By Keerthi Sreejith, Candok Health Coach @ candok.in
Get to know antioxidants, sources and their role in a healthy lifestyle.
‘Antioxidants’ seem to be the buzzword nowadays in health and nutrition. But what are antioxidants and what do they do? They protect our cells against free radicals. That leads to the question: what are free radicals? Free radicals are produced during the metabolic processes. Free radicals are required in small quantities to serve a purpose in the human body. They perform an important role in our immune system to fight off infection and virus attacks. If the body cannot process and remove excessive amounts of free radicals efficiently, an oxidative stress can result. This oxidative stress leads to lifestyle related diseases including arteriosclerosis, hypertension, diabetes mellitus, respiratory diseases, immune deficiency, etc.
Antioxidants can be natural or man made, in other words they can be endogenous or exogenous. Endogenous means produced by the body and exogenous means produced outside the body which can be natural or artificial. This article explains endogenous and exogenous antioxidants.
Endogenous antioxidants
Endogenous antioxidants are the products of the body’s metabolism. Some endogenous antioxidants are
● Glutathione
● Melatonin
● Ferritin
Rise in intra cellular level of Reactive Oxygen Species (ROS) leads to imbalance of homeostasis process in the body. These endogenous antioxidants are active against those ROS.
Exogenous antioxidants
Exogenous antioxidants are those which we get from outside sources i.e., through nutritious diet or by eating supplements etc.
There is lots exogenous antioxidants are available in plants and animals some of them are
● Polyphenols
● Flavonoids
● Isoflavonoids
● Carotenoids
● Lutein
● Anthocyanin
● Lignance
● Vit E
● Vit C
● Selenium
● Zinc
Polyphenols
There are many types of polyphenols present in plants. Researchers state that polyphenols can reduce risk of certain cancers, blood pressure, obesity, type2 diabetes, gut micro bacteria, etc. Some studies also reveal that it protects against oxidative stress and also helps to regulate immune function.
Sources : The main sources are nuts followed by tea and coffee. Other sources are fruits (cherries, citrus fruits) and vegetables (olives,spinach ,beans) , chocolates, red wine and pasta.
Flavonoids
Because of their antioxidative anti-inflammatory, anti-mutagenic, anti-carcinogenic properties, flavonoids are considered necessary. Flavonoids are also known to reduce cardiovascular diseases.
Sources : Present in all parts of the plants such as roots, fruits, flowers, stems, bark and grain. Also present in beverages of plant origin such as tea, wine.
Isoflavonoids
Some studies show isoflavonoids may have a protective effect against cardiovascular diseases, skin diseases, immunomodulation, osteoporosis, risk reduction of certain cancers, obesity and also relief of menopause symptoms.
Sources: Richest sources are soya and its products, beans, lentils etc. Other sources are cereals, potatoes, vegetables, fruits, milk and meat.
Carotenoids
Carotenoids are present in organisms such as plants, animals and some micro- organisms. Animals cannot produce carotenoids but some marine animals contain carotenoids such as arthropods, which acquired the ability from fungi.
For humans, major sources of carotenoids are fruits and vegetables which have various colors such as green, red, orange and yellow.
Carotenoids have bioactive properties such as antioxidants, anti-inflammatory and autophagy regulatory activities.
Sources : Vegetables like broccoli, kale, coriander leaves, spinach, carrot, pumpkin, tomato, etc and fruits like orange, mangoes, watermelon.
Lutein
Lutein is a type of carotenoid. Studies proved that lutein helps to improve or prevent age related macular diseases. Also some studies reported that Lutein has some positive effects in decreasing risk of cancer and improving cardiovascular health.
Sources: Spinach, and kale and yellow carrot are the sources rich in lutein. Lutein is also found in egg yolk, peppers and grapes.
Anthocyanins
Anthocyanins are a type of flavonoids. They may appear in red, purple, blue or black in color. They are commonly found in flowers and fruits of many plants. Anthocyanins are also used as natural food colorants. Some studies show that anthocyanins possess anti-oxidative and anti-microbial activities which help to improve visual and neurological health and protect against various non communicable diseases.
Sources : Richest sources of anthocyanins are fruits and vegetables. Fruits like berries, grapes, figs, plums, raisins and vegetables like purple cabbage, egg plants, purple carrot, purple pepper, etc.
Lignance :
Lignance are polyphenols. Studies suggest that lignance lower risk of heart diseases, menopausal symptoms, osteoporosis and breast cancer.
Sources : Sesame, flax seed, bran, whole grains, and vegetables.
Vitamin C
Vitamin C occurs naturally in some foods and is also available as dietary supplements. Humans are unable to synthesise Vitamin C so it is an essential dietary component.
Antioxidant properties of Vitamin C may help to limit the free radicals and reduce oxidative stress which might help to prevent or delay the development of certain cancers, cardiovascular disorders and other diseases.
Beside the antioxidants properties, vitamin c is essential for certain neuro- transmitters, protein metabolism and essential components of connective tissue which plays a vital role in wound healing. Vitamin C plays an important role in immune function and improves the absorption of Iron.
Sources: Citrus fruits such as oranges, lemons, guava, sweet yellow peppers, thyme, parsley, kale, kiwis, broccoli, lychee, papaya, strawberry, kakadu plums, etc are the richest sources.
Vitamin E
Vitamin E occurs naturally in some foods and are also available as dietary supplements. Studies proved that Vit E helps to limit free radicals production in the body and also helps to prevent or delay the chronic diseases associated with free radicals. In addition to this, Vit E is involved in immune function, vision, regulation of gene expression and other metabolic activities.
Sources : Nuts, seeds, vegetable oils are the best sources of Vit E. Vitamin E is also found in green leafy vegetables and fortified cereals.
Selenium
The antioxidant property of Selenium helps prevent cell damage caused by free radicals. It functions as an antioxidant through the catalytic action of copper. Studies prove that it reduces oxidative stress and helps to protect cells from damage caused by free radicals. This may help to lower the risk of certain cancers and protect against heart disease. Also Selenium boosts our immune system. Some studies suggest that a diet rich in Selenium may help to improve the memory loss in Alzheimer’s disease.
Sources : Richest sources of selenium are cereals, grains and brazil nuts. Other sources are meat and dairy products.
Zinc
Zinc is an essential trace metal. The functions of zinc include the following;
● It boosts body’s immune system
● It plays a role in cell division and growth
● Wound healing
● Protein synthesis
● Enzymatic reactions
● Gene expressionSources: Meat, sea foods, nuts, seeds, legumes, diary, eggs, whole grains and vegetables like potato, beans, etc.
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Understanding and applying Nutrition Series. Edited by Candok Editorial Board, Candok Lifestyle. Live Life, Naturally!
References:
● The Role of Polyphenols in Human Health and Food Systems: A Mini-Review
● Isoflavonoids – an overview of their biological activities and potential health benefits
● The Effect of Lutein on Eye and Extra-Eye Health
● Naturally Lignan-Rich Foods: A Dietary Tool for Health Promotion?
● Vitamin E – Health Professional Fact Sheet
● Vitamin C – Health Professional Fact Sheet
● Selenium – Health Professional Fact Sheet
● Zinc – Health Professional Fact Sheet● Oxidative Stress: Harms and Benefits for Human Health