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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
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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.
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The benefits and risks of beetroot juice consumption: a systematic review.
Zamani, H, de Joode, MEJR, Hossein, IJ, Henckens, NFT, Guggeis, MA, Berends, JE, de Kok, TMCM, van Breda, SGJ
Critical reviews in food science and nutrition. 2021;61(5):788-804
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Plain language summary
This review examined the health benefits and risks associated with beetroot juice (BRJ) from 86 studies. The nitrate contained in high amounts in BRJ increases nitric oxide (NO) levels in the body. NO has vasodilatory effects and thus reduces blood pressure and helps oxygen- and nutrient delivery to organs and muscles. Hence there has been an interest in BRJ for sports performance improvement and the prevention and treatment of cardiovascular disease. The review collected evidence of the effect of BRJ on the cardiovascular system and sports performance according to gender, trained and untrained individuals. Whilst the authors also briefly mention other health benefits of BRJ. From wider research, it is known that excess nitrate can form carcinogenic N-nitroso compounds (NOCs) in the body. Yet little is known whether this could also be a potential risk with BRJ consumption since vegetable consumption and many plant compounds generally appear to reduce the risk of cancers and can block the formation of NOCs. Hence the authors concluded that more research is needed to ensure that currently suggested dosages for BRJ do not aid NOCs production. In summary, BRJ has a beneficial effect on nitric oxide levels, oxygen consumption, blood flow, platelet aggregation, heart rate, cardiac output, blood pressure, improves sports performance and endurance and could be valuable for the management of cardiovascular disease. Yet high levels of consumption may not come without risks and more studies are needed to assess safety.
Abstract
Beetroot juice (BRJ) has become increasingly popular amongst athletes aiming to improve sport performances. BRJ contains high concentrations of nitrate, which can be converted into nitric oxide (NO) after consumption. NO has various functions in the human body, including a vasodilatory effect, which reduces blood pressure and increases oxygen- and nutrient delivery to various organs. These effects indicate that BRJ may have relevant applications in prevention and treatment of cardiovascular disease. Furthermore, the consumption of BRJ also has an impact on oxygen delivery to skeletal muscles, muscle efficiency, tolerance and endurance and may thus have a positive impact on sports performances. Aside from the beneficial aspects of BRJ consumption, there may also be potential health risks. Drinking BRJ may easily increase nitrate intake above the acceptable daily intake, which is known to stimulate the endogenous formation of N-nitroso compounds (NOC's), a class of compounds that is known to be carcinogenic and that may also induce several other adverse effects. Compared to studies on the beneficial effects, the amount of data and literature on the negative effects of BRJ is rather limited, and should be increased in order to perform a balanced risk assessment.
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Estimation of Primary Prevention of Gout in Men Through Modification of Obesity and Other Key Lifestyle Factors.
McCormick, N, Rai, SK, Lu, N, Yokose, C, Curhan, GC, Choi, HK
JAMA network open. 2020;3(11):e2027421
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Gout is prevalent in most Western countries. Modifying the contributary factors such as obesity and alcohol intake could prevent gout, however the impact this could have on prevention is unknown. This cohort study of 44,654 men, aimed to estimate the proportion of gout cases that could be prevented through the modification of risk factors. The results showed that the most important risk factor for gout was body mass index (BMI) and modifying other risk factors did not prevent gout. 77% of gout cases could be prevented if all men had been of normal weight, had no alcohol intake, if they adhered to a diet known as the Dietary Approaches to Stop Hypertension (DASH) diet and if they didn't take drugs to increase urine output. It was concluded that weight loss in men determines their ability to prevent gout, regardless of whether they have modified other contributory factors. This study could be used by healthcare professionals to understand that unless weight loss is achieved in individuals who are overweight and have gout, then other interventions may have minimal impact. Recommending the DASH diet to achieve weight loss, may be more successful in the long-term management of gout.
Abstract
Importance: The population impact of modifying obesity and other key risk factors for hyperuricemia has been estimated in cross-sectional studies; however, the proportion of incident gout cases (a clinical end point) that could be prevented by modifying such factors has not been evaluated. Objective: To estimate the proportion of incident gout cases that could be avoided through simultaneous modification of obesity and other key risk factors. Design, Setting, and Participants: The Health Professionals Follow-up Study is a US prospective cohort study of 51 529 male health professionals enrolled in 1986 and followed up through questionnaires every 2 years through 2012. Self-reported gout cases were confirmed through June 2015. Clean and complete data used for this analysis were available in June 2016, with statistical analyses performed from July 2016 to July 2019. Exposures: From data collected in the validated questionnaires, men were categorized to low-risk groups according to combinations of the following 4 factors: normal body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]; <25), no alcohol intake, adherence to Dietary Approaches to Stop Hypertension (DASH)-style diet (highest quintile of DASH diet score), and no diuretic use. Main Outcomes and Measures: Population attributable risks (PARs) for incident gout meeting the preliminary American College of Rheumatology survey criteria, overall and stratified by BMI. Results: We analyzed 44 654 men (mean [SD] age, 54.0 [9.8] years) with no history of gout at baseline. During 26 years of follow-up, 1741 (3.9%) developed incident gout. Among all participants, PAR for the 4 risk factors combined (BMI, diet, alcohol use, and diuretic use) was 77% (95% CI, 56%-88%). Among men with normal weight (BMI <25.0) and overweight (BMI 25.0-29.9), we estimated that more than half of incident gout cases (69% [95% CI, 42%-83%] and 59% [95% CI, 30%-75%], respectively) may have been prevented by the combination of DASH-style diet, no alcohol intake, and no diuretic use. However, among men with obesity (BMI ≥30), PAR was substantially lower and not significant (5% [95% CI, 0%-47%]). Conclusions and Relevance: The findings of this cohort study suggest that addressing excess adiposity and other key modifiable factors has the potential to prevent the majority of incident gout cases among men. Men with obesity may not benefit from other modifications unless weight loss is addressed.
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Potential Factors Influencing the Effects of Anthocyanins on Blood Pressure Regulation in Humans: A Review.
Vendrame, S, Klimis-Zacas, D
Nutrients. 2019;11(6)
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Anthocyanins (ACNs) are plant compounds belonging to the flavonoid group of polyphenols and are naturally occurring in a number of foods. They are responsible for the red, blue and purple pigmentation within plant foods, such as blueberries and raspberries and are known to contain therapeutic compounds. Several studies have investigated the anti-inflammatory, antioxidant and blood pressure modulation properties within ACNs, however, results for blood pressure modulation, unlike those for anti-inflammatory and antioxidant properties have been mixed and less consistent. This paper reviews 66 human intervention trials exploring the effects of various forms of ACNs, like whole berries, concentrates and freeze-dried powders in order to identify the singular variables related to blood pressure modulation in order to further investigate. Having looked at a number of variables within the trials, researchers concluded that ACNs do in fact contain blood pressure lowering properties, but further research into varying factors including dose effect, synergistic effects, absorption and metabolism and the functionality of the individuals gut microbiota is needed to clarify results further.
Abstract
Dietary intake of anthocyanins (ACNs) is associated with a reduced risk of cardiovascular and coronary heart disease. While the anti-inflammatory, antioxidant, and lipid-lowering effects of ACN consumption have been consistently reported, their effect(s) on blood pressure regulation is less consistent and results from human studies are mixed. The objective of this review is attempting to identify potential patterns which may explain the variability in results related to blood pressure. To do so, we review 66 human intervention trials testing the effects on blood pressure of purified ACN or ACN-rich extracts, or whole berries, berry juices, powders, purees and whole phenolic extracts, from berries that are rich in ACN and have ACNs as predominant bioactives. Several factors appear to be involved on the mixed results reported. In particular, the baseline characteristics of the population in terms of blood pressure and total flavonoid intake, the dose and duration of the intervention, the differential effects of individual ACN and their synergistic effects with other phytochemicals, the ACN content and bioavailability from the food matrix, and individual differences in ACN absorption and metabolism related to genotype and microbiota enterotypes.