Vitamin A helps your vision and increases your resistance to viruses, but as you may have heard, too much of certain kinds can be dangerous. Your body synthesizes beta carotene into vitamin A– beta carotene is what gives plants like carrots, mangoes and sweet potatoes their orange color, and greens like spinach and collards have some, too. It can also be found in animal products, such as liver and butter. Recommended daily allowance/ upper limit: 770 mcg during pregnancy, 1,300 mcg while breastfeeding, no more than 8,000 mcg (2,500 IU) per day.
You can’t overdose on beta carotene (though too much can make your skin get an orange tint). But the synthesized vitamin A, also known as retinol, you can overdose on. In animal sources the vitamin A is already partially converted, so you can also overdose too from too much liver or cod liver oil. A mere two ounces of beef liver will have 200% of your daily recommended dose. If you overdose you may experience dizziness, confusion and burred vision.
Carotene-rich vegetables are dark green, deep yellow, and orange: broccoli, greens, green peppers, sweet potatoes, carrots, pumpkins, winter squash, apricots, carrots, papaya, cantaloupe, spinach, pumpkin, sweet potatoes, and mangoes. Vitamin A deficiencies are rare. If you take multivitamin supplements, avoid those that contain more than the recommended dose; large doses of straight synthetic vitamin A are associated with birth defects. However, supplements that contain vitamin A in the form of beta-carotene are safe.