Antioxidants in diet

Polyphenols are the most abundant antioxidants in human diets. They are secondary metabolites of plants. These compounds are designed with an aromatic ring carrying one or more hydroxyl moieties. Several classes can be considered according to the number of phenol rings and to the structural elements that bind these rings. 

This chapter focuses on the DF in fruit and vegetables, with special attention to the phytochemicals associated with them. It also discusses the contribution of fruit and vegetables to the intake of DF and antioxidants in the diet. 

Contribution of Fruits and Vegetables to the Intake of Dietary Fiber and Antioxidants in the Diet... 

CN172 Ferre, N., J. Camps, A. Paul, et al. Effects of high-fat, low-cholesterol diets on hepatic lipid peroxidation and antioxidants in apolipoprotein E-defi-cient mice. Mol Cell Biochem 2001 218(1-2) 165-169. 

Regular exercise, a healthy and balanced diet, and a clean environment are central to this process. Supplementation by safe and efficient antioxidants in the food chain or in therapeutic preparations should be a material aid to this desirable outcome. 

It is also well documented that an antioxidant-rich diet protects against age-related macular degeneration (AMD), the leading cause of vision loss among the elderly. Development of AMD in the retinal pigment epithelium (RPE) is associated with oxidative stress. King and co-workers [2005] reported that resveratrol treatment (100 pmol/L) inhibited basal and H202-induced... 

Food and herbs are main natural sources of antioxidants. In this connection, antioxidant activity (AOA) of these products is essential for planning right diet as well as for sound therapy. Screen-printed platinum sensor and potentiometric method of measuring AOA of food and herbal extracts are presented below. 

In growing chicks, a deficiency can result in (i) encephalomalacia or crazy chick disease (ii) exudative diathesis, an oedema caused by excessive capillary permeability or (iii) muscular dystrophy. Encephalomalacia occurs when the diet contains unsaturated fats that are susceptible to rancidity. Some antioxidants, in addition to vitamin E, are also effective against encephalomalacia. Exudative diathesis is prevented by dietary selenium, and muscular dystrophy is a complex disease influenced by vitamin E, selenium, and the... 

Flavonoids are used in treatment of many diseases, mainly because of their capability to inhibit many harmful strains of bacteria and enzymes (proteases, reverse transcriptase), to stimulate hormones and neurotransmitters, and to capture free radicals (Havsteen 2002). There are reports confirming that supplementation of diet with an antioxidant (a-tocopherol), by increasing the concentration of the antioxidant in blood, can reduce the titer of antibodies in hypercholesterolemia (Table 2.2.4). 

There are interesting reports on possible application of certain antioxidants (1,3-glucan, levamisole, and vitamins C and E) in diet. For example, supplementation of a diet given to ill fish (carp) with the above components has resulted in... 

Vitamins are small biomolecules that are needed in small amounts in the diets of higher animals. The water-soluble vitamins are vitamin C (ascorbate, an antioxidant) and the vitamin B complex (components of coenzymes). Ascorbate is required for the hydroxylation of proline residues in collagen, a key protein of connective tissue. The fat-soluble vitamins are vitamin A (a precursor of retinal), D (a regulator of calcium and phosphorus metabolism), E (an antioxidant in membranes), and K (a participant in the carboxylation of glutamate). 

Interventions that block oxidative modification of LDL are currently under intensive study [1,3-5,10]. If oxidative modification of LDL results in enhanced uptake by macrophages, use of an appropriate antioxidant should protect LDL from oxidation, decrease the rate of LDL uptake by macrophage foam cells and slow the development of fatty streaks in the arterial wall. The role of antioxidants in preventing oxidative modification of LDL has been evaluated in a number of studies [1,5,8,10]. In our investigation we studied the influence of the vitamin E reach diet on the copper-mediated oxidizability of plasma LDL from patients with atherosclerosis. So far as LDL is the main transport form of natural antioxidant a-tocopherol we were surprised to find that during 3-months vitamin E supplementation in the daily dose 400 mg the oxidation resistance of LDL did not increase (Figure 14). 

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