List of antioxidants in food

Foods highest in antioxidants

Vitamins

• Vitamin A (retinol), also synthesized by the body from beta-carotene, protects dark green, yellow and orange vegetables and fruits from solar radiation damage, and is thought to play a similar role in the human body. Carrots, squash, broccoli, sweet potatoes, tomatoes (which gain their color from the compound lycopene), kale, seabuckthorn, collards, cantaloupe, peaches and apricots are particularly rich sources of beta-carotene.
• Vitamin C (ascorbic acid) is a water-soluble compound that fulfills several roles in living systems. Important sources include citrus fruits (such as oranges, sweet lime, etc.), green peppers, broccoli, green leafy vegetables, black currants, strawberries, blueberries, seabuckthorn, raw cabbage and tomatoes. Linus Pauling was a major advocate for its use.
• Vitamin E, including tocotrienol and tocopherol, is fat soluble and protects lipids. Sources include wheat germ, seabuckthorn, nuts, seeds, whole grains, green leafy vegetables, kiwifruit, vegetable oil, and fish-liver oil. Alpha-tocopherol is the main form in which vitamin E is consumed. Recent studies showed that some tocotrienol isomers have significant anti-oxidant properties.

Vitamin cofactors and minerals

• Coenzyme Q10
• Manganese, particularly when in its +2 valence state as part of the enzyme called superoxide dismutase (SOD).
• Iodide^[1][2][3]

Hormones

• Melatonin

Carotenoid terpenoids

Main article: carotenoid

• Alpha-carotene
• Astaxanthin - found naturally in red algae and animals higher in the marine food chain. It is a red pigment familiarly recognized in crustacean shells and salmon flesh/roe.
• Beta-carotene - found in high concentrations in butternut squash, carrots, orange bell peppers, pumpkins, and sweet potatoes.
• Canthaxanthin
• Lutein - found in high concentration in spinach, kiwifruit and red peppers.
• Lycopene - found in high concentration in ripe red tomatoes and watermelons.
• Zeaxanthin - the main pigment found in yellow corn. It is also abundant in kiwifruit.

Flavonoid polyphenolics

Flavonoids, a subset of polyphenol antioxidants, are present in many berries, as well as in coffee and tea.

• Flavones:
  • Apigenin
  • Luteolin
  • Tangeritin

• Flavonols:
  • Isorhamnetin
  • Kaempferol
  • Myricetin - walnuts are a rich source
  • Proanthocyanidins, or condensed tannins
  • Quercetin and related, such as rutin

• Flavanones:
  • Eriodictyol
  • Hesperetin (metabolizes to hesperidin)
  • Naringenin (metabolized from naringin)

• Flavanols and their polymers:
  • Catechin, gallocatechin and their corresponding gallate esters
  • Epicatechin, epigallocatechin and their corresponding gallate esters
  • Theaflavin its gallate esters
  • Thearubigins

• Isoflavone phytoestrogens - found primarily in soy, peanuts, and other members of the Fabaceae family
  • Daidzein
  • Genistein
  • Glycitein

• Stilbenoids:
  • Resveratrol - found in the skins of dark-colored grapes, and concentrated in red wine.
  • Pterostilbene - methoxylated analogue of resveratrol, abundant in Vaccinium berries

• Anthocyanins
  • Cyanidin
  • Delphinidin
  • Malvidin
  • Pelargonidin
  • Peonidin
  • Petunidin

The neuroprotective actions of cannabidiol and other cannabinoids were examined in rat cortical neuron cultures exposed to toxic levels of the excitatory neurotransmitter glutamate. Glutamate toxicity was reduced by both cannabidiol, a nonpsychoactive constituent of marijuana, and the psychotropic cannabinoid (−)Δ9-tetrahydrocannabinol (THC). Cannabinoids protected equally well against neurotoxicity mediated by N-methyl-d-aspartate receptors, 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid receptors, or kainate receptors. N-methyl-d-aspartate receptor-induced toxicity has been shown to be calcium dependent; this study demonstrates that 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid/kainate receptor-type neurotoxicity is also calcium-dependent, partly mediated by voltage sensitive calcium channels. The neuroprotection observed with cannabidiol and THC was unaffected by cannabinoid receptor antagonist, indicating it to be cannabinoid receptor independent. Previous studies have shown that glutamate toxicity may be prevented by antioxidants. Cannabidiol, THC and several synthetic cannabinoids all were demonstrated to be antioxidants by cyclic voltametry. Cannabidiol and THC also were shown to prevent hydroperoxide-induced oxidative damage as well as or better than other antioxidants in a chemical (Fenton reaction) system and neuronal cultures. Cannabidiol was more protective against glutamate neurotoxicity than either ascorbate or α-tocopherol, indicating it to be a potent antioxidant. These data also suggest that the naturally occurring, nonpsychotropic cannabinoid, cannabidiol, may be a potentially useful therapeutic agent for the treatment of oxidative neurological disorders such as cerebral ischemia.

Phenolic acids and their esters

Main article: polyphenol antioxidant

• Chicoric acid - another caffeic acid derivative, is found only in the popular medicinal herb Echinacea purpurea.
• Chlorogenic acid - found in high concentration in coffee (more concentrated in robusta than arabica beans), blueberries and tomatoes. Produced from esterification of caffeic acid.
• Cinnamic acid and its derivatives, such as ferulic acid - found in seeds of plants such as in brown rice, whole wheat and oats, as well as in coffee, apple, artichoke, peanut, orange and pineapple.
• Ellagic acid - found in high concentration in raspberry and strawberry, and in ester form in red wine tannins.
• Ellagitannins - hydrolyzable tannin polymer formed when ellagic acid, a polyphenol monomer, esterifies and binds with the hydroxyl group of a polyol carbohydrate such as glucose.
• Gallic acid - found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and many other plants.
• Gallotannins - hydrolyzable tannin polymer formed when gallic acid, a polyphenol monomer, esterifies and binds with the hydroxyl group of a polyol carbohydrate such as glucose.
• Rosmarinic acid - found in high concentration in rosemary, oregano, lemon balm, sage, and marjoram.
• Salicylic acid - found in most vegetables, fruits, and herbs; but most abundantly in the bark of willow trees, from where it was extracted for use in the early manufacture of aspirin.

Other nonflavonoid phenolics

• Curcumin - Curcumin has low bioavailability, because, much of it is excreted through glucuronidation.
• Flavonolignans - e.g silymarin - a mixture of flavonolignans extracted from milk thistle.
• Xanthones - mangosteen is purported to contain a large variety of xanthones, ^[4] but some of the xanthones like mangostin might be present only in the inedible shell.
• Eugenol

Other organic antioxidants

• Bilirubin, a breakdown product of blood, has been identified as a possibly significant antioxidant.^[5]
• Citric acid, oxalic acid, and phytic acid
• Lignan - antioxidant and phytoestrogen found in oats, flax seeds, pumpkin seeds, sesame seeds, rye, soybeans, broccoli, beans, and some berries.
• N-Acetylcysteine - water soluble
• R-α-Lipoic acid - fat and water soluble
• Uric acid In humans accounts for roughly half the antioxidant ability of plasme. Fructose which is found abundantly in fruits, significantly elevates uric acid levels in humans^[6]. This way it does indirectly increase the antioxidant capacity. High levels of uric acid are protective against Parkinson's disease^[7] and possibly other diseases related to oxidative stress.

Food sources

Main article: oxygen radical absorbance capacity

Many common foods are good sources of antioxidants.^[8] In the list of foods given below, rich in anti-oxidants usually means at least a ORAC rating of 1000 per 100 g. A typical apple or pear weighs around 200 g and hence 200 g can be considered as the serving size.

Spices, herbs, essential oils and cocoa are rich in anti-oxidant properties but the serving size is too small to be the top-contributors of anti-oxidants. Typical spices high in anti-oxidants are cinnamon, oregano, turmeric, cumin, parsley, basil, curry powder, mustard seed, ginger, pepper, chili powder, paprika, garlic, coriander, onion and cardamom. Typical herbs are sage, thyme, marjoram, tarragon, peppermint, oregano, savory, basil and dill weed. Chocolate is rich in cocoa.

Dried fruits are a good source of anti-oxidants by weight/serving size as the water has been removed making the ratio of anti-oxidants higher. Typical dried fruits are pears, apples, plums, peaches, raisins, figs and dates. Dried raisins are high in polyphenol count. Red wine is high in total anti-oxidants count as well as polyphenol count.

Sorghum bran, cocoa powder, and cinnamon are rich sources of procyanidins, which are very large compounds found in many fruits and some vegetables and that have been shown to be beneficial for health in humans. Because of the large size of these compounds, the amount that is actually absorbed into the body is thought to be low. These compounds can be degraded by bacteria in the gastrointestinal tract.^[9] Crude rice bran and other cereals like corn-flakes, oats and granola are also a good source of anti-oxidants.

Nuts are a rich source of anti-oxidants. Typical nuts are pecans, walnuts, hazelnuts, pistachio, almonds, cashew nuts, macademia nuts and peanut butter.

Fleshy fruits like cranberries, blueberries, plums, peaches, blackberries, raspberries, apples, strawberries, red currants, figs, cherries, gooseberry (not to be confused with Indian gooseberry which also has strong claims), pears, guava, peaches, oranges, apricots, mango, grape juice and pomegranate juice also rated highly on the ORAC scale.

Typical cooked vegetables rich in anti-oxidants are artichokes, cabbage, broccoli, asparagus, avocados, beetroot, radish, potato and raw lettuce and frozen spinach.

See also

• Colour retention agent
• Nutrition

References

1. ^ Venturi S & Venturi M. (1999) Iodide, thyroid and stomach carcinogenesis: evolutionary story of a primitive antioxidant? Eur J Endocrinol. 140(4):371-2. N PMID: 10097259
2. ^ Venturi S & Venturi M. (2007) Evolution of Dietary Antioxidant Defences. European EPI-Marker. 11, 3 :1-12
3. ^ Küpper FC et al. (2008) Iodide accumulation provides kelp with an inorganic antioxidant impacting atmospheric chemistry. Proc Natl Acad Sci U S A. May 5 . N PMID: 18458346
4. ^ http://www.choice.com.au/viewArticleAsOnePage.aspx?id=105902
5. ^ Stocker R, Yamamoto Y, McDonagh AF, Glazer AN, Ames BN (1987). "Bilirubin is an antioxidant of possible physiological importance". Science 235 (4792): 1043–6. doi:10.1126/science.3029864. PMID 3029864. 
6. ^ Zawiasa A, Szklarek-Kubicka M, Fijałkowska-Morawska J, Nowak D, Rysz J, Mamełka B, Nowicki M. Effect of oral fructose load on serum uric acid and lipids in kidney transplant recipients treated with cyclosporine or tacrolimus. Transplantation Proceedings 2009 Jan-Feb;41(1):188-91.
7. ^ De Vera M, Rahman MM, Rankin J, Kopec J, Gao X, Choi H. Gout and the risk of Parkinson's disease: a cohort study. Arthritis and Rheumatism 2008 Nov 15;59(11):1549-54.
8. ^ Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods – 2007, from the United States Department of Agriculture
9. ^ Dietary Factors Early in Human Development: Health Consequences of Phytochemical Intake, from the United States Department of Agriculture