1. Introduction

a) Pre-history
Life began in the oceans where the mineral-rich seawater provided ideal conditions for enzymatic antioxidants to protect marine life from the damaging effects of free radicals and other reactive species. When early life forms emerged out of the sea into the highly oxygenated gaseous atmosphere, the most urgent challenge was to replace their dependency on ubiquitous marine minerals and find antioxidants able to protect them against the higher levels of stress caused by exposure to their new hostile environment. For this purpose, the vitamins A, C and E, etc. were created. Later, the flowering plants evolved bitter-tasting polyphenols (vegetable tannins) to provide protection from the additional stress caused by predatory insect and animal attack, while to attract pollinating insects and seed dispersing animals and birds, they manufactured the colourful anthocyanin and carotenoid pigments. These chemicals are all antioxidants. The diets of early human hunter-gatherers contained high levels of toxins, many of them inedible plant-based antioxidants. Successful “browsers” learned to select food sources low in toxins and high in beneficial antioxidants. Agricultural domestication led to more reliable supplies of the staple crops, and herbalists kept alive the knowledge of therapeutic, indigenous plant sources. The refinement/selection process continues to this day via food processing, plant breeding and easier access to global supplies.

b) Early History
Since early times, certain foods have been known to aid certain human conditions. Much of this information is built into our folklore. The mediterranean diet of plentiful fresh fruits and vegetables, good wines, fish and mono-unsaturated olive oil has been associated with human health and well-being. For example, relics associated with the Roman Emperor, Hadrian (AD122) - e.g., a bronze head - indicate that the lobar creases on his ears suggest a propensity towards coronary arterial disease (CAD). However, it is also known that he arranged to have the foods of his mediterranean diet transported with him wherever he went during his widespread and dangerous military campaigns. No doubt this contributed to the fact that inspite of his hectic lifestyle he lived to be an old man (by Roman standards) of 62. There is growing evidence from epidemiological and clinical studies that the high antioxidant content of the Mediterranean diet may account for its health-giving properties, including its efficacy against CAD.

2. The analytical approach
In the first half of the twentieth century, the methods for the chemical analysis of the major components of foods were developed and standardised (proximate analysis). In the late 1950s and early 1960s, gas chromatographic (GC) separation, and mass spectrometric (MS) identification, followed by early versions of the coupled GC/MS on-line methods for identifying and quantifying the trace components of foods were developed, and in the 1970s using capillary column chromatography, these methods were used to identify the volatile odour and flavour compounds present in foods. In the 1980s and 90s, the initially more demanding analysis using liquid chromatography (especially high performance liquid chromatography, HPLC) became routine, and it too was coupled to MS (LCMS), to provide on-line identification of separated, non-volatile minor food components, and used to identify and quantify amounts of individual phytochemical food components, such as flavanoid antioxidants. From this work, a valuable database is available, listing the richest sources of various phytochemicals in biological materials, including human foods.

3. The biochemical nutrition science approach
The qualitative and quantitative data on food composition was used by nutritionists to move to the second stage, the measurement of absorption. The methods for human intervention studies were developed in the 1980s and tested on the relationship between e.g., saturated fats and CHD, and used to measure how much of the known amount of a particular antioxidant present in an aliquot of food was absorbed into the blood stream. The concentration of antioxidant in the blood was assayed by the same analytical methods as developed in 2. above for foodstuffs.

4. Total antioxidant capacity (TAC)
The third step which took place during the 1980s and 90s was to determine the contribution of the absorbed antioxidants to the total antioxidant capacity of the plasma. Similar analytical methods were used to measure TAC of plasma and foods. Increases in human plasma antioxidant capacity after consumption of controlled diets high in fruit and vegetables were recorded, e.g. G. Cao et al., Am. J. Clin. Nutr. 1998,68 (5):1081-1087.

5. The therapeutic value
The final stage is to ascertain the therapeutic value of the individual antioxidants in animal and human feeding trials, and from epidemiological surveys. However, The task of assigning an observed therapy associated with a food item, to the active phytochemical ingredient(s) is more difficult. Even the main phytochemical components, the minerals, vitamins and flavanoids, carotenoids, etc.(which are still only trace components when compared with the proximate analytes of the food (protein, fat, carbohydrate and water), are proving difficult to associate with the physiological effects. One serious complication is the current theory that antioxidants do not work in isolation, i.e., combinations of active compounds may be required to produce a therapeutic effect. This is exacerbated by the knowledge that it is the derivatives of some antioxidants that are absorbed, e.g. quercetin.

6. At this website
The information published in the scientific literature, which is often confusing, is being collated to enable the visitor to decide which foods are best to eat for their health and well-being.
It is only recently that the biological targets for active nutritional antioxidant components are beginning to be studied. So far, antioxidant supplements per se have not been proven to provide substantive therapeutic benefits, while, on the other hand, foods rich in antioxidants generally are associated with human well-being, and the hypothesis is that antioxidants neutralise free radicals at the target sites, which otherwise would damage essential mechanisms leading to oxidative stress and ill health. However, researchers have found that some antioxidant-rich foods do not increase the total plasma antioxidant capacity. As the negative evidence builds, i.e., neither supplements nor nutritional antioxidants in foods are solely responsible for the epidemiologically-attributed advantages of eating fruits and vegetables, it is more important now to examine critically the physiological mechanisms at work, and until there is an unambiguous relationship established between an antioxidant present in a particular food and the effect that it has on the human body, compromises have to made.

7. Current hypotheses
There is an increasing body of opinion that small quantities of ingested antioxidants that are absorbed, can trigger the production of cellular enzyme antioxidants that have longer lifetimes in vivo, explaining the extended protection initiated by food-based antioxidants absorbed at irregular diurnal intervals. Here, we accept the reality of the present situation and will present the scientific evidence, which is emerging slowly, and which purports to substantiate the new hypotheses.

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