Beta carotene: a supplement you may want to avoid

Beta carotene is a precursor to Vitamin A found in many fruits and vegetables. An antioxidant, it’s often associated with health benefits, particularly eye health: carotenoids have been shown to be protective against age-related macular degeneration (AMD).^[1] 

The overall impact of beta carotene, however, is not entirely positive. Studies have not found^[2] any cancer-protective benefits from supplementation, and high-dose (20 mg or more daily) beta-carotene supplements have actually been shown to increase lung and stomach cancer risk among smokers and those with significant asbestos^[3] exposure. 

The reasons for this paradoxical effect aren’t entirely clear, but one possibility is that beta-carotene acts differently in the body when taken as a high-dose supplement than when it’s naturally absorbed from foods. It’s also possible that it interacts specifically with tobacco byproducts and chemicals in asbestos. 

Foods^[4] that are naturally high in beta carotene include: 

• Carrots 
• Sweet potatoes
• Pumpkin
• Spinach
• Kale
• Collard greens 

Because supplementation may involve health risks, it’s better to get your beta carotene via dietary sources. It’s also important not to conflate the benefits of any antioxidant with the benefits of a specific antioxidant source. Antioxidants as a group offer many health benefits and decrease your overall cancer risk, but high doses of a single type may not provide all of these benefits, and in the case of beta carotene, may come with some risk. 

‍