Antioxidants: Free radical protection

Antioxidants: Protection against free radicals – a detailed review

Section 1: Free radicals – invisible threat

1. Definition and nature of free radicals: Free radicals are unstable molecules containing one or more non -fan electrons in external orbit. This instability makes them highly reactive, striving to “steal” electrons in other molecules to restore their stability. This process triggers a chain reaction leading to oxidative stress. Chemically, it can be both atoms and molecules. The most common free radicals in biological systems include superoxide (O₂⁻), hydroxyl radical (OH •), peroxhy radical (ROO •) and nitrogen oxide (No. •). It is important to note that not all radicals are harmful; Some, for example, play an important role in the immune system, destroying pathogens. The problem arises when the formation of free radicals exceeds the body’s ability to neutralize them, which leads to oxidative stress.

2. Mechanisms for the formation of free radicals: Free radicals are formed both naturally as a result of normal metabolic processes (for example, cellular respiration in mitochondria), and under the influence of external factors.

   • Cellular respiration: A process in which cells use oxygen for energy production (ATP). During this process, a small amount of oxygen can turn into a superoxide anion (O₂⁻), one of the first free radicals in the cascade.
   • Inflammation: Inflammatory processes caused by infections or injuries stimulate immune cells (for example, neutrophils) to the production of a large number of free radicals, such as superoxide and hypochlorite (HOCL), to destroy pathogens. This process is called an “oxidative explosion”.
   • Ionizing radiation: X-ray radiation, gamma radiation and ultraviolet radiation can split water molecules in the body, forming hydroxyl radicals (OH •), one of the most reactive and damaging free radicals.
   • Environmental pollution: Contaminated air containing ozone, nitrogen oxides and solid particles can cause the formation of free radicals in light and other tissues.
   • Smoking: Cigarette smoke contains thousands of chemicals, many of which are free radicals or contribute to their formation.
   • Some medicines and chemicals: Some drugs and industrial chemicals can be metabolized in the body with the formation of free radicals.
   • Metal metabolism: Some metals, such as iron and copper, can participate in the reactions of Fenton and Habera-Weis, which generate highly reactive free radicals from hydrogen peroxide (H₂O₂).
   • Excessive physical activity: Intensive physical exercises can temporarily increase the formation of free radicals in the muscles and other tissues. However, moderate exercises usually strengthen the antioxidant system of the body.
   • Food factors: Fried food, especially cooked at high temperatures, may contain free radicals and other oxidized compounds. Trans-fats can also contribute to oxidative stress.

3. Chain reactions and oxidative stress: Free radicals cause chain reactions, because, “stole” an electron at the molecule, they turn it into a new free radical. This chain reaction can lead to damage to a large number of molecules, including lipids, proteins and DNA. Oxidative stress occurs when the rate of formation of free radicals exceeds the body’s ability to neutralize them. This imbalance can lead to damage to cells and tissues, contributing to the development of various diseases.

4. Targets of free radicals in cells: Free radicals can attack various components of cells, causing functional disorders and damage.

   • Lipids: Free radicals can cause lipid peroxidation (floor), a process in which lipids in cell membranes are oxidized. Paul changes the structure and function of membranes, violating their permeability and leading to cell damage. Paul products, such as mild dialdehyde (MDA) and 4-hydroxynonenal (4-HNE), can be toxic and cause further damage.
   • Squirrels: Free radicals can oxidize amino acids in proteins, leading to their denaturation, aggregation and loss of function. Oxidized proteins can accumulate in cells, violating their normal work. Oxidative protein damage is associated with the development of many age diseases.
   • DNA: Free radicals can damage DNA, causing mutations, circuits and other genetic damage. These damage can lead to the development of cancer, genetic diseases and accelerated aging. 8-oxoguanin (8-Oxog) is one of the most common markers of oxidative DNA damage.
   • Mitochondria: Mitochondria, which are “energy stations” of cells, are especially vulnerable to damage to free radicals. Damage to mitochondrial DNA and membranes can reduce their effectiveness in energy production, leading to cell dysfunction. This process plays an important role in the aging and development of many diseases.

5. The role of free radicals in the development of diseases: Oxidative stress caused by free radicals plays an important role in the development and progression of many diseases.

   • Cardiovascular diseases: Oxidative stress contributes to the oxidation of LDL (low density lipoproteins), which is a key step in the development of atherosclerosis. Free radicals can also damage endothelial cells lining the blood vessels, disrupting their function and contributing to the formation of blood clots.
   • Cancer: DNA damage to free radicals can lead to mutations that contribute to the development of cancer. Oxidative stress can also stimulate the proliferation of cancer cells and their metastasis.
   • Neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease): Oxidative stress plays an important role in the death of neurons in these diseases. The accumulation of oxidized proteins and damage to mitochondria contribute to the progression of neurodegeneration.
   • Inflammatory diseases (arthritis, inflammatory intestinal diseases): Free radicals enhance inflammatory processes, damaging tissues and stimulating the release of inflammatory mediators.
   • Diabetes: Oxidizing stress can damage the pancreatic beta cells that produce insulin, which leads to a decrease in insulin secretion and the development of diabetes. It can also contribute to the development of diabetes, such as nephropathy and retinopathy.
   • Aging: The accumulation of oxidative damage over time is one of the main theories of aging. Damage to DNA, proteins and lipids with free radicals leads to a decrease in the function of cells and tissues, which manifests itself in the form of age -related changes.
   • Cataract and degeneration of the yellow spot: Oxidative stress plays a role in damage to the lens of the eye and retina, which leads to the development of cataracts and degeneration of the yellow spot, the main cause of blindness in the elderly.

Section 2: Antioxidants – Cell protectors

1. Definition and principle of action of antioxidants: Antioxidants are molecules that can slow down or prevent the oxidation of other molecules. They do this, giving their electrons to free radicals, neutralizing them and preventing their damaging effect. It is important to note that the antioxidants themselves are oxidized in the process of neutralizing free radicals, but they are usually regenerated by other antioxidants or enzymes to continue to fulfill their protective function.

2. Classification of antioxidants: Antioxidants can be classified in various ways, depending on their origin, mechanism of action and solubility.

   • By origin:
     • Endogenous (produced in the body): These include enzymes, such as superoxidsmouth (COD), catalase (CAT) and glutathioneperoxidase (GPX), as well as some non -table molecules, such as bilirubin and uric acid.
     • Exogenous (obtained from external sources): These include vitamins (for example, vitamin C, vitamin E), carotenoids (for example, beta-carotene, lycopine), polyphenols (for example, flavonoids, anthocyans) and other compounds contained in food products.
   • By the mechanism of action:
     • Primary (interrupting chain): These antioxidants directly respond with free radicals, giving them electrons and interrupting chain reactions. Examples: vitamin E, glutathione.
     • Secondary (preventing radical formation): These antioxidants prevent the formation of free radicals, for example, by connecting metals ions that can catalyze the formation of radicals. Examples: metals, such as Edta.
     • Restoring: These antioxidants are restored by other antioxidants that were oxidized after the neutralization of free radicals. Examples: Vitamin C, which can restore vitamin E.
     • Protectors: These antioxidants protect cells and tissues from damage, not necessarily reacting directly with free radicals. Examples: enzymes that restore damaged DNA.
   • In solubility:
     • Water -soluble: These antioxidants dissolve in water and act in the aquatic environment of cells and body fluids. Examples: vitamin C, glutathione, anthocyani.
     • Fat -soluble: These antioxidants dissolve in fats and oils and act in cell membranes and lipoproteins. Examples: vitamin E, carotenoids.

3. The main endogenous antioxidants: The body has a complex system of endogenous antioxidants that play a key role in maintaining the oxidative balance.

   • Superoxidydadysmutaza (sod): This is an enzyme that catalyzes the transformation of superoxide anion (O₂⁻) into hydrogen peroxide (H₂o₂) and oxygen (O₂). There are various forms of SOD containing copper and zinc (Cuzn-sod), manganese (MN-s) or iron (Fe-sod). SOD is one of the first lines of protection against free radicals formed in mitochondria and cytosol.
   • Catalase (CAT): This is an enzyme that catalyzes the decomposition of hydrogen peroxide (h₂o₂) into water (H₂O) and oxygen (O₂). Catalase is contained in peroxysomas and plays an important role in the removal of H₂o₂, which can be damaged for cells.
   • Glutathioneroxidase (GPX): This is a family of enzymes that catalyze the restoration of hydrogen peroxide (H₂o₂) and other lipid transfections using glutathione (GSH) as a reducing agent. GPX plays an important role in protecting cell membranes from lipid peroxidation. Selenium is an important cofactor for some GPX.
   • GlutathioneReductase (GR): This enzyme catalyzes the restoration of oxidized glutathione (GSSG) to restored glutathione (GSH), supporting the high level of GSH in cells. GSH is an important antioxidant and a GPX cofactor.
   • ThordoxinDuctase (TRXR): This enzyme catalyzes the restoration of thioredoxin (TRX), a small protein that is involved in the regulation of the oxidation and restoration state of the cells and protection against oxidative stress.
   • Bilirubin: The decay product of hemoglobin, bilirubin has antioxidant properties and can protect lipids from peroxidation.
   • Uric acid: The final product of the metabolism of purines, uric acid is a powerful antioxidant in the blood and can protect from oxidative stress.

4. The main exogenous antioxidants: Food is the main source of exogenous antioxidants that complement the endogenous antioxidant system of the body.

   • Vitamin C (ascorbic acid): Water -soluble vitamin, which is a powerful antioxidant. Vitamin C neutralizes free radicals in the aquatic medium of cells and body fluids. He can also restore oxidized vitamin E, supporting his antioxidant activity. It is important for the synthesis of collagen, strengthen the immune system and protection against infections. Sources: citrus fruits, berries, pepper, broccoli.

   • Vitamin E (Tokoferol): Fatable vitamin, which protects cell membranes from lipid peroxidation. Vitamin E is the main antioxidant in the lipid phase of cells. It also plays a role in the immune function and the prevention of blood clots. Sources: vegetable oils, nuts, seeds, avocados.

   • Carotenoids (beta-carotene, lycopin, lutein, zeaxanthin): Fatty pigments contained in vegetables and fruits. Beta-carotene is the predecessor of vitamin A and has antioxidant properties. Lycopin is contained in tomatoes and other red fruits and vegetables and can protect from prostate cancer. Luthein and zeaxantin are concentrated in the retina and protect from the degeneration of the yellow spot. Sources: carrots, pumpkin, spinach, tomatoes, pepper, mango, corn.

   • Polyphenols (flavonoids, anthocyans, resveratrol, curcumin, catechins): A large group of plant compounds with powerful antioxidant properties.

     • Flavonoids: Widely distributed in fruits, vegetables, tea and wine. They can neutralize free radicals, chelate metals and have an anti -inflammatory effect. Examples: Quercetin, Campferol, Miritsetin. Sources: apples, onions, berries, citrus fruits, tea.
     • Anthocials: They give a bright color to berries, fruits and vegetables. They have powerful antioxidant and anti -inflammatory properties. Sources: blueberries, raspberries, blackberries, cherries, red cabbage.
     • Resveratrol: Contained in grapes and red wine. It has antioxidant, anti -inflammatory and anti -cancer properties.
     • Curcumin: The main active component of turmeric. It has powerful antioxidant and anti -inflammatory properties.
     • Catechins: Contained in tea, especially in green tea. They have antioxidant, anti -cancer and cardi -protective properties. Epagallokatechin Gallat (EGCG) is the main catechin of green tea.

   • Selenium: A microelement necessary for the functioning of glutathioneperoxidase (GPX). Selenium is an important antioxidant and plays a role in immune function and cancer protection. Sources: Brazilian nuts, fish, meat, eggs.

   • Zinc: A microelement necessary for the functioning of superoxidsmouth (SOD) and other antioxidant enzymes. Zinc also plays a role in immune function and wound healing. Sources: meat, seafood, nuts, seeds.

   • Manganese: A microelement necessary for the functioning of superoxidsmouth (SOD). Sources: whole grains, nuts, seeds, tea.

5. Synergism of antioxidants: Antioxidants often act synergically, that is, their combined action is stronger than each of them separately. For example, vitamin C can restore oxidized vitamin E, and glutathione can regenerate vitamin C. A variety of nutrition rich in various antioxidants is the most effective way to maintain the antioxidant protection of the body. The “antioxidant network” includes vitamin C, vitamin E, glutathione, lipoic acid and Q10 coenzyme, which interact to protect cells from oxidative stress.

Section 3: Antioxidants in food – Healthy nutrition guide

1. The main sources of antioxidants in food: The optimal consumption of antioxidants is achieved due to a variety of and balanced nutrition, rich in fruits, vegetables, berries, nuts, seeds and whole grains.

   • Fruits: Berries (blueberries, raspberries, strawberries, blackberries), citrus fruits (oranges, grapefruit, lemons), apples, pears, grapes, kiwi, grenades.
   • Vegetables: Leaf green vegetables (spinach, cabbage, arugula), broccoli, colored cabbage, Brussels cabbage, carrots, pumpkin, tomatoes, pepper, onions, garlic, beets.
   • Berries: Contain especially high concentrations of anthocyans and other flavonoids.
   • Nuts and seeds: Walnuts, almonds, hazelnuts, Brazilian nuts, sunflower seeds, pumpkin seeds, flax seeds, chia seeds. Nuts and seeds contain vitamin E, selenium, zinc and other beneficial substances.
   • Whole grains: Oats, brown rice, cinema, buckwheat, barley. Whole grains contain vitamins, minerals and fiber, which also contribute to antioxidant protection.
   • Legumes: Beans, lentils, peas, chickpeas. Legumes contain flavonoids and other antioxidants.
   • Tea (green, black, white): Contains catechins and other polyphenols. Green tea is especially rich in Epagallokatechin Gallat (EGCG).
   • Coffee: Contains chlorogenic acid and other antioxidants.
   • Dark chocolate: Contains flavonoids. Choose dark chocolate with a high cocoa content (70% and higher).
   • Herbs and spices: Turmeric, ginger, rosemary, oregano, thyme, cinnamon. Herbs and spices contain various antioxidant compounds.

2. Recommendations for increasing consumption of antioxidants with food:

   • Eat a variety of fruits and vegetables: Strive for the consumption of at least five portions of fruits and vegetables per day. Choose fruits and vegetables of different colors to get a wide range of antioxidants.
   • Turn on the berries in your diet: Berries are an excellent source of antioxidants, so add them to yogurt, porridge, smoothie or eat like a snack.
   • Use herbs and spices: Add herbs and spices to your dishes to improve their taste and increase the content of antioxidants.
   • Choose whole grains: Prefer whole grains with processed grain products.
   • Drink tea and coffee in moderate quantities: Tea and coffee can be good sources of antioxidants, but use them in moderate quantities.
   • Swear with nuts and seeds: Nuts and seeds are an excellent snack that provides the body with antioxidants, healthy fats and protein.
   • Limit the consumption of processed products: Processed products often contain few antioxidants and can contribute to the formation of free radicals.
   • Prepare food correctly: Avoid baking food, as this can lead to the formation of free radicals. Prefer steaming, cooking or baking.
   • Read the labels of products: Pay attention to the content of vitamins, minerals and other antioxidants in products.

3. List of products with the highest content of antioxidants (ORAC): Orac (Oxygen Radical Absorbance Capacy) is a method for measuring antioxidant activity of food products. However, it is worth noting that Orac measures antioxidant activity in vitro (in a test tube) and does not always reflect the actual antioxidant activity in vain (in the body). Nevertheless, products with high ORAC are often good sources of antioxidants.

   • Spices: Cloves, cinnamon, oregano, turmeric, cocoa powder
   • Berries: Buzina, Aronia, Blueberries, Cranberry, Blackberry, Raspberry, Strawberries
   • Beans: Black beans, red beans, pinto beans
   • Nuts: Walnuts, bakers
   • Artichoke:
   • Dark chocolate:
   • Tea: Green tea, black tea

4. The influence of the method of preparation on the content of antioxidants: The method of cooking can affect the content of antioxidants.

   • Cooking: It can lead to the loss of water -soluble antioxidants, such as vitamin C and some polyphenols, into water.
   • Steaming: It retains more antioxidants than cooking, since food does not contact with a lot of water.
   • Baking: It can maintain more antioxidants than frying, as it does not require adding a large amount of oil.
   • Žarka: It can lead to the formation of free radicals and a decrease in the content of antioxidants. Frying at high temperatures can be especially harmful.
   • Microwave oven: It can be a good way to cook food, as it requires a small amount of water and time, which helps to preserve antioxidants.
   • Fermentation: It can increase the content of some antioxidants in food products. Examples: yogurt, kefir, sauerkraut, kimchi.

5. Organic products and content of antioxidants: Some studies show that organic products may contain more antioxidants than products grown by traditional methods. This may be due to the fact that organic plants are not exposed to synthetic pesticides and fertilizers, which can stimulate them with more protective compounds, including antioxidants. However, not all studies confirm this difference, and it is important to consider that other factors, such as plant variety, growing conditions and maturity, affect the content of antioxidants.

Section 4: antioxidant additives – benefits and risks

1. Indications for the use of antioxidant additives: In some cases, antioxidant additives can be useful, especially for people with certain diseases or a deficiency of nutrients. However, it is important to remember that additives should not replace full nutrition and that they should be taken only on the recommendation of a doctor.

   • Nutrient deficiency: People with a deficiency of vitamins or minerals, such as vitamin C, vitamin E, selenium or zinc, can benefit from taking appropriate additives.
   • Certain diseases: Some studies show that antioxidant additives can be useful for people with certain diseases, such as yellow stain degeneration, arthritis or cardiovascular diseases. However, further research is needed to confirm these results.
   • Intensive physical activity: Athletes involved in intensive physical exercises can experience increased oxidative stress and potentially benefit from taking antioxidant additives. However, it must be borne in mind that some studies have shown that high doses of antioxidants can prevent muscle adaptation to training.
   • Age: Elderly people may experience a decrease in the antioxidant protection of the body and potentially benefit from taking antioxidant additives. However, it is necessary to take into account possible interactions with other drugs and the general state of health.
   • Smoking and the effect of environmental pollution: People who are exposed to cigarette smoke or polluted air may experience increased oxidative stress and potentially benefit from taking antioxidant additives.

2. Types of antioxidant additives: Many antioxidant additives are available on the market, both in the form of separate vitamins and minerals, and in the form of complex drugs.

   • Vitamin C: Available in various forms, such as ascorbic acid, sodium ascorbate and liposomal vitamin C.
   • Vitamin E: Available in various forms, such as alpha-tocopherol and mixed tocopherols. It is preferable to choose a natural form of vitamin E (d-alpha tocopherol) instead of synthetic (DL-alpha the-tocopherol).
   • Beta-carotene: The predecessor of vitamin A. is not recommended for smoking people, since in high doses can increase the risk of lung cancer.
   • Selenium: Available in various forms, such as selenometionine and sodium selenite.
   • Zinc: Available in various forms, such as zinc citrate, zinc gluconate and zinc picoline.
   • Coenzim Q10 (COQ10): It is important for energy production in mitochondria and has antioxidant properties.
   • Alpha-lipoic acid (ALA): It has antioxidant properties and can regenerate other antioxidants.
   • Resveratrol: Contained in grapes and red wine.
   • Curcumin: The main active component of turmeric.
   • N-Acetylcistein (NAC): The predecessor of glutathione, an important antioxidant.
   • Green tea extracts: Contain catechins with antioxidant properties.
   • Extracts of berries (blueberries, raspberries, cranberries): They contain anti -Socialists with antioxidant properties.
   • Antioxidants mixtures: Many manufacturers offer complex drugs containing a mixture of various antioxidants.

3. Optimal dosages and method of admission: The optimal dosage of antioxidant additives depends on the type of antioxidant, individual needs and health status. It is important to follow the recommendations of a doctor or nutritionist and not exceed the recommended doses.

   • Vitamin C: The recommended daily dose for adults is 75-90 mg. The safe upper border is 2000 mg per day.
   • Vitamin E: The recommended daily dose for adults is 15 mg. The safe upper border is 1000 mg per day.
   • Selenium: The recommended daily dose for adults is 55 μg. The safe upper boundary is 400 mcg per day.
   • Zinc: The recommended daily dose for adults is 8-11 mg. The safe upper boundary is 40 mg per day.
   • Coenzim q10: Usually taken in doses from 30 to 200 mg per day.
   • Alpha-lipoic acid: Usually taken in doses from 200 to 600 mg per day.
   • Resveratrol: Usually taken in doses from 150 to 500 mg per day.
   • Curcumin: Usually taken in doses from 500 to 2000 mg per day. Take turmeric with piperin (black pepper extract) to improve its absorption.

4. Possible side effects and interactions: Antioxidant additives can cause side effects, especially when taking high doses. They can also interact with some drugs.

   • Vitamin C: High doses can cause stomach disorder, diarrhea and nausea.
   • Vitamin E: High doses can increase the risk of bleeding.
   • Beta-carotene: High doses can increase the risk of lung cancer in smokers.
   • Selenium: High doses can cause selenosis, which can lead to hair loss, nausea and damage to the nervous system.
   • Zinc: High doses can suppress the immune system and violate copper assimilation.
   • Interactions with drugs: Antioxidant additives can interact with anticoagulants (thinning blood), anti -signs (preventing blood clots) and some cancer drugs.

5. Cautions and contraindications: Before taking antioxidant additives, you need to consult a doctor, especially if you have any diseases, you take medicines or are pregnant or breastfeed.

   • Pregnancy and lactation: Some antioxidant additives can be unsafe during pregnancy and lactation.
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