NANP Board Domain I – Food and Nutrition Practice Exam

Fat-soluble vitamins can build up in the body's tissues because they are stored in the liver and fat and are not readily excreted like water-soluble vitamins. Vitamin A is the classic example of a fat-soluble vitamin that can accumulate to toxic levels when intake is excessive. When you consume too much preformed vitamin A (retinol) from supplements or highly concentrated foods, stores in the liver can become overloaded, leading to hypervitaminosis A. This toxicity can cause symptoms such as headaches, dizziness, nausea, dry skin, hair loss, liver effects, bone pain, and in pregnant individuals, potential birth defects. While other fat-soluble vitamins like D can also be toxic in very high amounts, vitamin A is the most commonly referenced one in relation to accumulation and toxicity. Vitamin C is water-soluble and is less prone to accumulation, and toxicity from vitamin K is rare.