Essential Micronutrients: Videos & Practice Problems

Fat-soluble vitamins (A, D, E, K) are absorbed with the help of dietary fats and stored in the liver and fat tissues for later use. This means they can accumulate in the body, potentially leading to toxicity if consumed in excess. Water-soluble vitamins, on the other hand, are absorbed directly into the bloodstream and are not stored in the body. Excess amounts are excreted through urine, making it necessary to consume them regularly. Examples of water-soluble vitamins include the B-complex vitamins (like B9 or folate) and vitamin C. Both types are essential for various bodily functions, but their storage and absorption mechanisms differ significantly.

Folate, also known as vitamin B9, plays a crucial role in DNA synthesis and cell division, making it essential during periods of rapid growth, such as fetal development. It helps prevent neural tube defects, which are serious birth defects affecting the brain and spinal cord. To ensure adequate intake, the FDA mandates the fortification of grain products like rice, cereals, and pasta with folic acid, the synthetic form of folate. Pregnant individuals are often advised to consume folate-rich foods and supplements to support healthy fetal development and reduce the risk of complications.

Major minerals are required in amounts greater than 100 milligrams per day and play significant roles in the body, such as fluid balance regulation (e.g., sodium) and bone health (e.g., calcium). Trace minerals, on the other hand, are needed in much smaller amounts but are equally vital. For example, iron, a trace mineral, is essential for oxygen transport in the blood. The key difference lies in the quantity required by the body, but both types are indispensable for maintaining overall health and proper physiological functions.

Iron deficiency is the most common nutrient deficiency worldwide. Iron is a trace mineral crucial for transporting oxygen in the blood via hemoglobin. Symptoms of deficiency include fatigue, weakness, and impaired cognitive function. To address this, individuals can consume iron-rich foods like red meat, spinach, and fortified cereals. Pairing iron sources with vitamin C-rich foods (e.g., citrus fruits) enhances absorption. In severe cases, iron supplements may be recommended under medical supervision. Regular monitoring and a balanced diet can help prevent and manage iron deficiency effectively.

Sun exposure triggers the synthesis of vitamin D in the skin. When ultraviolet (UV) rays from sunlight hit the skin, they convert a cholesterol-based compound into vitamin D3 (cholecalciferol). This form of vitamin D is then processed by the liver and kidneys to become active vitamin D, which helps regulate calcium and phosphorus levels, supporting bone health. Spending time outdoors, especially during midday when UV rays are strongest, can help maintain adequate vitamin D levels. However, sunscreen use and limited sun exposure may require supplementation or dietary sources like fortified milk and fatty fish.

Grain products are fortified with folic acid to prevent neural tube defects in newborns. Neural tube defects, such as spina bifida, occur when the neural tube fails to close properly during early fetal development. Folic acid, the synthetic form of folate (vitamin B9), is added to foods like rice, cereals, and pasta to ensure adequate intake among the population, especially pregnant individuals. This public health measure, mandated by the FDA, has significantly reduced the incidence of these birth defects and supports healthy fetal development.