We know that antioxidants are good but do we know what antioxidants are good for? I want to help break down what the benefits of antioxidants are, how they can protect us from free radicals and oxidative stress, and how we can get more of them into our diet.
Antioxidants – a term that is thrown loosely around in health food stores, grocery stores and pharmacies alike. But what exactly is an antioxidant? And what are they doing for me? I hope to shed some light into this insanely important area and help break it down so we can all have a good base core understanding of what these mean for our health.
What Are Antioxidants?
Antioxidants, simply put, are compounds that neutralize reactive and highly destructive molecules known as free radicals (also known as pro-oxidants).
What Are Free Radicals?
Free radicals are unstable atoms that can damage cells, and an accumulation of free radicals can lead to oxidative stress. It is fun to think of antioxidants as a superhero and free radicals as the disgusting evil villain that everyone despises. Too many evil villains (free radicals) leads to chaos (oxidative stress) in your body.
What Is The Science Behind Free Radicals?
To get into the science, free radicals have one or more unpaired electron which makes them super unstable. These little guys hate being unstable so will do anything to stabilize themselves – and to do this, they ‘steal’ the much-needed electrons from other molecules. But now the ‘victim’ molecule is unstable and turns into a free radical itself, leading to a continuous chain of destruction.
What Is Oxidative Stress?
Oxidative stress is an imbalance of free radicals and antioxidants in the body, which can lead to cell and tissue damage. Oxidative stress can lead to diseases such as cancer, diabetes and heart disease. Oxidative stress is also a normal part of ageing.
Where Do Free Radicals Come From?
How Are We Exposed To Free Radicals?
The origin of free radicals in our body can vary from routine body processes (which are normal and necessary) to our body’s immune system response to viruses and bacteria. They can also come from outside sources such as pollution, cigarette smoke, radiation, pesticides, chemical contaminants, and food components.
Chemical Contamination and Free Radical Development
The most well-recognized offenders are chemical contaminants such as PCBs, DDT, dioxin, furans (found in jarred and canned foods), and pesticides. Also, rancid fats and fats damaged by high -temperature cooking, metals including cadmium, chromium, cobalt, copper, iron, mercury, nickel, and vanadium and lastly, alcohol.
What Do Free Radicals Do To Our Health?
Free Radicals and DNA Damage
Your body is pretty good at dealing with free radicals, but if antioxidants are unavailable, or if free radical production becomes excessive, cell death can occur. Free radicals begin by attacking fats, proteins, carbohydrates and even DNA and RNA.
Free Radicals and Cell Damage
What they really love attacking is unsaturated fats – unsaturated fats are the main component of cell membranes. This type of oxidative damage can accelerate ageing, cause degeneration of the brain and eyes, and contribute to numerous chronic diseases such as cancer, diabetes and heart disease.
How Do Antioxidants Work?
Antioxidants and How They Fight Free Radicals
Remember how free radicals have unpaired electrons? What antioxidants contribute to this situation is the necessary electron to stabilize the free radical. How antioxidants differ from other molecules is that they continue to be protected from becoming a free radical themselves and remain stable, despite donating their electrons to the free radicals. Thus, they stop the destructive chain reaction and neutralize the situation.
What Are The Best Types of Antioxidants?
Antioxidants found in your food work as part of a team. They work together with an array of different nutrients to help extent one another’s lives and improve performance. But there are some that stand out stronger than others; these are carotenoids (converted into vitamin A), vitamin C, vitamin E, and selenium.
Which Are The Antioxidant Vitamins?
Vitamin A Antioxidant
Carotenoids that can be converted into vitamin A are part of this antioxidant army and include alpha-carotene, beta-carotene, and beta-cryptoxanthin. Vitamin A from animal meat and milk has no antioxidant activity.
How Do Carotenoids Work As Antioxidants?
Carotenoids acting as antioxidants may protect against many cancers and macular degeneration. They work by supporting communication between cells in the body.
Which Foods Are High in Carotenoids Vitamin A?
Carotenoids give fruits and vegetables their beautiful colours and are rich in apricots, chillies, guava, mangoes, papaya, persimmons, pink grapefruit, pumpkin, squash, sweet peppers (capsicum), sweet potatoes, tomatoes and watermelon. Also broccoli, collard greens green beans, kale and spinach.
Red peppers (capsicum) have significantly more carotenoids and antioxidant activity than other shades of peppers, and mature leaves of endive and lettuce contain more carotenoids than the younger, pale leaves on the same head.
Tips For Maximising Carotenoid Vitamin A Intake
- The body absorbs some carotenoids such as lycopene more effectively from cooked foods compared to raw. Lycopene is linked with reduced risk of prostate cancer and is better absorbed from cooked tomatoes or tomato paste compared to raw tomatoes,
- Certain carotenoids are more readily absorbed from foods that have been juiced, blended, or pureed because the plant matrix is disrupted and cells are broken,
- Vitamin A is a fat-soluble vitamin – including a fat source when consuming carotenoid-rich foods will increase absorption. Cook your carrots in oil, or have some nuts with your fruit.
Vitamin C Antioxidant
This water-soluble vitamin requires daily consumption as it is not stored in the body. Vitamin C not only protects against free radicals but also serves to regenerate other antioxidants such as vitamin E (more on that below).
Which Foods Are High In Vitamin C Antioxidant?
Best sources of vitamin C include citrus fruits, strawberries, kiwifruit and guava, and also broccoli and brussels sprouts. Vitamin C is easily destroyed by light, heat, and oxygen so minimal cooking and proper storage are important for ensuring your getting the maximum amount of this good guy out of your foods.
Tips For Maximising Vitamin C Intake
- Choose raw, fresh, organic plant foods that are grown in sunlight,
- Organic crops tend to be higher in vitamin C compared to nonorganic ones,
- Vegetables show seasonal changes- broccoli that is grown in the fall has double the amount of vitamin C than those grown in spring,
- Vitamin C is vulnerable to heat – less loss of vitamin C in broccoli occurs with steaming rather than boiling,
- Consider freezing – broccoli loses 38% of its vitamin C after 3 weeks of refrigeration and only 10% after 2 months of freezing.
Vitamin E Antioxidant
Vitamin E is not just one antioxidant – but 8! But the most important in terms of our health is alpha-tocopherol which is the only form of the vitamin that contributes towards the RDA of 15mg/day.
How Does Vitamin E Work As An Antioxidant?
What makes this fat-soluble vitamin so important is that it is a protector of our cell membranes. Remember that our cell membranes are made mainly of unsaturated fats which makes them extremely susceptible to free radical attacks – vitamin E works by neutralizing these free radicals.
Unfortunately, this good guy loses its antioxidant status after free radical neutralization, but vitamin C to the rescue has the ability to restore its activity. A chain reaction then occurs as vitamin E is able to protect vitamin A from destruction.
Which Foods Are High In Vitamin E Antioxidant?
Vitamin E is found in nuts, seeds, whole grains, avocados, leafy green vegetables and vegetable oils – most people only consume about half of the RDA for vitamin E. Sprouting wheat greatly increases its content of vitamin E (and vitamin C and beta-carotene- more on that later).
*supplement form of vitamin E is not always made from all-natural sources and synthetic vitamin E has only about half the potency of the natural alpha-tocopherol found in food. Best to source your vitamin E naturally.
The Antioxidant Mineral
This trace mineral is a key component of several antioxidant enzymes and also supports the activity of vitamin E in preventing the oxidation of lipids (such as cell membranes).
How Does Selenium Work As An Antioxidant?
Selenium acts to prevent oxidative damage to heart cells, red blood cells and other cells and also has a role in converting a thyroid hormone into its active form. Thyroid problems can be linked to low selenium intakes.
What Are The Best Food Sources of Selenium Antioxidant?
The best source of selenium is Brazil nuts. Other sources include sunflower seeds, whole grains, legumes and mushrooms. Selenium comes from the soil and levels vary greatly from one part of the world to another. Levels in the soil are low in Europe and Central Asia but tend to be higher in North America.
Which Foods Are Low In Antioxidants?
Animal Products and Free Radicals
Animal products are particularly high in free radicals (pro-oxidants) due to high concentrations of chemical contaminants such as DDT, PCBs, dioxins and furans that move up in the food chain. Animal products also contain very little antioxidants and no phytochemicals.
Processed Foods and Oxidative Damage
Processed foods and deep-fried foods can also promote oxidative damage, especially rancid fats and oils which can compromise cell membrane health. By limiting foods that are known to cause oxidative stress in your body we are effectively not only creating a harmonious state within ourselves but also limiting consumption of foods and products that are known environmental hazards.
What About Antioxidant Supplements?
Who Needs Supplements?
Very few people require supplements and those that do include the elderly and frail aged who have a reduced intake or ability to absorb some nutrients. During pregnancy, women should take a prenatal supplement as a safeguard to ensure their higher needs are provided for.
When Supplements Don’t Work
Studies on Vitamin C supplement use in combating the common cold show minimal effectiveness. Calcium supplements are being less routinely recommended due to their increased risk of kidney problems and heart disease. Multivitamins used in the general healthy population are generally a waste of money. We saw that when Beta-carotene was supplemented there was an increased risk not only of lung cancer but also of gastric cancer.
Why Food Is Better
Supplements are a poor substitution for nutritious foods and lack the complex and valuable components found in foods. Nutrients work together in synergy and we have little understanding of the many synergistic effects of nutrients and antioxidants.
Isolating a single nutrient can sometimes be dangerous. Many studies have shown that nutrients separated from food sources can act differently from what might be expected. There is much we still don’t understand, but what we do know is that fruit and vegetables play an important role in fighting off harmful free radicals and oxidative stress.
Rachel Dickens, The Conscious Dietitian, is a Registered Dietitian and Certified Diabetes Educator. She graduated with her Masters in Nutrition and Dietetics in 2010 from Griffith University. She strives to provide evidence-based nutrition information with a focus on plant-based nutrition, and share some of her favourite seasonal recipes and sustainable eating tips.