Health Articles

Your ever-wonder Antioxidants – 10 minutes-read

What are antioxidants?
Do we really need antioxidants?
You may have heard a lot about antioxidants but do you know how it works?

What are antioxidants?

Antioxidant is a chemical property that is able to act as an electron donor. Whereas some substances that act as antioxidants in one situation maybe pro-oxidants which is an electron-grabbers in some situation (we will talk about this later). Antioxidants are molecules that fight or neutralize free radicals in our body. Free radicals are compounds that can cause harm if their levels become too high in our body. Free radicals are linked with multiple illness including diabetes, heart disease and cancer. We have our own antioxidant defends to keep our free radicals low. However, that may not be enough for certain people.

Our body produces some antioxidants known as endogenous antioxidants while antioxidant supply from outside known as exogenous. We can obtain antioxidants from fruits, vegetables and plant-based food such as whole grains. Several vitamins such as vitamin C and E are known as potent antioxidants. Antioxidants also play an important role in food production as a preservative to increase shelf life.

Free Radical and Oxidative Stress

Free Radicals are constantly being formed in our body that would lead to oxidative stress. Our body generates free radicals as the inevitable by-products of turning food into energy. It would harm our body and resulting in cell death if our body are constantly being exposed to oxidative stress. Scientists believe free radicals can contribute to the aging process. Besides, oxidative stress is responsible for putting a series of protective mechanisms including enzymatic and non-enzymatic nature.

Enzymatic systems include dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Non-enzymatic system includes glutathione, a-tocopherol (vitamin E), ascorbic acid (Vitamin C), Flavonoids, the phenol compounds and minerals such as zinc (Zn), copper (Cu) and selenium (Sn). Therefore, free radicals and oxidative stress are essential for our body such that our immune cell use free radicals to fight infections and initiate oxidative defence. Hence, it is crucial for us to maintain certain balance of free radicals and antioxidants.

When free radicals are way more than antioxidants, it can lead to oxidative stress and oxidative stress will lead to cell and DNA damage eventually cell death. DNA damage increase risk of cancer and also initiate premature aging. Several lifestyle, stress and environmental factors are known to promote excessive free radical formation and oxidative stress:

  • Air pollution : Dust, air particles that invade our respiratory pathway and cause allergic and inflammation response.
  • Cigarette smoke : Cigarette smoke contains Nicotine, ammonia and other chemical compounds that trigger the increase of free radical that led to oxidative damage and reduce antioxidant defence.
  • Alcohol intake : Alcohol (ethanol) metabolism promote the conversion of xanthine dehydrogenase to xanthine oxidase which generate free radicals mostly Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) than lead to oxidative stress.
  • High Blood Sugar levels : Reaction of glucose with plasma protein in blood will form advanced glycation end products that trigger the production of ROS that initiate a chain reaction led to reduce nitric oxide availability, increase inflammation that increase the risk of atherogenesis, micro and macrovascular complications.
  • High intake of saturated fatty acids : High saturated fats diet is linked to metabolic syndrome suggest that high saturated fats intake is linked to high level of inflammation.
  • Excessive intake of antioxidants, such as vitamin C and E : Excessive intake of antioxidants way above their RNI will contribute to their pro-oxidant properties.

Antioxidants in food

Antioxidants are essential for us. We can generate our own antioxidant such as glutathione. We can also obtain antioxidants from diet mainly from plants that are linked to a variety of benefits. Meat and fish also contain antioxidants but they are not a significant source of antioxidant for us.

Antioxidant can be categorized as water or fat soluble. Water soluble antioxidant exhibit free radical scavenging activity the fluid inside and outside cell while fat soluble acts primarily in cell membranes. Among them, the important dietary antioxidants include vitamin C, vitamin E and flavonoids, polyphenol and carotenoids.

A diet high in antioxidants may reduce the risk of many diseases including heart disease. For instance, lutein that are found in spinach and corn has been linked to lower incidence of eye lens degeneration, flavonoids such as catechin found in green tea are believed to contribute to the lower rates of heart disease in Japan.

The antioxidant capacity of foods can be measured by Oxygen Radical Absorbance Capacity (ORAC). ORAC was created by scientists from the National Institute on Aging and the United States Department of Agriculture (USDA). According to them, our body can effectively use 3000-5000Te (Orac). The ORAC database from USDA highlight foods with high ORAC scores including berries, spices, cocoa and etc. Antioxidants tend to work best in combination with other nutrient and phytonutrients. For example, a cup of strawberries contains 80mg vitamin C and other phytonutrients work better than a supplement containing 500mg vitamin C without other phytonutrients.

Types of Antioxidants

  1. Phytonutrients
    These are chemicals and nutrients found in plants and they have a variety of health benefits for our body. While there are a lot of phytonutrients for antioxidant properties, we would only mention the common one in here.
    a. Anthocyanins
    These antioxidants help to promote blood vessel health.
    Food source: blue and purple fruits and vegetables such as berries, eggplant, sweet potatoes and etc.
    b. Resveratrol
    These antioxidants help to promote heart and lung health, help prevent certain types of cancer and reduce overall inflammation.
    Food source: dark chocolate, red wine, grapes and etc.
    c. Lycopene
    These antioxidants help to promote prostate and heart health.
    Food source: tomatoes, watermelon, capsicum and etc.
    d. Lutein
    These antioxidants help to promote eyes health.
    Food source: spinach, broccoli, artichokes and etc.
    e. Beta-carotene
    Act as precursor to Vitamin A. Important for vision, immunity and bone health.
    Food source: orange coloured food such as carrots, apricots, pumpkin and etc.
  2. Antioxidants Vitamin and Minerals
    a. Vitamin E
    There are various form of vitamin E in food, but only alpha-tocopherol is the form we need. Vitamin E ensure body normal function and reduce free radicals.
    Food source: vegetables oil and seeds.
    b. Vitamin C
    Natural occurring plant-based food, an important source of antioxidant. Vitamin C help protecting against various diseases, boosting immunity and collagen formation.
    Food sources: Citrus fruits including orange, lemon, lime and etc.
    c. Selenium
    There are 2 forms of selenium: inorganic – selenate and selenite and organic – selenomethonine and selenocysteine. Our body can use both forms of selenium that we get from various plants and animals. Selenium is a powerful antioxidant that help to protect heart and body.
    Food sources: rice, whole grain, tuna, halibut, sardine and etc.
    d. Manganese
    Manganese superoxide dismutase (MnSOD) is the main antioxidant enzyme in mitochondria of every cell in body.
    Food source: Nuts, brown rice, pineapple.
    e. Zinc
    Zinc helps in the protection of arteries as well as maximize our immune system. Zinc is involved in the activity of more than 100 enzymes in our body.
    Food sources: Seafood, oyster, crab, beef.
  3. Antioxidant Enzymes
    Enzymes that help converting free radicals to hydrogen peroxide and hydrogen peroxide further convert to water with the involvement of minerals such as zinc, copper, manganese and iron.
    a. Superoxide dismutase (SOD)
    Major antioxidant defence system in our body. They are formed in our body and they require copper and manganese to work together. There are 3 forms of SOD: two form of copper-zinc superoxide dismutase (CuZnSOD) with one being inside the cells and one outside the cells as well as manganese superoxide dismutase (MnSOD).
    b. Glutathione peroxidase (GSHPx)
    This is a cell antioxidant enzyme that reduce hydrogen peroxide to water. Selenium is needed for the activation, regulation and translation of GSHPx.
    c. Catalase (CAT)
    Iron as cofactor for reduction of hydrogen peroxide to water.

Million-dollar question: Should you take antioxidant supplements?

Dietary intake of antioxidants is essential for optimal health, but more is not always better for this case. Excessive intake of supplemental or isolated antioxidants can have toxic effect and may even promote rather than prevent oxidative damage what we call antioxidant paradox. For example, research showed that high dosage of vitamin E >400IU/day supplement may increase all-cause mortality and should be avoided.

Therefore, we should obtain antioxidant from whole food or from plant source. In addition, studies also indicate that foods reduce oxidative damage better than supplements. For example, study compared the effects of drinking blood orange juice and sugar water with equal amounts of vitamin C and found the juice had significantly greater antioxidant power. This is due to food compounds contain other phytonutrients that work synergistic with vitamin C and taking isolated nutrients won’t have the same beneficial effects. Hence, you should eat your orange instead of having orange flavoured vitamin C tablets. However, if you are unable to follow a healthy diet, you may opt for supplement that contains combination of natural plant extracts with combination of nutrients for antioxidant purposes.  Don’t worry, We’ve got you, PureMed Vital C made up of 30 types of natural fruits extract, contain wide spectrum of phytonutrients and vitamin C, just the right dose of antioxidant you need in amidst of everything.

To answer this question, Yes and No, it depends on your diet and lifestyle. If you are able to follow a healthy diet that is rich in fruits and vegetables, you don’t need antioxidant supplement and if you can’t, then you probably should opt for a natural antioxidant supplement. Still, the best strategy to ensure adequate antioxidant intake is to follow a diet rich in various vegetables and fruits, alongside with other healthy habits.

Takeaway from Nutritionist

Excessive free radicals contribute to chronic disease including cancer, heart disease, cognitive decline and etc. However, antioxidant alone does not prevent from chronic condition. There are a lot of evidence suggests that balance diet consisting of whole fruits, vegetable and whole grains that are in various colour which are all rich in networks of naturally occurring antioxidants and phytonutrients provide protection against oxidative stress. You may opt for natural antioxidant supplements that contains wide spectrum of phytonutrients if you can’t keep a healthy diet, be sure to consult with your healthcare professionals.

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Updated on 08/06/2021