An Assessment Of The Nitrate Levels In Raw And Cooked Vegetables Consumed By Patients With Non-Communicable Diseases In Ghana

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Date

2021-12

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University Of Ghana

Abstract

Background: Vegetables are major sources of dietary nitrates. They contain varying concentrations of nitrate depending on the type of vegetable, agricultural practices, environment, cooking methods and other factors. Aim: The aim of this study was to determine the level of nitrates in raw and cooked vegetables consumed by patients with non-communicable diseases (NCDs) in Ghana. Materials and Methods: The research employed an experimental study design. Vegetables consumed by patients with NCDs reporting for care at the Korle Bu Dietherapy Unit, were identified from a secondary data and sampled from Shoprite Mall, Agbogbloshie and Dome Markets. The nitrate contents in raw and cooked (boiled, fried, stewed, prepared soup and Abom) vegetables were determined using the steam distillation-titration method and reported as mean (mg/kg) ± SD. Statistical Package for Social Sciences (SPSS version 26.0) was used to analyse data -at a 95% confidence interval. One-Way ANOVA and Dunnett’s Post Hoc were used to determine variations in nitrate levels of vegetables after undergoing the different cooking treatments. Results Tomato stew (23.76%), tomato (light) soup (18.18%), tomato Abom (15.70%) and vegetable salad (8.47%) were consumed by a majority of the study participants. Nitrate concentration was highest in raw Kontomire (171.04 ± 13.37 mg/kg) and lowest in raw onion (101.60 ± 30.41 mg/kg). The highest mean nitrate level for boiled and fried vegetables were recorded for vegetable salad (52.96 ± 16.80 mg/kg) and cabbage (125.92 ± 40.75 mg/kg) whilst the least nitrate levels were recorded for cucumber (29.12 ± 4.02 mg/kg) and sweet pepper (92.64 ± 26.96 mg/kg). The highest and lowest nitrate levels in stews prepared were observed in Kontomire (45.28 ± 5.28 mg/kg) and tomato stew (29.76 ± 5.51 mg/kg). Kontomire soup (44.56 ± 5.90 mg/kg) and tomato soup (33.84 ± 3.99 mg/kg) recorded the highest and lowest nitrate levels amongst soups prepared. Garden egg Abom obtained a higher (43.12 ± 3.85 mg/kg) nitrate level and tomato Abom recorded the least (29.68 ± 5.51 mg/kg). One-Way ANOVA showed significant differences between the nitrate levels of the raw vegetable types and the cooking treatments they were subjected to (p<0.05). Dunnett’s post hoc analysis revealed significant differences in nitrate levels between raw and boiled; boiled and fried; raw and fried (mainly cabbage, sweet pepper and cucumber) vegetables, and between uncooked and composite vegetable foods (stew, soup and Abom) (all p- values <0.05). Conclusion: Vegetable salads and tomatoes in the form of stew, soup and Abom were consumed by a majority of the study participants. Mean nitrate levels were higher in Kontomire and cabbage but lower in other vegetables. Nitrate losses occurred in all cooking methods however fried vegetables retained the most nitrates.

Description

MSc. Dietetics

Keywords

Ghana, Non-Communicable Diseases, Patients, Nitrate, Vegetables

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