hypervitaminosis

Vitamins are substances that your body needs to grow and develop normally. Vitamin A plays a role in your:

• Vision
• Bone growth
• Reproduction
• Cell functions
• Immune system

Vitamin A is an antioxidant. It can come from plant or animal sources. Plant sources include colorful fruits and vegetables. Animal sources include liver and whole milk. Vitamin A is also added to foods like cereals.

Vegetarians, young children, and alcoholics may need extra Vitamin A. You might also need more if you have certain conditions, such as liver diseases, cystic fibrosis, and Crohn's disease. Check with your health care provider to see if you need to take vitamin A supplements.

NIH: National Institutes of Health Office of Dietary Supplements

Vitamins are substances that your body needs to grow and develop normally. Vitamin D is important to your body because:

• It helps your body absorb calcium. Calcium is one of the main building blocks of bone. A lack of vitamin D can lead to bone diseases such as osteoporosis or rickets.
• It also has a role in your nerve, muscle, and immune systems:
  • Your muscles need it to move
  • Your nerves need it to carry messages between your brain and your body
  • Your immune system needs vitamin D to fight off bacteria and viruses

You can get vitamin D in three ways: through your skin, from your diet, and from supplements. Your body forms vitamin D naturally after exposure to sunlight. However, too much sun exposure can lead to skin aging and skin cancer. So many people try to get their vitamin D from other sources.

Very few foods naturally contain vitamin D. Most people get vitamin D in their diet from foods that are fortified. This means that vitamin D is added to the food. These foods may include milk, cereal, and yogurt. Foods that naturally have vitamin D include egg yolks, saltwater fish, and liver.

Vitamin D is available in supplements. It is also included in many multivitamins. The two forms of vitamin D in supplements are D2 and D3. Both types increase vitamin D in your blood, but D3 might raise it higher and for longer than D2. Vitamin D is fat soluble. You can absorb it better when you take your supplements with a meal or snack that includes some fat.

The amount of vitamin D you need each day depends on your age. The recommended amounts, in international units (IU), are:

• Birth to 12 months: 400 IU
• Children 1-13 years: 600 IU
• Teens 14-18 years: 600 IU
• Adults 19-70 years: 600 IU
• Adults 71 years and older: 800 IU
• People who are pregnant or breastfeeding: 600 IU

But certain people may need extra vitamin D, such as:

• Older adults
• Breastfed infants
• People with dark skin
• People with certain conditions that limit the absorption of fat, such as Crohn's disease, celiac disease, and ulcerative colitis
• People who have obesity or have had gastric bypass surgery

Check with your health care provider to see if you need to take vitamin D supplements, and if so, how much you should take. Your provider may want to first do a vitamin D test to see if you are getting enough of it.

NIH: National Institutes of Health Office of Dietary Supplements