Oxidative Stress 101
Free Radicals is the colloquial term for Reactive Oxygen Species (ROS).
Oxidative stress occurs when there is an imbalance between the production of free radicals (ROS) and the body’s ability to counteract their damaging effects through the neutralisation action of antioxidants. A balance between free radical production and antioxidant defenses is important for maintaining health.
What causes Free Radicals to exist?
They are formed in our body in response to:
exposure to various external insults: air pollutants, cigarette smoke, X-Rays or any kind of radiation, industrial solvents, pesticides, other environmental pollutants
as a bi-product of the normal, essential metabolism of glucose and fats to create energy, ie mitochondrial function
excessive exercise – which is why over-training is a thing
poor diet - particularly highly refined foods
high blood sugar which creates oxidative damage in the lining of our arteries, which causes hypertension
high levels of stress hormones eg cortisol, epinephrine
sustained inflammation (and then higher oxidative stress generates more inflammation…)
trauma or infection
Advanced Glycation Products (AGE’s) in blood vessels - when sugar molecules are cooked until “browned”, caused internally by out of control diabetes, and externally by over-browning foods or cooking at high temperatures eg barbecues
What exactly is a Free Radical?
A free radical is an atom or compound that is missing one or more electrons and goes about replacing it in an uncontrolled manner. This makes it highly unstable and not selective about where it obtains the missing electron from. A free radical will steal an electron from the very first place it can. They attack healthy cells with a desire to either donate or accept an electron from another molecule, thereby setting off a chain reaction of destruction in your body that is called oxidation. Oxidation is the same process that causes metal to rust and cut apples to go brown.
Which kind of molecules are vulnerable to such an attack? The major targets are fats, proteins and nucleic acids (DNA and RNA), the oxidation of which changes their structure and functions. DNA is highly susceptible to free radical attacks, which cause genetic damage that can lead to cancer. It is estimated that more than ten thousand oxidative hits to the DNA of a human cell occur daily.
What will Oxidative Stress do to me?
As we age, our bodies tend to produce more free radicals and fewer antioxidants, slowly tipping the scales towards mental and physical decline. Genetics and exposure to environmental factors listed above can add fuel to the fire, potentially triggering disease – cancer (DNA damage) and atherosclerosis (clogged arteries) being the most associated.
The cell membrane is one of the most susceptible sites to free radical damage, and once free radicals break down the outer membrane of a cell, they are able to enter and cause damage to the mitochondria inside. Ironically free radical production is a normal bi-product of regular energy metabolism (i.e. mitochondrial function), and yet the mitochondria are also the most susceptible to oxidative damage. Damaged mitochondria are less ability to use glucose and oxygen to generate energy, leading to fatigue, neuropathy, loss of memory and cognitive impairment.
Oxidative stress also makes a significant contribution to all inflammatory diseases (arthritis, vasculitis, lupus, ARDS), type 2 diabetes, hemochromatosis, emphysema, gastric ulcers, hypertension and preeclampsia, neurological disorders (Alzheimer’s, Parkinson’s and muscular dystrophy), alcoholism, smoking related diseases and many others.
What can we do to make sure these nasties are kept in check?
Antioxidants are your body’s protectors against this damage as they neutralise free radicals and protect your cells from damage. Antioxidants and free radicals are a 1:1 match. For every one free radical produced, one antioxidant is used to squelch it. When there are not enough antioxidants present, free radicals storm the body like angry protesters, damaging DNA, mitochondria, tissues and cells.
However most people in the Western world receive a lot less antioxidants via their diet than they need. Our deficient soils have been identified as the main reason why our daily intake is so low – about 10 times lower than it should be. Therefore supplementation should be considered.
Low levels of antioxidants in the blood are linked to a high incidence of chronic and degenerative diseases. Many studies have found that people who eat a well-balanced, whole foods diet, have a lower risk of developing cancer.
What is an Antioxidant?
An antioxidant is a molecule stable enough to donate an electron to a rampaging free radical to neutralise it, thus reducing its capacity to damage. These antioxidants inhibit cellular damage mainly through their free radical scavenging property.
There are hundreds of substances that act as antioxidants. Some antioxidants excel at fighting certain types of oxidants, while others are effective only in specific parts of your cells. And some only work under the right conditions.
Some antioxidants (glutathione, superoxide dismutase, CoQ10, and uric acid) are produced in the body, during normal metabolism. Glutathione is considered the most powerful, playing many vital roles in the body. Made from three amino acids: cysteine, glutamine and glycine, it is crucial to maintain good levels of protein in order to keep glutathione at the right level. Vegetarians and vegans need to be aware of this point, particularly as they age.
However most of them come from food…….
Food sources of Antioxidants
External sources of antioxidants include vitamin C and vitamin E containing foods, and also plant metabolites. These work by generously donating an electron which neutralises the damaging effect free radicals can have on proteins, DNA, fats and mitochondria.
In a 2010 study published in Nutrition Journal, researchers measured the antioxidant concentration of more than 3100 foods, including everything from nuts and seeds to grilled chicken. The conclusion was that antioxidant rich foods originate mainly from the plant kingdom. Here are the top 15 antioxidant-rich foods and spices (organic if possible as pesticides cause free radicals!)
Clove – high levels of phenolic compounds
Red cabbage – the world’s cheapest source of antioxidants per ounce!
Curly Kale – on of the most nutrient dense foods, containing a whopping serving of antioxidants, including beta-carotene, vitamin C, vitamins K and B6, as well as manganese, calcium, copper, potassium and magnesium!
Globe artichokes – among the top antioxidant rich veggies. But leaves only, not the hearts.
Oregano – big on taste and nutrient density, research has found it to be a strong antioxidant and anticarcinogenic. Chris Wark uses it in the dressing with his cancer-fighting salad recipe.
Peppermint – packed with manganese, copper, vitamins A, B6, C, E and K, beta-carotene, folate, riboflavin, this is a powerful antioxidant
Cinnamon – topped a list of 26 spices for its high antioxidant properties
Coriander – this herb is big on quercetin, as well as iron, magnesium and manganese.
Blueberries – a 2012 study found that blueberries pack the strongest antioxidant punch when compared with blackberries and strawberries. Wild ones have nearly double the antioxidant content.
Dark chocolate – has a wealth of antioxidant compounds including polyphenols, flavanols and catechins. A 2011 study found that dark chocolate had more antioxidant capacity than any of the superfruits. The higher the percentage of cocoa the better.
Pecans – a 2011 study published in the Journal of Nutrition concluded that this tree nut’s unique mix of antioxidants might help prevent heart disease. After participants ate pecans, the unhealthy oxidation of LDL cholesterol in their blood decreased by as much as 33%.
Goji Berries - a staple of trad Chinese medicine for centuries, these have recently bec0ome more mainstream. They are loaded with antioxidants and have many other benefits besides.
Coffee – happily this happens to have loads of antioxidants and is probably the Number 1 source of antioxidants in the British diet!
Antioxidants nutrients:
Vitamin E – while there are eight forms of the fat soluble vitamin E, a-tocopherol is the most bioactive form of this antioxidant. Top food sources are: spinach, kiwi, tomatoes, hazelnuts, sunflower seeds, broccoli an almonds
Vitamin C – this crucial water-soluble antioxidant has actually been shown to regenerate other antioxidants. Top food sources are: brussels sprouts, cauliflower, green and red peppers, cabbage, sweet and white potatoes, tomatoes and winter squash.
Beta-carotene – this fat soluble red/orange plant pigment combines with other elements to form Vitamin A in your body. Top food sources include: carrots, sweet potatoes, winter squash, spinach, kale, cantaloupe melon and apricots.
Selenium – this important antioxidant is actually a mineral, and it originates in soil, where it is soaked up by growing plants. Top food sources: brazil nuts, brown rice, mushrooms, oatmeal and spinach.
Polyphenols – part of the defense mechanism of plants, of which the largest group is called flavonoids. Most powerful flavonoid is Quercetin, a much researched superstar anti-inflammatory AND antioxidant. Foods in which the highest concentration of quercetin is found are: capers, organic apples, onions and black/blue berries of all kinds. Top food sources for other flavonoids include: romaine lettuce, celery, tomatoes, peaches, apples, pears, oranges, almonds, strawberries and watermelon.
Omega 3 fatty acids – these polyunsaturated fatty acids come in three forms, but for now in this summary, we are only going to focus on the two most important: EPA and DHA. These are found mainly in fish and certain algae. Most people don’t eat enough of these to deliver the amount the body needs, so supplementing with a good quality fish oil might be wise.
Resveratrol - found in red wine. It is unique amongst antioxidants because it can cross the blood-brain barrier, the membrane that helps protect the brain and nervous system. When the anti-aging and antioxidant benefits of resveratrol were fully realised in the 1990’s scientists believed they had found the key to the “French paradox” (how the French were able to eat rich, fatty foods yet have an incidence of cardiovascular disease only one third of that in the US). It has been found to increase glutathione levels and minimise fat oxidation. (Americans have of course since extracted resveratrol and turned it into a supplement, which shows little if any benefit. Remember the cornerstone of a healthy diet is whole foods, not isolated components).
Summary
Oxidative stress is thought to be one of the leading causes of deterioration and chronic disease.
Every day your body creates free radicals, and you need to consume and produce antioxidants in order to keep your system in balance.
Antioxidants are the good guys who neutralise free radicals by given them the electrons they need. Overwhelming evidence now indicates that antioxidants play a critical role in wellness and health maintenance.