Food Supplements_3: How to assess them?

Article by Solongevity Research
Once established what a food supplement plan is and which are the key questions to adapt it to your needs, then you can (finally) proceed with your product selection. Every year, however, more than a thousand new supplements are brought to the market and getting your bearings may not be easy. What features should a good supplement have? In this third part of our “journey” in the world of dietary supplementation, we understand together what to pay attention to.


Just like regular food, supplements must have a label that mentions every single ingredient in a clear and transparent way. The labelling requirements for food supplements on the EU market are established by Directive 2002/46 / EC (legislation on food supplements transposed also in Italy) and, as specified on the website of the European Food Safety Agency (EFSA), includes:
  • The names of the categories of nutrients or substances used within the product formula or an indication of nutrients or substances source;
  • the portion of the product recommended for daily consumption;
  • the warning not to exceed the daily dose defined as recommendable;
  • the recommendation not to use dietary supplements as a substitute for a varied diet;
  • the recommendation to keep products out of the reach of children.
Within a label, not all ingredients have a recognized nutritional reference value, because nutritional science has not defined a minimum requirement for all nutritional principles in our body. Metabolic biochemistry is still a universe to be explored, and nutritional innovation often goes faster than the ability of regulation authorities to adjust their issues.

Product Certification

A certified formula implies that the product has been tested to assess its efficacy (which includes metabolic efficiency, functional capacity and safety) on specific physiological targets. To ensure its effectiveness, food supplements usually leverage on the deductive method: the formula is composed of ingredients that have been individually tested for tolerance, safety, and efficacy; then their mix (the formula) combining them is tested, safe, and effective. This approach, while logically sound, has inherent limitations:
  • ingredients can interact with each other, altering their individual biochemicals effectiveness.
  •  ingredients can be conveyed in a way (powder, gel, water, nanocapsules, liposomes, etc..) that influences their efficacy and that is not always the same used by the raw material supplier for the efficacy and safety test;
  • the same ingredients do not necessarily have the same efficacy. As an example, not all blueberry extracts have the same anti-oxidant capacity; not all forms of magnesium have the same neurological properties.
A dietary supplement is considered reliable when you certify the formula as a whole, that is, exactly what is taken by the consumer . Formulas can be certified in vitro (laboratory), i.e. on cultures of cells that reproduce the physiological environment of human organs, on animals (in vivo), or on people experimenting them with laboratory and functional tests conducted by a medical team. These in vivo tests are divided into observational and clinical tests, the latter being assimilated to those of drug development. Moreover, we should pay attention to the scientific literature to which the product refers: the demonstrations of the properties of the elements and the formula should not only be “laboratory”, i.e. obtained in vitro or on animal models, but also clinical, with tests on people. The observational or clinical part is what makes the difference between a promising product (but which still has some way to go) and an established and reliable one, which has proven efficacy in humans.
It’s important to know that a prospective clinical trial involves approval by an ethics committee, which ensures that the study protocol and how it is carried out are thoroughly monitored.
A food supplement with a tested formula , in laboratory or in vivo, and a specific physiological target is classified as a nutraceutical. The choice of a food supplement goes through the evaluation of elements such as transparent label, certification, bio-accessibility and bio-availability, synergies and antagonisms, production of the product, etc.

As for foods, the label of dietary supplements must report every single ingredient, indicating its nature, the daily recommended dosage and warnings for a correct usage

Bioaccessibility and Bioavailability

A good food supplement is designed to provide a useful contribution to human metabolism and to  different physiological targets. For this to be possible, it is essential to take into account two characteristics: bioaccessibility and bioavailability. Bioaccessibility represents that fraction of the food product useful for metabolic and nutritional purposes. In practice, it is the part that is released by digestion to be absorbed in the intestine. Bioavailability, on the other hand, is just that percentage of nutrients that can be absorbed by the intestine and entering the bloodstream to be used, in the correct form and in sufficient quantity, where it is needed. For example, it is absolutely useless to take high amounts of a nutrient when its bioavailability is low, because our body will “throw it away”. Evaluating whether the nutrients contained in a certain supplement are more or less bioavailable is a task for experts, which is why it is important to ask them. In any case, the fact that those selling a product have asked themselves this question can already be an indicator.
Clinical trials on humans make the difference between a promising product and reliable one

Synergies and antagonisms 

A reliable product takes into account the biochemical synergies and antagonisms between substances. Some nutrients, in fact, get along together and can, for example, promote the absorption of each other. Other substances, on the other hand, do not get along well and taking them at the same time may cancel out their benefits. An example is that of vitamin B1 (or thiamine): allicin converts it into a form which is more easily absorbed, whereas some polyphenols (caffeic acid, chlorogenic acid and tannic acid) and flavonoids (quercetin and rutin) interfere with its absorption.



Additional information to consider when evaluating a food supplement is to verify the production chain: where the product was made and whether it was packaged by licensed manufacturers, responsible for the entire production process and certification of ingredient origin. A series of investigations into products marketed in 2013 in North America ( revealed that most of them did not have the ingredients stated on the label and the hygiene and safety conditions were not met. Where can this information be found? It can be certainly requested to the customer service of the producer himself, to be found on its website, within the product label that must report the production chain. There is also a section of the Ministry of Health, (for Italy link) which provides information and details about the supplements on the market and eventual problems detected.

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