Nutrient and Total Polyphenol Contents of Dark Green Leafy Vegetables, and Estimation of Their Iron Bioaccessibility Using the In Vitro Digestion/Caco-2 Cell Model

Strategies for producing probiotic biomass and postbiotics from Akkermansia muciniphila in submerged cultivations incorporating prebiotic sources

This research propounds an innovative technology focused on sustainability to increase the biomass yield of Akkermansia muciniphila, the next-generation probiotic, using prebiotic sources to replace or reduce animal mucin levels. A series of experimental design approaches were developed aiming to optimize the growth of Akkermansiamuciniphila by incorporating extracts of green leafy vegetables and edible mushroom into the cultivation media. Experiments using kale extract (KE), Brassica oleracea L., associated with lyophilized mushroom extract (LME) of Pleurotus ostreatus were the most promising, highlighting the assays with 0.376% KE and 0.423% LME or 1.05% KE and 0.5% LME, in which 3.5 × 1010 CFU (Colony Forming Units) mL- 1 was achieved - higher than in experiments in optimized synthetic media. Such results enhance the potential of using KE and LME not only as mucin substitutes, but also as a source to increase Akkermansia muciniphila biomass yields and release short-chain fatty acids. The work is relevant to the food and pharmaceutical industries in the preparation of the probiotic ingredient.

Research on Moringa (Moringa oleifera Lam.) in Africa

While Moringa oleifera Lam. is gaining importance in Africa, especially sub-Saharan Africa, it is unclear whether research is following the quick pace of its development on the continent. Therefore, this article analyzes the landscape of research dealing with moringa in Africa. This systematic review draws upon 299 eligible articles identified through a search carried out on the Web of Science in April 2023. Research on M. oleifera is rather recent in Africa but interest is increasing among scholars. While the research field is multidisciplinary and cross-sectoral, the literature seems to focus on biological and environmental sciences. Moreover, research is performed mainly in South Africa, Nigeria, Egypt, and Ghana. The analysis suggests a significant potential contribution of moringa to food security and nutrition, climate change mitigation/adaptation, farming systems resilience, and livelihoods. Its versatility and diverse applications and uses make moringa particularly interesting for developing countries, such as African ones. However, this review also underscores some factors hindering its development. Therefore, there is a need to strengthen research on moringa to unlock its potential in Africa. Investments in research, innovation, and development can help address the many challenges that Africa faces and contribute to the transition towards sustainable and resilient food systems.

Dietary Patterns and Hypothyroidism in U.S. Adult Population

The thyroid gland produces hormones that are essential for various body functions. Hypothyroidism is defined as insufficient thyroid hormone production. Several studies have found associations between specific micronutrients and overall thyroid function; however, the amount of evidence regarding the relationship between dietary patterns and hypothyroidism among the U.S. population is limited. Data from three cycles of National Health and Nutrition Examination Surveys (NHANES), 2007-2008, 2009-2010, and 2011-2012, were used (n = 8317). Subjects with serum thyroid stimulating hormone >4.5 mIU/L or on levothyroxine were considered to have hypothyroidism. Age, sex, race/ethnicity, body mass index, and several lifestyle factors were considered as covariates. Three patterns were extracted using factor analysis. These were labeled as fat-processed grains-sugars-meats (FPSM), oils-nuts-potatoes-low-fat meats (ONPL), and fruits-whole grains-vegetables-dairy (FWVD) patterns. In a weighted multiple logistic regression, FPSM and ONPL were inversely associated with hypothyroidism (OR, 0.75; 95% CI, 0.57-1; p = 0.049 and OR, 0.81; 95% CI, 0.67-0.97; p = 0.025, respectively). However, FWVD demonstrated no association with hypothyroidism (p = 0.63). In conclusion, FPSM and ONPL patterns but not FWVD patterns were associated with hypothyroidism in U.S. adults. Nutrient deficiencies and their interactions may be linked to hypothyroidism.

Antioxidant Capacity of Polar and Non-Polar Extracts of Four African Green Leafy Vegetables and Correlation with Polyphenol and Carotenoid Contents

In sub-Saharan Africa, chronic malnutrition is often associated with intestinal inflammation and oxidative stress. African green leafy vegetables (GLVs), commonly consumed by these populations and rich in bioactive compounds, may improve the antioxidant status. The aim of this study was to measure the antioxidant capacity using complementary assays (DPPH, FRAP, ABTS, ORAC and NO scavenging) in polar and non-polar leaf extracts of four African GLVs, cassava (Manihot esculenta), roselle (Hibiscus sabdariffa), jute mallow (Corchorus olitorius), and amaranth (Amaranthus spp.), with spinach (Spinacia oleracea) chosen as a reference. Their antioxidant capacity was correlated with their total polyphenol (TPC), flavonoid (TFC), condensed tannin, lutein, and β-carotene contents. Identification of phenolic compounds by UHPLC-DAD-MS/MS revealed the presence of three main classes of compound: flavonols, flavones, and hydroxycinnamic acids. Cassava and roselle leaves presented significantly higher TPC and TFC than amaranth, jute mallow, and spinach. They also exhibited the highest antioxidant capacity, even higher than that of spinach, which is known for its important antioxidant effect. The antioxidant capacity was 2 to 18 times higher in polar than non-polar extracts, and was more strongly correlated with TPC and TFC (R > 0.8) than with β-carotene and lutein contents. These findings provide new data especially for cassava and roselle leaves, for which studies are scarce, suggesting an appreciable antioxidant capacity compared with other leafy vegetables.

Potential of moringa leaf and baobab fruit food-to-food fortification of wholegrain maize porridge to improve iron and zinc bioaccessibility

Food-to-food fortification (FtFF) with moringa leaf (iron source) and/or baobab fruit (citric acid and ascorbic acid source) (each 13-15 g/100 g porridge dry basis (db)) was studied to improve iron and zinc nutritive quality in African-type wholegrain maize-based porridges using in vitro dialysability assay. Moringa FtFF decreased percentage and total bioaccessible iron and zinc, by up to 84% and 45%, respectively. Moringa was very high in calcium, approximately 3% db and calcium-iron-phytate complexes inhibit iron bioavailability. Baobab FtFF increased percentage and total bioaccessible iron and zinc, especially in porridges containing carrot + mango (β-carotene source) and conventionally fortified with FeSO₄, by up to 111% and 60%, respectively. The effects were similar to those when ascorbic and citric acids were added as mineral absorption enhancers. While moringa FtFF could be inhibitory to iron and zinc bioavailability in cereal-based porridges, baobab fruit FtFF could improve their bioavailability, especially in combination with conventional iron fortification.

Environment-Based Impairment in Mineral Nutrient Status and Heavy Metal Contents of Commonly Consumed Leafy Vegetables Marketed in Kyrgyzstan: a Case Study for Health Risk Assessment

Leafy vegetables are important components of the human diet for providing mineral nutrients. However, due to the tendency of metal accumulation, metal contents of leafy vegetables need not only to be determined but also estimated health risk for revealing possible health effects on humans. The aims of this study are (I) to examine comprehensive concentrations of trace/heavy metals along with some macroelements including Ca, Cd, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn in selected leafy vegetables from Kyrgyzstan; (II) to assess recommended dietary allowances (RDA); and (III) to evaluate hazard quotient (HQ) and carcinogenic risk estimation with associated vegetable consumption. For this purpose, B, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn elements were quantified, utilizing an ICP-OES instrument, in 18 samples belonging to 12 different groups of leafy vegetables including celery, Chinese parsley, dill, garden sorrel, lettuce, parsley, purple basil, spinach, and white-red-napa cabbage collected from different bazaars of Kyrgyzstan. Average elemental contents of the analyzed vegetables were determined (in mg kg^-1) as follows: B (3.21-64.79), Ca (852.51-17,183.20), Cd (0.015-0.09), Cu (6.08-63.47), Fe (116.52-768.66), K (2347.04-17,305.42), Mg (136.34-1261.11), Na (54.75-526.42), Ni (0.09-1.3), Pb (1.91-9.54), and Zn (29.49-314.93). Estimated daily intake, recommended daily allowance, hazard quotients, and carcinogenic risk values of the vegetables were calculated with the help of these results. In considering HQ values, Chinese cabbage was determined to be safe for the consumption of both genders whereas parsley to be safe for only males. Based on the carcinogenic risk calculation, most of the vegetables examined in this study were categorized as moderately risky. It was inferred from the given results that airborne pollution has impaired/increased the mineral contents of vegetables for both genders. The findings obtained from this study were compared with international standards and will contribute to the data available on a global scale.

Influence of Iron on the Gut Microbiota in Colorectal Cancer

Perturbations of the colonic microbiota can contribute to the initiation and progression of colorectal cancer, leading to an increase in pathogenic bacteria at the expense of protective bacteria. This can contribute to disease through increasing carcinogenic metabolite/toxin production, inducing inflammation, and activating oncogenic signaling. To limit disease progression, external factors that may influence the colonic microbiota need to be considered in patients with colorectal cancer. One major factor that can influence the colonic microbiota is iron. Iron is an essential micronutrient that is required by both prokaryotes and eukaryotes for cellular function. Most pathogenic bacteria have heightened iron acquisition mechanisms and therefore tend to outcompete protective bacteria for free iron. Colorectal cancer patients often present with anemia due to iron deficiency, and thus they require iron therapy. Depending upon the route of administration, iron therapy has the potential to contribute to a procarciongenic microbiota. Orally administered iron is the common treatment for anemia in these patients but can lead to an increased gut iron concentration. This suggests the need to reassess the route of iron therapy in these patients. Currently, this has only been assessed in murine studies, with human trials being necessary to unravel the potential microbial outcomes of iron therapy.

The Impact of Dietary Supplementation of Whole Foods and Polyphenols on Atherosclerosis

The purpose of this review is to highlight current research on the benefits of supplementation with foods with a diverse polyphenol composition, including fruits, vegetables, nuts, grains, oils, spices, and teas in blunting atherosclerosis. We searched PubMed for publications utilizing whole food or polyphenols prepared from whole foods in Apolipoprotein E (ApoE) or Low-Density Lipoprotein Receptor (LDLR) knockout mice, and identified 73 studies in which plaque was measured. The majority of the studies reported a reduction in plaque. Nine interventions showed no effect, while three using Agaricus blazei mushroom, HYJA-ri-4 rice variety, and safrole-2', 3'-oxide (SFO) increased plaque. The mechanisms by which atherosclerosis was reduced include improved lipid profile, antioxidant status, and cholesterol clearance, and reduced inflammation. Importantly, not all dietary interventions that reduce plaque showed an improvement in lipid profile. Additionally, we found that, out of 73 studies, only 9 used female mice and only 6 compared both sexes. Only one study compared the two models (LDLR vs. ApoE), showing that the treatment worked in one but not the other. Not all supplementations work in both male and female animals, suggesting that increasing the variety of foods with different polyphenol compositions may be more effective in mitigating atherosclerosis.

Effect of drying methods on chemical composition and antioxidant activity of underutilized stinging nettle leaves

Stinging nettles provide low-cost quality nutrition for alleviating malnutrition. Previous research on stinging nettles focused mainly on the nutritional quality of fresh leaves. In this study, the effect of drying method on macronutrients, mineral content, ascorbic acid, β-carotene content and total phenols content and antioxidant activity were investigated. The contribution of fresh, oven dried or freeze dried stinging nettle leaves to the required daily value for the nutrients were also determined. Oven drying of nettle leaves resulted in a higher loss of β-carotene and ascorbic acid content compared to freeze drying. In contrast, the total phenols content and total antioxidant activity were higher in oven dried stinging nettle leaves compared to freeze dried leaves. Overall, freeze dried and oven dried nettle leaves can be considered as a rich source of Ca, Mg and vitamin A; a good source of vitamin C, Fe, and Mn; and a source for Mg and K. Stinging nettle leaves could potentially be used as a cheap natural source of antioxidants and for addressing micronutrient malnutrition.

Lemon Juice, Sesame Paste, and Autoclaving Influence Iron Bioavailability of Hummus: Assessment by an In Vitro Digestion/Caco-2 Cell Model

Hummus, an iron-containing plant-based dish mainly made from chickpea purée, tahini, lemon juice and garlic, could be a valuable source of iron when bioavailable. Since the processing and formulation of food influence iron bioavailability, the present study investigated for the first time, their effects on hummus. Firstly, iron bioaccessibility was assessed on eight samples (prepared according to the screening Hadamard matrix) by in vitro digestion preceding iron dialysis. Then, iron bioavailability of four selected samples was estimated by the in vitro digestion/Caco-2 cell model. Total and dialyzable iron were determined by the atomic absorption spectrometry and ferritin formation was determined using an ELISA kit. Only autoclaving, among other processes, had a significant effect on iron bioaccessibility (+9.5, p < 0.05). Lemon juice had the highest positive effect (+15.9, p < 0.05). Consequently, the effect of its acidic components were investigated based on a full factorial 23 experimental design; no significant difference was detected. Garlic's effect was not significant, but tahini's effect was negative (-8.9, p < 0.05). Despite the latter, hummus had a higher iron bioavailability than only cooked chickpeas (30.4 and 7.23 ng ferritin/mg protein, respectively). In conclusion, hummus may be a promising source of iron; further in vivo studies are needed for confirmation.

Provitamin A Carotenoids, Tocopherols, Ascorbic Acid and Minerals in Indigenous Leafy Vegetables from Tanzania

The essential micronutrients in indigenous leafy vegetables (ILVs) could substantially contribute to the micronutrient supply in rural communities in Tanzania, but concentrations differ between species. Provitamin A carotenoids, tocopherols, ascorbic acid, minerals, and phytate were analysed in 13 different species using HPLC-, ICP-OES, and photometric techniques. Eight of the 13 ILVs, including Amaranthus ssp. and Sesamum angustifolium, had high β-carotene concentrations (2.91–4.84 mg/100 g fresh weight), which could provide ≥50% of vitamin A’s recommended nutrient intake (RNI). Six ILVs including Cleome hirta and Sonchus luxurians had high iron contents (34.5–60.4 mg/100 g, >50% RNI); Amaranthus ssp. represented the ILV with high calcium, magnesium and zinc contents (85%, 207% and 21% of RNI per 100 g); Cleome hirta and Cleome gynandra had high ascorbic acid contents (>15 mg/100 g, 34–35% of RNI), while Sesamum angustifolium was the only ILV with a high tocopherol content (7.34 mg α-TE/100 g). The highest phytate concentration was found in Amaranthus ssp., which could negatively affect its role as a very good source of minerals. Results indicate that the analysed ILVs could make a substantial contribution to the vitamin A and iron supply in the diets of rural Tanzanian populations.

Ethiopian Orthodox Fasting and Lactating Mothers: Longitudinal Study on Dietary Pattern and Nutritional Status in Rural Tigray, Ethiopia

About half of Ethiopians belong to the Orthodox Tewahedo religion. Annually, more than 200 days are dedicated to religious fasting, which includes abstaining from all types of food, animal source foods, and water. However, the association of fasting with undernutrition remains unknown in Ethiopia. Therefore, dietary pattern and nutritional status of lactating women during lent fasting and non-fasting periods were studied, and predictor variables for maternal underweight were identified. To achieve this, lactating mothers in lent fasting (N = 572) and non-fasting (N = 522) periods participated from rural Tigray, Northern Ethiopia. Average minimum diet diversity (MDD-W) was computed from two 24-h recalls, and nutritional status was assessed using body mass index (BMI). Binary logistic regression was used to identify potential predictors of maternal underweight. Wilcoxon signed-rank (WSRT) and McNemar's tests were used for comparison of the two periods. The prevalence of underweight in fasting mothers was 50.6%. In the multivariate logistic regression model, younger age, sickness in the last four weeks preceding the survey, fasting during pregnancy, lactation periods, grandfathers' as household decision makers, previous aid experience, non-improved water source, and not owning chicken were positively associated with maternal underweight. In WSRT, there was no significant (p > 0.05) difference on maternal body weight and BMI between periods. The average number of meals, diet diversity, and animal source foods (ASFs), consumption scores were significantly increased in non-fasting compared to fasting periods in both fasting and non-fasting mothers (p < 0.001, p < 0.05, and p < 0.001, respectively). Consumption of dark green leafy vegetables was higher in the fasting period (11%) than non-fasting (3.6%), in the study population. As a conclusion, Ethiopian Orthodox fasting negatively affected maternal nutritional status and dietary pattern in rural Tigray, Northern Ethiopia. To reduce maternal malnutrition in Ethiopia, existing multi-sectoral nutrition intervention strategies, should include religious institutions in a sustainable manner.

Wild and domesticated Moringa oleifera differ in taste, glucosinolate composition, and antioxidant potential, but not myrosinase activity or protein content

Taste drives consumption of foods. The tropical tree Moringa oleifera is grown worldwide as a protein-rich leafy vegetable and for the medicinal value of its phytochemicals, in particular its glucosinolates, which can lead to a pronounced harsh taste. All studies to date have examined only cultivated, domestic variants, meaning that potentially useful variation in wild type plants has been overlooked. We examine whether domesticated and wild type M. oleifera differ in myrosinase or glucosinolate levels, and whether these different levels impact taste in ways that could affect consumption. We assessed taste and measured levels of protein, glucosinolate, myrosinase content, and direct antioxidant activity of the leaves of 36 M. oleifera accessions grown in a common garden. Taste tests readily highlighted differences between wild type and domesticated M. oleifera. There were differences in direct antioxidant potential, but not in myrosinase activity or protein quantity. However, these two populations were readily separated based solely upon their proportions of the two predominant glucosinolates (glucomoringin and glucosoonjnain). This study demonstrates substantial variation in glucosinolate composition within M. oleifera. The domestication of M. oleifera appears to have involved increases in levels of glucomoringin and substantial reduction of glucosoonjnain, with marked changes in taste.