If you’ve ever found yourself confused by terms like carotenoids, antioxidants, free radicals, and oxidative stress, you are not alone. These concepts are often used in nutrition and wellness—but they can easily blur together. To compound matters, there seem to be a gazillion supplements out there by an almost equally gargantuan number of industries that claim, ‘optimal health’. I’m not making any promises to make you a nutritional expert after reading this blog, but the hope is that things might become a little bit clearer. A little!
So, let’s start with an explanation of what these are…
Carotenoids are natural pigments found in plants, algae and some bacteria. They’re what give foods their bright red, orange and yellow colours. There are 600+ known carotenoids, but only about 20 are active in the human body. The most well-known ones are Beta-carotene (carrots, sweet potato), Lutein and Zeaxanthin (leafy greens), Lycopene (tomatoes), Astaxanthin (microalgae, salmon).
Carotenoids help neutralise free radicals, there’s that word! Now bear with me. Free radicals are unstable molecules that damage healthy cells by stealing particles from them. Think of free radicals like pickpockets—stealing from healthy cells to stabilise themselves, and in the process causing damage.
Antioxidants are the ‘good guys’—they safely give away particles, stopping the damage to cells. Think of them as your natural defences or your body’s protective shield. Carotenoids are one group within the larger family of antioxidants. So, carotenoids are the good guys!
Oxidative stress, there’s that word! Oxidative stress occurs when there is an imbalance between free radicals and antioxidants. When free radicals outnumber antioxidants, damage begins to build up in cells
The best analogy… Think of oxidative stress like the process of rusting on metal:
Free radicals = the process causing “rusting”
Antioxidants = protective coating
Oxidative stress = when the rusting overwhelms the protection
Why does all this matter?
This matters because over time, oxidative stress slowly damages cells, tissues, and organs, increasing the risk of ageing, inflammation, and conditions such as cardiovascular disease, type 2 diabetes, cancer as well as neurodegenerative diseases.
But… it gets interesting! Did you know that carotenoids come almost entirely from the diet? Your body doesn’t make them. So, blood levels strongly reflect fruit and vegetable intake. Levels of carotenoids in the blood are easy to measure, and levels are more stable unlike many other antioxidants that are rapidly used up. That’s why plasma carotenoid levels are now used as a marker of nutritional quality and antioxidant protection!
For best food sources of carotenoids think colour: Orange: carrots, pumpkin, sweet potato; Red: tomatoes, watermelon, red peppers; Yellow: corn, peppers; Green: spinach, kale
Want to know your Carotenoid level?
At our clinic, Nutritionist Julie uses the Prysm 10 nutritional wellness tracker, which provides real-time, evidence-based insight into nutritional status.
Based on your results, a personalised nutritional plan can be created to support your overall health.
For more information, contact: admin@2meclinic.com
References
General carotenoids & human health • Krinsky NI, Johnson EJ. Carotenoid actions and their relation to health and disease. Mol Aspects Med. 2005;26(6):459–516.
Eggersdorfer M, Wyss A. Carotenoids in human nutrition and health. Arch Biochem Biophys. 2018;652:18–26.
Antioxidant activity & oxidative stress • Stahl W, Sies H. Antioxidant activity of carotenoids. Mol Aspects Med. 2003;24(6):345–351.
Fiedor J, Burda K. Potential role of carotenoids as antioxidants in human health and disease. Nutrients. 2014;6(2):466–488.
Published March 2026
