Effects of low-fat dairy intake on blood pressure, endothelial function, and lipoprotein lipids in subjects with prehypertension or stage 1 hypertension

Figures & data

Table 1 Nutritional composition of study products (per serving)a

Nutrient	Dairy products			Nondairy products
	Low-fat (1%) milk (8 oz)b	Low-fat Yoplait strawberry yogurt (6 oz)	Part-skim mozzarella string cheese (1 oz)	Juicy Juice apple juice (6.75 f oz)	Special K chocolate chip cereal bar (23 g)	Snyder’s pretzels (0.9 oz)
Energy (kcal)	110	100	80	100	90	110
Carbohydrate (g)	13	21	1	24	18	22
Protein (g)	8	5	8	0	1	2
Fat (g)	2.5	0	6	0	1.5	0
Calcium (mg)	300	200	200	0	0	0
Potassium (mg)	500c	260	27c	190	68c	39c
Sodium (mg)	130	100	200	15	100	280
Magnesium (mg)	27c	19c	7c	10c	10c	8c
Dietary fiber (g)	0	0	0	0	3	1c

Notes:

a Exact study products varied slightly depending on availability. All study products were commercially available food products providing roughly the same nutritional content as described in the examples above;

b lactose-free 1% milk was provided to subjects when appropriate;

c content was not available on the food label or in the FoodPro database. Value was estimated from the United States Department of Agriculture database that related to the specific food product.

Table 2 Baseline demographic, anthropometric, and hemodynamic characteristics of subjects

Characteristic	Value, N = 62
	n (%)
Male	34 (54.8)
Female	28 (45.2)
Race/ethnicity
Non-Hispanic white	42 (67.7)
Black/African American	16 (25.8)
Asian or Pacific Islander	4 (6.5)
Prehypertension	52 (83.9)
Stage 1 hypertension	10 (16.1)
	Mean ± SEM
Age (years)	54.7 ± 1.2
Body weight (kg)	86.2 ± 2.1
Body mass index (kg/m^2)	29.2 ± 0.6
Hemodynamic variables
Systolic blood pressure (mmHg)	129.8 ± 0.9
Diastolic blood pressure (mmHg)	80.8 ± 0.9
Heart rate (beats/minute)	67.8 ± 1.0

Abbreviation: SEM, standard error of the mean.

Figure 1 Mean systolic (A) and diastolic (B) blood pressure values at time points throughout a meal challenge test and overall mean (inset) for dairy and nondairy treatments (N = 62). The average blood pressure was calculated as total AUC_{0–3.5 h} (h × mmHg) or divided by 3.5 h (inset).

Abbreviations: AUC, area under the curve; DBP, diastolic blood pressure; h, hour(s); SBP, systolic blood pressure; SD, standard deviation; SEM, standard error of the mean.

Table 3 EndoPAT reactive hyperemia and augmentation indices of endothelial function for dairy and nondairy treatments before and after a meal challenge

Parameter	Mean ± SEM		P-valuea
	Dairy	Nondairy
All subjects (N = 62)
Reactive hyperemia index
Premeal (−0.5 h)	2.35 ± 0.08	2.20 ± 0.08	0.229
Postmeal (2.0 h)	2.33 ± 0.08	2.30 ± 0.09	0.646
Augmentation index
Premeal (−0.5 h)	22.5 ± 2.3	23.8 ± 2.7	0.705
Postmeal (2.0 h)	12.4 ± 2.2	13.2 ± 2.4	0.794
Subjects with endothelial dysfunction (n = 14)
Reactive hyperemia index
Premeal (−0.5 h)	2.32 ± 0.19	1.50 ± 0.04	0.002
Postmeal (2.0 h)	2.34 ± 0.19	2.27 ± 0.29	0.383
Augmentation index
Premeal (−0.5 h)	26.1 ± 5.7	23.6 ± 5.5	0.752
Postmeal (2.0 h)	14.8 ± 5.3	12.5 ± 3.9	0.714

Notes:

a P-values were calculated from a repeated measures analysis of variance model between dairy and nondairy treatments.

Abbreviations: h, hour; SEM, standard error of the mean.

Table 4 Fasting lipids at baseline and percent changes from baseline to the end of each treatment period after dairy and nondairy conditions (N = 62)

Parameter	Mean ± SEM			P-valuea
	Baseline, mg/dL	Dairy, %Δ	Nondairy, %Δ
LDL-C	132.1 ± 3.8	−2.9 ± 1.3	−3.3 ± 1.1	0.782
Non-HDL-C	159.6 ± 4.5	−2.3 ± 1.1	−2.2 ± 1.0	0.955
Total-C	210.2 ± 4.4	−2.0 ± 0.8	−2.4 ± 0.9	0.767
HDL-C	50.6 ± 1.9	−0.9 ± 1.3	−2.4 ± 1.6	0.459
TG	138.4 ± 8.8	3.3 ± 3.7	6.5 ± 3.5	0.368
Total-C/HDL-C	4.47 ± 0.17	−0.4 ± 1.3	1.1 ± 1.5	0.668

Notes:

a P-values were calculated from a repeated measures analysis of variance model between dairy and nondairy treatments.

Abbreviations: HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; Non-HDL-C, non-high-density lipoprotein cholesterol; TG, triglycerides; Total-C, total cholesterol; SEM, standard error of the mean.

Table 5 Intake of energy, macronutrients, and minerals at baseline and during dairy and nondairy treatment periods

Parameter	Mean ± SEM			P-valuea
	Baseline	Dairy	Nondairy
Energy (kcal/d)	1748 ± 67.2	1740 ± 51.6	1750 ± 58.5	0.867
Carbohydrate (% energy)	47.7 ± 1.2	42.8 ± 1.6	48.0 ± 1.7	0.003
Protein (% energy)	17.1 ± 0.8	18.7 ± 0.9	15.0 ± 0.8	<0.001
Total Fat (% energy)	33.4 ± 1.1	30.0 ± 1.2	26.4 ± 1.1	0.008
SFA (% energy)	10.5 ± 0.5	9.9 ± 0.4	8.1 ± 0.4	0.004
PUFA (% energy)	4.8 ± 0.3	4.0 ± 0.2	3.7 ± 0.3	0.226
MUFA (% energy)	8.9 ± 0.5	7.2 ± 0.5	6.9 ± 0.4	0.645
Dietary fiber (g/d)	17.5 ± 1.3	15.3 ± 0.9	18.9 ± 1.1	0.003
Soluble fiber (g/d)	1.7 ± 0.2	1.7 ± 0.1	1.4 ± 0.1	0.118
Cholesterol (mg/d)	244 ± 14.0	252 ± 14.2	228 ± 12.2	0.210
Calcium (mg/d)	603 ± 31.5	1068 ± 17.7	461 ± 18.7	<0.001
Magnesium (mg/d)	211 ± 12.5	238 ± 10.3	206 ± 10.2	0.006
Potassium (mg/d)	1945 ± 96.4	2375 ± 67.1	1925 ± 78.0	<0.001
Sodium (mg/d)	2665 ± 172	2597 ± 109	2676 ± 114	0.667

Notes:

a P-values were calculated from a repeated measures analysis of variance model between dairy and nondairy treatments.

Abbreviations: d, day; MUFA, monounsaturated fatty acids; PUFA, polyunsaturated fatty acids; SEM, standard error of the mean; SFA, saturated fatty acids.