Antioxidants are substances that can prevent or delay cell damage from free radicals, unstable molecules produced by the body as a reaction to environmental and other pressures.
Occasionally, they are called “free-radical scavengers.”
Antioxidant sources may be natural or artificial. Some foods based on plants are believed to be rich in antioxidants. Antioxidants based on plants are a type of phytonutrient or nutrient based on plants.
Some antioxidants are also produced by the body, known as endogenous antioxidants. Antioxidants which occur outside the body are called exogenous.
Free radicals are cell-produced waste products, as the body processes food and reacts to the environment. If the body can not effectively absorb and remove free radicals, the result may be oxidative stress. This can affect the working of cells and the body. The reactive oxygen species (ROS) are also known as free radicals.
Factors that stimulate the body’s development of free radicals may be internal, such as inflammation, or external, such as pollution, UV exposure, and cigarette smoke.
Oxidative stress was associated with heart disease, cancer, asthma, stroke, respiratory illness, immune deficiency, emphysema, Parkinson’s disease, and other inflammatory or ischemic disorders.
Antioxidants are said to help our bodies neutralize free radicals, and this is believed to boost overall safety.
Benefits
Antioxidants, known as oxidative stress, can protect against the cell damage that free radicals cause.
Activities and processes which could result in oxidative stress include:
- mitochondrial activity
- excessive exercise
- tissue trauma, due to inflammation and injury
- ischemia and reperfusion damage
- consumption of certain foods, especially refined and processed foods, trans fats, artificial sweeteners, and certain dyes and additives
- smoking
- environmental pollution
- radiation
- exposure to chemicals, such as pesticides and drugs, including chemotherapy
- industrial solvents
- ozone
These actions and exposures can cause damage to cells.
This can, in turn, result in:
- an excessive release of free iron or copper ions
- an activation of phagocytes, a type of white blood cell with a role in fighting infection
- an increase in enzymes that generate free radicals
- a disruption of electron transport chains
All these can result in oxidative stress.
These can all lead to oxidative stress.
The antioxidant damage was linked to cancer, atherosclerosis and loss of vision. The free radicals are thought to cause changes in the cells that lead to these conditions, and possibly other ones.
It is assumed that an intake of antioxidants decreases those risks.
According to one study: “Antioxidants act as radical scavenger, donor of hydrogen, donor of electrons, decomposer of peroxides, quencher of single oxygen, inhibitor of enzymes, synergist and chelating agents of metals.”
Other research has shown that antioxidant supplements will help to reduce vision loss in older people due to age-related macular degeneration.
However, overall there is a lack of evidence that a higher intake of particular antioxidants can reduce the risk of illness. Results tended to show no benefit, no detrimental effect, or they were conflicting in most cases.
Types
Hundreds and possibly thousands of substances are thought to be capable of acting as antioxidants. Each one has their own role and can interact with others to help the body function effectively.
“Antioxidant” is not actually a substance’s name, but rather describes what a range of substances can do.
Examples of antioxidants which originate outside the body include:
- vitamin A
- vitamin C
- vitamin E
- beta-carotene
- lycopene
- lutein
- selenium
- manganese
- zeaxanthin
All forms of antioxidants and phytonutrients are flavonoids, flavones, catechins, polyphenols and phytoestrogens and they are all present in plant-based food.
Every antioxidant serves another purpose, and can not be interchanged with another. Hence, having a varied diet is essential.
Food sources
Plant-based foods, especially fruit and vegetables, are the best sources of antioxidants.
Foods that are particularly high in antioxidants are often referred to as’ superfood’ or’ good food.’
Consider including the following in your diet to acquire some different antioxidants:
Vitamin A: Dairy produce, eggs, and liver
Vitamin C: Most fruits and vegetables, especially berries, oranges, and bell peppers
Vitamin E: Nuts and seeds, sunflower and other vegetable oils, and green, leafy vegetables
Beta-carotene: Brightly colored fruits and vegetables, such as carrots, peas, spinach, and mangoes
Lycopene: Pink and red fruits and vegetables, including tomatoes and watermelon
Lutein: Green, leafy vegetables, corn, papaya, and oranges
Selenium: Rice, corn, wheat, and other whole grains, as well as nuts, eggs, cheese, and legumes
Other foods that are believed to be good sources of antioxidants include:
- eggplants
- legumes such as black beans or kidney beans
- green and black teas
- red grapes
- dark chocolate
- pomegranates
- goji berries
Feedingstuffs with bright, vibrant colors often have the most antioxidants.
The following foods are strong antioxidant sources. Tap on each to find out more about their food and health benefits:
- blueberries
- apples
- broccoli
- spinach
- lentils
The Cooking Effect
Cooking can either increase or decrease levels of antioxidants in particular foods.
Lycopene is the antioxidant that gives the tomatoes the rich color of red. The lycopene becomes more bio-available (easier for our bodies to digest and use) when the tomatoes are heat-treated.
Studies have however shown that in the cooking process, cauliflower, peas, and zucchini lose much of their antioxidant content. Keep in mind that eating a range of antioxidant rich foods, cooked and raw, is the important thing.
Dietary tips
The following tips could help boost your intake of antioxidants:
- Include a fruit or a vegetable every time you eat, meals and snacks included.
- Have a cup of green or matcha tea every day.
- Look at the colors on your plate. If your food is mostly brown or beige, the antioxidant levels are likely to be low. Add in foods with rich colors, such as kale, beets, and berries.
- Use turmeric, cumin, oregano, ginger, clove, and cinnamon to spice up the flavor and antioxidant content of your meals.
- Snack on nuts, seeds, especially Brazil nuts, sunflower seeds, and dried fruit, but choose those with no added sugar or salt.
Or, try these delicious, healthy recipes developed by registered dietitians:
- Cherry-almond smoothie
- Spicy cinnamon-ginger roasted carrots
- Roast beet and red quinoa salad with orange-beet balsamic vinaigrette
- Carrot cake power smoothie
- Chickpea, kale and cashew superfood soup
- Spicy Thai lettuce wraps
- Cure-all juice.
There is no set recommended daily allowance (RDA) for antioxidants, but a high intake of fresh plant-based produce is considered healthful
Risks
It is worth recalling that while studies relate fruit and vegetable consumption to a better overall health, it is not clear how far this is due to antioxidant activity. Additionally, there is a need for caution as regards supplements.
Supplements
The National Institutes of Health (NIH) Warn about the harmful effect of high doses of antioxidant supplements.
For example, a high intake of beta-carotene has been associated with increased lung cancer risk in smokers. A high dose of vitamin E has been found to increase the risk of prostate cancer, and the use of other antioxidant supplements has been associated with an increased risk of growth of tumors.
Supplements with antioxidants can also interfere with certain drugs. Before using any of these products, it is important to talk to a health care provider.
Ultimately, work has failed to prove that taking any specific antioxidant as a supplement or as a meal will protect against a disease.
People at risk of age-related macular degeneration may have some benefit, but it is essential to seek advice from a doctor on whether to use supplements and what to use.
Takeaway
Free radicals have been related to a variety of diseases, including heart disease, cancer and loss of vision, but this does not mean that increased antioxidant intake can prevent these diseases. Artificially derived antioxidants can increase the risk of certain health problems.
As a result, it is important to look for natural antioxidant sources, in the form of a healthy diet.
A lower rate of chronic diseases has been associated with the consumption of fruits and vegetables, and antioxidants may play a role. Nonetheless, the consumption of added antioxidants, particularly in processed foods, is unlikely to bring significant benefits.
Finally, anyone considering taking antioxidant supplements should first talk with a health care provider.
