and excretion in what are often complex pathways.
In addition, in vitro studies cannot fully predict the influence that the active ingredient will have on organs and systems, or the interaction with others.
Knowledge of a dietary ingredient's pathway and in vivo metabolism will allow the most appropriate interpretation of the relevance of compound concentrations used in in vitro experiments to amounts ingested by humans.
To clarify all the missing information that cannot be obtained through in vitro assays, in vivo studies still are necessary.