Which of the following is not a water-soluble vitamin?

Vitamin D is classified as a fat-soluble vitamin rather than a water-soluble one. This classification is based on how the body absorbs, transports, and stores these vitamins. Water-soluble vitamins, like pantothenic acid, B12, and B6, dissolve in water, and the body utilizes them quickly, often excreting any excess in urine. Fat-soluble vitamins, such as vitamin D, are absorbed in the intestines in the presence of fats and can be stored in the body’s fatty tissues and liver for later use. This distinction is important in nutrition, as water-soluble vitamins typically require more frequent consumption due to their limited storage capacity in the body, whereas fat-soluble vitamins can be stored and used over a longer period. Understanding these differences is crucial for proper dietary planning and nutrient intake.