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Objective: To examine interrelationships between (1) dietary habits, (2) socioeconomic and (3) environmental factors, and their impact on plasma retinol and plasma ascorbic acid. Design: Cross-sectional study on adults from Western India. Setting: Rural, semi urban, urban higher=middle=lower socioeconomic regions (HSE=MSE=LSE) having diverse dietary habits and environmental conditions. Subjects: A total of 214 men and 108 women (20 -50 y), apparently healthy and non-anemic. Main outcome measures: Food intake by food frequency questionnaire, weight, height, age, smoking, environmental score, education, income, plasma retinol and plasma ascorbic acid. Results: Mean plasma retinol in women (24.84 AE 5.1 mg=dl) and men (24.75 AE 4.53 mg=dl) were not significantly different and 21% had plasma retinol below 20 mg=dl. Mean plasma ascorbic acid in women (0.35 AE 0.12 mg=dl) and men (0.30 AE 0.12 mg=dl) was similar with 75% having plasma ascorbic acid below 0.4 mg=dl. Vitamin A intake (as retinol equivalent) and plasma retinol showed a significant dose response (P < 0.05) but not vitamin C intake and plasma ascorbic acid. Plasma retinol showed significant correlation with income (r ¼ 0.24), education (r ¼ 0.27), and environment (r ¼ 0.21; r ¼ 0.0001). Similar correlations with plasma ascorbic acid were 0.29, 031, 7 0.23 respectively (P ¼ 0.0001). Logistic regression showed education, environment, green leafy vegetables (GLV) and milk intake as predictors of plasma retinol deficiency, while nonsweet fruit intake, education and passive smoking for plasma ascorbic acid deficiency (P < 0.05). Conclusions: Subnormal status of retinol and vitamin C emphasizes the need to increase consumption of fruit, GLV and milk products, and also better education and environment. Avoiding passive smoking demands attention in order to improve levels of these vitamins.

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Nonenzymatic glycation of long-lived proteins has been implicated in several complications related to age and diabetes. Dicarbonyl compounds such as methylglyoxal (MGO) have been identified as the predominant source for the formation of advanced glycation end-products (AGEs) in various tissues. We investigated the effect of 13 micronutrients on MGO-mediated in vitro glycation of bovine serum albumin (BSA), as formation of AGEs and protein carbonyls. BSA (10 mg/ml) was incubated at 37°C with 100 mM MGO for 24 hours, in presence of ascorbic acid, Trolox (water-soluble α-tocopherol analog), β-carotene, retinol, riboflavin, thiamin, folic acid, niacin, pyridoxine, zinc, iron, manganese, and selenium. Fluorescence was measured at the wavelength pair of 370 and 440 nm as an index of the formation of AGEs and spectra were recorded for promising interactions at λex=280 nm and λex=370 nm. Within four standard antiglycating agents, aminoguanidine showed highest inhibitory response for BSA glycation followed by quercetin, gallic acid, and tannic acid. Promising antiglycation potential was seen for Trolox, riboflavin, Zn, and Mn as evidenced by decrease in the formation of AGEs and protein carbonyls.

Green leafy vegetables (GLV) offer a cheap but rich source of a number of micronutrients and other phytochemicals having antioxidant properties. The potential of 30 GLV in the raw and cooked form as natural antioxidant supplements for vegetarian diets was assessed. There was a large variability in the values of antioxidant activity of various GLV extracts in the lipid micelles (1.5-5.6 mM vitamin E/100 g for raw samples and 1.6-3.8 mM vitamin E/100 g for cooked samples). Similar to thiobarbituric acid reactive substances values, the super oxide scavenging ability values also exibited large variation (10.6-55.9), with significantly higher values in the raw state than the cooked state (P<0.001). Omum leaves, radish leaves and lettuce had high values for this index. The range of values for ferrous iron chelating activity was from 9.3 to 65.7 mM EDTA/100 g food material, indicating again a large variability in this assay. Leaves of coriander, amaranthus viridis, colcasia green and drumstick showed high values, while Amaranthus p. Colocasia black and amaranthus red exibited low values. Differences between raw and cooked values were highly significant for all the three indices (P<0.001).

During recent years importance of B complex vitamins, beta-carotene and vitamin C has been realised in terms of their antioxidative and anticarcinogenic properties. Fruits and vegetables are the rich sources of these vitamins. However, there are considerable cooking losses of vitamins, and information on vitamin contents of cooked foods is essential for assessing the adequacy of vitamin intakes. Secondly, there is a growing trend to consume ready-to-eat foods such as stuffed pancakes (samosa, patties), pastries, French fries; replacing traditional foods for lunch or dinner like roti, vegetable curry, bread, non-vegetarian items. Ready-to-eat foods are considered to give empty calories rather than a balanced diet. A study was undertaken to estimate ascorbic acid, folic acid, riboflavin, thiamine and beta-carotene of 263 cooked food samples and 260 meals representing dietary patterns of Asia, Africa, Europe, USA and Latin America by spectrophotometry and photoflurometry. A broad range of beta-carotene (84-2038 mcg%), riboflavin (0.01-0.48 mg%), thiamine (0.04-0.36 mg%), vitamin C (1-28 mg%) and folate (26-111 mcg%) was observed in individual foods. Bakery products and sweets were found to be poor sources and green leafy vegetables and fruits were good sources of these five vitamins. The differences between ready-to-eat foods and meals consumed during lunch or dinner were prominent for beta-carotene, ascorbic acid, riboflavin and folic acid (P < 0.05). The cooking losses were 34.6, 30, 52.2, 45.9 and 32.2% in case of ascorbic acid, thiamine, riboflavin, beta-carotene and folic acid respectively. Irrespective of whether it is ready-to-eat or a lunch/dinner food item, the contribution of vegetables in the preparations was found to make a marked impact on the vitamin profile. While results justify the concept of a food pyramid, emphasis needs to be given to types of fruits and vegetables rich in vitamins; preferably in their uncooked form, rather than considering their total consumption.

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