As vegans are among the individuals with the lowest serum selenium levels, the randomized controlled SelVeg study aims to address the question of whether Brazil nuts could be an adequate source of selenium for diets potentially low in selenium. For this purpose, we will investigate in individuals with a vegan or omnivorous dietary pattern how a daily selenium intervention in the form of a food (here Brazil nut butter) or an over-the-counter selenium supplement affects the selenium status.
The vegan diet is characterized by an exclusion of all animal foods and is associated with positive health effects. However, dietary restriction can lead to inadequate intake of both macro- and micronutrients. Selenium and zinc, among others are critical nutrients in a vegan diet. Brazil nuts represent a particularly selenium-rich plant food. In addition to selenium Brazil nuts have also relevant amounts of other trace elements, including zinc, iron and copper. Therefore, the aim of this study is to evaluate the effect of a daily selenium supplementation in the form of Brazil nut butter in comparison to a selenium supplement. As primary outcome, the serum selenium concentration and other serum biomarkers of the selenium status will be analyzed. Additionally, serum levels of other trace elements such as zinc will be quantified. Dietary questionnaires will provide information on dietary intake of nutrients (focus on dietary fiber, zinc and phytate intake) to identify potential factors influencing selenium bioavailability. The SelVeg study will enroll 90 healthy subjects with either a vegan (defined as exclusion of animal products) or omnivore (defined as weekly consumption of meat and/or sausage) dietary pattern. After categorizing in vegans or omnivores, participants are than randomized in one of the three intervention groups (placebo, Brazil nut or selenium supplement) and will receive 55 µg of additional daily selenium (as Brazil nut butter or tablet) or no additional selenium in case of placebo. The intervention period is 2 weeks.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
90
Selenium supplement containing 55 µg of sodium selenate
Brazil nut butter; consumption corresponds to a selenium intake of 55 µg/d
Placebo pill
Friedrich Schiller University Jena
Jena, Thuringia, Germany
Selenium status
Changes in serum selenium concentration \[µg/L\] and selenoprotein-based biomarkers (SELENOP and GPX \[U/L\]) after intervention
Time frame: baseline and after 2 weeks
Trace element serum concentrations
Change in serum concentration of trace elements (zinc, copper, manganese, iron, potassium and calcium \[µg/L\]) after intervention
Time frame: baseline and after 2 weeks
Anthropometric data
body mass index \[kg/m2\]
Time frame: baseline and after 2 weeks
Mean macro- and micronutrient intake over 5 days
Time frame: baseline
Dietary zinc and phytate intake
Zinc and Phytate Diet Score (= frequency index \* quantity index \* zinc or phytate content \[mg\])
Time frame: 6 months
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