The effects of three different daily plant stanol ester intakes on influenza vaccination responses: a double-blind, randomized, placebo-controlled intervention study in older adults

Abstract

Aging is accompanied by a gradual decline in immune function. Previously, we demonstrated that daily intake of 4 g plant stanols, provided as fatty-acid esters, increased antibody titre responses following different vaccinations. Effects of lower intakes, however, are unknown. We therefore evaluated whether daily consumption of 2, 3 or 4 g of plant stanols, provided as fatty-acid esters, improved immune responses following influenza vaccination in older adults. A double-blind, randomized, placebo-controlled parallel trial was performed. Older participants (59–87 years) consumed products with added plant stanols (2, 3 or 4 g d⁻¹ provided as fatty-acid esters) or control products for approximately 14 days prior to vaccination until 4 weeks post-vaccination. Antibody titres, serum metabolic risk markers, and haematological and immunological parameters were measured and statistically evaluated using linear mixed models. Data of 128 participants were analysed. Changes in IgM and IgG concentrations did not differ significantly between the control and plant stanol groups. Also, changes in Hemagglutination Inhibition (HI) antibody titres were not significantly different between the groups for either the Phuket or Victoria strains. Serum LDL-cholesterol concentrations decreased significantly in the 4 g d⁻¹ and 3 g d⁻¹ groups compared with control. Serum LDL-cholesterol concentrations in the 2 g d⁻¹ group were also lowered, but did not reach statistical significance. No between-group differences in haematological and immunological parameters were observed. Daily consumption of 2, 3 or 4 g of plant stanols provided as fatty-acid esters, did not improve vaccination responses following annual influenza vaccination in men and women aged 60 years or older.