Effects of walnut consumption on anti-MDA-LDL antibodies and immunoglobulins in the WAHA randomized trial
File(s)
Accepted version
Author(s)
Khamis, Ramzi
Type
Journal Article
Abstract
Background: Higher total serum IgG levels have been associated with protection from cardiovascular events in the ASCOT Trial. Antibodies against Ox-LDL have also been linked to favourable clinical and vascular imaging outcomes.
Objective: To determine whether regular walnut consumption influences circulating immunoglobulins, malondialdehyde-modified low-density lipoprotein (MDA-LDL), a highly immunogenic form of Ox-LDL, and antibodies against MDA-LDL.
Methods: The Walnuts and Healthy Aging (WAHA) study was a two-centre, randomised controlled trial conducted in Spain and the USA. Adults aged 63-79 years were assigned to a walnut-enriched diet or a control diet excluding walnuts for two years. Serum total IgG, total IgM, MDA-LDL as well as IgG and IgM anti MDA-LDL antibodies were measured by enzyme-linked immunoassays in 474 participants.
Results: Baseline immunoglobulin concentrations differed substantially by study centre. Participants from the USA had 25% lower total IgM and IgG concentrations than participants from Spain. Walnut consumption increased total serum IgG by 11% in the US cohort (95% CI: 0-24%; p=0.04), while pooled analysis showed a 6% increase across both cohorts (95% CI: 0-12%; p=0.04). Over the two-year study period, total IgM and both IgG and IgM anti-MDA-LDL concentrations declined significantly in both control and intervention groups.
Conclusion: Long-term walnut consumption was associated with a modest increase in total serum IgG but had no significant effect on total IgM, MDA-LDL, or antibodies against MDA-LDL. Baseline IgG and IgM concentrations were substantially lower among US participants, suggesting that geographic, environmental, social, or genetic factors may modulate immune biomarkers independently of dietary intervention.
Objective: To determine whether regular walnut consumption influences circulating immunoglobulins, malondialdehyde-modified low-density lipoprotein (MDA-LDL), a highly immunogenic form of Ox-LDL, and antibodies against MDA-LDL.
Methods: The Walnuts and Healthy Aging (WAHA) study was a two-centre, randomised controlled trial conducted in Spain and the USA. Adults aged 63-79 years were assigned to a walnut-enriched diet or a control diet excluding walnuts for two years. Serum total IgG, total IgM, MDA-LDL as well as IgG and IgM anti MDA-LDL antibodies were measured by enzyme-linked immunoassays in 474 participants.
Results: Baseline immunoglobulin concentrations differed substantially by study centre. Participants from the USA had 25% lower total IgM and IgG concentrations than participants from Spain. Walnut consumption increased total serum IgG by 11% in the US cohort (95% CI: 0-24%; p=0.04), while pooled analysis showed a 6% increase across both cohorts (95% CI: 0-12%; p=0.04). Over the two-year study period, total IgM and both IgG and IgM anti-MDA-LDL concentrations declined significantly in both control and intervention groups.
Conclusion: Long-term walnut consumption was associated with a modest increase in total serum IgG but had no significant effect on total IgM, MDA-LDL, or antibodies against MDA-LDL. Baseline IgG and IgM concentrations were substantially lower among US participants, suggesting that geographic, environmental, social, or genetic factors may modulate immune biomarkers independently of dietary intervention.
Date Acceptance
2026-08-25
Citation
JACC: Advances
ISSN
2772-963X
Publisher
Elsevier
Journal / Book Title
JACC: Advances
Copyright Statement
Copyright This paper is embargoed until publication. Once published the Version of Record (VoR) will be available on immediate open access.
License URL
Publication Status
Accepted