What is converted to vitamin a in the body

Updated visitor guidelines. Top of the page. Vitamins: Their Functions and Sources. Topic Overview The tables below list the vitamins , what they do in the body their functions , and their sources in food.

Water-soluble vitamins Water-soluble vitamins travel freely through the body, and excess amounts usually are excreted by the kidneys. Needed for vision, healthy skin and mucous membranes, bone and tooth growth, immune system health Vitamin A from animal sources retinol : fortified milk, cheese, cream, butter, fortified margarine, eggs, liver Beta-carotene from plant sources : Leafy, dark green vegetables; dark orange fruits apricots, cantaloupe and vegetables carrots, winter squash, sweet potatoes, pumpkin Vitamin D Needed for proper absorption of calcium ; stored in bones Egg yolks, liver, fatty fish, fortified milk, fortified margarine.

Vitamin E Antioxidant; protects cell walls Polyunsaturated plant oils soybean, corn, cottonseed, safflower ; leafy green vegetables; wheat germ; whole-grain products; liver; egg yolks; nuts and seeds Vitamin K Needed for proper blood clotting Leafy green vegetables such as kale, collard greens, and spinach; green vegetables such as broccoli, brussels sprouts, and asparagus; also produced in intestinal tract by bacteria.

Credits Current as of: December 17, Top of the page Next Section: Related Information. Previous Section: Related Information Top of the page. Current as of: December 17, Part of an enzyme needed for energy metabolism; important for normal vision and skin health. Milk and milk products; leafy green vegetables; whole-grain, enriched breads and cereals. Part of an enzyme needed for energy metabolism. The answer seems to be yes. A study that looked into the effects of the BCMO1 genetic variants on lung cancer risk and fruit and vegetable consumption found that, regardless of enzyme function, higher fruit and vegetable consumption reduced the risk of lung cancer considerably.

Even with reduced enzyme function, you still get some vitamin A from fruits and vegetables — along with all of the other nutritional benefits. Testing your vitamin A levels: If you have symptoms of vitamin A deficiency poor night vision, lowered immunity, skin problems, keratosis pillaris, etc , possibly check your vitamin A levels with a blood test. You could get this through your doctor or order it online. Related article: Foods rich in retinol and recipe ideas.

Increasing beta-carotene consumption may help your vitamin A status — up to a point. Another option is to consider supplementing with a retinol form of Vitamin A. Some supplement forms of retinyl palmitate are derived from soy oil and considered vegan.

You may be wondering if the overconsumption of dietary beta-carotene would have the same detrimental cancer-risk increasing effects as the supplementation studies. First, keep in mind the studies were multi-year studies in smokers, so the results may not apply to non-smokers.

The absorption of beta-carotene from foods is going to be lower than from a supplement due to the need for digestion, mixing with fat, and then transport into the intestinal cells. So even if you eat 20 mg of beta-carotene per day — every day — you are still probably not absorbing nearly as much from food as you would from a 20mg supplement pill.

So how much beta-carotene is in carrot juice? According to the Nutridesk website, one cup of carrot juice contains 22mg of beta-carotene. If you are a poor converter of beta-carotene, you would get less than 1. Beta-carotene is hydrophobic and needs fat to be absorbed in the intestines. Adding a little fat to your beta-carotene rich food should help a little with absorption. Get a blood test to determine your level. Most supplements list the amount of vitamin A in IU international units.

One IU is equivalent to 0. So IU would equal 2. High doses of vitamin A can cause birth defects, so if you are planning to get pregnant, talk with your doctor before taking vitamin A supplements. If you take vitamin A for its antioxidant properties, keep in mind that the supplement might not offer the same benefits as naturally occurring antioxidants in food.

The recommended daily amount of vitamin A is micrograms mcg for adult men and mcg for adult women. Beyond use as an oral supplement, vitamin A is used in topical creams to reduce fine wrinkles, splotches and roughness and treat acne. A healthy and varied diet will provide most people with enough vitamin A.

If you're interested in the antioxidant properties of vitamin A, food sources are best. It's not clear if vitamin A supplements offer the same benefits as naturally occurring antioxidants in food.

Too much vitamin A can be harmful and excess vitamin A during pregnancy has been linked to birth defects. Too much vitamin A can be harmful. Even a single large dose — over , mcg — can cause:. If you are or might become pregnant, talk to your doctor before taking vitamin A. Excess use of vitamin A during pregnancy has been linked to birth defects.

There is a problem with information submitted for this request. Sign up for free, and stay up-to-date on research advancements, health tips and current health topics, like COVID, plus expert advice on managing your health. Error Email field is required. Error Include a valid email address. The best sources of vitamin A are: Cod liver oil.

Fortified breakfast cereals. Fortified skim milk. Orange and yellow vegetables and fruits. Other sources of beta-carotene such as broccoli, spinach, and most dark green, leafy vegetables. How can you increase the bioavailability of vitamin A?

HFP's contribution can be maximized by increasing the amount of vitamin A-rich food consumed, including animal source foods, choosing foods with higher vitamin A content, and improving bioavailability by adding fat, destroying the matrix of vegetables, and deworming. Can you take too much vitamin A? Yes, high intakes of some forms of vitamin A can be harmful. Getting too much preformed vitamin A usually from supplements or certain medicines can cause dizziness, nausea, headaches, coma, and even death.

Women who might be pregnant should not take high doses of vitamin A supplements. Is too much beta carotene bad for you? Taking big doses of vitamin A can be toxic, but your body only converts as much vitamin A from beta-carotene as it needs. That means beta-carotene is considered a safe source of vitamin A. However, too much beta-carotene can be dangerous for people who smoke.