Antioxidants: protection against free radicals and aging

Antioxidants: protection against free radicals and aging

I. Free radicals: threat at the cellular level

A. Definition and nature of free radicals:

Free radicals are unstable molecules characterized by the presence of an immutable electron on the outer electronic shell. This electronic configuration makes them extremely reactionary, striving to take away the electron from other molecules in order to gain stability. As a result of this reaction, a molecule that has lost the electron itself becomes a free radical, starting a chain reaction, which can lead to cell damage.

At a chemical level, free radicals can be represented by various forms, including superoxide anion (O₂⁻), hydroxyl radical (OH •) and peroxidal radical (ROO •). Each of them has a specific reactionary ability and is involved in various biochemical processes. For example, hydroxyl radical is considered one of the strongest oxidizing agents in biological systems and can damage almost all types of macromolecules.

B. Mechanisms for the formation of free radicals:

Free radicals are formed both as a result of normal metabolic processes occurring in the body and under the influence of external factors. Endogenous sources include:

1. Mitochondrial breathing: The process of oxidative phosphorylation that occurs in mitochondria for the production of energy (ATP) inevitably leads to a leakage of electrons and the formation of a superoxide anion. This radical can be neutralized by the enzyme superoxidsmutase (SOD), but part of it can turn into more dangerous forms, such as hydroxyl radical.

2. Inflammatory processes: Immune cells, such as neutrophils and macrophages, use free radicals (for example, hypochlorite formed from hydrogen peroxide) to destroy bacteria and other pathogens. However, if inflammation becomes chronic, excessive formation of free radicals can damage the surrounding tissues.

3. Metabolism of xenobiotics: Enzymes of cytochrome P450, involved in detoxification of foreign substances (xenobiotics), can generate free radicals as a by -product. This process is important for the removal of toxins, but with a high load it can lead to oxidative stress.

The exogenous sources of the formation of free radicals include:

1. Ultraviolet (UV) radiation: UV radiation, especially UV-B, has high energy and can split molecules, forming free radicals in the skin. This is one of the main factors that contribute to photographic glasses and development of skin cancer.

2. Ionizing radiation: X-ray and gamma radiation also have sufficient energy to ionize water molecules in cells, generating hydroxyl radicals and other dangerous forms.

3. Environmental pollution: Air pollutants, such as ozone, nitrogen dioxide, solid particles and tobacco smoke, contain or contribute to the formation of free radicals in the lungs and other tissues.

4. Some medicines and chemicals: Some drugs and industrial chemicals can increase the formation of free radicals or disrupt the antioxidant protection of the body.

C. Cell damage mechanisms with free radicals:

Free radicals, due to their high reactionary ability, can damage various components of cells, including:

1. Lipids: Lipid oxidation (floor) is a chain reaction initiated by free radicals that damages cell membranes lipids. This leads to a violation of the integrity of the membranes, a change in their permeability and dysfunction of membrane proteins. The floor is especially dangerous for polyunsaturated fatty acids, which are the main components of membranes.

2. Squirrels: Free radicals can oxidize amino acid residues in proteins, leading to a change in their conformation, aggregation and loss of activity. Oxidized proteins can accumulate in cells, disrupting their function and contributing to the development of various diseases, such as Alzheimer and Parkinson’s disease.

3. DNA: Free radicals can damage DNA, causing ruptures of threads, modifying the bases and the formation of stitching. DNA damage can lead to mutations, cell death or cancer.

D. The role of free radicals in the development of diseases:

The accumulation of damage caused by free radicals contributes to the development of a wide range of diseases, including:

1. Cardiovascular diseases: The oxidation of low density lipoproteins (LDL) with free radicals plays a key role in the development of atherosclerosis. Oxidized LDLs are more actively captured by macrophages, which leads to the formation of foamy cells and the formation of atherosclerotic plaques. In addition, free radicals can damage the vascular endothelium, disrupting its function and promoting vasoconstriction and thrombosis.

2. Neurodegenerative diseases: Oxidizing stress is an important factor in the pathogenesis of Alzheimer, Parkinson and other neurodegenerative diseases. Free radicals can damage neurons, violating their function and leading to their death. In addition, oxidative stress can contribute to the aggregation of proteins, such as beta-amyloid and alpha-synuclein, which form toxic deposits in the brain with these diseases.

3. Cancer: DNA damage to free radicals can lead to mutations that can cause uncontrolled cell growth and cancer development. In addition, free radicals can contribute to proliferation and metastasis of cancer cells.

4. Inflammatory diseases: Free radicals are involved in the development of chronic inflammatory diseases, such as rheumatoid arthritis and inflammatory intestinal diseases. They can activate the inflammatory paths and enhance the release of inflammatory mediators.

5. Diabetes: Oxidative stress plays a role in the development of insulin resistance and damage to the pancreatic beta cells in diabetes. Free radicals can violate the transmission of insulin signals and reduce insulin secretion.

6. Aging: The accumulation of damage caused by free radicals over time contributes to the aging of the body. The theory of free radical aging radicals suggests that oxidative stress is the main cause of age -related changes in cells and tissues.

II. Antioxidants: a shield against oxidative stress

A. Definition and classification of antioxidants:

Antioxidants are substances that can slow down or prevent oxidation of other molecules. They act by neutralizing free radicals, giving them an electron without themselves becoming unstable. This interrupts the chain reaction and prevents cell damage.

Antioxidants can be classified according to various criteria, including their origin (endogenous or exogenous), the chemical structure and mechanism of action.

1. By origin:

   • Endogenous antioxidants: It is produced by the body. These include enzymes, such as superoxidsmouth (SOD), catalase and glutathioneperoxidase, as well as non -control molecules, such as glutathione, lipoic acid and Q10 coenzyme.

   • Exogenous antioxidants: They enter the body from the outside, mainly with food. These include vitamins (vitamin C, vitamin E, beta-carotene), minerals (selenium, zinc, manganese) and polyphenols (flavonoids, anthocyanins, reveratrol).

2. In chemical structure:

   • Enzymes: Protein molecules with catalytic activity. They accelerate the neutralization of free radicals.

   • Vitamins: Organic compounds necessary for the normal functioning of the body. Some vitamins have antioxidant properties.

   • Minerals: Inorganic substances that also play an important role in antioxidant protection.

   • Polyphenols: A large group of plant compounds with powerful antioxidant properties.

B. The mechanisms of the action of antioxidants:

Antioxidants act in various ways to protect the cells from damage by free radicals.

1. Direct neutralization of free radicals: Some antioxidants, such as vitamin C and polyphenols, directly respond with free radicals, giving them an electron and neutralizing them. At the same time, the antioxidant itself becomes a free radical, but usually it is less reactionary and can be neutralized by other antioxidants.

2. Interruption of chain reactions of lipid peroxidation (floor): Vitamin E is a powerful antioxidant that protects the lipids of cell membranes from the floor. It is introduced into the membranes and reacts with peroxypes formed in the process of the floor, interrupting the chain reaction.

3. Helating of metals: Some antioxidants, such as EDTA and Fitinic acid, can connect metals, such as iron and copper, which are involved in the formation of free radicals. The binding of these metals reduces their ability to catalyze the reactions of the formation of free radicals.

4. Restoration of oxidized molecules: Some antioxidants, such as glutathione and lipoic acid, can restore oxidized molecules, returning them their original function. For example, glutathione can restore oxidized vitamin C, allowing it to continue to perform his antioxidant functions.

5. Activation of endogenous antioxidant enzymes: Some antioxidants, such as sulforafan, can activate the NRF2 transcription factor, which regulates the expression of genes encoding antioxidant enzymes, such as COD, Catalase and Glutathioneperoxidase. This leads to increased antioxidant protection of the body.

C. The most important antioxidants and their sources:

1. Vitamin C (ascorbic acid): Water -soluble vitamin, a powerful antioxidant that neutralizes free radicals in the aqueous phase of the cell. He also participates in the restoration of oxidized vitamin E and other antioxidants.

   • Sources: Citrus fruits (oranges, lemons, grapefruits), berries (strawberries, blueberries, raspberries), kiwi, pepper, broccoli, spinach.

2. Vitamin E (tocopherols and tocotrienols): Fatable vitamin, which protects lipids of cell membranes from the floor. He can also protect the LDL from oxidation, reducing the risk of atherosclerosis.

   • Sources: Vegetable oils (sunflower, olive, soy), nuts (almonds, walnuts), seeds (sunflower), avocado, green leafy vegetables.

3. Beta-carotene (provitamin A): Carotinoid, which can turn into vitamin A into the body. It is a powerful antioxidant that protects the cells from damage to free radicals.

   • Sources: Carrots, sweet potatoes, pumpkin, spinach, cabbage, apricots, mangoes.

4. Selenium: A microelement necessary for the functioning of glutathioneperoxidase, an important antioxidant enzyme.

   • Sources: Brazilian walnut, tuna, cod, beef, chicken, eggs, mushrooms.

5. Zinc: A trace element involved in the work of SOD and other antioxidant enzymes.

   • Sources: Oysters, beef, pork, chicken, legumes (beans, lentils), nuts, seeds.

6. Manganese: A microelement necessary for the functioning of the manganese-containing SOD, an important antioxidant enzyme in mitochondria.

   • Sources: Whole grain products, nuts, seeds, legumes, green leafy vegetables.

7. Glutathione: Tripeptide, synthesized in the body, is a powerful antioxidant. It is involved in detoxification, DNA protection and regeneration of other antioxidants.

   • Sources: Glutation is contained in many foods, but its bioavailability from food is limited. Products rich in the predecessors of glutathione, such as cysteine, glycine and glutamine, can help increase its level in the body. These include: asparagus, avocados, spinach, broccoli, cauliflower.

8. Lipoic acid: An organic compound, which acts as an antioxidant and participates in energy metabolism. It can regenerate other antioxidants, such as vitamin C, vitamin E and glutathione.

   • Sources: Lipoic acid is contained in small quantities in some foods, such as red meat, offal (liver, kidneys), spinach, broccoli, Brussels cabbage.

9. Coenzim Q10 (Uthihinone): The fat -soluble compound involved in the production of energy in mitochondria and has antioxidant properties.

   • Sources: Meat, fish (salmon, tuna), offal (liver, heart), vegetable oils, nuts, seeds.

10. Polyphenols: A large group of plant compounds with powerful antioxidant properties. These include flavonoids, anthocyans, reveratrol and others.

    • Flavonoids: Widely distributed in fruits, vegetables, tea, wine and chocolate. They have antioxidant, anti -inflammatory and anticandogenic properties.

    • Anthocials: They give red, purple and blue to fruits and vegetables. They are powerful antioxidants and have anti -inflammatory properties.

    • Reveratrol: Contained in red wine, grapes, berries and peanuts. It has antioxidant, anti -inflammatory and cardioprotective properties.

D. The role of antioxidants in the prevention and treatment of diseases:

Numerous studies have shown that the consumption of a sufficient amount of antioxidants can reduce the risk of developing many diseases associated with oxidative stress.

1. Cardiovascular diseases: Antioxidants, such as vitamin E, vitamin C and polyphenols, can protect the LDL from oxidation, reducing the risk of atherosclerosis. They can also improve the function of the vascular endothelium and reduce blood pressure.

2. Neurodegenerative diseases: Antioxidants can protect neurons from damage to free radicals, reducing the risk of developing Alzheimer, Parkinson and other neurodegenerative diseases.

3. Cancer: Antioxidants can protect DNA from damage by free radicals, reducing the risk of cancer. They can also suppress proliferation and metastasis of cancer cells.

4. Inflammatory diseases: Antioxidants can suppress the inflammatory tracts and reduce the release of inflammatory mediators, facilitating the symptoms of chronic inflammatory diseases.

5. Diabetes: Antioxidants can improve insulin sensitivity and protect pancreatic beta cells from damage, reducing the risk of diabetes.

6. Age changes: Antioxidants can slow down the aging process, protecting the cells from damage by free radicals and maintaining their function.

E. Antioxidant additives: benefits and warnings:

Antioxidant additives can be useful for people who do not get enough antioxidants from food, for example, for those who adhere to an unbalanced diet or have an increased need for antioxidants due to age, stress or diseases. However, it is important to remember that additives do not replace healthy nutrition.

It is important to be cautioned with antioxidant additives, since high doses of some antioxidants can be harmful. For example, high doses of vitamin E can increase the risk of bleeding, and high doses of beta-carotene can increase the risk of lung cancer in smokers.

Before taking any antioxidant additives, it is necessary to consult a doctor or a nutritionist in order to determine the optimal dose and avoid undesirable side effects.

III. Antioxidants and aging:

A. Oxidizing stress as a factor in aging:

The theory of free aging radicals proposed by Denham Harman in 1956 argues that the accumulation of damage caused by free radicals is the main cause of age -related changes in cells and tissues. Oxidative stress leads to damage to DNA, proteins and lipids, which disrupts cell function and promotes the development of age -related diseases.

With age, the effectiveness of endogenous antioxidant systems decreases, and the formation of free radicals increases, which leads to an increase in oxidative stress. This contributes to the development of such age -related changes as a decrease in cognitive functions, visual impairment, a decrease in immunity and an increase in the risk of developing chronic diseases.

B. The influence of antioxidants on life expectancy and quality of life:

Numerous animal studies have shown that an increase in the consumption of antioxidants can extend life and improve the quality of life. For example, the addition of antioxidants to the ration of worms C. elegans and Drosophil Drosophila melanogaster increases their life expectancy.

In human studies, it has also been shown that the consumption of a sufficient amount of antioxidants is associated with a decrease in the risk of developing age diseases and improving cognitive functions. For example, people consuming a lot of fruits and vegetables rich in antioxidants have a lower risk of developing Alzheimer’s disease and other neurodegenerative diseases.

C. Strategies for increasing the consumption of antioxidants for slowing down aging:

1. Balanced diet, rich in fruits and vegetables: It is necessary to use at least five portions of fruits and vegetables per day to provide the body with a sufficient amount of antioxidants. It is important to choose a variety of fruits and vegetables of different colors, as they contain different types of antioxidants.

2. The inclusion in the diet of products rich in specific antioxidants: It should be included in the diet products rich in vitamin C (citrus fruits, berries), vitamin E (vegetable oils, nuts, seeds), beta-carotene (carrots, sweet potatoes), selenium (Brazilian nut, tuna) and polyphenols (tea, grapes, berries).

3. Restriction of the effects of factors contributing to the formation of free radicals: It is necessary to avoid smoking, excessive alcohol use, exposure to ultraviolet radiation and environmental pollution.

4. Regular physical exercises: Moderate physical exercises can stimulate the endogenous antioxidant system of the body, increasing the level of SOD, catalase and glutathioneperoxidase.

5. Stress control: Chronic stress can increase the formation of free radicals. It is necessary to use stress management strategies, such as meditation, yoga and deep breathing to reduce the level of oxidative stress.

6. Consideration of the possibility of taking antioxidant additives (after consulting a doctor): Antioxidant additives can be useful for people who do not get enough antioxidants from food, but it is important to observe caution and consult a doctor to avoid unwanted side effects.

D. Prospects for research of antioxidants and aging:

Studies in the field of antioxidants and aging are ongoing, and scientists are actively studying new methods of using antioxidants to slow down aging and prevention of age -related diseases.

1. Study of new antioxidants: Researchers are looking for new antioxidants with a more powerful effect and better bioavailability.

2. Development of strategies for targeted delivery of antioxidants: Scientists develop strategies for targeted delivery of antioxidants to cells and tissues, where they are most necessary.

3. Studying the influence of antioxidants on various age processes: Researchers study the effect of antioxidants on various age processes, such as skin aging, a decrease in cognitive functions and weakening immunity.

4. Development of new methods for evaluating oxidative stress: Scientists are developing new methods for assessing oxidative stress in the body to better understand its role in aging and the development of diseases.

5. The study of genetic factors affecting antioxidant protection: Researchers study genetic factors that affect the antioxidant protection of the body to develop personalized aging prevention strategies.

IV. Practical recommendations for the inclusion of antioxidants in the diet and lifestyle:

A. Compilation of a diet rich in antioxidants:

1. Include a variety of fruits and vegetables of different colors in the diet: Eat a rainbow of fruits and vegetables to get a wide range of antioxidants.

2. Give preference to fresh, unprocessed products: Fresh fruits and vegetables contain more antioxidants than processed products.

3. Do not digest vegetables: Digging can destroy some antioxidants. Prepare the vegetables steam, cook them or fry in a pan for a short time.

4. Use herbs and spices: Herbs and spices, such as turmeric, ginger, rosemary and oregano, are rich in antioxidants.

5. Drink tea and coffee: Tea and coffee contain polyphenols with antioxidant properties.

6. Eat dark chocolate: Dark chocolate contains flavonoids that are powerful antioxidants.

B. Examples of antioxidant dishes:

1. Berry smoothie: Mix berries (blueberries, strawberries, raspberries) with yogurt or milk and spinach.

2. Avocado spinach salad and walnuts: Spinach, avocado and walnuts are rich in antioxidants and healthy fats.

3. Frying salmon with vegetables: Salmon is rich in omega-3 fatty acids and antioxidants. Fry it with broccoli, carrots and pepper.

4. Chicken soup with vegetables and turmeric: Chicken soup with vegetables and turmeric has antioxidant and anti -inflammatory properties.

5. Oatmeal porridge with berries and nuts: Oat porridge with berries and nuts is a great way to start a day with antioxidants.

C. Recommendations on lifestyle to increase antioxidant protection:

1. Quit smoking: Smoking significantly increases the formation of free radicals in the body.

2. Limit alcohol use: Excessive alcohol consumption can also contribute to the formation of free radicals.

3. Protect the skin from ultraviolet radiation: Use sunscreen and wear protective clothes to protect the skin from damage to UV radiation.

4. Avoid environmental pollution: Try to avoid polluted areas and use air filters in the room.

5. Farm up: The lack of sleep can increase the level of oxidative stress in the body.

6. Manage stress: Use stress management strategies such as meditation, yoga and deep breathing to reduce the level of oxidative stress.

7. Do physical exercises regularly: Moderate physical exercises can stimulate the endogenous antioxidant system of the body.

D. The importance of consulting a doctor or nutritionist:

Before making any significant changes to your diet or lifestyle, it is necessary to consult a doctor or nutritionist. They will help you develop an individual plan that will meet your needs and goals, and prevent possible side effects. It is especially important to consult a doctor if you have any chronic diseases or take medications.