What are the side effects of beta carotene supplementation?

From the Guidelines

Beta carotene supplements can cause harm, particularly in smokers and those exposed to asbestos, and their use is not recommended for the prevention of cancer or cardiovascular disease. The most common side effects of beta carotene supplementation include carotenodermia, a harmless condition where the skin turns yellowish-orange, and digestive issues like nausea, diarrhea, or stomach cramps 1. High-dose beta carotene supplementation (typically above 20-30 mg daily) has been associated with increased lung cancer risk in smokers and those exposed to asbestos, so these groups should avoid supplements containing beta carotene 1. Additionally, beta carotene supplements may interact with certain medications, including cholesterol-lowering statins, weight loss drugs like orlistat, and some antibiotics, potentially reducing their effectiveness.

Some key points to consider when evaluating the safety of beta carotene supplements include:

• The USPSTF recommends against the use of beta-carotene supplements for the prevention of cancer or cardiovascular disease, citing a lack of benefit and potential harm in some groups 1
• High-dose beta carotene supplementation has been shown to increase the risk of lung cancer in smokers and those exposed to asbestos 1
• Beta carotene supplements may interact with certain medications, potentially reducing their effectiveness 1
• Most people can get adequate beta carotene through diet by consuming orange, yellow, and green fruits and vegetables, which is generally safer than supplementation 1

Overall, the potential risks and harms associated with beta carotene supplementation, particularly in certain populations, outweigh any potential benefits, and their use is not recommended for the prevention of cancer or cardiovascular disease. If you experience persistent side effects from beta carotene supplements, you should discontinue use and consult a healthcare provider.

From the FDA Drug Label

ADVERSE REACTIONS Adverse reactions have been reported with specific vitamins and minerals but generally at levels substantially higher than those contained herein. However, allergic and idiosyncratic reactions are possible at lower levels. The FDA drug label does not answer the question.

From the Research

Side Effects of Beta Carotene Supplementation

The side effects of beta carotene supplementation have been studied in various research papers. Some of the key findings include:

• Increased risk of lung cancer: Studies have shown that high-dose beta carotene supplementation may increase the risk of lung cancer, particularly in smokers 2, 3, 4, 5, 6.
• Elevated risk of small-cell lung cancer: One study found that individual supplemental beta carotene was associated with a statistically significantly elevated risk of small-cell lung cancer 2.
• Increased mortality: Beta carotene supplementation has been linked to increased total mortality, primarily due to more deaths from lung cancer and ischemic heart disease 3.
• No benefit for lung cancer prevention: Supplementation with alpha-tocopherol or beta carotene does not prevent lung cancer in older men who smoke, and beta carotene supplementation at pharmacologic levels may modestly increase lung cancer incidence in cigarette smokers 4.
• Potential harmful effects: The findings of these studies suggest that beta carotene supplements may have harmful as well as beneficial effects, and that caution should be exercised in recommending supplemental beta carotene, particularly for smokers 3, 5.

Key Findings

Some of the key findings from the studies include:

• The Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC Study) found that lung cancer incidence was increased among participants who received beta carotene as a supplement 4.
• The Beta-Carotene and Retinol Efficacy Trial (CARET) found similar results, with a higher incidence of lung cancer among participants who received beta carotene and vitamin A supplements 5.
• A review of the available evidence found that while dietary beta carotene intake was associated with a lower risk of lung cancer, supplemental beta carotene was not effective in preventing lung cancer and may even increase the risk 5.
• The VITamins And Lifestyle (VITAL) study found that longer duration of use of individual beta carotene supplements was associated with a statistically significantly elevated risk of total lung cancer and histologic cell types 2.