Daily intake of non-fried potato does not affect markers of glycaemia and is associated with better diet quality compared with refined grains: a randomised, crossover study in healthy adults

Abstract

Epidemiological studies suggest that consumption of potatoes is associated with increased risk of cardiometabolic diseases. However, few clinical trials have empirically tested this. The aim of this single-blind, randomised, crossover study was to evaluate the effect of daily potato consumption, compared with refined grains, on risk factors for cardiometabolic diseases. It was hypothesised that no difference in cardiometabolic endpoints would be detected between conditions, but diet quality would improve with potato consumption. Healthy participants on self-selected diets received one potato-based side dish or one refined grain-based side dish daily, for 4 weeks, separated by a minimum 2-week break. Dishes were isoenergetic, carbohydrate-matched and prepared without excess saturated fat or Na. Participants were instructed to consume the side dish with a meal in place of carbohydrates habitually consumed. Lipids/lipoproteins, markers of glycaemic control, blood pressure, weight and pulse wave velocity were measured at baseline and condition endpoints. Diet quality was calculated, based on 24-h recalls, using the Healthy Eating Index (HEI)-2015. Fifty adults (female n 34; age 40 (sd 13) years; BMI 24·5 (sd 3·6) kg/m2) completed the present study. No between-condition differences were detected for fasting plasma glucose (-0·05 mmol/l, 95 % CI -0·14, 0·04; P = 0·15), the primary outcome or any other outcomes. Compared with refined grains, the HEI-2015 score (3·5, 95 % CI 0·6, 6·4; P = 0·01), K (547 mg, 95 % CI 331, 764, P < 0·001) and fibre (2·4 g, 95 % CI 0·6, 4·2, P = 0·01) were higher following the potato condition. Consuming non-fried potatoes resulted in higher diet quality, K and fibre intake, without adversely affecting cardiometabolic risk.

Keywords: Cardiometabolic health; Diet quality; Fasting glucose; Potatoes; Supplemental feeding studies.

Figures

Fig. 1.

Study design. Up arrows signify testing at baseline (days 1 and 2) and at the end of supplementation periods 1 and 2 (days 28 and 29 of each period).

Fig. 2.

CONSORT diagram.

Fig. 3.

Within- and between-condition change from baseline for all biochemical endpoints. There were no between-condition differences. * Significant within-condition change from baseline (P < 0·05); Data are mean values and 95 % confidence intervals; TAG and weight presented as geometric mean values and 95 % confidence intervals. , Potato; , refined grain. HS-CRP, high-sensitivity C-reactive protein.

Fig. 4.

Within- and between-condition change from baseline for all vascular endpoints. There were no between-condition differences. Data are mean values and 95 % confidence intervals. , Potato; , refined grain. bSBP, brachial systolic blood pressure; bDBP, brachial diastolic blood pressure; cSBP, central systolic blood pressure; cDBP, central diastolic blood pressure; cPP, central pulse pressure; AP, arterial pressure; HR, heart rate; PWV, pulse wave velocity; PTT, pulse transit time.