Vitamins, calcium, Omega-3, probiotics, bran, ginseng, beer yeast and energy bars are just some of the food supplements most widely consumed by Spaniards. The Spanish Academy of Nutrition and Dietetics drafted a comprehensive study for Fundación MAPFRE in which they analyzed the causes of this ever-growing phenomenon. In our country, around 50 percent of the population consumes this kind of product, with food supplements being the most widely accepted among those surveyed.


As soon as you turn on the television or surf the Internet, it is easy to come across advertising related to some food, nutritional or dietary supplement. Or even just browsing the shelves of any supermarket. So much so, that they have become commonplace in many homes. Indeed, sales have grown constantly over the last decade, with figures in the millions. According to 2017 data from AFEPADI (Association of Dietary and Food Supplement Companies), annual sales of food supplements worldwide came to a total of $121.2 billion that year. And growing… Some studies point to an increase by 2026 of between 18 and 45 billion euros, which represents an estimated growth rate of between 4.89 and 6.5 percent.

This would pose no problem whatsoever, were it not for the tremendous lack of knowledge regarding the true beneficial effects of consuming these products. And what is worse, regarding the harmful effects too. Because not all supplements have been researched to the same degree. The fact is that there is also no robust legislative framework to clarify under what circumstances their consumption is advisable. Suffice it to say that even their classification differs from country to country and there is no clear definition for this type of product.

The following comes from Use of Nutritional Supplements in the Spanish Population, drafted by the Spanish Academy of Nutrition and Dietetics for Fundación MAPFRE: “There is a lack of clarity regarding the definition of plant-based products, given that they are sometimes classified as medicinal products, yet other times defined as food supplements, with the final decision falling on each Member State of the European Union.”

Despite all this uncertainty, these products are really widespread. In fact, according to the study, “seven out of every ten Spaniards say they took some form of supplement in the last year.” According to Eduard Baladia, coordinator of the study and member of the Spanish Academy of Nutrition and Dietetics, “those supplements whose sales have increased, such as vitamins C and D, antioxidants, selenium or zinc, are all immunerelated nutrients. However, the fact that they are related to immunity does not mean that taking such supplements can increase or enhance our immunity, but rather that a deficiency of these nutrients could weaken our immune system, although we don’t know by how much.” The study places Spain among those countries that consume the most food supplements, alongside others such as Denmark and the United States, with rates that exceed 50 percent of the population.

A la carte supplements

Moreover, four out of ten Spaniards are fond of consuming vitamins and vitamin complexes, “this being more common among the younger age groups.” Of all the vitamin groups, D and C stand out, as they are taken by three out of ten people surveyed. As for minerals, the most widely consumed are magnesium and calcium, by 13 and 12 percent of the sample, respectively. Omega-3 is consumed by two out of ten people surveyed, doing so through plant-based sources such as evening primrose oil, flax or nuts. Highly similar is the proportion of respondents who consume probiotics.

In other words, a large majority of the population in our country is taking some kind of supplement, mainly nutritional ones. The argument most commonly put forward is that of ‘improving their overall health’, followed by those wishing to lose weight, who consume special products.

El auge de los suplementos alimenticios a estudio

Given this reality, it seems clear that most of those surveyed perceive them as being safe.

Interestingly, while a high percentage are selfadministered, many of these products are prescribed by physicians. In this regard, the study emphasizes the need for physicians to “acquire sufficient academic skills so that their professional practice can be guided according to evidence-based principles. However, the lack of certainty regarding beneficial health effects and their possible mild, transient adverse effects must be considered when making a professional decision. Not forgetting the economic cost that taking these products represents for their patients, a choice which, in any case, impedes them from investing in health products with sufficient guarantees of effectiveness.”

Lack of scientific evidence

Indeed, the study by the Spanish Academy of Nutrition and Dietetics underscores “the lack of scientific evidence on the safety and efficacy of these products, which should therefore be considered a possible public health issue.” “After extensive review of the pertinent literature, an additional problem detected is that many of them are not endorsed by sufficient studies to be able to verify the potential benefits attributed to them, and what is worse, any that certify that they are actually safe,” Baladía declares. However, to understand this phenomenon, we must look for the causes. “The sports market, the emergence of so-called personalized nutrition, and the aging population, as well as the growing online market and ease of acquisition, are some of the factors driving growth, especially among millennials, women and those over the age of 60,” according to this report which provides an overview of the evidence that exists in this regard, drawn from various studies.

The study emphasizes the need for physicians to be able to acquire sufficient academic skills so that their professional practice can be guided according to evidence-based principles

No clear conclusions

The first thing to consider when it comes to seeking scientific evidence is that, as the study points out, “clear evidence of the benefits and proof of the top quality health properties claimed for such supplements are still scarce and, in some cases, non-existent.” Despite this, it can be said that “calcium supplementation could have positive effects on the primary prevention of hypertension, this effect being more pronounced in men and in people under the age of 35. In relation to the progression of age-related macular degeneration, it has been observed that zinc supplementation could have beneficial effects.”

As for probiotics, of all their possible beneficial effects for diseases such as persistent or acute infectious diarrhea, infant colic, eczema or gestational diabetes, they have only been shown to clearly have a positive impact on a limited number of conditions. Something similar happens with the consumption of plants and their extracts, studied for improving joint issues, memory, menopause, diabetes or asthma. “In most cases, however, there is insufficient or poor quality evidence and this therefore does not allow clear conclusions to be drawn regarding any positive impact on their health,” the report states.

Adverse effects have also been studied. “A wide variety of vitamins and minerals and their combinations have been associated with adverse effects of varying significance, ranging from an increased risk of mortality for supplementation with antioxidants such as beta carotene and vitamins E and A , or fetal and neonatal mortality for magnesium supplementation in pregnant women.” The conclusion is that the benefits shown do not correspond to the magnitude of the business they represent, or to their high consumption rates. In short, discretion is always the best advice when it comes to consuming these products.