Antioxidants are substances that protect against free radicals and a great deal is known about them. In the following, you will learn more about these substances, which are also known as free radical scavengers, and where they can be found in food.
Oxidative processes take place constantly in the human body. Aggressive oxygen particles (free radicals) roam freely here and can have a cell-damaging effect. They want to combine with other particles and damage fatty acids, for example, from which they remove electrons. The fat is oxidized in the process, similar to a cooking oil that becomes rancid.
Oxidative stress due to increased free radicals is caused in the body by various environmental influences such as UV radiation, ozone exposure, nicotine, drugs or environmental toxins, but can also be caused by lifestyle.
For this reason, the human organism has developed an endogenous, antioxidant protection system. On the one hand, we form antioxidants ourselves, and on the other hand, plant components are also involved in these functions as part of the human diet. These antioxidants contribute to the prevention and treatment of oxidative stress in various target organs and tissues. They capture the freely bonding, aggressive oxygen molecules (free radicals) by binding them to themselves. Bound oxygen molecules can no longer have an oxidative effect. This results in the term radical scavenger for antioxidants.
With a varied diet characterised by fresh foods, we consume many antioxidants. The following:
apply as antioxidants.
There are still many other antioxidants, such as certain proteins and enzymes, which are also partly produced by the body itself from other substances. The same applies to coenzyme Q10. It is also interesting in this context that certain antioxidants are already passed on to the infant with breast milk.
Antioxidants are contained in fruit, vegetables, eggs, high-quality vegetable oils, but also in green tea, coffee, soy, cocoa, various spices and red wine.
The secondary plant substances mentioned are particularly interesting in this context. Although secondary plant substances are not vital for the survival of a plant, they still fulfill important functions. Plants use these substances to protect themselves against various external environmental influences, such as UV radiation, pests and other harmful factors. They have not yet been sufficiently researched with regard to their effect on the human body. However, there is a growing number of indications that people often benefit greatly from the absorption of secondary plant substances. This specifically concerns the antioxidant effect of many of these secondary plant substances. In the meantime, people have become aware that the different antioxidants can often support one another in their effect. This may result in a possible synergistic effect, but it has not yet been definitively researched scientifically.
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Antioxidants |
Contained in |
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Vitamin C |
Red currants, strawberries, peppers, kale, brussel sprouts, lemons |
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Vitamin E |
Wheat germ oil, rapeseed oil, peanuts, hazelnuts, almonds, sunflower seeds |
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Selenium |
Mushrooms, coconuts, brazil nuts, tuna, prawns |
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Zinc |
Oysters, cheese, lentils, beef, oatmeal |
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Carotinoids |
Carrots, sweet potatoes, tomatoes, apricots, fennel, parsley |
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Polyphenols |
Cocoa powder, dark chocolate, cloves, star anise, blueberries, cherries |
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Capers, red onion, kale, redcurrants, dark grapes |
Antioxidants are natural protective substances that can protect our bodies from oxidative stress and neutralise free radicals. They help to maintain the balance in the body and support the cells in their regeneration. But how exactly do these protective substances work and what role do they play in our health?
Free radicals are not per se harmful to the human organism. On the contrary, in small quantities they perform signal functions according to the type of messenger substances in our body. However, an excess of these free radicals leads to oxidative stress. According to current scientific findings, ageing processes and diseases are thought to be often associated with oxidative stress.
Antioxidants are micronutrients that react with so-called free radicals before these have a chance to change or destroy important structures in the body. The human body itself forms antioxidants from the inside out. Thus, the body's own defence system is also focused on defending against free radicals.
Since these enter the body on an almost continuous basis, the ability of the human immune system to defend itself is continuously re-activated, as with a vaccination.
Antioxidants play a crucial role in eye health as they protect the sensitive cells in the retina from oxidative stress. Every day, our eyes are exposed to intense light and environmental influences that can promote free radical formation and increase the risk of eye disease. Antioxidants counteract these damaging processes. Lutein and zeaxanthin, found in green leafy greens, are particularly effective because they accumulate specifically in the macula, the central area of the retina, and act there as an “inner sun protection”. An adequate supply of these antioxidants can thus protect the eyes from damage or disease of the retina.
Free radicals attack the cells of the vessel walls and promote the formation of deposits (plaques) in the arteries – a risk factor for arteriosclerosis and high blood pressure. Antioxidants can slow this process by neutralising the free radicals and inhibiting any inflammatory processes in the vessel walls. Studies indicate that an antioxidant diet supports the elasticity of the blood vessels, improves blood circulation and can thus reduce the risk of cardiovascular diseases.
Antioxidants play an important role in diabetes, as oxidative stress and inflammatory processes are more common in this disease. High blood sugar levels lead to increased free radical formation, which can damage the cells and promote inflammation. This oxidative damage particularly affects blood vessels and nerves, which increases the risk of typical complications such as neuropathy, cardiovascular disease and eye damage (diabetic retinopathy).
Antioxidants like vitamin C, vitamin E and the trace element selenium can help reduce free radical damage and strengthen the body’s antioxidant defence. A sufficient supply of antioxidants thus supports cell health and can help to alleviate inflammation, which can positively influence the control of the consequences of diabetes.
Antioxidants play a central role in the ageing process by helping the body neutralise the harmful free radicals that play a major role in cellular ageing. As we age, our body’s production of antioxidants decreases, making our cells more susceptible to oxidative damage. This damage not only affects the skin, which forms wrinkles and loses elasticity, but also the internal organs and tissues, which increases the risk of age-related diseases such as cardiovascular problems and neurodegenerative diseases.
An antioxidant diet and targeted dietary supplements can positively influence this process: They can help maintain cellular health, thereby slowing the ageing process.
Current research indicates that the body forms a certain balance in terms of antioxidants and free radicals, even down to the level of the individual cell. This balance is important for the health of each individual and also for the integrity of the cells.
Thus the equation “More antioxidants = better health and longer youth” is unfortunately not quite so simple. Here, it always depends on the individual person and his/her physical condition.
There are various measuring options available for the antioxidant activity of various substances. Many of the measurements are taken in body fluids. A substrate is thereby exposed to an attack by a free radical. An antioxidant administered in the same way as vitamin C, for example, develops antioxidant activity. It is now measured how long it takes for the substrate to oxidise. The longer this time period is, the stronger the antioxidant capacity of the respective antioxidant. Sometimes you will find test names such as ORAC, TRAP or TEAC in this context. These refer to measuring the antioxidant capacity.
Without further penetration into the body, it is possible to measure the status quo of antioxidants with certain light measurement methods via the skin, in which a laser is usually used.
Antioxidants are present in fruits (e.g. grapes, blueberries, elderberries, apples),vegetables (e.g. in bell peppers, kale, mushrooms, carrots, sweet potatoes), in high-quality vegetable oils, and also in green tea, coffee, soy, cocoa, various spices and red wine.
Antioxidants are important for us because they protect our bodies from oxidative stress caused by free radicals. Free radicals are unstable molecules that can attack and damage cells, which can lead to inflammation, premature cell ageing and an increased risk of chronic diseases such as cardiovascular diseases and neurodegenerative diseases.
Antioxidants neutralise these free radicals by providing electrons to help limit their damaging effects. As a result, antioxidants support cellular health, strengthen the immune system and contribute to overall health and vitality. An adequate antioxidant supply can therefore help reduce the risk of many health problems and slow the ageing processes.
There is no “best” antioxidant as different antioxidants each perform specific protective functions in the body and often work most effectively when combined. However, vitamin C and vitamin E are often referred to as strong antioxidants with a high level of efficacy in protecting against oxidative damage. Similarly, phytonutrients such as polyphenols (e.g. in berries) and carotenoids (e.g. in carrots) are extremely effective. Therefore, a varied diet rich in different antioxidants is the most beneficial for your health.
Further reading:
Caruso, F. et al. 2004. Structural basis for antioxidant activity of transresveratrol: ab initio calculations and crystal and molecular structure. J Agric Food Chem. 52(24):7279-85.
Dueñas M et al., Studies on Modulation of Gut Microbiota by Wine Poly phenols: From Isolated Cultures to Omic Approaches, Antioxidants (Basel), Jan. 2015; Bd. 4, Nr. 1:1–21.
Friedrichsen, H.P. 2006. Antioxidative Therapie. Zs F Orthomol Med. 29-30.
Holecek, V. et al. 2004. The significance of free radicals and antioxidants due to the load induced by sport activity. Cesk Fysiol. 53(2):76-9.
Mokni, M. et al. 2007. Effect of resveratrol on antioxidant enzyme activites in the brain of healthy rat. Neurochem Res. 32(6):981-987.
Prior, R. L., Wu, X., Schaich, K. 2005. Standardized methods for the determination of antioxidant capacity and phenolics in foods and dietary supplements. J Agric Food Chem. 53(10):4290-302.
Privat, C. et al. 2002. Antioxidant properties of trans-epsilon-viniferin as compared to stilbene derivates in aqueous and nonaqueous media. J Agric Food Chem. 50(5):1213-1217.
Rekha, C. et al. 2012. Ascorbic Acid, Total Phenol Content and Antioxidant Activity of Fresh Juices of Four Ripe and Unripe Citrus Fruits. Chem Sci Trans. 1(2):303–10.
Zandi, P. P. et al. 2004. Reduced risk of Alzheimer disease in users of antioxidant vitamin supplements: the Cache County Study. Arch Neurol. 61(1):82-8.
