1. Bone Health: Vitamin D plays a critical role in maintaining healthy bones and teeth. It helps the body absorb calcium and phosphorus, which are essential for bone growth and maintenance. Vitamin D deficiency can lead to a condition called osteomalacia, which causes weak bones and muscle weakness.
2. Immune System Function: Vitamin D is important for immune system function, as it helps to regulate the production and activity of white blood cells, which are responsible for fighting off infections and diseases.
3. Cell Growth: Vitamin D is necessary for the normal growth and development of cells in the body.

1. Sunlight: The body can produce vitamin D when the skin is exposed to sunlight. The amount of vitamin D produced depends on the time of day, season, latitude, and skin color. People who live in areas with limited sunlight or who spend most of their time indoors may be at risk for vitamin D deficiency.
2. Food Sources: Vitamin D is found naturally in a few foods, including fatty fish (such as salmon and tuna), egg yolks, and mushrooms. Some foods, such as milk, cereal, and orange juice, are fortified with vitamin D to help people meet their daily needs.
3. Supplements: Vitamin D supplements are available in various forms, including tablets, capsules, and liquid drops.

The recommended daily intake of vitamin D for adults is 600-800 IU (International Units) per day. However, some people may require higher doses, especially those who have limited sun exposure or who have conditions that affect vitamin D absorption. It’s important to talk to a healthcare professional before taking vitamin D supplements, as excessive intake can lead to toxicity. Symptoms of vitamin D toxicity include nausea, vomiting, weakness, and kidney damage.