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> Dr. Pantuso reports no financial relationships relevant to this field of study.
A randomized, double-blind, placebo-controlled clinical trial design was used to investigate the effects of freeze-dried blueberries on blood pressure and arterial stiffness in postmenopausal women with pre- or stage 1 hypertension (HTN) (≥ 125/85 mmHg and ≤ 160/90 mmHg). Eighty-one postmenopausal women between the ages of 45-65 years with pre- or stage 1-HTN were recruited in the greater Tallahassee, FL, area.
Women were excluded from the study if they were diagnosed with uncontrolled HTN (> 160/100 mmHg) or cardiovascular disease; were heavy smokers (> 20 cigarettes/day); were diagnosed with asthma, glaucoma, thyroid, kidney, liver, or pancreatic disease; had active cancer; or were receiving hormone replacement therapy or insulin. Forty-eight women who met the inclusion criteria were enrolled in the study and were instructed to not change their diet or physical activity pattern throughout the study.
The women were instructed to mix 11 grams of freeze-dried blueberry powder in water twice daily (the equivalent of 1 cup of fresh blueberries per day). The freeze-dried blueberry powder contained a 50/50 mix of Vaccinium virgatum and Vaccinium corymbosum high brush berries. The authors also instructed the women to mix in Splenda or vanilla for extra flavoring if required. The placebo powder contained artificial and natural blueberry flavoring, maltodextrin, fructose, artificial purple and red color, and citric acid and silica dioxide. The nutritional composition of both the freeze-dried blueberry powder and placebo powder were measured; however, the authors did not comment on whether a taste comparison was performed between the powders (see Table 1).
| Table 1: Different Blueberry Preparations and Their Nutrient Compositions | |||
| Placebo powder (22 g) | Freeze-dried blueberry powder (22 g) | Fresh blueberry (1 cup) | |
| Anthocyanins (mg/g) | 0 | 4.69 | Not measured |
| Phenolics (mg/g) | 0 | 8.45 | Not measured |
| Oxygen Radical Absorbance (µmol TEC/g) | 0 | 80.52 | Not measured |
| Potassium (mg) | 0 | 103.18 | 112 |
| Calcium (mg) | 0 | 7.50 | 9.00 |
| Vitamin C (mg) | 0 | 2.27 | 14.10 |
| Protein (g) | 0.17 | 0.59 | 1.08 |
| Fiber (g) | 0 | 4.73 | 3.50 |
| Total Carb (g) | 20.82 | 20.57 | 21.02 |
| kCal | 86 | 87 | 83 |
| Adapted from: Johnson SA, et al. Daily blueberry consumption improves blood pressure and arterial stiffness in postmenopausal women with pre- and Stage 1- hypertension: A randomized, double-blind, placebo-controlled clinical trial. J... |