Nutritional supplements are products that contain vitamins, minerals, herbs, amino acids, or other dietary substances that are intended to supplement an individual's diet. These products are commonly used to improve overall health and well-being, support specific health conditions, or enhance athletic performance. Some common types of nutritional supplements include multivitamins, protein powders, fish oil, probiotics, and herbal supplements. Research in this area often focuses on the efficacy and safety of these products, as well as their potential benefits and risks for various health conditions. Studies may also examine the interactions between supplements and medications, as well as the impact of dietary supplements on overall diet quality and nutrient intake.