Around 250,000 people in Sweden live with heart failure, a condition in which the heart struggles to pump enough blood to meet the body’s needs. A new large-scale clinical study, led by WCMM Clinical Researcher Martin Magnusson, will now investigate whether selenium deficiency plays a causal role in the disease and whether supplementation can improve outcomes.
The Selenium Intervention Registry Randomized Trial in Heart Failure (SIRI-HF) is the largest randomized heart failure study ever conducted in Scandinavia that is not funded by the pharmaceutical industry. More than 4,300 patients will be enrolled across 22 hospitals in Sweden and Norway. Participants will receive either selenium or placebo for three years and will then be followed for an additional year to assess long-term benefits and risks.
A widespread deficiency in the Nordics
Selenium is an essential micronutrient found in soil and transferred into food. Because Nordic soils contain relatively little selenium, the average intake in Sweden is lower than in many other countries. Although selenium is routinely added to animal feed, raising levels in meat, milk and eggs, many individuals still fall below recommended levels.
Selenium supports both immune function and thyroid regulation and acts as a key antioxidant that maintains mitochondrial activity in heart muscle cells. This function is critical for maintaining the heart’s ability to contract effectively.
Previous research from Magnusson’s group has shown that selenium deficiency is linked to worse outcomes in patients with established heart failure. Additional analyses indicate that people with the lowest selenium levels also have a significantly higher risk of developing heart failure over time.
What SIRI-HF aims to answer
Despite promising findings, it remains unclear whether low selenium directly contributes to heart failure or merely reflects poor health in affected individuals. The SIRI-HF trial will provide the strongest evidence to date by testing whether correcting the deficiency leads to fewer hospitalizations, better everyday functioning and improved survival.
Early, unpublished data from Magnusson’s team show that 93% of older heart failure patients in a Swedish clinical registry had low selenium levels. If supplementation proves effective, it could become an inexpensive and widely accessible treatment option. The estimated cost of a daily dose is less than four kronor.
Broad support for a major research effort
The study is funded by the Swedish Heart-Lung Foundation, the Swedish Research Council, Lund University, and Skåne University Hospital. The SIRI‑HF trial represents a major step forward in exploring non-pharmaceutical strategies to support patients with heart failure across Scandinavia.
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- Faculty of Medicine - article: Largest Scandinavian Selenium Study Launches
