Estimated Amounts of β-Carotene, Vitamin B6, Riboflavin and Niacin in the Daily Diet of Older Subjects Associate Negatively with ADP-Induced Aggregation of Blood Platelets Independently of Cardiovascular Risk Factors

<b>Background/Objectives:</b> Platelet-dependent thrombotic risk increases with age. Little is known, however, about the potential effect of vitamins on platelet reactivity in older subjects. <b>Methods:</b> Therefore, in the present study we examined the dependencies of whole blood platelet aggregability (in response to arachidonic acid (AA), collagen (COL) or adenosinediphosphate (ADP), using impedance aggregometry) in older men and women (60-65 yr, <i>n</i> = 246) on the intakes of vitamins (vitamins A, E, C, B₆, B₁₂ and D, niacin, thiamine, riboflavin, retinol, β-carotene and folates) with a typical daily diet (vitamin contents estimated using Dieta 5.0 software). <b>Results:</b> Overall, significant negative bootstrap-boosted partial correlation coefficients, adjusted for selected cardiovascular risk factors, were revealed for AA and β-carotene, and ADP and β-carotene, riboflavin, vitamin B₆ and niacin. These findings were further validated by the outcomes of the bootstrap-boosted canonical analysis, confirming the relationships revealed for ADP, and to a lesser extent for AA. COL-dependent platelet aggregation appeared to not be associated with the amount of vitamins in the subjects' daily diet. <b>Conclusions:</b> Hence, we conclude that the intake of vitamins in the daily diet of older subjects is negatively associated with platelet aggregability in an agonist- and vitamin-specific manner.