List of antioxidants in food


This is a list of antioxidants naturally occurring in food. Vitamin C and vitamin E - which are ubiquitous among raw plant foods - are confirmed as dietary antioxidants, whereas vitamin A becomes an antioxidant following metabolism of provitamin A beta-carotene and cryptoxanthin. Most food compounds listed as antioxidants - such as polyphenols common in colorful, edible plants - have antioxidant activity only in vitro, as their fate in vivo is to be rapidly metabolized and excreted, and the in vivo properties of their metabolites remain poorly understood. For antioxidants added to food to preserve them, see butylated hydroxyanisole and butylated hydroxytoluene.

Regulatory guidance

In the following discussion, the term "antioxidant" refers mainly to non-nutrient compounds in foods, such as polyphenols, which have antioxidant capacity in vitro and so provide an artificial index of antioxidant strength – the ORAC measurement. Other than for dietary antioxidant vitamins – vitamin A, vitamin C and vitamin E – no food compounds have been proved with antioxidant efficacy in vivo. Accordingly, regulatory agencies like the Food and Drug Administration of the United States and the European Food Safety Authority have published guidance disallowing food product labels to claim an inferred antioxidant benefit when no such physiological evidence exists.

Physiological context

Despite the above discussion implying that ORAC-rich foods with polyphenols may provide antioxidant benefits when in the diet, there remains no physiological evidence that any polyphenols have such actions or that ORAC has any relevance in the human body.
On the contrary, research indicates that although polyphenols are antioxidants in vitro, antioxidant effects in vivo are probably negligible or absent. By non-antioxidant mechanisms still undefined, polyphenols may affect mechanisms of cardiovascular disease or cancer.
The increase in antioxidant capacity of blood seen after the consumption of polyphenol-rich foods is not caused directly by the polyphenols, but most likely results from increased uric acid levels derived from metabolism of flavonoids. According to Frei, "we can now follow the activity of flavonoids in the body, and one thing that is clear is that the body sees them as foreign compounds and is trying to get rid of them." Another mechanism may be the increase in activities of paraoxonases by dietary antioxidants which can reduce oxidative stress.

Vitamins

Natural phenols are a class of molecules found in abundance in plants.

Flavonoids

s, a subset of polyphenol antioxidants, are present in many berries, as well as in coffee and tea.
Many common foods contain rich sources of polyphenols which have antioxidant properties only in test tube studies. As interpreted by the Linus Pauling Institute, dietary polyphenols have little or no direct antioxidant food value following digestion. Not like controlled test tube conditions, the fate of flavones or polyphenols in vivo shows they are poorly absorbed and poorly conserved, so that most of what is absorbed exists as metabolites modified during digestion, destined for rapid excretion.
Spices, herbs, and essential oils are rich in polyphenols in the plant itself and shown with antioxidant potential in vitro. Typical spices high in polyphenols are clove, 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.
Dried fruits are a good source of polyphenols by weight/serving size as the water has been removed making the ratio of polyphenols 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 polyphenol count which supplies antioxidant quality which is unlikely to be conserved following digestion.
Deeply pigmented fruits like cranberries, blueberries, plums, blackberries, raspberries, strawberries, blackcurrants, figs, cherries, guava, oranges, mango, grape juice and pomegranate juice also have significant polyphenol content.
Typical cooked vegetables rich in antioxidants are artichokes, cabbage, broccoli, asparagus, avocados, beetroot and spinach.
Nuts are a moderate source of polyphenol antioxidants. Typical nuts are pecans, walnuts, hazelnuts, pistachio, almonds, cashew nuts, macadamia nuts and peanut butter.
Sorghum bran, cocoa powder, and cinnamon are rich sources of procyanidins, which are large molecular weight compounds found in many fruits and some vegetables. Partly due to the large molecular weight of these compounds, their amount actually absorbed in the body is low, an effect also resulting from the action of stomach acids, enzymes and bacteria in the gastrointestinal tract where smaller derivatives are metabolized and prepared for rapid excretion.

Other compounds