Nutritional deficiency occurs when the body does not receive enough essential nutrients, such as vitamins, minerals, proteins, carbohydrates, or fats. This lack can lead to various health issues, including weakened immune function, fatigue, and impaired growth. Common deficiencies include iron, vitamin D, and vitamin B12, which can arise from poor diet, certain medical conditions, or absorption issues. Symptoms of nutritional deficiency vary depending on the nutrient lacking. For example, a deficiency in vitamin C can cause scurvy, leading to symptoms like swollen gums and fatigue. Addressing these deficiencies often involves dietary changes, supplementation, or medical intervention to restore proper nutrient levels.