Publications by authors named "Michael B Zimmermann"

Iodine is a trace element whose adequate intakes are essential during pregnancy to promote the correct development of the fetus. Iodine excess or deficiency is the cause of several disorders associated with a rise risk of miscarriage or premature birth. The aim of our study was to assess the urinary iodine concentration (UIC) and thyroid function of pregnant women (PW) in northern Algeria.

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Iron supplementation to African weaning infants was associated with increased enteropathogen levels. While cohort studies demonstrated that specific prebiotics inhibit enteropathogens during iron supplementation, their mechanisms remain elusive. Here, we investigated the impact of galacto-oligosaccharides (GOS) and iron-sequestering bovine lactoferrin (bLF) alone and combined on the gut microbiota of Kenyan infants during low-dose iron supplementation.

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Edible insects have been proposed as a novel and sustainable source of protein and other essential nutrients for human consumption but nutrient absorption efficiency is still uncertain. We investigated zinc absorption from house crickets (Acheta domesticus) in a single-center and single-blinded cross-over study with children aged 24-36 months old in Kenya from September-November 2021. For this, children were randomized to consume two different experimental meals labeled with stable isotopes of zinc (Zn) at two different days, separated by a wash-out period of one month.

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Indigenous peoples are often not routinely included in iodine programmes because of language barriers and remote access and may thus be at higher risk of iodine deficiency disorders, which could adversely impact their quality of life. We conducted this cross-sectional study in the remote Pwo Karen community of Thailand to determine the urinary iodine concentration of school-aged children and women of reproductive age and investigate the iodine content in household salt. We measured urinary iodine concentration in spot urine samples from healthy school-aged children and women of reproductive age, administered a questionnaire, estimated daily iodine intake and collected household salt samples to determine salt iodine concentration.

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Article Synopsis
  • Adding vitamin C-rich fruits like guava to iron-containing meals, such as mungbean dal, may help improve hemoglobin levels and reduce anemia in children.
  • A study with 200 rural school children in India found that eating mungbean dal with guava led to significant increases in hemoglobin and a decrease in anemia prevalence compared to eating mungbean dal alone.
  • Although there was a positive effect on hemoglobin and anemia rates, the addition of guava did not significantly improve the overall body iron stores of the children.
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Stable iron isotope techniques are critical for developing strategies to combat iron deficiency anemia, a leading cause of global disability. There are four primary stable iron isotope methods to assess ferrokinetics in humans. (i) The fecal recovery method applies the principles of a metabolic balance study but offers enhanced accuracy because the amount of iron isotope present in feces can be directly traced back to the labeled dose, distinguishing it from endogenous iron lost in stool from shed intestinal cells.

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Depression has been associated with subclinical hypothyroidism and altered hypothalamic-pituitary-thyroid axis functioning. Adequate iodine nutrition is essential for healthy thyroid functioning. We therefore determined associations of iodine and thyroid status with paediatric major depressive disorder (pMDD) among Swiss adolescents and explored whether associations are sex-specific and mediated by stress.

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Deoxy-hexose sugars, such as rhamnose and quinovose, and the dideoxy-hexoses colitose, abequose, and tyvelose are highly antigenic given that they are absent from animal glycoconjugates. To investigate the specificity of antibodies towards structurally similar carbohydrate epitopes found in bacteria, we synthesized trisaccharides containing colitose, abequose, and fucose motifs. Each trisaccharide was designed with a spacer ending with a primary amino group.

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Breast milk is a vital source of nutrients, prebiotics, probiotics, and protective factors, including antibodies, immune cells and antimicrobial proteins. Using bacterial lipopolysaccharide arrays, we investigated the reactivity and specificity of breast milk antibodies towards microbial antigens, comparing samples from rural Kenya and urban Switzerland. Results showed considerable variability in antibody reactivity both within and between these locations.

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Background: Previous studies showed that pre- and probiotics may enhance iron absorption. Probiotics combined with prebiotics (synbiotics), including human-identical milk oligosaccharides (HiMOs), are commonly added to infant and follow-up formula (FUF). Whether these additions enhance iron absorption from iron-fortified commercial milk formula is uncertain.

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Cardiovascular diseases account for almost 18 million deaths annually, the most of all non-communicable diseases. The reduction of dietary salt consumption is a modifiable risk factor. The WHO recommends a daily sodium intake of <2000 mg but average consumption exceeds this in many countries globally.

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Article Synopsis
  • * The study measured iron intake, absorption, and overall gains in breastfed, formula-fed, and mixed-fed infants, showing significant differences in iron levels, particularly between breastfed and formula-fed babies.
  • * The findings suggest that using isotope dilution techniques can effectively track how infants absorb iron over time and how their iron levels may drop in early infancy.
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  • A study was conducted to assess whether daily oral iron supplements increase iron loss in iron-depleted Kenyan children aged 24-27 months.
  • The findings revealed that, over 3 months, the average absorption of iron was 1.10 mg/day, while daily iron loss was 0.55 mg, accounting for half of the absorbed iron.
  • The results suggest that daily iron supplementation raises iron loss, potentially reducing the effectiveness of the supplements in children, with a significant correlation between iron absorption and loss.
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Purpose: Depression is associated with low-grade systemic inflammation and impaired intestinal function, both of which may reduce dietary iron absorption. Low iron status has been associated with depression in adults and adolescents. In Swiss adolescents, we determined the associations between paediatric major depressive disorder (pMDD), inflammation, intestinal permeability and iron status.

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Iron is arguably the most important nutrient in the ongoing battle between hosts and bacteria. Recently in Nature, a unique iron storage organelle, the ferrosome, was discovered in the human pathogen Clostridioides difficile. But what is the role of ferrosomes and how do they affect bacterial behavior and infection?

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Purpose: We examined iron absorption and its regulation during two common scenarios experienced by endurance athletes. Our aims were to: (i) compare the effects of preexercise versus postexercise iron intake on iron absorption; and (ii) compare the impact of training at altitude (1800 m) on iron absorption preexercise.

Methods: Male runners (n = 18) completed three exercise trials over a 5-wk period, each preceded by 24 h of standardized low-iron diets.

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Background: Iron fortificants tend to be poorly absorbed and may adversely affect the gut, especially in African children.

Objective: We assessed the effects of prebiotic galacto-oligosaccharides/fructo-oligosaccharides (GOS/FOS) on iron absorption and gut health when added to iron-fortified infant cereal.

Methods: We randomly assigned Kenyan infants (n = 191) to receive daily for 3 wk a cereal containing iron and 7.

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Background: Guidelines to treat iron deficiency recommend daily provision of oral iron, but this may decrease fractional iron absorption and increase side effects. Our objective was to compare consecutive-day versus alternate-day iron supplementation.

Methods: In a double-masked, randomized, placebo-controlled trial, young Swiss women (n = 150; serum ferritin ≤30 μg/L) were assigned to: daily 100 mg iron for 90 d, followed by daily placebo for another 90 d (consecutive-day group) or the same daily dose of iron and placebo on alternate days for 180 d (alternate-day group).

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Background: Zinc-biofortified potatoes have considerable potential to reduce zinc deficiency because of their low levels of phytate, an inhibitor of zinc absorption, and their high consumption, especially in the Andean region of Peru.

Objectives: The purpose of this study was to measure fractional and total zinc absorption from a test meal of biofortified compared with regular potatoes.

Methods: We undertook a single-blinded randomized crossover study (using Zn and Zn stable isotopes) in which 37 women consumed 500-g biofortified or regular potatoes twice a day.

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Background: Agronomic zinc biofortification of wheat by foliar application increases wheat zinc content and total zinc absorption in humans.

Objectives: To assess the effect of agronomically biofortified whole wheat flour (BFW) on plasma zinc (PZC) compared with a postharvest fortified wheat (PHFW) and unfortified control wheat (CW) when integrated in a midday school meal scheme.

Methods: We conducted a 20-wk double-blind intervention trial in children (4-12 y, n = 273) individually randomly assigned to 3 groups to receive a daily school lunch consisting of 3 chapattis prepared with the 3 different wheat flour types.

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Background: Observational studies suggest a link between n-3 polyunsaturated fatty acid (PUFA) intake, n-3 PUFA status, and depression in adults, but studies in adolescents are scarce. This study aimed to determine associations of n-3 PUFA status and intake with paediatric major depressive disorder (pMDD) in Swiss adolescents.

Methods: We conducted a matched case-control study in 95 adolescents diagnosed with pMDD and 95 healthy controls aged 13 to <18 years.

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Article Synopsis
  • The study focused on analyzing the gut microbiota of Kenyan infants through in vitro cultivation techniques, utilizing fecal samples from 10 infants in rural areas.
  • A diet-specific cultivation medium replicating typical foods like human milk and maize porridge was employed, with DNA sequencing and metabolite analysis conducted after 24 hours.
  • Results showed a high presence of Bifidobacterium and specific metabolites, while variations in bacterial populations were noted depending on the acidity of the environment, highlighting the potential for individualized microbiota profiles.
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Guidelines generally recommend taking iron supplements in the morning away from meals and with ascorbic acid (AA) to increase iron absorption. However, there is little direct evidence on the effects of dietary factors and time of day on absorption from iron supplements. In iron-depleted women (n = 34; median serum ferritin 19.

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Background: The habitual/usual iodine intake and the prevalence of iodine inadequacy may be estimated from spot urinary iodine concentrations in cross-sectional studies by collecting a repeat spot urine in a subgroup of the study population and accounting for within-person variability in iodine intake. However, guidance on the required overall sample size (N) and the replicate rate (n) is lacking.

Objectives: To determine the sample size (N) and replicate rate (n) needed to estimate the prevalence of iodine inadequacy in cross-sectional studies.

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