Background and aim: The intake of wholemeal foods is consistently associated with reduced risk of type 2 diabetes and cardiovascular diseases in epidemiological studies, although the mechanisms of this association are unclear. Here we aim to compare in healthy subjects the metabolic effects of a diet rich in wholemeal wheat foods versus one based on the same products in refined form.
Methods and results: Fifteen healthy individuals (12 M/3 F), mean age 54.5+/-7.6 years, BMI 27.4+/-3.0 kg/m(2) (mean+/-SD), participated in a randomized sequential crossover study. After 2 weeks run-in, participants were randomly assigned to two isoenergetic diets with similar macronutrient composition, one rich in wholemeal wheat foods and the other with the same foods but in refined form (cereal fibre 23.1 vs. 9.8 g/day). After the two treatment periods (each lasting 3 weeks) plasma glucose and lipid metabolism, antioxidant activity, acetic acid, magnesium, adipokines, incretins and high-sensitivity C-reactive protein (hs-CRP) were measured at fasting and for 4h after a standard test meal (kcal 1103, protein 12%, CHO 53%, fat 35%) based on wholemeal or refined wheat foods, respectively. After the two diets there were no differences in fasting nor in postprandial plasma parameter responses; only glucose was slightly but significantly lower at 240 min after the refined wheat food meal compared to the wholemeal wheat food meal. Conversely, after the wholemeal diet both total (-4.3%; p<0.03) and LDL (-4.9%; p<0.04) cholesterol levels were lower than after the refined wheat diet at fasting.
Conclusions: Consumption of wholemeal wheat foods for 3 weeks reduces significantly fasting plasma cholesterol as well as LDL cholesterol levels in healthy individuals without major effects on glucose and insulin metabolism, antioxidant status and sub-clinical inflammation markers.
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