Vaishali Agte

Vitamin profile of cooked foods: how healthy is the practice of ready-to-eat foods?

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 betacarotene 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 (26-111mcg%) 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.

Potential of commonly consumed green leafy vegetables for their antioxidant capacity and its linkage with the micronutrient profile

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).

Fortification of vegetarian diets for increasing bioavailable iron density using green leafy vegetables

There is a high prevalence of iron deficiency anaemia in many developing countries today; especially in vegetarian women. The major cause of this state is low bioavailability of nonheme iron from vegetarian diets. An investigation was undertaken to improve bioavailable contents of nonheme iron from vegetarian meals. Forty-eight meals with combinations of roti (unleavened whole cereal pancake) of one of the six cereals and one of the four commonly consumed green leafy vegetables (GLV) along with 35 meals with cereal roti and fruit vegetable/legume were tested for their in vitro dialysability of iron using simulated gastrointestinal conditions and standardised protocol with 59Fe as a tracer. Average bioavailable iron density of GLV-based meals was significantly higher (1.2±0.7 mg /1000 kcal) as against the value in prevailing dietary patterns having cereal-legume or cereal-fruit vegetable combinations (0.36±0.17 mg/1000 kcal, p⩽0.001). Around 31 GLV-based meals were identified as having higher amounts of bioavailable iron density than 0.75 mg/1000 kcal. Thus, one such GLV-based meal per day will increase gross as well as bioavailable iron intake which will help in meeting daily requirements of iron especially for vegetarian women of reproductive age.

Micronutrient Deficiencies as Predisposing Factors for Hypertension in Lacto-Vegetarian Indian Adults

Objective: With the increasing knowledge about the antioxidant potential of many micronutrients such as zinc and vitamin C, their roles in oxidative stress related health disorders have been postulated. This study therefore investigated low micronutrient status as a predisposing factor for hypertension in a traditionally lacto-vegetarian population like Indians. Methods: Micronutrient profile was assessed in 109 hypertensives with age-gender-socio-economic status matched 115 healthy normotensives (30–58 years of age). Food intakes were estimated through a semi-quantitative food frequency questionnaire. Nutrient intakes were then evaluated by previous estimates of cooked foods from our laboratory. Systolic and diastolic blood pressure (SBP, DBP), age, weight, height, waist and hip circumference, occupation, physical activity, smoking habits were recorded. Fasting blood samples were analyzed for hemoglobin, serum level of glucose, triglycerides, total cholesterol, HDL, ceruloplasmin, plasma level of ascorbic acid, folic acid, retinol, erythrocyte glutathione reductase activity coefficient (EGRAC) and erythrocyte membrane zinc. Results: There were no significant differences between protein, fat intakes of normal and hypertensive individuals, though intakes of men were higher than those of women (p < 0.05). Intakes of omega-6 fatty acids were higher (p = 0.08) and omega-3 fatty acids were lower in hypertensive men than normotensive men (p = 0.04). Gender differences were also significant for micronutrient intakes except vitamin C and β-carotene. Intakes of potassium, copper, folic acid and vitamin C were significantly lower in hypertensive individuals than in normotenisves. No significant association was found between occupation or activity level and hypertension (p > 0.2) in these subjects. Conditional logistic regression analysis indicated that intakes of vitamin C, folic acid and zinc were associated with 18% (OR = 1.18, 95% CI:1.08, 1.26), 51% (OR = 1.51, 95% CI 0.94, 2.1) higher odds for hypertension, and 3% lower odds for hypertension (OR = 0.97, 95% CI 0.92, 1.01), respectively. Mean plasma vitamin C and folic acid were significantly higher (p < 0.01), and serum ceruloplasmin and erythrocyte membrane zinc were marginally higher (p = 0.07) in normal than hypertensive subjects. In multivariate linear regression analyses, plasma vitamin C, serum ceruloplasmin and erythrocyte membrane zinc were negatively associated with SBP (p = 0.00001) and plasma vitamin C was negatively associated with DBP (p = 0.0001). Conclusion: Low dietary intakes of vitamin C, folic acid and zinc emerged as the possible risk factors for hypertension. Further, lower levels of plasma vitamin C, erythrocyte membrane zinc and ceruloplasmin were found to be the putative intermediary biomarkers in pathogenesis of hypertension.

Assessment of pearl millet vs rice based diets for bioavailability of four trace metals

Cereals including millets are consumed in India as a staple with wide variety of pulses and vegetables in varying proportions. Trace mineral contents of pearl millet are two to ten times higher than that of rice. Comparative performance of pearl millet based (PM) diets as against rice based (RB) diets in terms of trace mineral bioavailability was studied, based on the prevailing dietary patterns in India. In vitro percent dialysability of zinc, iron, copper and manganese under simulated gastrointestinal conditions was considered as indicator of metal bioavailability. Dialysable zinc and iron were estimated using 65 Zn and 59 Fe as tracers, while dialysable copper and manganese were measured by Atomic absorption spectrophotometer for 20 food items and 15 RB and 17 PM diets prepared from these items. Results indicated that percent dialysability of zinc and copper was higher for RB diets than PM diets, while that of iron and manganese were comparable. Total dialysable iron, copper and manganese in PM diet was 2 to 4 times higher than RB diet.

The Importance of Nutrition in the Prevention of Ocular Disease with Special Reference to Cataract

Background: The lens is the ocular structure most susceptible to oxidative damage. Antioxidants, micronutrients and phytochemicals have been extensively studied for their possible effects to prevent or delay the progression of various eye diseases. Objectives: A brief overview of the updated literature on the role of antioxidants and micronutrients in the prevention and treatment of ocular diseases is to be presented with an emphasis on cataract. Data Sources: PubMed search and individual papers from journals. Data Synthesis: The review discusses linkages of various micronutrients and antioxidants as well as oxidative stress with cataract. Dietary interventions as strategy for prevention of cataract and other ocular disorders are also reviewed. Conclusions: Consumption of food-based antioxidants like β-carotene lutein and zeaxanthin seem to be useful for the treatment of macular degeneration and cataracts. Supplements of vitamin A, vitamin C, vitamin E and zinc may prevent advanced age-related macular degeneration only in high-risk individuals.

Antioxidant and micronutrient potential of common fruits available in the Indian subcontinent

Considering the scanty information on Indian fruits, 36 commonly consumed fruits were assessed for inhibition of thiobarbituric acid reactive substances, superoxide scavenging activity and ferrous ion-chelating ability along with levels of micronutrients (namely ascorbic acid, β-carotene, riboflavin, thiamine, zinc, copper, iron, manganese, selenium and total polyphenols). Fruits exhibited 24–173% variability for the 13 study parameters. Fresh fruits exhibited 3.5–4 times higher antioxidant capacity than dry fruits. Ascorbic acid was highest in gooseberry (445 mg/100 g), and β-carotene was highest in ripe mango 1,200 mg/100 g. Selenium levels could supply 0–33% of the recommended dietary allowance. There was a strong association between different indices of antioxidant capacity (P<0.001), thiobarbituric acid reactive substances with selenium levels (P<0.01), and superoxide scavenging activity and ferrous ion-chelating ability with zinc content (P<0.05). Results emphasize need for the antioxidant quality of fruit in addition to the quantity of fruit consumption.

Role of zinc along with ascorbic acid and folic acid during long-term in vitro albumin glycation

The present study aimed to investigate the role of Zn alone and in the presence of ascorbic acid (AA) and folic acid (FA) in albumin glycation. Glycation was performed by incubations of bovine serum albumin with glucose at 37 degrees C along with Zn, AA or FA separately and Zn + AA or Zn + FA for 150 d. Glycation-mediated modifications were monitored as fluorescence of advanced glycation endproducts, carbonyl formation, beta aggregation (thioflavin T and Congo red dyes), albumin-bound Zn, thiol groups and glycated aggregates toxicity in HepG2 cells. Zn inhibited glycation and beta aggregation, probably due to observed higher protein-bound Zn. It also protected protein thiols and increased cell survival. AA and FA enhanced glycation, which was lowered in Zn-co-incubated samples. FA increased albumin-bound Zn and showed maximum cell survival. Although these results warrant further in vivo investigation, the present data help in the understanding of the interplay of Zn with micronutrients in albumin glycation.

Dietary and nutritional biomarkers of lens degeneration, oxidative stress and micronutrient inadequacies in Indian cataract patients ☆

BACKGROUND & AIMS Habitual food and nutrient intakes of 140 Indian cataract patients and 100 age- and sex-matched controls (50-75 years), from high income group and low income groups, were assessed. METHODS Food intake was recorded by food frequency questionnaire and data were examined for linkages with blood/lens parameters of oxidative stress through a case-control study. RESULTS Intake of animal foods and fried snacks was significantly higher while vegetables, green leafy vegetables, fruit, tea and micronutrient intakes were lower in patients than in controls (p<0.001). Lens oxidative stress and opacity showed a significant negative association with fruit intake (p<0.05). Multiple regression analysis indicated association of intakes of iron, beta-carotene, ascorbic acid, tannic acid and inositol pentaphosphate with plasma oxidative stress (p<0.01) and association of intakes of iron, ascorbic acid and inositol triphosphate with lens oxidative stress (p<0.01). Weighted least square regression for lens opacity revealed that intakes of ascorbic acid, folic acid and inositol pentaphosphate explained 59.7% of the total variation (p<0.01). CONCLUSIONS Dietary deficiency of antioxidant micronutrients was greater for patients than controls. Deficiency of beta-carotene, ascorbic acid, folic acid, iron, phytate and polyphenols increased oxidative stress in blood and lens.

Predicting Bioavailable Zinc from Lower Phytate Forms, Folic Acid and Their Interactions with Zinc in Vegetarian Meals

Objective: To develop a statistical model for predicting zinc bioavailability from cereal-based vegetarian meals using relative proportion of nutrients, non-nutrients and their interactive effects. Methods: A database on in vitro zinc dialysability (by isotopic tracer, 65Zn) of vegetarian meals (266 out of 326) from Asia, Africa, Europe /US and Latin America was used to develop a model for estimating zinc bioavailability. A multiple regression analysis adjusted for energy content was carried out for net bioavailable zinc from a meal with the predictor variables as meal contents of iron, zinc, copper, ascorbic acid, β-carotene, riboflavin, thiamine, folic acid, tannic acid, fiber, phytate degradation products (IP6 to IP1), along with their interaction terms. Reproducibility of the model was tested with remaining 60 meals. Validation of the model was done with zinc absorption data of i) 12 young adults on 24 meals and ii) 5 adults with ileostomy on 7 meals. Results: Folic acid, IP3 and IP5 were significant influencing factors for bioavailable zinc. Weighted multiple regression equation was: ln (bioavailable zinc in mg) = −1.701 + 1.285 × ln [(IP5 in mg] ×(Zn in mg)] −1.222 × ln(IP5 in mg) −0.0078 × folic acid in μg −0.137 × ln [(IP3 in mg) ×(Zn in mg)] with adjusted R^[2] = 0.64, p = 0.0001. The correlation between predicted and observed dialysability of meals was found to be 0.96 (p < 0.01). A significant correlation between observed and predicted amount of absorbed zinc (r = 0.85, p < 0.01) was obtained for the human data of zinc absorption in 12 healthy and 5 subjects with ileostomy. Conclusions: Bioavailable amount of zinc from vegetarian meals was influenced by IP3, IP5 and folic acid content and their interactive effect with zinc content.