Stability of blood pressure in vegetarians receiving dietary protein supplements.

Abstract

Vegetarians have relatively low blood pressure (BP) levels and consume less protein than do nonvegetarians , and there have been suggestions that certain proteins may raise BP. To determine whether dietary protein supplements raise the BP of vegetarians, 58 g/per day of a 60:40 mixture of soy and wheat proteins and an isocaloric low protein supplement supplying 7 g/day of rice protein were added for 6-week periods to the diet of 18 vegetarians in a 2-group crossover design. Mean daily protein intake during consumption of the low and high protein supplements was 63 and 119 g, respectively. Mean BP was 109/72 mm Hg after the high protein and 108/71 mm Hg after the low protein diet. Consumption of other major nutrients, mean body weight, and sodium and potassium excretion did not change significantly. Thus, protein supplementation of a vegetarian diet that contained a below average but nutritionally adequate amount of protein did not significantly affect BP over 6 weeks.

Dietary Protein and Blood Pressure: A Systematic Review

“…Most trials were only small (number of participants per intervention group: n = 7 to n = 30), and the conflicting results may be due to chance findings. [29] – [39] In one of the larger trials, a parallel trial in which 121 type 2 diabetes patients received counseling on normal or reduced protein intake, an increase in BP was found (+5.4 mmHg systolic, p = 0.07). [40] However, the low range of intake may have influenced the results.…”

“… [5] This difference of protein effect in subgroups of BP could not be recognized in observational studies. In trials, however, populations with, on average, elevated BP were more sensitive to the BP lowering effect of protein than populations with, on average, normal BP (Out of 9 trials in populations with elevated BP [5] , [29] , [30] , [35] , [37] , [38] , [40] , [42] , [43] 7 trials showed a decrease in BP with high protein intake [5] , [30] , [35] , [37] , [38] , [42] , [43] , whereas out of 7 trials in populations with normal BP [31] – [34] , [36] , [39] , [41] only 2 trials [34] , [41] showed a decrease).…”

“…With regard to age, in the INTERSALT study a stronger inverse association of urinary nitrogen with BP was observed in respondents aged 40–59 y than in respondents aged 20–39 y (systolic BP: −0.9 mmHg/g versus −0.2 g/d). [25] Furthermore, inverse associations were found more often in studies conducted in participants aged over 50 (out of 5 studies [5] , [29] , [30] , [35] , [40] , in 3 studies an inverse association or a BP lowering effect was found [5] , [30] , [35] ) than in studies conducted in younger participants (out of 9 studies [16] , [22] , [23] , [31] – [34] , [39] , [41] , in 4 studies an inverse association was found [16] , [23] , [34] , [41] ). However, the number of studies that were conducted among these specific populations was small, and solid conclusions cannot be drawn.…”

The Effect of Vegan Protein-Based Diets on Metabolic Parameters, Expressions of Adiponectin and Its Receptors in Wistar Rats

“…Vegan protein-based diet has attracted increasing interest in the prevention and treatment of MetS [8,12,17]. In the present study, two different types of vegan protein-based diets—soy diet and gluten-soy mixture diet—were employed in Wistar rats against the control diet (casein diet) to investigate the changes in metabolic parameters and expressions of adiponectin and its receptors in tissues.…”

“…After acclimatization for a period of 1 week, rats were randomly assigned into three different groups and given diets containing 20% of one of the following proteins for 12 weeks: casein (CAS, n = 12), soy protein (SOY, n = 12) and wheat gluten-soy mixed protein (GSM, mixing ratio 1:1, n = 12). The 50:50 mixture of soy and wheat protein may be expected to produce an amino acid composition of high biological value based on amino acid content of gluten and soy protein [11,12]. Rat chow diets were prepared based on the Association of Official Analytical Chemists (AOAC) and AIN-93G formulas to meet the nutrient and energy requirements for the growth and development of rats [13].…”