Changes in plasma antioxidant status following consumption of diets high or low in fruit and vegetables or following dietary supplementation with an antioxidant mixture.

The aim of the present study was to examine the effect of consumption of a high-fruit and vegetable diet, or a spray-dried extract of selected fruits and vegetables of high antioxidant content, on indices of antioxidant status of individuals consuming a background diet with minimal antioxidant intake. Plasma antioxidant concentrations were determined in twenty-five men following a 2-week depletion period during which they consumed self-selected low-antioxidant diets (less than three servings of fruit and vegetables with no tea, coffee, red wine or fruit juice). Following this period the volunteers consumed either a self-selected diet containing five to seven servings of fruit and vegetables/d, or 30 g of a spray-dried supplement designed to provide the equivalent antioxidant activity of five to seven servings of fruit and vegetables for 2 weeks in a crossover trial.

Zinc and the gene.

A significant portion of cellular zinc is found in the nucleus where it appears to be critically involved in maintaining genetic stability and in the process of gene expression. With regard to gene expression zinc functions mechanistically at several levels but recent interest has focussed especially on the involvement of zinc in DNA transcription through the activity of transcription factors which contain specific zinc-finger regions which bind to DNA and, in conjunction with other families of transcription factors, control cell proliferation, differentiation and cell death. Because of the central importance of zinc in cell division and growth, considerable attention is paid to zinc as an essential trace element and much has been written concerning dietary sources of zinc and recommended dietary intakes of the metal.

Recommended dietary intake levels for phytochemicals: Feasible or fanciful?

Phytochemicals are biologically active compounds, found in plants in small amounts, which are not established nutrients but which nevertheless seem to contribute significantly to protection against degenerative disease. At present, most interest in phytochemicals is focused on the polyphenolic flavonoids and on the carotenoids, although allium compounds, glucosinolates, indoles and coumarins have also received attention, especially with respect to cancer. Mechanistically, phytochemicals are thought to act in many ways, which include their activity as anti-oxidants, antibacterial/viral agents, phytoestrogens and as inducers or inhibitors of a variety of key enzymes.