- High blood pressure, or hypertension, raises the risk of heart disease and stroke, both of which are significant causes of mortality in the United States.
- Nutrition advice on how to decrease blood pressure generally includes using herbs and spices rather than salt to flavor meals. However, researchers know little about the health advantages of herbs and spices.
- A new randomized controlled experiment reveals that a diet rich in herbs and spices may lower blood pressure in those at risk of cardiovascular disease.
Dietary recommendations for controlling blood pressure involves limiting salt consumption. The Dietary Guidelines for Americans encourage using herbs and spices instead of salt to flavor meals.
Experts know less about the health consequences of herbs and spices than they do about those of salt. However, some studies have suggested that herbs and spices help lower lipemia — the excess of lipids in the blood — hyperglycemia, and oxidative stress.
To dive a bit further, researchers at Pennsylvania State University recently performed a randomized controlled experiment exploring the influence of longer-term use of herbs and spices on risk factors for cardiovascular disease.
They observed that a higher amount of herbs and spices in diet lowered 24-hour blood pressure measurements.
The study’s results were published in the American Journal of Clinical Nutrition.
Prof. Penny Kris-Etherton, one of the principal authors of the study, told Medical News Today, “Indeed, the blood pressure-lowering benefits of herbs and spices in an ordinary Western diet were surprise to me.”
“We [already know] about the effects of many lifestyle factors, especially dietary factors, that can increase blood pressure — such as sodium, alcohol, and caffeine — and others that can decrease blood pressure, such as potassium, magnesium, and calcium, […] weight loss, physical activity, and some vitamins, including folate and vitamin D when intake is low, but the blood pressure-lowering effects of herbs and spices are new!”
“In terms of herbs and spices,” she said, “there hasn’t been a clinical investigation indicating advantages on blood pressure reduction until our study.”
Three test diets
After the subjects fasted for 12 hours, the researchers completed baseline evaluations. These included height, weight, waist circumference, a fasting blood sample, and vascular testing.
Vascular examination comprised central and peripheral blood pressure and artery stiffness assessments. The participants also wore a blood pressure monitor for 24 hours.
The researchers then randomly allocated the subjects to one of three groups. Each group would consume one of three diets: a low spice diet, a moderately spiced diet, or a high spice diet. These diets contained a daily consumption of 0.5 grams (g), 3.3 g, and 6.6 g of herbs and spices, respectively.
The individuals followed their various diets for 4 weeks, with a 2-week vacation in between. At the end of each diet phase, the subjects returned for follow-up examinations. A total of 63 participants finished the trial.
Improvement in blood pressure
The study found that the high spice diet tended to enhance 24-hour blood pressure measurements, compared with the medium and low spice diets.
The researchers did not notice any effect of the diets on low-density lipoprotein cholesterol, clinic-measured blood pressure, indicators of glycemia, vascular function, or oxidative stress.
However, they suggest that 24-hour blood pressure data are a greater predictor of cardiovascular mortality than clinic blood pressure measurement.
The authors feel the research was too brief for vascular remodeling to occur, which might explain why no effect on arterial stiffness was seen.
They also point out that the doses of herbs and spices may not be sufficient to counteract the metabolic consequences of a poor diet. As a result, they cannot propose increasing the intake of herbs and spices alone to reduce the risk of cardiovascular disease in the setting of a poor quality diet.
Furthermore, because the 24 herbs and spices were used in varied amounts on different days of the week, exposure was not constant. Because herbs and spices do not stay in the system for very long, the food eaten in the days leading up to the test may have had a greater impact on the findings.
“This study implies there might be potential advantage in terms of blood pressure reduction by having more herbs and spices within our diet,” Dr. Simon Steenson, a nutrition scientist at the British Nutrition Foundation, told MNT.
“However,” he continued, “the effects seen were small and not significant between all levels of intake. While the authors suggest there may be some benefit to including herbs and spices in a suboptimal diet, clearly, the aim from a public health point of view must be to improve dietary patterns in line with evidence-based guidance on diet and health.”
“It will be important to examine the effects of specific spices on blood pressure and to understand the mechanism[s] by which each decreases blood pressure,” Prof. Kris-Etherton told MNT.
“It would also be interesting to analyze the effects of herbs and spices on the microbiome, and to see if any changes in the gut microbiota regulate the effects of herbs and spices on [blood pressure].”
“In addition to clinical trial research, studies are needed to evaluate the impact of effective education programs that teach the use of herbs and spices in a healthy dietary pattern that is lower in sodium, saturated fat, and added sugar on diet quality and clinical endpoints, such as chronic disease risk factors.”
Dr. Steenson came to the following conclusion:
“It is important to note that while the aim of this study was to look at the average American diet, we need major shifts in average dietary patterns to make our eating habits healthier and more sustainable. While certain foods or ingredients may have a small benefit alone, we need to encourage a shift to healthier eating across the board.”