Which Fruit Is High In Antioxidants?/Antioxidants are compounds that inhibit oxidation. Oxidation is a chemical reaction that can produce free radicals, thereby leading to chain reactions that may damage the cells of organisms. Antioxidants such as thiols or ascorbic acid (vitamin C) terminate these chain reactions. To balance the oxidative state, plants and animals maintain complex systems of overlapping antioxidants, such as glutathione and enzymes (e.g., catalase and superoxide dismutase), produced internally, or the dietary antioxidants vitamin A, vitamin C, and vitamin E.
An antioxidant is a molecule stable enough to donate an electron to a rampaging free radical and neutralize it, thus reducing its capacity to damage. These antioxidants delay or inhibit cellular damage mainly through their free radical scavenging property.[rx] These low-molecular-weight antioxidants can safely interact with free radicals and terminate the chain reaction before vital molecules are damaged. Some of such antioxidants, including glutathione, ubiquinol, and uric acid, are produced during normal metabolism in the body.[rx] Other lighter antioxidants are found in the diet. Although there are several enzymes system within the body that scavenge free radicals, the principle micronutrient (vitamins) antioxidants are vitamin E (α-tocopherol), vitamin C (ascorbic acid), and B-carotene.[rx]
Antioxidants are the key to healthy eating. Which foods pack the most nutrients?
Researchers at the University of Oslo wanted to know which foods have the highest concentration of antioxidants, the natural chemicals in food that make it healthy and prevent disease, so they tested 1,113 common foods and drinks, from apples to waffles. Their findings: Ounce for ounce, spices, herbs, nuts, and seeds pack the most nutrients. But if we’re talking typical serving size, berries (five different kinds) also dominate the top ranks. The most surprising find? Chocolate ice cream rated higher than fruits like honeydew and green grapes! Here, the best 10 foods to eat to “anti” up.
Types of Antioxidants
Some compounds contribute to antioxidant defense by chelating transition metals and preventing them from catalyzing the production of free radicals in the cell. Particularly important is the ability to sequester iron, which is the function of iron-binding proteins such as transferrin and ferritin. Selenium and zinc are commonly referred to as antioxidant nutrients, but these chemical elements have no antioxidant action themselves and are instead required for the activity of some antioxidant enzymes, as is discussed below.
|Antioxidant||Solubility||Concentration in human serum (μM)||Concentration in liver tissue (μmol/kg)|
|Ascorbic acid (vitamin C)||Water||50–60||260 (human)|
|Lipoic acid||Water||0.1–0.7||4–5 (rat)|
|Uric acid||Water||200–400||1,600 (human)|
|Carotenes||Lipid||β-carotene: 0.5–1retinol (vitamin A): 1–3||5 (human, total carotenoids)|
|α-Tocopherol (vitamin E)||Lipid||10–40||50 (human)|
|Ubiquinol (coenzyme Q)||Lipid||5||200 (human)|
Uric acid has the highest concentration of any blood antioxidant and provides over half of the total antioxidant capacity of human serum. Uric acid’s antioxidant activities are also complex, given that it does not react with some oxidants, such as superoxide, but does act against peroxynitrite, peroxides, and hypochlorous acid. Concerns over elevated UA’s contribution to gout must be considered as one of many risk factors. By itself, UA-related risk of gout at high levels (415–530 μmol/L) is only 0.5% per year with an increase to 4.5% per year at UA supersaturation levels (535+ μmol/L). Many of these aforementioned studies determined UA’s antioxidant actions within normal physiological levels, and some found antioxidant activity at levels as high as 285 μmol/L.
- Ascorbic acid or “vitamin C” is a monosaccharide oxidation-reduction (redox) catalyst found in both animals and plants. As one of the enzymes needed to make ascorbic acid has been lost by mutation during primate evolution, humans must obtain it from the diet; it is, therefore, a vitamin. Most other animals are able to produce this compound in their bodies and do not require it in their diets.
- Ascorbic acid is required for the conversion of the procollagen to collagen by oxidizing proline residues to hydroxyproline. In other cells, it is maintained in its reduced form by reaction with glutathione, which can be catalyzed by protein disulfide isomerase and glutaredoxins.
- Vitamin E is the collective name for a set of eight related tocopherols and tocotrienols, which are fat-soluble vitamins with antioxidant properties. Of these, α-tocopherol has been most studied as it has the highest bioavailability, with the body preferentially absorbing and metabolizing this form.
- It has been claimed that the α-tocopherol form is the most important lipid-soluble antioxidant and that it protects membranes from oxidation by reacting with lipid radicals produced in the lipid peroxidation chain reaction. This removes the free radical intermediates and prevents the propagation reaction from continuing. This reaction produces oxidized α-tocopherol radicals that can be recycled back to the active reduced form through reduction by other antioxidants, such as ascorbate, retinol or ubiquinol. This is in line with findings showing that α-tocopherol, but not water-soluble antioxidants, efficiently protects glutathione peroxidase 4 (GPX4)-deficient cells from cell death. GPx4 is the only known enzyme that efficiently reduces lipid-hydroperoxides within biological membranes.
- Enzymatic antioxidants – benefit you by breaking down and removing free radicals. They can flush out dangerous oxidative products by converting them into hydrogen peroxide, then into the water. This is done through a multi-step process that requires a number of trace metal cofactors, such as zinc, copper, manganese, and iron. Enzymatic antioxidants cannot be found in supplements, but instead, are produced in your body.
- Superoxide dismutase (SOD) – can break down superoxide into hydrogen peroxide and oxygen, with the help of copper, zinc, manganese, and iron. It is found in almost all aerobic cells and extracellular fluids.
- Catalase (CAT) – works by converting hydrogen peroxide into water and oxygen, using iron and manganese cofactors. It finishes up the detoxification process started by SOD.
- Glutathione peroxidase (GSHpx) and glutathione reductase – are selenium-containing enzymes that help break down hydrogen peroxide and organic peroxides into alcohols. They are most abundant in your liver.
- Non-enzymatic antioxidants – benefit you by interrupting free radical chain reactions. Some examples are carotenoids, vitamin C, vitamin E, plant polyphenols, and glutathione (GSH). Most antioxidants found in supplements and foods are non-enzymatic, and they provide support to enzymatic antioxidants by doing a “first sweep” and disarming the free radicals. This helps prevent your enzymatic antioxidants from being depleted.
- Small-molecule antioxidants – work by mopping up or “scavenging” the reactive oxygen species and carrying them away through chemical neutralization. The main players in this category are vitamins C and E, glutathione, lipoic acid, carotenoids, and CoQ10.
- Large-protein antioxidants– tend to be the enzymatic enzymes outlined above, as well as “sacrificial proteins,” that absorb ROS and stop them from attacking your essential proteins. One example of these sacrificial proteins is albumin, which “take the bullet” for crucial enzymes and DNA.
- Quercetin –Derived naturally from foods like berries and leafy greens, quercetin seems to be safe for almost everyone and poses little risks. Most studies have found little to no side effects in people eating nutrient-dense diets high in quercetin or taking supplements by mouth short term.
- Lutein –Lutein has benefits for the eyes, skin, arteries, heart and immune system, although food sources seem to be generally more effective and safer than supplements. Some evidence shows that people who obtain more lutein from their diets experience lower rates of breast, colon, cervical and lung cancers.
- Resveratrol – Resveratrol is an active ingredient found in cocoa, red grapes, and dark berries, such as lingonberries, blueberries, mulberries, and bilberries. It’s a polyphonic bioflavonoid antioxidant that’s produced by these plants as a response to stress, injury and fungal infection, helping protect the heart, arteries and more.
- Astaxanthin –Astaxanthin is found in wild-caught salmon and krill and has benefits like reducing age spots, boosting energy levels, supporting joint health and preventing symptoms of ADHD.
- Selenium – Selenium is a trace mineral found naturally in the soil that also appears in certain foods, and there are even small amounts in water. It supports the adrenal and thyroid glands and helps protect cognition. It may also fight off viruses, defend against heart disease and slow down symptoms correlated with other serious conditions like asthma.
- Lavender Essential Oil –Lavender oil reduces inflammation and helps the body in many ways, such as producing important antioxidant enzymes – especially glutathione, catalase, and superoxide dismutase.
- Chlorophyll – Chlorophyll is very helpful for detoxification and linked to natural cancer prevention, blocking carcinogenic effects within the body, and protecting DNA from damage caused by toxins or stress. It’s found in things like spirulina, leafy green veggies, certain powdered green juices, and blue-green algae.
- Frankincense Essential Oil – Frankincense oil has been clinically shown to be a vital treatment for various forms of cancer, including breast, brain, colon and prostate cancers. Frankincense has the ability to help regulate cellular epigenetic function, which positively influences genes to promote healing. Rub frankincense essential oil on your body (neck area) three times daily, and take three drops internally in eight ounces of water three times daily as part of a natural prevention plan.
Important Benefits of Antioxidants Include
- Repairing damaged molecules – Some unique types of antioxidants can repair damaged molecules by donating a hydrogen atom. This is very important when the molecule is a critical one, like your DNA.
- Blocking metal radical production – Some antioxidants have a chelating effect – they can grab toxic metals like mercury and arsenic, which can cause free radical formation, and “hug” them so strongly to prevent any chemical reaction from taking place. Water-soluble chelating agents can also escort toxic metals out of your body through your urine.
- Stimulating gene expression and endogenous antioxidant production – Some antioxidants can stimulate your body’s genes and increase your natural defenses.
- Providing a “shield effect” – Antioxidants, such as flavonoids, can act as a virtual shield by attaching to your DNA to protect it from free radicals attacks.
- Promoting cancer cells to “commit suicide” – Some antioxidants can provide anti-cancer chemicals that halt cancer growth and force some cancer cells to self-destruct (apoptosis).
- Allium sulfur compounds – Leeks, onions, garlic
- Anthocyanins – Eggplant, grapes, berries
- Beta carotene – Pumpkin, mangoes, apricots, carrots, spinach, parsley
- Catechins – Red wine, tea
- Copper – Seafood, lean meat, milk, nuts, legumes
- Cryptoxanthins – Red peppers, pumpkin, mangoes
- Flavonoids – Tea, green tea, red wine, citrus fruits, onion, apples
- Indoles – Cruciferous vegetables such as broccoli, cabbage, cauliflower
- Lignans – Sesame seeds, bran, whole grains, vegetables
- Lutein – Corn, leafy greens (such as spinach)
- Lycopene – Tomatoes, pink grapefruit, watermelon
- Manganese – Seafood, lean meat, milk, nuts
- Polyphenols – Thyme, oregano
- Selenium – Seafood, offal, lean meat, whole grains
- Vitamin C – Oranges, berries, kiwi fruit, mangoes, broccoli, spinach, peppers
- Vitamin E – Vegetable oils, nuts, avocados, seeds, whole grains
- Zinc – Seafood, lean meat, milk, nuts
- Zoochemical – Red meat, offal, fish
Antioxidants from our diet play an important role in helping endogenous antioxidants for the neutralization of oxidative stress. Nutrient antioxidant deficiency is one of the causes of numerous chronic and degenerative pathologies. Each nutrient is unique in terms of its structure and antioxidant function (rx, rx).
- Vitamin E is a fat-soluble vitamin with high antioxidant potency. Vitamin E is a chiral compound with eight stereoisomers: α, β, γ, δ tocopherol and α, β, γ, δ tocotrienol. Only α-tocopherol is the most bioactive form in humans. Studies in both animals and humans indicate that natural dextrorotary d-α-tocopherol is nearly twice as effective as synthetic racemic dl-α-tocopherol (rx).
- Because it is fat-soluble, α-tocopherol safeguards cell membranes from damage by free radicals. Its antioxidant function mainly resides in the protection against lipid peroxidation. Vitamin E has been proposed for the prevention against colon, prostate and breast cancers, some cardiovascular diseases, ischemia, cataract, arthritis, and certain neurological disorders. (rx).
- However, a recent trial revealed that daily α-tocopherol doses of 400 IU or more can increase the risk of death and should be avoided. In contrast, there is no increased risk of death with a dose of 200 IU per day or less, and there may even be some benefit (rx). Although controversial, the use of long-term vitamin E supplementation in high dose should be approached cautiously until further evidence for its safety is available. The dietary sources of vitamin E are vegetable oils, wheat germ oil, whole grains, nuts, cereals, fruits, eggs, poultry, meat (rx, rx). Cooking and storage may destroy natural d-α-tocopherol in foods (rx).
- Vitamin C also known as ascorbic acid, is a water-soluble vitamin. It is essential for collagen, carnitine and neurotransmitters biosynthesis (rx). Health benefits of vitamin C are antioxidant, anti-atherogenic, anti-carcinogenic, immunomodulator.
- The positive effect of vitamin C resides in reducing the incidence of stomach cancer, and in preventing lung and colorectal cancer. Vitamin C works synergistically with vitamin E to quench free radicals and also regenerates the reduced form of vitamin E.
- However, the intake of high doses of vitamin C (2000mg or more/day) has been the subject of debate for its eventual pro-oxidant or carcinogen property (rx–rx). Natural sources of vitamin C are acid fruits, green vegetables, tomatoes. Ascorbic acid is a labile molecule, therefore it may be lost from during cooking (rx).
- Beta-carotene is a fat-soluble member of the carotenoids which are considered provitamins because they can be converted to active vitamin A. Beta-carotene is converted to retinol, which is essential for vision. It is a strong antioxidant and is the best quencher of singlet oxygen.
- However, beta-carotene supplement in doses of 20mg daily for 5-8 years has been associated with an increased risk of lung and prostate cancer and increased total mortality in cigarette smokers (rx). Beta-carotene 20-30mg daily in smokers may also increase cardiovascular mortality by 12% to 26% (rx). These adverse effects do not appear to occur in people who eat foods high in beta-carotene content. Beta-carotene is present in many fruits, grains, oil and vegetables (carrots, green plants, squash, spinach) (rx).
- Lycopene, a carotenoid, possesses antioxidant and antiproliferative properties in animal and in vitro studies on breast, prostate and lung cell lines, although anticancer activity in humans remains controversial (rx, rx, rx). Lycopene has been found to be very protective, particularly for prostate cancer (rx).
- Several prospective cohort studies have found associations between high intake of lycopene and reduced incidence of prostate cancer, though not all studies have produced consistent results (rx). The major dietary source of lycopene is tomatoes, with the lycopene in cooked tomatoes, tomato juice and tomato sauce included, being more bioavailable than that in raw tomatoes (rx).
- Se is a trace mineral found in soil, water, vegetables (garlic, onion, grains, nuts, soybean), seafood, meat, liver, yeast (rx). It forms the active site of several antioxidant enzymes including glutathione peroxidase. At low dose, health benefits of Se are antioxidant, anti-carcinogenic and immunomodulator (rx). Selenium is also necessary for the thyroid function (rx).
- Exceeding the Tolerable Upper Intake Level of 400 μg Se/day can lead to selenosis which is a selenium poisoning characterized by gastrointestinal disorders, hair and nail loss, cirrhosis, pulmonary edema and death (rx).
- Selenium deficiency can occur in patients on total parenteral nutrition (TPN) and in patients with gastrointestinal disorders. In certain China areas with Se poor soil, people have developed a fatal cardiomyopathy called Keshan disease which was cured with Se supplement (rx). The role of Se in cancer prevention has been the subject of recent study and debate. Results from clinical and cohort studies about cancer prevention, especially lung, colorectal, and prostate cancers are mixed (rx, rx).
- Flavonoids are polyphenolic compounds which are present in most plants. According to chemical structure, over 4000 flavonoids have been identified and classified into flavonols, flavanones, flavones, isoflavones, catechins, anthocyanins, proanthocyanidins. Beneficial effects of flavonoids on human health mainly reside in their potent antioxidant activity (rx).
- They have been reported to prevent or delay a number of chronic and degenerative ailments such as cancer, cardiovascular diseases, arthritis, aging, cataract, memory loss, stroke, Alzheimer’s disease, inflammation, infection. Every plant contains a unique combination of flavonoids, which is why different herbs, all rich in these substances, have very different effects on the body (rx). The main natural sources of flavonoids include green tea, grapes (red wine), apple, cocoa (chocolate), ginkgo Biloba, soybean, Curcuma, berries, onion, broccoli, etc.
- For example, green tea is a rich source of flavonoids, especially flavonols (catechins) and quercetin. Catechin levels are 4-6 times greater in green tea than in black tea. Many health benefits of green tea reside in its antioxidant, anticarcinogenic, antihypercholesterolemic, antibacterial (dental caries), anti-inflammatory activities (rx).
Omega-3 and omega-6 fatty acids
- They are essential long-chain polyunsaturated fatty acids because the human body cannot synthesize them. Therefore, they are only derived from food. Omega-3 fatty acids can be found in fat fish (salmon, tuna, halibut, sardines, pollock), krill, algae, walnut, nut oils and flaxseed. However, certain big fishes like tilefish, shark, swordfish are to be avoided because of their high mercury levels (rx).
- There are three major dietary types of omega-3 fatty acids: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA). EPA and DHA are abundant in fish and are directly used by the body; while ALA is found in nuts and has to be converted to DHA and EPA by the body. Dietary sources of omega-6 fatty acids (linoleic acid) include vegetable oils, nuts, cereals, eggs, poultry.
- It is important to maintain an appropriate balance of omega-3s and omega-6s in the diet, as these two substances work together to promote health (rx, rx). Omega-3 fatty acids help reduce inflammation, and most omega-6 fatty acids tend to promote inflammation. An inappropriate balance of these essential fatty acids contributes to the development of disease while a proper balance helps maintain and even improve health. A healthy diet should consist of about 2-4 times more omega-6s than omega-3s. In the American diet, omega-6s are 14-25 times more abundant than omega-3s, that explains the rising rate of inflammatory disorders in the USA (rx). Omega-3s reduce inflammation and prevent chronic ailments such as heart disease, stroke, memory loss, depression, arthritis, cataract, cancer. Omega-6s improve diabetic neuropathy, eczema, psoriasis, osteoporosis, and aid in cancer treatment (rx, rx, rx).
Antioxidants Home Treatments
- One cup of blackberries contains the most antioxidants of all the berries tested, beating out blueberries, strawberries, cranberries, and raspberries. Plus, one cupful provides half your daily recommended intake of vitamin C.
- Nutrition facts (1 cup): 62 calories, less than 1g fat, 14g carbohydrates, 7.6g fiber, 2g protein
- Just an ounce of walnuts, or 15 to 20 halves, is loaded with antioxidants. They’re also cholesterol-free and low in sodium and sugar. Nuts are laden with calories, though, so be mindful of your intake.
- Nutrition facts (1 ounce): 185 calories, 18.5g fat (1.7g saturated fat), 4g carbohydrates, 8g fiber, 4g protein
- Bursting with fiber and vitamin C (149 percent of your daily recommended intake!), a cup of sliced strawberries is a cup full of healthy benefits.
- Nutrition facts (1 cup): 49 calories, 0.5g fat, 11.7g carbohydrates, 3g fiber, 1g protein
- Add a cup of antioxidant-rich artichoke hearts to your diet.
- Nutrition facts (1 cup): 70 calories, 0g fat, 11.5g carbohydrates, 4.5g fiber, 2.5g protein
- One cup of whole cranberries is full of disease-fighting and health-boosting antioxidants.
- Nutrition facts (1 cup): 51 calories, 0.2g fat, 13.5g carbohydrates, 5g fiber, 1g protein
- Your morning cup of joe does more than perk you up — it also boosts your health.
- Nutrition facts (8 fluid ounces): 18 calories, 2mg sodium
- Another super-healthy berry to add to your diet. One cup is loaded with vitamin C (54 percent of your daily recommended intake) and antioxidants.
- Nutrition facts (1 cup): 64 calories, 1g fat, 15g carbohydrates, 8g fiber, 1.5g protein
- As if you needed any more reason to take a bite out of that pecan pie. One ounce, or 20 jumbo kernels, of pecans is rich in antioxidants.
- Nutrition facts (1 ounce): 196 calories, 20.5g fat (1.7g saturated), 3.9g carbohydrates, 2.7g fiber, 2.6g protein
- This superfood is good for your health and can help protect your skin from premature aging.
- Nutrition facts (1 cup): 83 calories, 0.5g fat, 21g carbohydrates, 3.5g fiber, 1.1g protein
- Just a teaspoon of ground cloves can do wonders for your body. Spice up your meals and boost your health at the same time.
- Nutrition facts (1 tablespoon): 21 calories, 1.3g fat (0.4g saturated), 4g carbohydrates, 2.3g fiber, 0.4g protein
- Rich in cancer-fighting antioxidants and vitamins, kale is also a good source of beta-carotene and is the top combo of both lutein and zeaxanthin.
- Spinach is packed with carotenoids—antioxidants that promote healthy eyes and help prevent macular degeneration, the leading cause of blindness in older people.
- These broccoli cousins have plenty of bitter sulforaphane as well as compounds called isothiocyanates, which detoxify cancer-causing substances in the body before they can do their dirty work. In one Dutch study, guys who ate Brussels sprouts daily for three weeks had 28 percent less genetic damage (gene damage is a root cause of cancer) than those who didn’t eat sprouts.
- This tiny powerhouse is rich in beta-carotene, an antioxidant that protects against lung cancer and helps maintain healthy skin, hair, nails, gums, glands, bones, and teeth. It’s also a good source of vitamin E, which may help prevent heart attacks, strokes, and lower the risk of death from bladder cancer.
- Broccoli is full of cancer-fighting antioxidants. One study found men who ate 5 servings or more per week of cruciferous veggies like broccoli were half as likely to develop bladder cancers over a 10-year period as men who rarely ate them.
Beets are packed with healthy nutrients, like five essential vitamins, calcium, iron, potassium, and protein.
Red Bell Peppers
- One medium pepper is light on calories (only 32!) but heavy on vitamin C, providing 150 percent of your recommended daily value and warding off atherosclerosis, which can lead to heart disease.
- You’ll get the most out of this veggie’s cancer-fighting antioxidants by eating it raw; cooking onions at a high heat significantly reduces the benefits of phytochemicals that protect against lung and prostate cancer.
- A study in the Journal of Agricultural Food and Chemistry found that the longer corn was cooked, the higher the level of antioxidants like lutein, which combats blindness in older adults.
- All types of eggplant are rich in bitter chlorogenic acid, which protects against the buildup of heart-threatening plaque in artery walls (and fights cancer, too!), say USDA scientists in Beltsville, Maryland. In lab studies, eggplant lowered cholesterol and helped artery walls relax, which can cut your risk of high blood pressure.
Lifestyle Changes to Maximize Your Antioxidant Intake.
- Reduce and eventually eliminate sugar (especially fructose) and grains from your diet – According to Dr. Robert Lustig, professor of pediatrics in the Division of Endocrinology at the University of California, San Francisco, fructose undergoes the Maillard reaction with proteins, which leads to superoxide free radicals to form in your body. These damaging free radicals can cause liver inflammation similar to that caused by alcohol. Less sugar and grains (which convert into sugar in your body) in your diet can help decrease your antioxidant stress, meaning you will need to get fewer amounts. Plus, the antioxidants you have will work better and last longer. I also advise against consuming any type of processed foods, especially soda, as these usually contain high amounts of fructose.
- Exercise – Exercise can boost your body’s antioxidant production but in a paradoxical way, as it actually creates potent oxidative stress. However, if you do it properly and in moderation, it can help improve your body’s capacity to produce antioxidants. This is why I recommend doing short bursts of high-intensity exercises like Peak Fitness, instead of prolonged cardio like marathon running, which puts excessive stress on your heart.
- Manage your stress – Stress can exacerbate the inflammation and poor immune function caused by free radical formation. Studies have found significant links between acute and/or chronic emotional and psychological stress and numerous health issues. Even the Centers for Disease Control (CDC) acknowledges this link and says that 85 percent of all disease has an emotional element.
- Avoid smoking – Smoking forms free radicals in your body, which accelerates the aging process. Even being around people who smoke can affect your health by damaging the microcapillaries in your skin, which limits its ability to absorb nutrients, leading to accelerated wrinkling and aging. Smoking also contributes to the pathobiology of various diseases, the most well-known of which is lung cancer.
- Get enough sleep – High-quality sleep is one of the cornerstones of good health, and science has now established that a sleep deficit can have severe far-reaching effects on your health. Six to eight hours of sleep per night seems to be the optimal amount for most adults, and too much or too little can have adverse effects on your wellbeing.
- Try grounding – Also called “earthing,” grounding has a potent antioxidant effect that helps alleviate inflammation in your body. There is a constant flow of energy between our bodies and the earth, which has a greater negative charge. Walking barefoot on the earth helps you absorb large amounts of negative electrons through the soles of your feet.