Unit III Lesson 2

Oxidative stress and chronic inflammation are two processes that are closely linked and, fortunately, we are increasingly aware of their importance and of studying them in greater detail, since the vast majority of diseases start from these disorders.

Oxidation is a natural process of the cell through which oxygen intervenes to oxidize molecules such as sugars and fats, resulting in the obtaining of energy essential for cell function. This process is called catabolic metabolism.
Oxidative stress is a state of the cell in which intracellular oxidation-reduction homeostasis is altered, that is, the balance between prooxidants and antioxidants. As a result of cellular metabolism, substances such as nitric oxide (NO-) and reactive nitrogen species (ERNs) derived from it are generated, which have the power to damage organic molecules within the cell. To neutralize oxidation, the cell uses antioxidants, which it must obtain or manufacture through the nutrients in food.
Oxidative stress is mainly due to three factors:

• The first is the lack of antioxidants, which are found in vitamins and minerals, which is obtained through a correct diet, abundant in fruits and vegetables.
• The second factor is excess free radicals. Free radicals are also unstable molecules or elements capable of “stealing” electrons from the organic compounds of the cell, and therefore damaging it, in a similar way to the substances resulting from the catabolic activity of the cell. The end effect is the same. Damage to cell structures, which over time can lead to countless diseases: In principle, the cell has fewer resources to defend itself against pathogenic organisms, so it is easier for an infection to occur. Over time, the alteration of the cellular balance leads to a whole series of complex and degenerative diseases.
  But we will see a little more on the subject later. Free radicals are harmful substances that we can find in many elements such as cigarette smoke, alcohol, chemicals present in food such as sweeteners, flavorings, dyes, emulsifiers, also in elements present in the air or water due to environmental pollution.



• The third least mentioned factor is the lack of balance of the circadian cycles that lead the cell to remain longer in catabolic mode without leaving time for rest that allows self-repair and return to the balance zone, or homeostasis.
  When sleeping, our body secretes a series of hormones such as melatonin and the parasympathetic nervous system sends the order to our body so that our organs and cells rest and regenerate. This activates another type of metabolism called anabolic, which allows the cell to regenerate and regain its balance.
  If we go to bed stressed, we will not be able to sleep well and will suffer from insomnia or restless sleep. When we get up the next day, we will feel tired and in a bad mood, because in reality our body has not obtained the necessary rest. Our cells, our organs and our entire body are weakening and becoming unbalanced day by day due to lack of rest. It is like a runner, who is exercising all the time, without leaving room for rest, at some point he will present symptoms of extreme fatigue, which is called "burn-out".

If you have taken note of all the above, you will have already realized that there are actually two types of oxidative stress:

1. The one that is caused by the same metabolism of the cell that we can call endogenous.
2. And the exogenous, which is due to elements from outside the cell such as free radicals or radiation.

In addition to causing various diseases, oxidative stress also affects aging processes, and aging in turn favors oxidative stress, since the body loses resources to avoid or minimize cell oxidation. Therefore, it is very important to cultivate healthy lifestyle habits: as we already mentioned, a diet rich in fruits and vegetables.
Vitamin E especially captures the hydroxyl radical, its main source being wheat germ.
Vitamin A is present in fish liver oil, in vegetables (such as carrots) rich in carotenoids and vitamin C in citrus fruits, tomatoes, strawberries and vegetables.
The first two, because they are fat-soluble, can accumulate in fats and/or membranes and it is not yet known what consequence their abusive use can have, which is why it is more advisable to ingest them in natural products than in their isolated form.

Epidemiological studies indicate that the ingestion of fruits and vegetables confers protection against the development of cancer, frequently associated with oxidative stress. Although it has been proposed that the beneficial effect of this type of food lies in the antioxidant properties of the vitamins they contain, when vitamins C and E (1, 2) and pure carotenoids are administered, such conclusive results are not obtained.
From this study, Potter (2) concludes that fruits and vegetables would act as a "polypharmacy" against the development of chronic diseases, containing not only vitamins but also other antioxidant agents, such as polyphenols (with free radical scavenging and metal chelating properties), forming a complex antioxidant network.
Flavonoids are antioxidant polyphenols, present in plants and possibly the benefits of eating fruits, vegetables and red wine, touted by nutritionists, lie in their high content of these polyphenolic antioxidants. Polyols (e.g., sorbitol) also strongly activate stress-sensitive signal pathways (3).
Some elements such as glutathione and melatonin (produced by the pineal gland) have the ability to “trap” free radicals, minimizing their damaging effects.
Avoiding free radicals is also of vital importance, avoiding alcohol, tobacco, as well as harmful elements that may be present in processed foods, already mentioned, or in the environment (factory smoke, solvents, etc.).
Exercise stimulates cells, activates antioxidants, as well as other mechanisms that allow the body to deal with oxidation. However, strenuous exercise is harmful to the body, since beyond a certain limit the body is not able to handle the excess of nitric oxide, lactic acid and other substances derived from physical activity, which causes damage and an imbalance that it will take time to resolve. Therefore, exercise should be practiced, but in a moderate way, in accordance with the age, sex and physical condition of the person.

So, it has to be the right exercise, at the right intensity, and even at the right time of day. We will not dwell too much on this topic, since it is very broad, but in general terms, let's say that it is better to exercise daily, in a moderate way, than to practice a single day exceeding the limits of the body.
It is advisable to intersperse more forceful exercises with weights or gym machines, the next day do cardiovascular exercise such as running, riding a bicycle. Disciplines such as yoga, tai-chi, meditation are invaluable tools, as they help the body achieve hormonal balance, the autonomic nervous system, and circadian cycles. They can be practiced for a few minutes after having performed the intense exercise routines.

 

 

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1, 2, 3: Potter J D, 1997. Cancer prevention: epidemiology and experiment. Cancer Lett. 114: 7-9. 31. Lee A Y, Chung S S, 1999. Contributions of polyol pathway to oxidative stress in diabetic cataract. FASER J. 13: 23-30.

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