Effects of altered salt intake and diet on cytokines in humans: A 20-week randomized cross-over intervention study

Area of Science:

• Immunology and Nutrition Science
• Investigating the impact of dietary factors on immune responses.

Background:

• High sodium concentration is linked to altered leukocyte activation and autoimmune disease development in preclinical and in vitro studies.
• Salt has been implicated as a potential risk factor for autoimmune diseases based on existing research.

Purpose of the Study:

• To investigate whether physiologically relevant changes in salt intake or diet affect plasma cytokine concentrations in humans.
• To examine the in vivo effects of dietary salt on immune system markers.

Main Methods:

• A 20-week double-blinded, placebo-controlled crossover study involving 106 participants.
• Participants were randomized to Habitual and Healthy Nordic diets, with usual and reduced sodium intake groups.
• Plasma concentrations of 45 cytokines were measured using a multiplex assay at three time-points.

Main Results:

• High salt ingestion or dietary changes did not induce significant alterations in signature cytokines controlling T-helper cell polarization (Th1, Th2, Th17).
• Pro-inflammatory interleukins, chemokines, and growth factors remained unaffected by varying salt intake levels or dietary modifications.
• No significant changes in systemic cytokine concentrations were observed in relation to salt intake or diet.

Conclusions:

• Clinically relevant changes in salt intake or diet do not significantly impact systemic concentrations of pro-inflammatory cytokines in vivo in humans.
• The study suggests that the link between salt and autoimmune diseases in humans may not be mediated by direct changes in these specific cytokine profiles.
• Further research may be needed to explore other potential mechanisms or specific populations affected by salt intake.