1.
Acute beetroot juice reduces blood pressure in young Black and White males but not females.
Grosicki, GJ, Flatt, AA, Cross, BL, Vondrasek, JD, Blumenburg, WT, Lincoln, ZR, Chall, A, Bryan, A, Patel, RP, Ricart, K, et al
Redox biology. 2023;63:102718
-
-
-
Free full text
Plain language summary
Cardiovascular (CV) disease is the leading cause of death in the United States. Out of all ethnic groups, CV disease is particularly common in black Americans. High blood pressure (BP) is one of the main contributors to CV disease, and black Americans exhibit a disproportionally higher incident rate of high BP when compared to other ethnic groups. Partly this is due to genetic and physiological differences, yet is also influenced by social, socioeconomic, and environmental factors. One physiological difference that may contribute to higher BP in black adults appears to be a reduced availability of nitric oxide (NO). NO is a gas that is abundant in the human body. It regulates vascular tone and elasticity of the arteries, and therefore helps to manage blood pressure. Nitrates that occur in foods can be converted to NO and thus contribute to NO levels in the body. Beetroot juice (BRJ) is rich in nitrates. This study examined whether BRJ supplementation can reduce resting BP and cardiovascular reactivity in adults. The randomized, placebo-controlled, crossover-design study was completed by 18 black and 20 white young adults, male and female, with an average age of 21. The study monitored heart rate, BP and arterial stiffness in a variety of settings. The study also assessed socioeconomic status, perceived discrimination, sleep and dietary intake. The main findings from this investigation were that despite young black adults having higher resting BP, acute BRJ supplementation reduced the pressure to a similar extent in young black and white adults, but primarily in males. This reduction correlated with increased levels of circulating nitrites. However, acute BRJ supplementation did not influence resting arterial stiffness. The result also highlighted previously seen racial differences relating to social determinants of health and lifestyle, which may contribute to the elevated BP values seen in black participants. The study demonstrated that dietary nitrate from beetroot juice has the potential to be a cost-effective blood pressure-lowering strategy for young black and white males. Yet the findings also highlighted the complex interplay of social, lifestyle, and underlying physiological factors that influence racial differences when it comes to CV health
Abstract
A complex interplay of social, lifestyle, and physiological factors contribute to Black Americans having the highest blood pressure (BP) in America. One potential contributor to Black adult's higher BP may be reduced nitric oxide (NO) bioavailability. Therefore, we sought to determine whether augmenting NO bioavailability with acute beetroot juice (BRJ) supplementation would reduce resting BP and cardiovascular reactivity in Black and White adults, but to a greater extent in Black adults. A total of 18 Black and 20 White (∼equal split by biological sex) young adults completed this randomized, placebo-controlled (nitrate (NO3-)-depleted BRJ), crossover design study. We measured heart rate, brachial and central BP, and arterial stiffness (via pulse wave velocity) at rest, during handgrip exercise, and during post-exercise circulatory occlusion. Compared with White adults, Black adults exhibited higher pre-supplementation resting brachial and central BP (Ps ≤0.035; e.g., brachial systolic BP: 116(11) vs. 121(7) mmHg, P = 0.023). Compared with placebo, BRJ (∼12.8 mmol NO3-) reduced resting brachial systolic BP similarly in Black (Δ-4±10 mmHg) and White (Δ-4±7 mmHg) adults (P = 0.029). However, BRJ supplementation reduced BP in males (Ps ≤ 0.020) but not females (Ps ≥ 0.299). Irrespective of race or sex, increases in plasma NO3- were associated with reduced brachial systolic BP (ρ = -0.237, P = 0.042). No other treatment effects were observed for BP or arterial stiffness at rest or during physical stress (i.e., reactivity); Ps ≥ 0.075. Despite young Black adults having higher resting BP, acute BRJ supplementation reduced systolic BP in young Black and White adults by a similar magnitude, an effect that was driven by males.
2.
Favourable effects of consuming a Palaeolithic-type diet on characteristics of the metabolic syndrome: a randomized controlled pilot-study.
Boers, I, Muskiet, FA, Berkelaar, E, Schut, E, Penders, R, Hoenderdos, K, Wichers, HJ, Jong, MC
Lipids in health and disease. 2014;13:160
-
-
-
Free full text
Plain language summary
The prevalence of metabolic syndrome (MetS) is increasing rapidly worldwide and is a major risk factor for type 2 diabetes (DM2) and cardiovascular disease (CVD). Modern lifestyle-induced insulin resistance and chronic systemic low grade inflammation are considered at the root of the MetS. Therefore, dietary patterns of our Palaeolithic ancestors may be ideal for prevention and treatment of metabolic disorders since they are thought to be in line with the evolution of human physiology and metabolism. The aim of this randomized controlled pilot study was to assess the efficacy of a Palaeolithic-type diet in improving the characteristics of MetS, compared to a diet based on healthy eating guidelines. The study included 34 participants with MetS who consumed their allocated diets for two weeks. Efforts were made to prevent weight loss so that any favourable effects could be explained by the dietary intervention and not by the positive health effects of weight loss. The findings of this study showed that the Palaeolithic-type diet significantly lowered blood pressure, total cholesterol and triglycerides, as well as improved HDL-cholesterol, compared to the reference diet. The participants in the Palaeolithic diet intervention also had fewer characteristics of MetS and a tendency to higher insulin sensitivity at the end of the study. Despite efforts to keep body-weight stable, more weight was lost by the participants in the Palaeolithic group. No changes were observed in the secondary outcomes of inflammation, intestinal permeability and salivary cortisol, which the authors explain by the short duration of the intervention and the attempt to prevent weight loss. The authors conclude that future studies should take full additional advantage of the greater weight loss with the Palaeolithic diet, which may be more satiating than other diets, hence allowing weight loss to happen.
Abstract
BACKGROUND The main goal of this randomized controlled single-blinded pilot study was to study whether, independent of weight loss, a Palaeolithic-type diet alters characteristics of the metabolic syndrome. Next we searched for outcome variables that might become favourably influenced by a Paleolithic-type diet and may provide new insights in the pathophysiological mechanisms underlying the metabolic syndrome. In addition, more information on feasibility and designing an innovative dietary research program on the basis of a Palaeolithic-type diet was obtained. METHODS Thirty-four subjects, with at least two characteristics of the metabolic syndrome, were randomized to a two weeks Palaeolithic-type diet (n = 18) or an isoenergetic healthy reference diet, based on the guidelines of the Dutch Health Council (n = 14). Thirty-two subjects completed the study. Measures were taken to keep bodyweight stable. As primary outcomes oral glucose tolerance and characteristics of the metabolic syndrome (abdominal circumference, blood pressure, glucose, lipids) were measured. Secondary outcomes were intestinal permeability, inflammation and salivary cortisol. Data were collected at baseline and after the intervention. RESULTS Subjects were 53.5 (SD9.7) year old men (n = 9) and women (n = 25) with mean BMI of 31.8 (SD5.7) kg/m2. The Palaeolithic-type diet resulted in lower systolic blood pressure (-9.1 mmHg; P = 0.015), diastolic blood pressure (-5.2 mmHg; P = 0.038), total cholesterol (-0.52 mmol/l; P = 0.037), triglycerides (-0.89 mmol/l; P = 0.001) and higher HDL-cholesterol (+0.15 mmol/l; P = 0.013), compared to reference. The number of characteristics of the metabolic syndrome decreased with 1.07 (P = 0.010) upon the Palaeolithic-type diet, compared to reference. Despite efforts to keep bodyweight stable, it decreased in the Palaeolithic group compared to reference (-1.32 kg; P = 0.012). However, favourable effects remained after post-hoc adjustments for this unintended weight loss. No changes were observed for intestinal permeability, inflammation and salivary cortisol. CONCLUSIONS We conclude that consuming a Palaeolithic-type diet for two weeks improved several cardiovascular risk factors compared to a healthy reference diet in subjects with the metabolic syndrome. TRIAL REGISTRATION Nederlands Trial Register NTR3002.