Evidence

These uses have been tested in humans or animals.  Safety and effectiveness have not always been proven.  Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Key to grades

A
Strong scientific evidence for this use
B
Good scientific evidence for this use
C
Unclear scientific evidence for this use
D
Fair scientific evidence against this use (it may not work)
F
Strong scientific evidence against this use (it likely does not work)

Grading rationale

Evidence gradeCondition to which grade level applies
B

Oral leukoplakia (pre-cancerous mouth lesions)

In early research, taking beta-carotene by mouth induced remission in people with oral leukoplakia. Further research is needed to confirm these results.
B

Sunburn

Beta-carotene alone or with other antioxidants helped prevent sunburn. Further research is needed in this area.
C

Abdominal aortic aneurysm (AAA) prevention

Limited research has shown that beta-carotene lacked an effect in preventing abdominal aortic aneurysm, in which the large blood vessel supplying blood to the stomach becomes abnormally large. Further research is needed in this area.
C

Age-related macular disease (eye disorder causing vision loss)

Taking beta-carotene and other antioxidants has been proposed to help delay progression of age-related macular degeneration, which results in vision loss. However, human research to support this claim is lacking. Further research is necessary in this area.
C

Alzheimer's disease

Limited research has suggested there is a relationship in beta-carotene intake and Alzheimer's disease. Further research is needed in this area.
C

Angioplasty (surgery for blocked arteries)

Antioxidant vitamins, including beta-carotene, might have harmful effects in patients after angioplasty. Additional research is needed to determine the effect of beta-carotene specifically.
C

Arthritis

According to early research, beta-carotene might slow progression of osteoarthritis. Further research is needed before a conclusion can be drawn.
C

Carotenoid deficiency

Consumption of provitamin A carotenoids (such as beta-carotene) can prevent vitamin A deficiency. However, if people take vitamin A without carotenoids, they will still avoid vitamin A deficiency. The Food and Nutrition Board of the Institute of Medicine (IOM) concluded that sufficient evidence was lacking to establish a recommended dietary allowance (RDA) or adequate intake (AI) for carotenoids.
C

Chemotherapy side effects

Limited research suggests beta-carotene may lower side effects in children being treated for lymphoblastic leukemia, a cancer of the blood. However, in theory high-dose antioxidants may interfere with certain cancer therapies. Further research is needed before a conclusion can be drawn.
C

Chronic lung conditions

In limited research, beta-carotene improved breathing function in people with chronic obstructive pulmonary disorder (COPD). However, beta-carotene lacked an overall effect on COPD. Further research is needed in this area.
C

Enhancing recovery from surgery or illness

Limited research shows that supplementation with micronutrients, including beta-carotene, may have beneficial effects on strength and physical function after surgery. Further research is needed in this area.
C

Erythropoietic protoporphyria

Erythropoietic protoporphyria is a rare genetic disorder that involves painful skin sensitivity to sunlight, gallstones, and liver dysfunction. The over-the-counter synthetic beta-carotene product Lumitene® is U.S. Food and Drug Administration (FDA)-approved for helping with the sensitivity to sunlight in this disease. Limited research showed mixed results of beta-carotene in protecting the skin from sunlight. Further research is needed in this area.
C

Exercise-induced asthma prevention

Early evidence shows that a mix of beta-carotene isomers may prevent exercise-induced asthma. Further research is needed in this area.
C

Exercise performance (oxidative stress prevention)

Research presents mixed results for use of beta-carotene in combination with other antioxidants to prevent exercise-induced oxidative stress. Further research is needed in this area.
C

Heart disease

Early research shows that vitamin and mineral combinations, including beta-carotene, lacked an effect on the progression of artery hardening. Further research is needed to determine the effects of beta-carotene on heart disease.
C

HIV

Limited research shows that beta-carotene supplementation increased CD4 counts and lacked an effect on viral count in HIV. Further study is needed.
C

Liver disease

Combination antioxidant supplements containing beta-carotene may increase mortality in patients with liver disease but also decreased liver enzymes levels. Further research on the effect of beta-carotene alone is needed.
C

Mental performance

Limited research showed benefits of beta-carotene for cognition and long term memory and a lack of benefit for short-term memory. Further research is needed in this area.
C

Night vision enhancement

In limited study, beta-carotene lacked an effect on the development of night vision. Further research is needed in this area.
C

Polymorphous light eruption (itchy rash)

Early evidence shows a lack of effect of beta-carotene on polymorphous light eruption. Additional study is needed in this area.
C

Pregnancy

Some research shows that beta-carotene improves anemia, low birth weight, and premature birth. Other research shows a lack of beneficial effects of beta-carotene supplementation during pregnancy. Further research is necessary before a clear conclusion can be made.
D

Actinic keratosis (scaly skin due to sun damage)

Early research shows that beta-carotene lacks an effect on actinic keratosis development. Further well-designed study is needed
D

Birthmark/mole (dysplastic nevi) prevention

Beta-carotene lacked an effect on total number new moles in people with many atypical moles; however there was a decrease in moles on the lower arms and feet.
D

Cystic fibrosis

Individuals with cystic fibrosis (mucus build-up in organs) may be deficient in beta-carotene and vitamin E, and may be more susceptible to cell damage. Limited research shows a lack of effect of beta-carotene on lung function in cystic fibrosis. Further research is needed in this area.
D

Heart disease prevention

Research suggests that diets high in fruits and vegetables containing beta-carotene appear to reduce the risk of heart disease. However, research assessing supplementation with beta-carotene show a lack of effect on heart disease risk. Also, further research showed increased risk of death from heart disease with beta-carotene supplementation. A Science Advisory from the American Heart Association states that there is a lack of evidence to justify the use of beta-carotene for reducing heart disease risk.
D

Research suggests that diets high in fruits and vegetables containing beta-carotene appear to reduce the risk of heart disease. However, research assessing supplementation with beta-carotene show a lack of effect on heart disease risk. Also, further research showed increased risk of death from heart disease with beta-carotene supplementation. A Science Advisory from the American Heart Association states that there is a lack of evidence to justify the use of beta-carotene for reducing heart disease risk.
F

Cancer prevention

While diets high in fruits and vegetables rich in beta-carotene may reduce the risk of certain cancers, evidence for benefit of beta-carotene supplements is mixed. There is some concern that beta-carotene may have cancer-causing effects. Human research shows that beta-carotene supplements have increased the risk of bladder, stomach, and lung cancer and increased the risk of death in smokers and people exposed to asbestos.
F

Cataracts

Research shows that beta-carotene supplementation lacks an effect on cataract prevention. Further well-designed research is needed before a conclusion can be drawn.
F

Diabetes

Limited research shows that higher blood levels of beta-carotene may reduce the risk of type 2 diabetes. However, high-quality research in humans shows a lack of effect of beta-carotene on diabetes.
F

Mortality reduction

Beta-carotene supplements lack support for reduction in mortality rates. Some research has associated beta-carotene supplementation with increased mortality.
F

Stroke

Beta-carotene lacks an effect on incidence of stroke in male smokers. Additionally, research suggests that beta-carotene increases the risk of bleeding inside the head in people who also drink alcohol.

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Anemia, antioxidant, asbestosis (a type of lung disease), bone marrow transplantation, breast disease, gastritis (inflammation of stomach lining), Graves' disease (overactive thyroid), high cholesterol, human papilloma virus (HPV), immune function, infections, lung conditions (premature infants), nasal problems, nutrition (during alcohol rehab), obesity (excessive weight), osteoporosis, Parkinson's disease, respiratory infections, sepsis (severe response to infection), weight loss (after giving birth or in people with HIV).

This evidence-based monograph was prepared by The Natural Standard Research Collaboration

www.naturalstandard.com