Colors signal life – and when it comes to longevity, it is primarily the bright reds of tomatoes, the vibrant orange of carrots, and the rich green of spinach that play a central role. Behind these intense colors lie carotenoids, an interesting group of secondary plant compounds that are increasingly coming into focus in modern longevity research.
Carotenoids are much more than natural colorants. They are among the plant pigments that have been linked in scientific studies to processes related to oxidative stress. Research findings suggest that certain carotenoids may play a role in various cellular functions. In a world heavily influenced by environmental factors and dietary habits, carotenoids are therefore playing an increasingly important role in nutritional science.
From colorful fruits and vegetables to special microalgae – carotenoids can be found wherever nature unfolds its most intense colors. Let's discover together what role these exciting molecules play in our metabolism.
What are carotenoids?
Carotenoids belong to the secondary plant substances and are chemically classified as tetraterpenes – organic compounds made up of isoprene units. These fat-soluble pigments give plants, algae, fungi, and some bacteria their characteristic colors, ranging from yellow to orange to deep red.
In nature, carotenoids fulfill vital functions: they are essential components of photosynthesis and protect plants from damage caused by light radiation.More than 800 different natural carotenoids have been identified so far, and their structural diversity is impressive.
Two main groups are distinguished: Carotines (such as beta-carotene and lycopene), which consist solely of carbon and hydrogen, and Xanthophylls (such as lutein, zeaxanthin, and astaxanthin), which additionally contain oxygen atoms. These oxygen groups significantly influence the biological properties of the molecules.
What particularly distinguishes carotenoids is their structure: They possess a long chain of conjugated double bonds – which is relevant for their antioxidant activity at the molecular level. The more conjugated double bonds a carotenoid has, the higher its antioxidant capacity typically is.Beta-carotene and lycopene, for example, have eleven such double bonds, while astaxanthin, with thirteen double bonds, can exhibit even more pronounced antioxidant activity.
Carotenoids are among the most fascinating plant pigments in our diet. Particularly exciting: Some of them – such as alpha and beta-carotene – can be converted into vitamin A in the body. Vitamin A has been shown to contribute to the maintenance of normal vision, the normal function of the immune system, and a normal process of cell division.
Carotenoid foods: The best natural sources
The good news: Carotenoids are found in a variety of everyday foods. A colorful, diverse diet automatically provides you with these valuable plant pigments.
Carrots are the icon among carotenoid suppliers.Their high content of beta-carotene makes them an excellent source of provitamin A. Just one medium-sized carrot can cover a large part of the daily requirement.
Sweet potatoes offer a similarly impressive concentration of carotenoids. Their orange variety is particularly rich in beta-carotene, while purple varieties additionally provide anthocyanins – a perfect combination for your antioxidant portfolio.
Spinach and green leafy vegetables may not look orange, but that is misleading: The green chlorophyll merely covers the yellow-orange carotenoids. Spinach is an excellent source of lutein and zeaxanthin – two xanthophylls that are particularly discussed in research in connection with eye health.
Tomatoes owe their red color to lycopene, one of the most studied carotenoids.Interestingly, lycopene from heated or processed tomatoes is better absorbed than from raw ones – a rare case where cooking increases bioavailability.
Bell peppers in all colors – from yellow to orange to red – provide various carotenoids. The riper and redder the bell pepper, the higher the carotenoid content is usually.
Corn contains not only beta-carotene but also lutein and zeaxanthin. These two xanthophylls are structurally designed to preferentially accumulate in the macula of the eye.
A particularly concentrated source is represented by microalgae, especially the green algae Haematococcus pluvialis. Under stress conditions, this algae produces astaxanthin in high concentrations – a carotenoid known for its pronounced antioxidant activity at the molecular level.
Important for absorption: Since carotenoids are fat-soluble, the simultaneous intake of fats significantly improves their bioavailability. A spoonful of olive oil on salad or a handful of nuts with carrots optimizes absorption in the intestine. Preparation also plays a role: chopping, cooking, or pureeing can break down cell walls and make carotenoids more available.
What do studies show about carotenoids?
The scientific literature on carotenoids is extensive and continues to grow. Numerous studies in recent years have investigated the role these plant pigments can play in human health.
Antioxidative capacity: Carotenoids are considered particularly effective quenchers of
singlet oxygen and radical scavengers.Your conjugated double bonds allow them to neutralize reactive oxygen species (ROS) at the molecular level. In model systems with liposomes – artificial membranes that resemble human cell membranes – it has been shown that carotenoids can neutralize various aggressive oxidants.
A recent cross-sectional study involving over 27,000 US adults from the NHANES cohort (1999-2018) found significant associations between carotenoid intake and various biomarkers of biological aging. The results suggest that higher carotenoid intake may be associated with more favorable values for allostatic load, homeostatic dysregulation, and other aging indices.
Oxidative Stress and Inflammation: A comprehensive review of antioxidants in smokers showed that individuals with increased oxidative stress – such as smokers – often have lower plasma levels of carotenoids. Intervention studies suggested that a diet rich in fruits and vegetables, which naturally contain many carotenoids, could help reduce oxidative damage. Importantly, the positive effects were primarily observed with carotenoids from natural food sources.
Biochemical Processes at the DNA and Cellular Level: Experimental work, including studies with the model organism Caenorhabditis elegans, shows that certain carotenoids can influence the expression of antioxidant enzymes such as superoxide dismutase and catalase. These enzymes play a central role in the cellular response to oxidative stress.In various model and in vitro systems, it has also been observed that carotenoids can significantly reduce lipid peroxidation – that is, the oxidative damage of fats by reactive oxygen species (ROS).
Research on carotenoids in the cardiovascular context: In nutritional research, there has been great interest for years in how carotenoids – particularly lycopene – might statistically correlate with various markers of the cardiovascular system. Several meta-analyses report inverse relationships between dietary intake and cardiovascular events. In one study, it was also observed that individuals with a higher lycopene intake had a lower incidence of such events.In the scientific literature, various biological processes are discussed that could accompany these observations, including effects on LDL oxidation processes, endothelial-related parameters, and inflammation-related signaling pathways.
Skin and Photoprotection: Studies on skin biology investigate how carotenoids interact with UV-induced oxidative processes in experimental model systems. It has been examined to what extent carotenoids can neutralize reactive oxygen species (ROS) and may be involved in signaling pathways such as MAPK, Nrf2, or NF-κB. Both oral and topical applications have been tested in various research approaches, with indications of altered parameters of skin barrier function and collagen homeostasis.
Astaxanthin as an example of a carotenoid
Astaxanthin deserves special attention.This xanthophyll is produced by the microalga Haematococcus pluvialis under stress conditions such as nutrient deficiency or intense UV radiation – a natural protective mechanism of the alga.
What makes astaxanthin unique is its molecular structure: With thirteen conjugated double bonds and polar end groups, it can accumulate in model membranes both within the lipid layer and on their surfaces. This structural peculiarity influences its positioning in membrane-like systems.
Experimental studies show that astaxanthin can exhibit pronounced antioxidant activity. In various test systems, it has been described as more reactive towards singlet oxygen and certain oxidative molecules than beta-carotene or vitamin E. In in vitro models, lower rates of lipid peroxidation have also been observed.
Research on the model organism C.elegans provided indications that astaxanthin can extend lifespan under experimental conditions. Discussed mechanisms include changes in the expression of antioxidant enzymes as well as effects on the insulin/IGF-1 signaling pathway – an evolutionarily conserved pathway that is also being studied in mammals.
In humans, astaxanthin has been studied in smaller studies in relation to various physiological parameters, including vascular-related markers, inflammation-related signaling pathways, and aspects of exercise physiology. There is also increasing interest in dermatological, visual, and cognitive research fields.
However, these previous results come from different research approaches and should not be understood as established efficacy claims. Further studies are necessary to confirm these findings.
Carotenoids and Longevity
Longevity – the concept of long-lasting, functional aging – is more than just the mere extension of lifespan. It is about cellular resilience, metabolic flexibility, and the body's ability to cope with stressors. Carotenoids are also discussed in connection with this concept.
Cellular Stress Responses: Neutralizing oxidative stress is a central component of longevity research. Research studies – particularly in cell culture and animal models – investigate how carotenoids interact with reactive oxygen species (ROS) and to what extent they may influence oxidative processes. Chronic oxidative stress is associated in longevity research with mechanisms such as telomere shortening, mitochondrial dysfunction, and inflammatory processes.Carotenoids are often analyzed in this context regarding their involvement in antioxidant signaling pathways.
Mitochondrial processes: Mitochondria, the power plants of our cells, are both producers and targets of ROS. In experimental models, it can be observed that carotenoids can incorporate into membrane-like structures and influence oxidative reactions there. Studies investigate how carotenoids support mitochondrial integrity and thus could contribute to metabolic health.
Inflammation-related signaling pathways: Chronic low-grade inflammatory processes are seen as a hallmark of aging and are associated with age-related diseases. Many studies therefore focus on the role of carotenoids in inflammation-related signaling pathways, including NF-κB or cytokine regulation.
Everyday Tips: How to Increase Your Carotenoid Intake
Theoretical knowledge is important – but implementation in everyday life makes the difference. Here are practical strategies to optimize your carotenoid intake:
Eat the Rainbow: The simplest rule for a carotenoid-rich diet. The more colorful your plate, the more diverse the spectrum of plant pigments. Combine different colors: red tomatoes, orange carrots, yellow bell peppers, green spinach, purple red cabbage.
Fat is your friend: Always add some healthy fat to carotenoid-rich meals. A tablespoon of olive oil on salad, half an avocado with vegetables, or a handful of nuts as a snack increases absorption.
Enjoy cooked tomatoes:Lycopene from tomatoes becomes more bioavailable when heated.Tomato sauce, roasted tomatoes, or tomato soup are excellent sources of lycopene. A splash of olive oil helps with absorption.
Mixing smoothies cleverly: A smoothie made from carrots, orange, a bit of ginger, and a teaspoon of flaxseed oil or nut butter provides carotenoids plus fat in a delicious combination.
Microalgae as a supplement: If you want to expand your diet, microalgae products with astaxanthin, such as Astaxanthin capsules, can be an option.
Regularity matters: The body stores carotenoids to a limited extent. A constant intake through daily diet is therefore more effective than sporadic mega doses.
Shop seasonally and locally: Fresh, ripe vegetables and fruits from the region often have higher nutrient content than long-stored imported vegetables.Tomatoes that have ripened in the sun are richer in carotenoids than those that were harvested green.
Prepare gently: While some carotenoids become more available through cooking, others can be heat-sensitive. A mix of raw and cooked vegetables is optimal. Steaming and gentle cooking are more gentle methods than long boiling.
What you can do now
Carotenoids are much more than color-giving plant pigments – they belong to a group of bioactive substances that are being intensively researched in nutritional science. Studies focus on how carotenoids are integrated into cellular processes, particularly in relation to oxidative stress and metabolic adaptation mechanisms.A diet rich in carotenoid-containing foods is often discussed in the context of a general, balanced lifestyle.
The most important message: Focus on variety and natural sources. A colorful, plant-based diet with plenty of fruits, vegetables, whole grains, and high-quality fats not only provides carotenoids but also numerous other secondary plant compounds that are often studied together in research.
Colors on the plate are more than aesthetics – they are biochemistry in its most beautiful form. Every colorful bite brings you closer to a diverse dietary pattern that is often associated with positive lifestyle factors in research. Make the power of plant pigments a regular part of your daily life and discover how much enjoyment, variety, and vibrancy it contains.
