Antioxidants In Food: The Most Faithful Defenders Of Our Body

Antioxidants are the body's most devoted, most loyal defenders, preventing the development of oxidative stress. These are a kind of policemen, whose task is to tirelessly maintain order on the streets of the human body.

Ideally, our body, in its internal structure, should resemble the Swiss economy: all processes are established, the mechanisms are honed, the internal currency is stable. In fact, it can rather be compared with the Middle East: you never know where and when the bomb will explode in the form of another failure at the level of cells, organs or even systems.

It's all about the mitochondria - they, in the past bacteria, and in the present - power plants, now the heart, now the inside of the plant, which allows its cranes to work, conveyor belts to slowly flow, and car engines to start - a powerful factory for the production of energy. But just as any enterprise has by-products (waste, in other words), their work does not proceed without small errors. Small but permanent. And this imperfection is precisely what free radicals represent.

The task of the electro-transport chains, arbitrarily located inside these small organelles, resembling a crookedly drawn shoe, is to create a difference (not mathematical, but still no less important) through the sequential transfer of electrons from one specific complex to another and the parallel transfer of protons chemical potentials. Let's call it one of the key conditions for the final assembly of a product called energy.

Not distinguished by special nobility, they are eager to return the missing part of the body - to return by stealing from a normal, healthy compatriot. Well, as they say, in war all methods are good.

Unshakable guardians of order - antioxidants prevent the development of chaos. They trap free radicals and neutralize their effects, usually by converting them into products that are non-toxic to cells (such as water). Tocopherol - vitamin E - acts much more humanely: it shares the missing electron with them, and, surprisingly, does not itself turn into a free radical (at least in the typical sense of the term): nature, after all, has a rich fantasy!

Classification of antioxidants

All selfless cell police can be divided into two large groups:

• Superoxide dismutase - catalyzes the conversion of reactive oxygen species (superoxide) into oxygen and hydrogen peroxide. There are several types of this enzyme, which differ in localization and depending on the metal that is part of them - but, as a rule, it is copper, manganese or zinc (respectively, with their deficiency, a decrease in its functional activity will also be observed).

  Mutations in the genes responsible for the expression of this enzyme (it has three forms in humans) are associated with the development of neurodegenerative diseases (in particular, amphiotrophic lateral sclerosis) and thinning of the cornea.

• Catalase is an enzyme responsible for neutralizing the hydrogen peroxide formed during the previous reaction by decomposing it into water and oxygen. It is interesting that catalase (as well as peroxidase) contain heme in their structures, one of the key structures of hemoglobin.

• Peroxidase - like catalase, is involved in the mechanisms of neutralization of hydrogen peroxide.

• Glutathione peroxidase is a selenium-containing enzyme that protects cells from oxidative stress. Thus, polymorphisms in the genes encoding its formation in mice were associated with their intrauterine death. This enzyme works in tandem with glutathione reductase, which provides the reaction of glutathione reduction after peroxide neutralization.

• Vitamin E is a well-known and widely used antioxidant that prevents lipid peroxidation by donating its hydrogen to a free radical. At the same time, he himself turns into a radical, but much more stable - this is ensured by the nature of his original structure.

• Vitamin C (ascorbic acid) is a water-soluble organic compound necessary for the synthesis of adrenal hormones, the formation of bile acids, neurotransmitters, collagen, as well as for the normal functioning of bone tissue and the neutralization of superoxide radicals.

  Found in kiwi, spinach, strawberries, sauerkraut, cranberries, avocados, apples and pears.

• Beta-carotenoids are fat-soluble antioxidants and vitamin A precursors that play a significant protective role (especially in carcinogenesis).

• Flavonoids are a large class of polyphenols, many of which give a variety of colors to plants, acting as pigments. In addition to antioxidant effects, most of them, having tannic properties, are widely used as antidotes and for various heavy metal poisoning. In addition, the group of vitamin P related to them, together with ascorbic acid, reduces the permeability and fragility of blood vessels.

The role of antioxidants

1. They prevent the development of eye pathology - in particular, retinopathy - one of the most colorful flowers in the bouquet of the consequences of diabetes. Elevated serum glucose (hyperglycemia) leads to its penetration through a special carrier (GLUT1) through the blood-renal barrier - the customs border that separates the circulating blood from the retina.

   This is comparable to passport control at the airport - when the flow of aircraft is relatively stable, the work of scanning and measured tapping with strains of seals on blank pages of passports is also established. But what happens when the influx of emigrants or refugees rises sharply and suddenly? The state turns a blind eye and loosens the rules.

   When this carbohydrate is oxidized, reactive oxygen species are formed - and the violation of their inactivation underlies oxidative stress, impaired capillary permeability and reduced visual acuity.

   The use of drugs based on antioxidants (in particular, carotene and bioflavonoids) protects retinal cells from damage, reduces the risk of thrombosis, and also stimulates the division and differentiation of T- and B-lymphocytes.

   Study: Diabetic retinopathy and antioxidants

2. The most delicate and sensitive nervous tissue is especially susceptible to the action of free radicals - peroxidation is one of the key factors in neuronal damage.

   So, succinic acid (one of the key figures in the Krebs cycle) normalizes the content of serotonin and histamine in the brain, by activating enzymes and complexes of the electron transport chain in mitochondria, it prevents the development of hypoxia (oxygen starvation).

   Study: Antioxidants in angioneurology

3. The use of water-soluble antioxidants (or their synthetic analogues) in the treatment of myocardial infarction was accompanied by a decrease in the focus of damage, stimulation of recovery processes, improvement of gas exchange and blood supply to the heart muscle.

   Study: Antioxidants-Cytoprotectors in Cardiology

   Within 2 years, an equally large-scale study was conducted, the authors of which noted with confidence: the risk of coronary heart disease in patients taking vitamin E for a long time decreased by more than 40%.

4. Antioxidants (as studies have shown on the effects of polyphenols derived from the chaga mushroom) stimulate the growth of beneficial intestinal microflora - in particular, lacto- and bifidobacteria. In addition, they are able to accumulate in the process of metabolism and vital activity of microorganisms and then are noted in the products of bacterial fermentation.

   Study: Activating Probiotics with Antioxidants

   In addition, antioxidants are also used in the fight against pathogenic bacteria and fungi: for example, the introduction of ascorbic acid was associated with increased migration of neutrophils, while selenium deficiency was associated with a weakened activity of these leukocytes in relation to Candida.

   Introduction for 5 weeks to guinea pigs of vitamin E at a concentration of 15-150 mg/kg per day) increased the phagocytic activity of macrophages. In addition, the same vitamin in combination with melatonin inhibited the formation of reactive oxygen species and lipid oxidation in the structure of the surfactant - a thin film that prevents the alveoli of the lungs from collapsing during exhalation.

5. They prevent the development of skin diseases - the serum concentration of antioxidants in a particular pathology, as a rule, is significantly reduced compared to the control group.

   The precursor of vitamin C, nicotinamide (vitamin B3) and zinc have shown their effectiveness (both oral and topical) in the complex treatment of acne. In other studies, the use of N-acetylcysteine ​​​​(a precursor of glutathione) reduced scarring of connective tissue (fibrosis) in an autoimmune disease such as scleroderma.

   Study: Oxidative stress and antioxidant strategies in dermatology

6. Prevent thrombosis. So, a study in which diabetic patients took part shared impressive results: taking tocopherol (vitamin E) at a concentration of 100 IU / day for 3 months was associated with suppression of platelet aggregation (connection to each other) by inhibiting the formation of platelets necessary for the course of this process of biologically active substances (in particular, thromboxane A2).

1. They improve the sensitivity of tissues to glucose - in particular, alpha-lipoic acid (which is an indispensable coenzyme in several reactions of energy production) activates the protein carriers GLUT-1 and GLUT-4 - this contributes to the transport of glucose into the cell and, accordingly, a decrease in its concentration in serum.

   Vitamin E prevented the glycation ("sugaring") of proteins under conditions of high blood glucose concentration.

2. Impact on the reproductive system.

   Beta-carotenoids, for example, protect lipid membranes from peroxidation. Healthy men with a higher intake of these antioxidants have normal sperm motility and better morphology compared to deficient compatriots.

   Study: Antioxidants for male subfertility

   L-acetylcartin (which is especially rich in animal products: meat, fish, poultry and dairy products) affects the metabolic processes in germ cells and their maturation - it is assumed that its deficiency in the diet may also be associated with male fertility.

Foods Containing Antioxidants

1. Grapes - perhaps the very solution to the "French paradox". The diversity of polyphenols in this product is associated with numerous beneficial effects: free radical scavenging, anti-toxic and anti-cancer effects.

   Enriched with biologically active substances, it showed a protective effect on the gastric mucosa, which was exposed to a mixture of 60% alcohol and hydrochloric acid.

   Anthocyanins (one of the varieties of natural antioxidants) also prevented the carcinogenic effects of such a neurotoxic substance as azoxymethane in rats, reduced DNA damage and showed antimicrobial activity (against protozoa and fungi).

    

   Recently, more and more attention has been paid to resveratrol (also found in blueberries) - this biological compound actively counteracts the formation of pro-inflammatory molecules, helps to relax the walls of blood vessels (and, consequently, increase their lumen), suppresses thrombosis, and also has an antitumor effect against hormone-dependent neoplasms. (by inducing programmed death in them - apoptosis).

   Study: Grapevine Phenolic Compounds: Structure, Antioxidant Activity, Applications

2. Blueberries are one of the richest berries in antioxidants (more than 56 mg of polyphenols were found per 100 mg of the product). Antioxidants in its composition (anthocyanides) are involved in the stabilization of collagen molecules, one of the main proteins of connective tissue; reduce the fragility of blood capillaries and increase their tone; prevent thrombosis, and also inhibit the formation of inflammatory mediators (histamine, prostaglandins and other derivatives of arachidonic acid).

   Its widespread use in ophthalmology as a drug to improve vision is associated with stimulation of blood circulation and oxygenation of the retina, deactivation of free radicals - for example, blueberry jam was used a century ago by pilots to improve visual acuity.

   The use of these berries was accompanied by a decrease in the intensity of pelvic pain in women during menstruation, as well as a decrease in swelling.

   Study: Blueberry-based medicines in modern ophthalmology

3. Kiwi is an excellent source of nutrients, in particular ascorbic acid - so, in green and golden kiwi, 161.3 mg and 92.7 mg / 100 g are concentrated, respectively.

   Vitamin C reduces lipid peroxidation damage, affects the maintenance of normal morphology by germ cells, and prevents DNA damage.

    

   It is also a cofactor for enzymes needed for the synthesis of collagen, L-carnitine, adrenal hormones, neurotransmitters, and oxytocin (one of the three hormones of happiness). It traps reactive oxygen and nitrogen species, protecting cellular structures from oxidative stress.

   Vitamin C is necessary for the normal functioning of the immune system - for example, neutrophils, which are the first to be involved in inflammatory reactions, contain a high concentration of ascorbic acid.

   In addition, clinical studies have confirmed that insufficient intake of ascorbic acid reduces bone density and increases the risk of fractures. Moreover, it is also important that people, like other primates, cannot synthesize it due to the mutated and non-functioning GULO gene (one of those who are involved in the formation of this vitamin) - that is why it must be outside, with food .

   In addition, kiwi contains vitamin E, folic acid and potassium. It also contains a unique proteolytic enzyme - actinidin, which breaks down proteins in the digestive tract.

   Research: A novel osteoporosis model with ascorbic acid deficiency in Akr1A1 gene knockout mice, The nutritional and health attributes of kiwifruit: a review

4. The Brazil nut, a South American plant native to the Amazon region, is an excellent source of selenium. Its use has beneficial effects on the correction of the lipid profile due to the ability of selenium to maintain metabolically active forms of thyroid hormones.

   In addition to selenium, Brazil nuts contain tocopherols, phenolic compounds, folic acid, magnesium and calcium, mono- and polyunsaturated fatty acids, potentially useful in the context of the prevention of cardiovascular diseases.

   Study: Comparison of the Effects of Brazil Nut Oil and Soybean Oil on the Cardiometabolic Parameters of Patients with Metabolic Syndrome: A Randomized Trial

5. Green bananas are a food source of provitamin A, vitamins B6 and C, as well as many minerals: potassium, phosphorus, magnesium, zinc, bioactive compounds (phenols and resistant starch).

   They also contain dietary fiber - an equally important ingredient with a variety of functions: fiber regulates intestinal motility, participates in the mechanisms of satiety and appetite control, and even prevents the development of cancer.

   Studies of children's groups have shown that banana pulp acts as a kind of double agent: it reduces the symptoms of diarrhea and at the same time prevents the development of constipation.

   Study: Health Benefits of Green Banana Consumption: A Systematic Review

6. Tea.

   Drinking tea increases the functional activity of antioxidant enzymes (catalase, quinone reductase, glutathione reductase, glutathione-S-transferase and glutathione peroxidase). In particular, the antioxidant potential in blood serum increased by 34 to 29% after the use of green and black tea, respectively.

   In addition, both infusions inhibited the peroxidation of linoleic acid, one of the main omega-6-unsaturated fatty acids (and this effect reached a maximum of 2 hours after the drink was drunk).

   In addition, catechins, organic compounds found in green tea and belonging to the group of flavonoids, have powerful antioxidant abilities. So, for example, one of their representatives - epigallocatechin - is ten times stronger than vitamins C and E.

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   Catechins (or rather, epigallocatechin gallate) have proven to be effective in the treatment of such a common gynecological disease among women as endometriosis (characterized by the growth of the inner layer of the uterine wall outside its cavity). So, experiments on mouse models and on human cell cultures have shown: EGCG suppresses excessive cell division, reduces the density of blood vessels, and also contributes to an increase in self-programmed cell death - apoptosis. It inhibits the scar growth of connective tissue and actively counteracts free radicals.

   The results of its use in the treatment of patients with uterine myoma (tumor) were no less interesting: for example, in the placebo group, there was an increase in the size of the neoplasm by 24%, while in women using EGCG it decreased by 32.6%.

   Study: Green tea active for the treatment of endometriosis and uterine fibroids. A look at the problem of German and Russian specialists

7. Apples - contain quercetin - another representative of flavonoids, a strong antioxidant with a pronounced anti-inflammatory effect. It prevents the development of atherosclerosis and obesity, inhibits the excessive division of tumor cells, and suppresses the formation of risk factors for pathologies of the cardiovascular system.

   This biological compound scavenges free radicals, inhibits the activity of enzymes involved in the formation of reactive oxygen species, and also has a modulating effect on superoxide dismutase, catalase and glutathione-S-transferase, thereby protecting nerve fibers, brain tissue and other cells from oxidative damage.

    

   Quercetin inhibits oxidative stress caused by an imbalance between oxidants and antioxidants, leading to inflammatory neutrophil infiltration and high secretion of protein-degrading proteases.

   It is used to prevent oncology - in particular, the development of cancer of the lung, prostate and breast, lung, liver, cervix and colon - by inhibiting carcinogens through various enzymatic processes and triggering signaling pathways.

8. Chicken eggs.

   Eggs consist of three parts: the shell, white and yolk, which make up approximately 9.5%, 63% and 27.5%, respectively.

   Egg yolk contains phospholipids (about 30% of all fats), which are an indispensable component of cell membranes, as well as long-chain polyunsaturated fatty acids - in particular, DHA (docosahexaenoic acid), which belongs to the omega-3 class.

   In addition, eggs contain important minerals such as phosphorus, selenium, iron and zinc. They are also a food source of many vitamins: biotin, pantothenic acid, B2 and B12, A, D, E, K.

   Ovotransferrin, a protein in their composition, has superoxide dismutase-like activity against reactive oxygen species. It is also able to bind iron - this fact plays an indirect role in preventing lipid peroxidation induced by these trace elements.

   Lysozyme, an enzyme that is present in almost all organisms, binds advanced glycation end products (AGEs) that contribute to the production of free radicals. In laboratory animal studies, lysozyme protected transgenic mice from oxidative damage (both acute and chronic) - while the survival rate in rodents with its deficiency was significantly lower compared to control groups.

   A protein such as cystatin exhibits an immunomodulatory function and activates the release of nitric oxide (a powerful vasodilator) in mouse macrophages - this is a necessary condition for the regulation of certain antioxidant pathways in cells.

   Study: Hen Egg as an Antioxidant Food Commodity: A Review

9. Cacao was not in vain considered the food of the gods by the ancient civilizations of the Aztecs and Mayans, who used it as food as early as 600 BC. Phenolic compounds in its composition are beneficial for health - especially in the presence of chronic inflammation, pathologies from the cardiovascular system, neurodegenerative disorders and cancer. In addition, the presence of theobromine and caffeine in it can also affect the antioxidant capacity.

10. Cherry.

    In 2016, the world production of sour cherries was over 1.3 million tons. Let us dwell in more detail on the antioxidant properties of these berries.

    Cherry is rich in catechins, flavonoids with anti-inflammatory, anti-mutagenic, anti-carcinogenic properties, the ability to modulate the function of key enzyme systems, and it also has a significant accumulation of melatonin.

Possible negative consequences

Everything is good, but in moderation - especially when it comes to biologically active substances. So, vitamins A and E, although they are antioxidants, are capable of accumulation in the liver due to their fat solubility. Many sources mark a dose of 25,000 IU or more as toxic.

1. Excess intake of vitamin A can lead to the following consequences:

   • Nausea.

   • Headaches.

   • Vertigo.

   • Fatigue and loss of energy.

   • Dryness of the skin, its peeling.

   • Swelling of the brain.

   • Pain in joints and bones.

   • Liver damage.

   • Coma.

   • Hemorrhages.

2. Vitamin E and its derivatives can also have (with uncontrolled intake) adverse effects: in particular, a violation of blood clotting.

   ATTENTION! All fat-soluble vitamins must be consumed in COURSES and, preferably, under the supervision of a nutritionist and/or doctor.

3. Flavonoids, already described earlier as antioxidants, also have a toxic effect. For example, taking quercetin at a concentration of more than 1 g / day is accompanied by:

   • Tingling in limbs.

   • Migraine.

   • Nausea.

   Consumption of more than 6g/day of green tea extracts is associated with:

   • Nausea and vomiting.

   • diarrhoea.

   • Pain in the abdomen.

4. Selenium is an element necessary for the functioning of many enzymes (in particular, glutathione peroxidase); if taken in excess, it can provoke nervous system disorders, hair loss, vomiting, weakness, and irritability.

   Taking selenium supplements against the background of iodine deficiency will additionally help to reduce the activity of the thyroid gland.

5. Excess intake of vitamin C is accompanied by disorders of the gastrointestinal tract and diarrhea.

Contraindications to the use of products with antioxidants

There are no "good" products, just as there are no bad ones - the same applies to biological compounds: in everything there is only knowledge of their structure, properties of effects and the ability to choose the right amount.

And dietary supplements can be harmful, no matter how paradoxical it may sound at first glance. Consider some contraindications regarding the intake of certain nutrients.

1. Grapefruit juice inhibits the activity of cytochrome P450 3A4, which is responsible for the conversion of estrone to the highly proliferative 16-OH-estrone.

   However, the same cytochrome also metabolizes most drugs into their inactive forms - thus, the inhibition of its work leads to an increase in the availability and toxicity of many drugs (for example, antibiotics, codeine, diazepam, etc.).

2. Patients with iron deficiency (or at risk for it) should also be careful with the intake of flavonoids - the latter can inhibit the absorption of non-heme (found in plant products) iron, the absorption of which is already quite low.

3. Curcumin, which has proven itself as an antidepressant, antitumor, antibacterial, anti-inflammatory agent, nevertheless inhibits the work of such a detoxification enzyme in the liver as cytochrome P450 1A2, which is involved in the conversion of caffeine, paracetamol, aflatoxin B1.

   In addition, taking it with anticoagulants may increase the risk of bleeding.

4. Alpha-lipoic acid, another known antioxidant, can induce hypoglycemia (lowering blood glucose levels) in diabetic patients.

5. High dosages of ascorbic acid suppress the effects of anticoagulants - this must be taken into account for persons at risk for thrombosis.

How to Eat Foods with Antioxidants Properly

1. If you are taking dietary supplements on your own, you need to carefully familiarize yourself with the interaction of vitamins and minerals with each other.

    

2. Try not to take multivitamin complexes - as a rule, manufacturers do not particularly care and do not delve deeply into the antagonistic processes between certain substances in their products.

3. Take fat-soluble vitamins with a high-fat meal.

4. An equally important condition for the absorption of vitamins A, D, E, K is the normal outflow of bile. If these processes are disturbed, you can take dietary supplements for years, sit on a high-fat diet, but still see a deficiency of one or another vitamin in laboratory tests or general symptoms.

   Start small - add drugs with phospholipids and taurine to the diet, and in the absence of gallstone disease (determined by ultrasound !!!), you can also consider options for taking cholagogues - bitterness is perfect (like tinctures of dandelion and wormwood).

1. When taking medications at the same time, make sure that there is no antagonism between them and supplements:

   • Anticonvulsants reduce the absorption of vitamin E.

   • Cholestyramine (a cholesterol-lowering drug) inhibits the absorption of fat-soluble vitamins.

   • Omeprazole (inhibits the secretion of hydrochloric acid in the stomach) inhibits the absorption of carotenoids.

   • Phenobarbitals reduce vitamin D levels.

2. A few more admission rules:

   • Zinc is required for the metabolism of vitamin A.

   • Alcohol prevents the conversion of carotenoids into vitamin A.

   • Taking vitamin E in the presence of vitamin K deficiency increases the risk of bleeding.