Antioxidants: our natural protection against free radicals and oxidative stress

Antioxidants are on everyone's lips and have a very healthy reputation. But what are these antioxidants and what do they do in your body? Are You Really That Healthy? You can find out all this and much more here.


What are antioxidants?

Antioxidants are part of a protective mechanism in your body that protects your cells from oxidative damage. Various metabolic processes produce particularly reactive molecules that can primarily damage cell membranes, proteins and DNA through oxidation. That is why they are called reactive oxygen species (ROS).

Antioxidants prevent the damaging chemical reaction of the ROS. Many plants are rich in antioxidants and can thus strengthen your body's antioxidant protective mechanism.


What antioxidants do you find in food?

Some of the most popular antioxidants found in food include:

  • Vitamin C
  • Vitamin A (beta-carotene)
  • Tocopherols (vitamin E)
  • Secondary plant substances such as flavonoids and carotenoids
  • Coumarin (in cinnamon)
  • Allicin (in garlic, onions, leek)
  • Astaxanthin (in algae, crustaceans, and salmon)
  • Trace elements such as selenium, manganese and zinc

Antioxidants red onions

What are free radicals and reactive oxygen species?

Reactive oxygen species (ROS) are often referred to simply as oxygen radicals. They are a group of very reactive oxygen compounds, of which chemically only some are radicals. Nevertheless, in connection with antioxidants, the term “free radicals” is often used synonymously with the term “reactive oxygen species”.

In contrast to the other ROS, free radicals have unpaired electrons, which makes them chemically unstable. This chemical instability makes them particularly reactive. Just as there are dangerous ROSs that are not radicals, there are also less dangerous radicals. Even pure oxygen is a radical in its basic form. For these reasons, the term “ROS” is much more precise than the term “free radicals” when it comes to oxidative stress.

ROS have a high potential to chemically react with other molecules. ROS take over electrons from the other molecules. Oxidation refers to the release of electrons. So ROS oxidize the other molecules.


How do ROS arise?

The formation of ROS is a completely natural process. The mitochondria, the power plants of your cells, inevitably produce ROS as a by-product during cell respiration. In addition, your cells also need ROS for various vital processes. ROS thus serve as important signaling and messenger substances. ROS can even benefit your health in low concentrations.

However, if there is too much ROS for any reason, it is harmful to your body. The immune system shows how harmful reactive oxygen species can be. It uses oxygen radicals to kill bacteria, parasites and certain tumor cells. These can also damage the body's own healthy cells in the wrong place or in excess.


What is Oxidative Stress?

Excessive production of ROS is known as oxidative stress. Oxidative stress is therefore always bad and should be kept to a minimum. Naturally occurring antioxidants in the body counteract oxidative stress. But sometimes it can be helpful to make more antioxidants available to the body. This can be achieved, for example, through a healthy diet.


How does oxidative stress arise and what are the consequences?

Certain factors such as an unhealthy diet, smoking, high blood pressure, and diabetes increase oxidative stress. They are known to be risk factors for cardiovascular disease. Because oxidative stress causes blood vessels to constrict and blood clotting increases. In addition, the vessel walls can thicken and atherosclerosis can develop. The risk of stroke, cardiovascular and vascular diseases increases due to oxidative stress.

But not only the vessels are affected by oxidative stress. Oxidative stress is harmful to all cells in your body. Oxidative stress is also linked to aging, neurodegenerative and neurological diseases, and cancer.

Antioxidants oxidative stress

What do antioxidants do in the body?

Antioxidants disrupt the harmful reactions caused by ROS. They serve as free radical scavengers, reducing agents or as an enzyme that converts ROS. As radical scavengers, antioxidants stop a chain reaction that would otherwise lead to the formation of new radicals. Antioxidants, which act as reducing agents, are preferred as reactants to other molecules of ROS.

Some ROS can literally tear electrons out of other molecules and force them to oxidize. This is what makes ROS so aggressive. Antioxidants prevent this ROS-mediated oxidation in different ways.


How do reducing agents have an antioxidant effect?

Some antioxidants like vitamin C can be oxidized very easily, more easily than the molecule that is being protected. ROS receives electrons from the antioxidant and, so to speak, spares the molecule that is vital for the cell. Since the uptake of electrons is called reduction, the antioxidant in this case is a reducing agent that chemically reduces ROS.


What are radical scavengers?

Antioxidants such as tocopherols serve as radical scavengers. They take over the unpaired electrons of the radicals and thus become a radical themselves. However, due to their chemical structure, they form less dangerous radicals that are less reactive and therefore harmless. They therefore do not belong to the ROS.


What do antioxidant enzymes do?

In addition, your body has antioxidant enzymes, which are also known as antioxidants. They break down excess ROS in a way that creates more harmless compounds. In order for the enzymes to function properly, they need trace elements such as selenium, manganese and zinc. If these trace elements are not available in sufficient quantities, this increases oxidative stress. Because the enzymes can only break down ROS less and the balance shifts in favor of ROS.


Why Are Antioxidants So Important?

The right ratio of antioxidants to ROS is crucial. When your body does not have enough antioxidants available and ROS gains the upper hand, your cells are seriously damaged. In the long run, cancer, cardiovascular diseases and neurodegenerative diseases can develop. On the other hand, scientific studies make it clear that antioxidants can also be harmful in excess.


How Healthy Are Antioxidants?

There is general agreement about the health-promoting effects of antioxidants ingested through vegetables and fruits. Some scientists take a critical view of the intake of high-dose food supplements. It will be some time before clear scientific results on the possible health-promoting or even harmful effects of any antioxidant are available.

After all, when it comes to food supplements, it should be noted that not all antioxidants are the same. Often only antioxidants are mentioned in general, without further differentiation. Scientific findings show quite different tendencies. In addition, the different modes of action suggest that not all antioxidants can simply be lumped together and either only cheered or only demoned.


A few positive examples from antioxidant research

In the case of secondary plant substances such as flavonoids, according to scientists, the positive effects on health predominate. In the case of the cocoa plant, for example, there is evidence that the flavonoids it contains are antioxidants that are beneficial for health.1 Flavonoids are said to have a positive effect on the cardiovascular system, among other things.2, 3

In general, when it comes to flavonoids, scientists do not agree on whether the effect is unequivocally antioxidant or in some other way. Ultimately, it is only crucial for your health that the flavonoids develop their effect.

The antioxidant curcumin found in turmeric also has a good reputation. Scientists see curcumin as having a protective effect on kidney function and attribute it to the antioxidant properties of curcumin.4 In addition, curcumin is said to be helpful in diabetes. It is said to lower blood sugar levels and improve insulin resistance.5

Another example is the polyphenol epigallocatechin gallate (EGCG) from green tea. It should limit the growth of cancer cells, strengthen the cardiovascular system and protect the nervous system. According to the researchers, the decisive factor is the dosage as always.6

Antioxidant EGCG from green tea

What is special about the Ironman antioxidant astaxanthin?

Astaxanthin is very popular among Ironman athletes to protect themselves from the strong rays of the sun in Hawaii. As an antioxidant, astaxanthin is said to protect the skin from the damaging effects of UV rays. Some even claim that astaxanthin is more effective than sunscreens because astaxanthin is supposed to work from the inside out and cannot be removed by water or friction.

In order to get enough astaxanthin for this effect, you would have to eat about one and a half kilos of salmon. Since this is a little difficult to implement, many Ironman athletes swear by astaxanthin as a dietary supplement. A recently published study came to very promising results. Astaxanthin also sees this as having a protective effect against UV radiation.7

What else can astaxanthin do?

According to current studies, astaxanthin has a number of other positive properties. Studies with mice provide evidence that astaxanthin could improve metabolism, performance and recovery during or after training. However, there are still no satisfactory human studies that confirm this effect of astaxanthin.8

In addition, according to various studies, astaxanthin is said to reduce the risk of stroke and cardiovascular diseases.9 Scientists also suspect that astaxanthin has neuroprotective properties. These could have a positive effect on various neurological diseases.10 According to researchers, astaxanthin is also said to have a stimulating effect on the immune system, reduce the risk of diabetes and even weaken cancer.11

Ironman antioxidant astaxanthin

What are the disadvantages of antioxidants?

A careful use of antioxidants is mandatory in any case. Because antioxidants cannot distinguish whether ROS is performing an important function or causing damage. Either way, they render ROS inoperative.

Therefore, antioxidants must not be ingested in excess and indiscriminately and disrupt the balance of your cells. After all, as is often the case, the right balance is important in order to get the best benefits for your health.

Beta-carotene and tocopherols in particular are suspected of increasing mortality in high doses.12 Beta-carotene in high doses is said to promote lung cancer and stomach cancer, especially in smokers.13 However, within the group of tocopherols, researchers assume that there are differences. They suspect that gamma- and delta-tocopherol prevents cancer, while alpha-tocopherol in high concentrations can aggravate cancer.14


How can you avoid oxidative stress?

It is of course optimal to limit oxidative stress from the outset. You should therefore avoid smoking, alcohol and unhealthy food as much as possible. The less the better. You should also avoid strong UV radiation. For vitamin D production in summer, it is best to use the sun in the morning or late afternoon and otherwise use good sunscreen.


Ingestion of antioxidants

It is generally recommended that antioxidants be consumed through fresh fruits and vegetables. This way it's hard to overdose on antioxidants. However, there may be reasons to use antioxidant supplements.

This includes, for example, achieving maximum physical performance or increased exposure to UV radiation. Because this leads to increased ROS and consequently oxidative stress. However, according to scientists, moderate exercise also boosts your body's own antioxidants, so that the balance between ROS and antioxidants is maintained.15

Which foods are high in antioxidants?

Almost every fruit and vegetable contains flavonoids, many of which are said to have an antioxidant effect. There are also a number of other antioxidant substances that are characteristic of certain plants. It is therefore particularly advisable to combine fruits and vegetables as varied as possible. It should ideally be beautifully colorful.

For example, green tea is rich in polyphenols, which are secondary plant substances and are said to have an antioxidant effect. The antioxidant astaxanthin is contained in the blood rain algae, but also in crustaceans and salmon due to the food chain. Garlic and other onion plants provide you with allicin, which is known for its antioxidant effects and the healthy reputation of garlic and Co.

Foods rich in antioxidants

What do you have to look out for when using antioxidants as a dietary supplement?

If you have an increased need for antioxidants that you cannot meet with a healthy diet, nutritional supplements with antioxidants can help. However, you should be careful which antioxidants you consume and not too many. The current state of studies on antioxidants is still quite controversial and currently suggests that depending on the antioxidant, too much and too little of it can cause damage.


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