Redox Reactions


Antioxidants are substances that can prevent or sometimes slow the damage to cells caused by free radicals. These are unstable molecules that our body produces as a reaction to environmental and some other pressures. These are sometimes termed as free-radical scavengers. The sources of the antioxidants can be natural or even artificial. Thus, antioxidants are the molecules that fight free radicals in our bodies. Free radicals are those compounds that can cause harm if their levels become too high in our bodies. They are linked to multiple illnesses, including diabetes, heart disease, and even cancer.

Actually, our body has its own antioxidant defences to keep free radicals in check. But, antioxidants are also found in food, especially in fruits, vegetables, and other plant-based foods. Many vitamins, like vitamins E and C, are effective antioxidants. Antioxidant preservatives are also playing a crucial role in food production by increasing shelf life.



Introduction to Antioxidants

Antioxidants are the substances responsible for the prevention of our cells from the damage caused by free radicals. Our body also produces some antioxidants, termed endogenous antioxidants. Antioxidants which come from outside the body are exogenous. Free radicals are those waste substances that are produced by cells as our body processes food and reacts with the environment. If our body cannot process and remove these free radicals efficiently, then oxidative stress can result. This also may harm cells and body function. Free radicals are also known popularly as reactive oxygen species i.e. ROS.

Factors which are increasing the production of free radicals in the body can be internal, like inflammation. These can be external like pollution, UV exposure, and cigarette smoke.
Oxidative stress is being linked to heart disease, cancer, arthritis, stroke, respiratory diseases, immune deficiency and other inflammatory conditions. Antioxidants are mainly helping us to neutralize the free radicals in our bodies, and this is thought to boost overall health. More importantly, it can protect against the cell damage that free radicals may cause.

Benefits of Antioxidants

Various activities and processes which are leading to oxidative stress are:

  1. Mitochondrial activity
  2. Excessive exercise
  3. Tissue trauma, due to inflammation and injury
  4. Ischemia and reperfusion damage
  5. Consumption of any kind of foods, like refined and processed foods, trans fats, artificial sweeteners, and certain dyes and additives
  6. Smoking
  7. Environmental pollution
  8. Radiation
  9. Exposure to chemicals, such as pesticides and drugs, including the treatment of chemotherapy
  10. Industrial solvents
  11. Ozone

Above mentioned activities and exposures can result in cell damage. And hence may lead to:

• An excessive release of the free iron/ copper ions.
• An activation of the phagocytes, which is a type of white blood cell with a role in fighting infection.
• An increase in the levels of enzymes that generate free radicals.
• A disruption of electron transport chains.

All of these are behind oxidative stress. The damage due to oxidative stress has been linked to the disease like cancer, atherosclerosis, and even vision loss. It is widely accepted that free radicals cause changes in the cells that lead to these and possibly other conditions. An intake of antioxidants is believed to reduce the risks.
One recent study says that antioxidants will act as the radical scavenger, electron donor, peroxide decomposer, enzyme inhibitor and metal-chelating agents too.

It is also proved that antioxidant supplements may help reduce vision loss due to much age-related macular degenerations. But, there is a lack of evidence about the higher intake of specific antioxidants which can reduce the risk of disease. In many cases, results have tended to show no benefit or a detrimental effect, or they have been conflicting.

Types of Antioxidants

There are considered to be hundreds and possibly thousands of substances which can act as antioxidants. Each one is having its own role and also can interact with others to help the bodywork effectively. Antioxidants are not really the name of some specific substance, but rather it is describing the range of substances can do.

Some examples of antioxidants that come from outside the body are:

  1. Vitamin A, Vitamin C and Vitamin E
  2. Beta-carotene
  3. Lycopene
  4. Lutein
  5. Selenium
  6. Manganese
  7. Zeaxanthin

Flavonoids, flavones, catechins, polyphenols, and phytoestrogens are different types of antioxidants and phytonutrients, and one can get these in plant-based foods. Each antioxidant serves many kinds of functions and is not interchangeable with another. This is the reason that it is important to have a varied diet.

Food Sources for Antioxidants

The best sources of antioxidants are plant-based foods mainly fruits and vegetables. Foods that are particularly high in antioxidants often known as a superfood or functional food. To get some specific kind of antioxidants, we must try to have the following in our diet:

  1. Vitamin A: In many dairy products, eggs, and liver
  2. Vitamin C: In many fruits and vegetables, especially berries, oranges, and bell peppers
  3. Beta-carotene: It is found in brightly coloured fruits and vegetables like carrots, peas, spinach, and mangoes.
  4. Vitamin E: In many nuts and seeds, sunflower and other vegetable oils, and green, leafy vegetables
  5. Lycopene: It is found in pink and red fruits and vegetables like tomatoes and watermelon.
  6. Lutein: In green, leafy vegetables as well as in corn, papaya, and oranges.
  7. Selenium: In rice, corn, wheat, and other whole grains.

Some other foods which are good sources of antioxidants include:

  1. Eggplants
  2. Legumes like black beans/kidney beans
  3. Green and black teas
  4. Red grapes
  5. Dark chocolate
  6. Pomegranates
  7. Goji berries

Also, foods with rich, vibrant colours often contain the most antioxidants. The following mentioned foods are good sources of antioxidants: Blueberries, apples, broccoli, spinach, lentils etc.

FAQs about Antioxidants

Q.1: How do antioxidants work in our body?
Answer: Antioxidants are those compounds that are produced in our body and found in many foods. These are helping to defend our cells from damage caused by potentially harmful molecules i.e. free radicals. When such free radicals accumulate, they may cause oxidative stress.

Q.2: Can we say the lemon as an antioxidant?
Answer: Lemons are healthful and refreshing. Lemons are a good source of vitamin C and flavonoids, which are antioxidants. Such nutrients can help to prevent diseases and boost health and wellbeing. Thus lemon is a kind of antioxidants.

Q.3: What juice is having the highest antioxidants?
Answer: Among many kinds of juice, cloudy apple juice is having the highest antioxidants. Actually, it was found to have three to four times the antioxidant content of the clear apple juice. Apple juice is available in both clear and cloudy varieties.

Q.4: What are the three antioxidant vitamins famous?
Answer: It will help our health. Some foods are having higher antioxidants than others, though. The three major antioxidant vitamins are beta-carotene, vitamin C, and vitamin E.

Q.5: What is the effect of cooking on antioxidants?
Answer: Due to the cooking of particular foods, may cause an increase or decrease in antioxidant levels. Lycopene is the antioxidant that gives the tomatoes their rich red colour. When tomatoes are heat-treated then the lycopene becomes more bio-available. But, many studies have shown that cauliflower, peas, and zucchini lose much of their antioxidant activity during the cooking process. Remember that the important thing is eating a variety of antioxidant-rich foods, cooked and raw.

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