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.

Inclusion Criteria:

• Apparently healthy participant
• Adherence to one of following eating habit (vegan or omnivore) confirmed by food frequency protocol (5 d), lifestyle and nutrition questionnaires
• Stable eating habit for at least 1 year before enrollment

Exclusion Criteria:

• Diet other than omnivore or vegan
• Changing diet during the study period
• Baseline serum selenium concentration > 150 µg/L
• Acute or chronic disease (tumor, infection, other), gastrointestinal diseases, chronic renal disease, diseases of the parathyroids, diseases necessitating regular phlebotomies
• Nut allergy
• Pregnancy or lactation

female (before menopause) and male gender (50% each)

Open access publications

end of 2023