a1 Department of Public Health, University of Parma, Parma, Italy
a2 Department of Internal Medicine and Biomedical Sciences, University of Parma, Via Gramsci 14, 43 100, Parma, Italy
a3 Cardiovascular and Metabolic Rehabilitation Unit, IRCCS H. San Raffaele, Milan, Italy
a4 Antioxidant Research Laboratory, National Institute for Food and Nutrition Research, Rome, Italy
Inflammation, a risk factor for cardiovascular disease, is associated with low plasma levels of antioxidant vitamins. In addition to vitamins, other antioxidants modulate the synthesis of inflammatory markers in vitro and contribute to the total antioxidant capacity (TAC) of a diet. However, the relationship between dietary TAC and markers of inflammation has never been evaluated in vivo. We investigated the relationship between dietary TAC and markers of systemic (high-sensitivity C-reactive protein (hs-CRP), leucocytes) and vascular (soluble intercellular cell adhesion molecule-1) inflammation in 243 non-diabetic subjects. General Linear Model (GLM) analysis showed a significant (P=0·005) inverse relationship between hs-CRP and quartiles of energy-adjusted dietary TAC, even when recognized modulating factors of inflammation, namely alcohol, fibre, vitamin C, α-tocopherol, β-carotene, BMI, waist circumference, HDL-cholesterol, hypertension, insulin sensitivity and plasma β-carotene, were included in the model as covariates (P=0·004). The relationship was stronger for subjects with hypertension (P=0·013 v. P=0·109 for normotensive individuals). Among dietary factors, TAC was significantly higher (5·3 (sd 3·0) v. 4·9 (sd 2·7) mmol Trolox/d; P=0·026) in subjects with low plasma hs-CRP (range: 0·0–4·1 mg/l) than in subjects with high plasma hs-CRP (range: 4·2–27·8 mg/l). We conclude that dietary TAC is inversely and independently correlated with plasma concentrations of hs-CRP and this could be one of the mechanisms explaining the protective effects against CVD of antioxidant-rich foods such as fruits, whole cereals and red wine. This could be of particular significance for subjects with high blood pressure.
(Received August 24 2004)
(Revised December 10 2004)
(Accepted December 20 2004)