The Dietary Approaches to Stop Hypertension (DASH) diet is recommended by the American Heart Association to lower blood pressure (BP); however, its effects in Japanese participants have not been rigorously studied. We assessed the effects of the DASH-Japan Ube Modified diet Program (DASH-JUMP), a modified DASH diet, on cardiometabolic and inflammatory biomarkers in Japanese participants with untreated high-normal BP or stage 1 hypertension. Fifty-eight participants (30 men and 28 women; mean age 54.1 +/- 8.1 years) with untreated high-normal BP or stage 1 hypertension followed the DASH-JUMP (salt 8.0 g per day) for 2 months. After the intervention period, they resumed their usual diets for 4 months. The DASH-JUMP significantly decreased the participants' body mass index values (24.6 +/- 3.5 kg m(-2) at baseline -> 23.2 +/- 3.3 kg m(-2) at 2 months, P=0.000), BP (153 +/- 14/91 +/- 11 mm Hg at baseline -> 130 +/- 16/80 +/- 9 mm Hg at 2 months, P=0.000 and 139 +/- 16/85 +/- 10 mm Hg at 6 months, P=0.000), fasting serum glucose level (100 +/- 26 mg dl(-1). 94 +/- 15 mg dl(-1) at 2 months, P=0.003) and fasting insulin level (6.9 +/- 5.9 mu IU ml(-1) -> 4.4 +/- 2.7 +/- mu IU ml(-1) at 2 months, P=0.000). The mean compliance of the participants for the DASH-JUMP diet was 88.5%. The DASH-JUMP diet reduced cardiovascular risk factors and may be an effective nutritional strategy for preventing cardiovascular events.