Beta-Carotene
Other name(s)
vitamin A, b-carotene, provitamin A
General
Beta-carotene is a type of substance called a carotenoid. Carotenoids give plants
such as carrots, sweet potatoes, and apricots t heir reddish-violet colors.
Beta-carotene is a provitamin. This means it's used by your body to make vitamin A.
It's only found in plants. Vitamin A is also found in foods from animals. Vitamin
A from animal sources is called preformed. This means it is in a form your body can
use directly. It's found in dairy products, fish oils, eggs, and meat (especially
liver). The vitamin A your body makes from beta-carotene doesn’t build up in your
body to toxic levels. But vitamin A from animal sources can. Vitamin A is available
in multivitamins and as a stand-alone supplement. Vitamin A supplements can contain
only beta-carotene, only preformed vitamin A, or a combination of both types of vitamin
A.
If your body doesn't use all the beta-carotene you eat to make vitamin A, the beta-carotene
that remains circulates in your body. Beta-carotene is also an antioxidant. It helps
keep cells healthy.
Main functions
Beta-carotene and vitamin A play a vital part in the reproductive process. They also
help keep skin, eyes, and the immune system healthy.
Demonstrated uses
Beta-carotene and other carotenoids help reduce free radical damage in your body.
Taking beta-carotene supplements can help you get enough vitamin A. These supplements
are considered safe.
Reasons for increased need
Poor nutrition is a leading cause of beta-carotene and vitamin A deficiency. These
problems can keep you from getting enough vitamin A:
-
Lactose intolerance
-
Sprue
-
Cystic fibrosis
Women who are pregnant or breastfeeding may need to take supplements. Be sure to talk
to your healthcare provider before doing this.
Claims
Beta-carotene may reduce the risk of some types of cancer, such as prostate cancer.
But more research is needed to know the effects of vitamin A on other types of cancer.
It may reduce the risk of heart disease and stroke. But studies seem to show that
neither beta-carotene nor vitamin A help prevent coronary heart disease.
One study found a higher risk of lung cancer in smokers and workers exposed to asbestos
when they had more beta-carotene.
Recommended intake
There are no Dietary Reference Intakes for beta-carotene. The Recommended Dietary
Allowance for vitamin A are noted below. They’re noted in micrograms (mcg) of retinol
activity equivalents (RAE). They’re also noted in International Units (IUs).
Age
(years)
|
Children
(mcg RAE)
|
Males
(mcg RAE)
|
Females
(mcg RAE)
|
Pregnancy
(mcg RAE)
|
Lactation
(mcg RAE)
|
1-3
|
300 (1,000 IU)
|
|
|
|
|
4-8
|
400 (1,321 IU)
|
|
|
|
|
9-13
|
600 (2,000 IU)
|
|
|
|
|
14-18
|
|
900 (3,000 IU)
|
700 (2,310 IU)
|
750 (2,500 IU)
|
1,200 (4,000 IU)
|
19+
|
|
900 (3,000 IU)
|
700 (2,310 IU)
|
770 (2,565 IU)
|
1,300 (4,300 IU)
|
Age (months)
|
Males and Females (mcg RAE)
|
0-6
|
400 (1,320 IU)
|
7-12
|
500 (1,650 IU)
|
Food sources
This table notes the IU of vitamin A in foods. It also notes the percentage of your
daily value of vitamin A that the food meets.
Food
|
Vitamin A (IU)
|
%DV
|
Sweet potato, baked in skin, 1 whole
|
28,058
|
561
|
Spinach, frozen, boiled, ½ cup
|
11,458
|
229
|
Carrots, raw, ½ cup
|
9,189
|
184
|
Cantaloupe, raw, ½ cup
|
2,706
|
54
|
Black-eyed peas (cowpeas), boiled, 1 cup
|
1,305
|
26
|
Apricots, dried, sulfured, 10 halves
|
1,261
|
25
|
Eating more fruits and vegetables can help you get more beta-carotene. Red, orange,
deep yellow, and dark green produce tends to be high in carotenoids.
Signs of deficiency
Vitamin A deficiency can cause symptoms. These can include night blindness, fatigue,
skin issues, and a weakened immune system. Severe vitamin A problems can lead to blindness.
This is a leading cause of blindness in some parts of the world.
Toxicity
Beta-carotene doesn’t seem to be toxic in large doses. But high doses over a long
time can lead to carotenemia. This causes your skin to become yellowish orange.
Too much beta-carotene is a problem for some people. This includes people who can't
convert beta-carotene to vitamin A. This can happen to people who have hypothyroidism.
Higher doses of vitamin A may increase the risk for fractures in both women past menopause,
and in men.
Interactions
Orlistat, a medicine for weight loss, decreases how well beta-carotene and vitamin
E are absorbed. It’s unknown if it reduces absorption of vitamin A.
You should not use vitamin A or beta-carotene supplements if you take any of these
medicines:
-
Isotretinoin
-
Acitretin
-
Etretinate
Warfarin is a medicine used to slow blood clotting. Large amounts of vitamin A can
slow blood clotting. Be sure to let your healthcare provider know if you are taking
warfarin and vitamin A. You may need to have your blood clotting time checked more
often. Your provider man need to change dose of your warfarin.