From Chapter 3.1 of the book “Live Young, Longer”, by  Éric Simard (English version coming soon)

In the previous article, we described the risk/benefit balance in assessing the suitability of a health approach. Thus, after discussing the risks, we will now define the 5 categories of information considered, related to the evidence towards health benefits:

  1. Consumption history;
  2. Scientific literature;
  3. Identification of a mechanism of action;
  4. Preclinical studies;
  5. The results in humans.

We will end by explaining what the longevity index was created for, in the first book by Dr. Simard, doctor in biology, and researcher in the field of aging (

1. Consumption history

Being relevant information that can tell us about certain plant extracts that have been used for thousands of years, this category does not however, guarantee the efficacy or safety of a plant extract.

To demonstrate this, let’s take valerian as an example. Known primarily for its effects on reducing stress and anxiety as well as helping sleep, it has been used for several health problems in the past. Many scientific studies have shown the efficacy and safety of this plant. However, it is important to use standardized extracts of valerian, as the concentration of its active compounds can vary widely.

There is also the Galega officinalis which is a plant that is found around the Mediterranean Sea and in Northern Africa. This plant is the source of one of the most widely prescribed drugs for type 2 diabetes: metformin. This plant has been considered medicinal since the Middle Ages. It is used in different parts of the world for lowering blood glucose and as a diuretic. Although its use has been used since the Middle Ages, certain toxic compounds are also present in this plant. It seems that as little as 100 grams of the dried plant can be enough to cause the death of a sheep.

It is therefore essential to ensure the quality of plant extracts from natural products, despite their consumption history.

2. Scientific literature

It is important to know that the more studies and literature there is about a plant extract, food or other ingredients, the more credible the results. In other words, the fact that there are a lot of studies that have been done by various researchers who have used various sources of products or approaches, increases credibility.

Let’s clarify this by taking olive polyphenols as an example. Many studies speak of the benefits of these polyphenols for cardiovascular health, inflammation, oxidation of blood lipids, as well as a general antioxidant. When it comes to bone growth, there are only a few studies on this topic. It can therefore be concluded that olive polyphenols potentially have a positive effect on bone growth, but that this benefit is much less sustained than the impact on cardiovascular health.

3. Mechanisms of action

Not being an essential element, the identification of one or more mechanism(s) of action is still an important element in supporting the health benefits. Note that there are many drugs that have been approved without knowing their mechanism of action.

Let us come back to the case of valerian which is a significant example. The evidence of the effects of valerian on the brain is not new, but it is only recently that the mechanisms of action of valerian have been able to be explained a little better. It still seems obvious that other mechanisms, as yet unknown, are responsible for part of its profits.

4. Preclinical studies

When it comes to health benefits, the validity of preclinical studies will depend on the type of research performed. These may be exploratory cell models, or even animal models known to study the effectiveness of certain drugs.

Here, the principle is the same as for the scientific literature (in point 2). The more clinical studies that are performed by various research groups or different approaches, the stronger the credibility compared to extracts or molecules that have only one study. However, this point is not sufficient to conclude that there is a beneficial activity in humans.

5. Results in humans

Also called clinical results, results in humans have the best level of evidence concerning a health benefit. Warning! The fact that a natural health product has been tested in a clinical study does not necessarily guarantee its effectiveness. What is important is to take into account the quality of the study as well as the results obtained. The best way to judge the suitability of a product is to seek the advice of a healthcare professional, regardless of whether or not there has been any validation of clinical studies.

What is the longevity index?

The longevity index is a composite index; an index that relates a sum of information from the various sources mentioned. This index was created for the writing of the first book by Dr. Simard, doctor in biology and researcher in the field of aging (Live Young, Longer – English version coming soon). It brings together the latest knowledge in terms of anti-aging health benefits and makes it possible to compare an extract, a molecule, or a food on the basis of the quality of existing scientific studies. Its objective is to categorize the importance of scientific studies in relation to longevity in health for the extract, molecule, or food considered. Therefore, the higher the value of the index, the more the expert committee judged the healthy results to be valid.

To illustrate, here are some examples of longevity indices from the book:

Be aware that in the field of aging, studies are more difficult, because it is a question of benefits on complex systems and over long periods of time. You might be thinking to yourself: So, what is the basis of the expert committee to judge scientific studies?

Here are the elements included in the longevity index:

  • No known risks or interactions with drugs
  • Consumption history
  • Abundance of scientific literature on health benefits related to aging, or diseases related to aging
  • Presence of one or more known mechanisms of action
  • Preclinical studies available
  • Demonstrated benefits in humans

This article therefore closes the series of our articles on scientific research. With the previous 3 articles (Scientific research: what you need to know – article 1 of 4, Scientific research: studies vs quality – article 2 of 4 and Scientific research: risk / benefit ratio – article 3 of 4), we have covered the stages of scientific research, the various studies, the quality standards, the risk/benefit ratio as seen above, and the categories linked to the information supporting the health benefits. For any questions, write to us at!


Further suggested reading:




  • Cicerale et al, 2010. Biological Activities of Phenolic Compounds Present in Virgin Olive Oil. Int J Mol Sci. 2010; 11(2): 458–479.
  • de Pablos et al, 2019. Hydroxytyrosol protects from aging process via AMPK and autophagy; a review of its effects on cancer, metabolic syndrome, osteoporosis, immunemediated and neurodegenerative diseases. Pharmacological Research 143 (2019) 58–72.
  • Eric Simard, Dr en biologie. 2016. Vivre jeune plus longtemps; Chapitre 3.2, Les polyphénols d’olives et la diète méditerranéenne. Marcel Broquet la Nouvelle édition. 364 pages.
  • Menendez et al, 2013. Xenohormetic and anti-aging activity of secoiridoid polyphenols present in extra virgin olive oil. A new family of gerosuppressant agents. Cell Cycle 12:4, 555–578; February 15, 2013.