Supplementation: types and when it's healthy to take them

In a world where the pace of life doesn’t always support a complete and balanced diet, supplements have become an increasingly common ally. Vitamins, minerals, proteins, amino acids, fatty acids and plant extracts are all part of these supplements, designed to support the body when the diet doesn’t fully meet its needs or when a specific health or performance goal is being pursued. Whether they are of natural or synthetic, their role is clear: not to replace food, but to complement it in a targeted and mindful way.

Types of supplements: natural or synthetic

When discussing supplementation, one of the most common distinctions is between natural and synthetic supplements. While both can serve similar purposes, they mainly differ in the origin of their ingredients and the way they are produced.

Natural supplements are derived from foods, plants or other biological sources and often retain part of the nutrient’s natural matrix. This means they may provide not only the main nutrient but also other compounds that naturally occur alongside it. For this reason, they’re often associated with a more holistic approach to nutrition. Common examples include:

• Food-derived vitamins and minerals, extracted from fruits, vegetables, or algae.
• Plant extracts, such as turmeric, ginger, green tea or ashwagandha.
• Natural oils and fats, such as omega-3 from fish or algae.
• Natural proteins, such as whey protein or plant proteins (pea, rice, soy, etc.).
• Probiotics and naturally derived ferments.

Synthetic supplements, on the other hand, are produced through chemical or industrial processes that isolate and recreate specific nutrients in precise, standardised doses. In many cases, the chemical structure of these nutrients is identical to that found in nature. These supplements stand out for their strict quality control, stability and accuracy of dosage. Common examples include:

• Synthesised vitamins, such as vitamin C (ascorbic acid), vitamin D or B complex.
• Minerals in the form of salts or chelates, such as iron, magnesium or zinc.
• Isolated amino acids, such as leucine, glutamine or arginine
• Functional compounds, such as creatine, caffeine or carnitine.
• Purified fatty acids, such as concentrated omega-3.

When are supplements necessary and in what quantity?

Supplements are necessary when the diet does not meet certain nutritional requirements or when specific conditions are present, such as diagnosed deficiencies, particular stages of life (pregnancy, ageing), restrictive diets or high physical demands. In these cases, their use can help prevent deficiencies or support health and performance.

Entrevista
Elena Díez

Clinical dietitian–nutritionist, registered with CoDiNuCat (Col·legi de Dietistes-Nutricionistes de Catalunya), specialising in digestive disorders, sports nutrition and oncology. She currently works at leading centres in Barcelona such as Dexeus, Clínica Diagonal and Núcleo Sarrià.

Do you think everyone can take supplements?

No. Supplementation is not risk-free and should always be individualised. Any supplement should be recommended and monitored by a healthcare professional (a doctor or dietitian–nutritionist), as there can be significant drug–supplement and supplement–food interactions. It’s also important to consider the potential risks of inappropriate dosages or unnecessary use.

If I follow a varied and healthy diet, do I need supplements?

In general, no. A balanced, well-planned diet should cover the body’s needs for both macro- and micronutrients. In the absence of illness, diagnosed deficiencies, intestinal malabsorption, or other specific conditions, supplements are usually not necessary.

Are supplements equivalent to nutrients obtained from food?

No. Foods provide nutrients within a complex matrix that includes fibre, bioactive compounds and natural synergies that cannot be fully replicated in a supplement, or at least not in the same way our bodies absorb them. For this reason, whenever possible, the priority should be to meet nutritional needs through diet and use supplements only when the diet is insufficient, impractical or difficult to maintain.

Why are vitamin D and magnesium such common supplements? 

Vitamin D deficiency is very common in the current population, especially among people with limited sun exposure or during the winter months. In these cases, supplementation may be useful when a deficiency has been confirmed through blood tests. Magnesium can be beneficial in situations of stress, muscle cramps or certain neuromuscular disorders, provided that an insufficient intake or malabsorption of this mineral has been identified; otherwise, they’re not necessary.