Responsible for the red and orange pigments of fruits, vegetables, and some legumes, beta-carotene is the precursor to vitamin A (or retinol).1,2 When we consume foods that contain beta-carotene, our intestines convert this nutrient into vitamin A, which plays an important role in maintaining eye, skin, immune system, and bone health.1-3 According to researchers, the body will only convert as much beta-carotene as it needs; unlike the potential risk of ingesting toxic levels of vitamin A through supplementation, consuming beta-carotene rich foods is the safer way to provide your body with an optimal amount of vitamin A.1-3
HEALTH BENEFITS
Antioxidant properties. Classified as an antioxidant, beta-carotene has been shown to combat oxidative stress, which can negatively impact many bodily systems (see sidebar “What is Oxidative Stress?). Oxidative stress can result from factors such as poor diet (too high in saturated fat, refine sugar, and processed foods), obesity, certain genetic conditions, and exposure to environmental pollutants, and can result in cell and tissue damage, systemic inflammation, and chronic diseases, such as heart disease, diabetes, and cancer.4,5 Consuming a diet rich in beta-carotene can reduce the risk of developing these diseases.
Eye health. In addition to its antioxidative properties, beta-carotene can also protect against diseases and infections of the eye, such as age-related macular degeneration, that can lead to vision loss.6–8 A study published in JAMA Ophthalmology found that increasing beta-carotene intake reduced the risk of eye disease by 35 percent.8 Additionally, vitamin A (either taken as a supplement or converted from beta-carotene in the body) protects the cornea of the eye, and has been shown to be more effective in treating and preventing dry eye syndrome and eye inflammation (superior limbic keratoconjunctivitis) than most synthetic eye-drop therapies.6,7
Brain health. Beta-carotene has been shown to preserve brain health by slowing the cognitive decline that accompanies aging and enhancing memory function.9,10 A study published in the Archives of Internal Medicine reported, “Men who took high-dose beta-carotene supplements for an average of 18 years had modestly sharper memory skills and less cognitive decline than their age-matched peers taking a placebo.”9 A reduction in risk of Alzheimer’s disease has also been positively associated with long-term consumption of a diet high in beta-carotene.10 With oxidative stress being a notable correlative of neurodegenerative diseases (as well as cognitive decline) the antioxidative abilities of beta-carotene protect the brain.9,10 In the briefest terms, beta carotene keeps the brain youthful and sharp.
Skin health. Beta-carotene exhibits skin health benefits as well. The epidermis and dermis contain proteins and receptors that moderate the metabolic effects of vitamin A and vitamin A-derived molecules, making the skin highly receptive to this nutrient and its precursor(s).11,12 The American Journal of Clinical Nutrition reported that beta-carotene consumption can boost the skin’s defenses against exposure to ultraviolet (UV) radiation from the sun and prevent and slow photoaging (or fine lines and wrinkles).12
DIETARY SOURCES, SUPPLEMENTATION, AND BIOAVAILABILITY
To identify sources of beta-carotene, look for fruits and vegetables with orange, yellow, or red pigment. Prime examples include sweet potatoes, carrots, butternut squash, peppers, cantaloupe, and apricots.13 Beyond the color element, dark, leafy greens, broccoli, and peas are also chock-full of this nutrient. Herbs and spices that contain beta-carotene include parsley, cilantro, paprika, cayenne, chili, sage, marjoram, and coriander.13 Beta-carotene is an oil-soluble nutrient, which means cooking beta-carotene-rich foods in oil can aid the body’s absorption of the nutrient.13
According to the National Institute of Health, Office of Dietary Supplements, there is not an established recommended daily allowance (RDA) for beta-carotene, but it is part of the RDA for vitamin A.14 Vitamin A daily recommendations are provided as Retinol Activity Equivalents (RAE), accounting for the various functions of vitamin A, beta-carotene, and other carotenoids. Based on this criterion, the National Institute of Health suggests adult women should aim to consume 700mcg RAE of vitamin A daily, and adult men should aim to consume 900mcg RAE of vitamin A daily.14For individuals who are pregnant or breastfeeding, 770mcg RAE and 1,300mcg RAE, respectively, are recommended.14 RDAs for other age groups are as follows: birth to 6 months, 400mcg; 7 to 12 months 500mcg; 1 to 3 years, 300mcg; 4 to 8 years, 400 mcg; 9 to 13 years, 600mcg; 14 to 18 years, boys 900mcg and girls 700mcg.14
Editor’s note: Contrary to its benefits, beta-carotene, in conjunction with supplemental vitamin A, can heighten the risk of lung cancer in patients who are smokers or former smokers.15 In the Beta-Carotene and Retinol Efficacy Trial (CARET), researchers evaluated the effects of a daily combination 30mg of beta-carotene and 25,000UI of vitamin A in patients who were smokers, former smokers, or had an asbestos exposure history. After six years of this treatment, researchers reported a 16-percent increase in lung cancer among these patients.15 Four years following the trial, that percentage increased by 28 percent.15 The researchers postulated that this was due to the participants’ pre-existing conditions and oxidative stress load within their lungs. Individuals who smoke or have a history of smoking should moderate their beta-carotene and vitamin A supplementation intake and discuss options with their healthcare provider.
References
Haskell MJ. The challenge to reach nutritional adequacy for vitamin A: β-carotene bioavailability and conversion—evidence in humans. Am J Clin Nutr. 2012;9(5):1193S–1203S.
Higdon J. α-carotene, β-carotene, β-cryptoxanthin, lycopene, lutein, and zeaxanthin. https://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/carotenoids.
Accessed 26 Jul 2021.
The Editors of Encyclopaedia Britannica. Vitamin A. Updated 9 Jan 2020. https://www.britannica.com/science/vitamin-A#ref119565.
Accessed 26 Jul 2021.
Valko M, Leibfritz D, Moncol J, et al. Free radicals and antioxidants in normal physiological functions and human disease. Int J Biochem Cell Biol.
2007;39(1):44–84.
Aruoma OI. Free radicals, oxidative stress, and antioxidants in human health and disease. JAOCS. 1998(75): 1–14.
Rasmussen HM, Johnson EJ. Nutrients for the aging eye. Clin Interv Aging. 2013;8:741–748.
Heiting G. Eye benefits of vitamin A and beta-carotene. https://www.allaboutvision.com/nutrition/vitamin_a.htm. Accessed 26 Jul 2021.
Wu J, Cho E, Willett WC, Sastry SM, Schaumberg DA. Intakes of lutein, zeaxanthin, and other carotenoids and age-related macular degeneration during 2 decades of prospective follow-up. JAMA Ophthalmol. 2015;133(12):1415–1424.
GrodsteinF, Kang JH, Glynn, RJ, et al. A randomized trial of beta carotene supplementation and cognitive function in men: The Physicians Health Study II. Arch Intern Med. 2007;167(20):
2184–2190.
Fisher Center for Alzheimer’s Research Foundation site. Beta carotene may help keep the brain young. 5 Dec 2007. https://www.alzinfo.org/articles/drugs-and-treatment-29/. Accessed 28 Jul 2021.
