What Are Dietary Supplements, and Who Can Use Them?

Dietary supplements are among the most popular nutrition topics in recent years. They are products containing vitamins, minerals, protein, and similar nutrients, intended to supplement a regular diet. Available as capsules, tablets, powders, or liquids, they are sold with a defined daily intake amount. Because labeling, presentation, and advertising are tightly regulated, it is important to know what information to look for when buying a dietary supplement. Below, we cover the legal definition of dietary supplements, common types, label-reading rules, and situations in which they may be useful.

How Are Dietary Supplements Legally Defined?

Under Law No. 5996, dietary supplements are defined as products prepared in forms with a specified daily intake amount. They contain concentrated nutrients such as vitamins, minerals, protein, carbohydrates, fiber, fatty acids, and amino acids, or concentrates and extracts of plant- or animal-derived substances with nutritional or physiological effects, for the purpose of supplementing a regular diet. This definition places dietary supplements in a different category from medicines; supplements may not be marketed as products that prevent or treat disease. The Turkish Food Codex Communiqué requires these products to be offered to final consumers only in prepackaged form.

What Should You Check on the Label?

Dietary supplement labeling is subject to strict rules. Claims on labels, in presentations, or in advertisements that a product can prevent or treat a disease are prohibited. Checking for this rule is an initial indication of whether a product has been marketed in compliance with regulations. The daily intake amount, ingredient list, and manufacturer information are expected to appear clearly on the label; if any of these details are missing, the product’s reliability should be questioned. Since some products outside the scope of the communiqué may contain active pharmaceutical ingredients, it is important to buy from reliable sources.

Common Types of Dietary Supplements

In Türkiye, the most commonly used dietary supplements include multivitamins and fish-oil capsules; these two product groups are sold in a wide variety at pharmacies and grocery stores. It is reported that vitamin B12 absorption decreases with age, particularly among older adults, so multivitamin supplements are often chosen for this group. Supplements containing iron, vitamin D, and calcium are also widely used and are generally chosen to address a specific deficiency. Protein powders and amino-acid supplements are prominent in sports nutrition.

When Might a Dietary Supplement Be Useful?

People with health conditions that make them unable to eat certain foods, such as food allergies, may use supplements to make up for nutrients they are missing. People with liver or gastrointestinal conditions that make it harder to absorb certain nutrients may also use supplements on a doctor’s advice. Certain vitamins formulated for pregnancy are considered important for the health of women who are pregnant or planning pregnancy and their babies. People who do not get enough sunlight and have a diagnosed vitamin D deficiency may also use supplements to address that deficiency.

Risks to Keep in Mind

Taking excessive amounts of dietary supplements is reported to cause problems such as cellular toxicity and reduced absorption of other nutrients. For this reason, supplement use should not continue without identifying a need and obtaining a doctor’s approval. Basic safe-use practices include not exceeding the daily intake amount and considering possible interactions when taking supplements with other medicines. Avoid products made outside the scope of the communiqué because they may contain active pharmaceutical ingredients.