There is nothing quite like a bite of watermelon on a balmy summer day.
It is so refreshing, but what makes it so nutritious?
As seasons change as do the fresh fruits and vegetables in our local farmers markets. Entering summer, many of the fruits and vegetables in season are abundant with nutrients, including dietary phytochemicals, a group of compounds produced in plants that provide the visible color as well as natural defense system to thrive and combat predators and pathogens.
In these trying times, both mentally and physically, let’s discuss how we can support our immune systems; apart from regular physical activity, high sleep quality and social engagement, we cannot underscore the importance of eating a well-balanced, colorful diet rich in dietary phytochemicals, particularly carotenoids.
Carotenoids are the reason that many of the fruits and vegetables in season in the summer are pigmented yellow, orange and red. Although carotenoids are considered ‘nonessential’ with no set dietary reference intake, they can be vital in the maintenance and improvement of optimal health, including immune function.
Most commonly known as beta-carotene, lutein, lycopene, astaxanthin and retinol, many of these carotenoids have been studied in animals and humans, with most investigating specifically beta-carotene. In one study, beta-carotene supplementation (≥30 mg) in older adults demonstrated an immunostimulatory effect with a resulting increase in T-helper and natural killer cells. Though not all studies agree on this effect and state that perhaps beta-carotene does not have an effect. Researchers do agree, however, that designing an effective human clinical trial with carotenoids is difficult given the intrinsic relationship between carotenoids and vitamin A.
As a practitioner, when evaluating supplementation for a patient, I am always looking at the potential risks versus the benefits. Given the published data, it seems as though there could be a benefit of beta-carotene supplementation accompanied by low risk, but not enough data for me to say one way or another for supplementing with other carotenoids. If one of my patients is interested, taking into account other factors, such as their diagnoses, prescription medications, dietary supplements and nutritional preferences, is crucial to determine if supplementation is the right choice for them.
Regardless of supplementation, the inclusion of carotenoids in a person’s diet can be beneficial for many reasons beyond immunomodulation; studies have shown that they could also be valuable in inhibiting cancer growth and impacting cardiovascular health. Many of the plant foods we eat every day have a number of phytochemicals, meaning that when you are eating the rainbow, you are likely to be consuming many nutrients that could improve your overall health status.
In the summer months, fruits like apricots, cantaloupe, peach, tomato, strawberry and watermelon, are in season and known to be some of the most carotenoid-dense plant foods. Though it are not of the stereotypical warm spectrum of colors, kale also has high carotenoid content; but, worry not, even if you do not like kale, many other greens could be substituted with a similar amount of carotenoids (eg. spinach, collard greens and turnip greens).
So, as you're preparing for that friend’s BBQ or picnic in the park, think about how you can incorporate carotenoids into what you are bringing. Perhaps consider a strawberry and mixed greens salad with a grapefruit vinaigrette, a tray of sliced bell peppers for the hot grill, or simply a freshly sliced watermelon.
As the Chief Scientific Officer, please do not hesitate to contact me with any questions regarding integrative wellness or cannabis.
At Element Apothec, we are here for you and your immune system.
Chew BP, Park JS. Carotenoid action on the immune response. J Nutr. 2004;134(1):257S‐261S.
Hughes DA, Wright AJ, Finglas PM, et al. The effect of β-carotene supplementation on the immune function of blood monocytes from healthy male nonsmokers. J Lab Clin Med. 1997;129(3):309-317.
Santos MS, Gaziano JM, Leka LS, Beharka AA, Hennekens CH, Meydani SN. β-Carotene-induced enhancement of natural killer cell activity in elderly men: an investigation of the role of cytokines. Am J Clin Nutr. 1998;68(1):164-170.
Schmitz H, Chevaux K. Defining the Role of Dietary Phytochemicals in Modulating Human Immune Function. In: Gershwin ME, German JB, Keen CL, ed. Nutrition and Immunology. Totowa: Humana Press; 2000.