Daily beetroot juice may promote cardiovascular health in women at the postmenopausal stage, a new study claims. The juice may be a good source of critical nitrate that keeps blood vessels functioning well. The study found, however, that when participants stopped drinking beetroot juice, the beneficial effects waned within 24 hours. During and after menopause, the body produces less estrogen, often leading to poorer blood vessel function and a greater risk of cardiovascular disease. A new randomized, placebo-controlled, double-blind, crossover clinical trial from The Pennsylvania State University (Penn State) suggests that consuming beetroot juice daily may improve blood flow through blood vessels, reducing the risk of heart problems. Beets — and beetroot juice — are high in nitrates. The study observed improved blood vessel performance in participants who drank beetroot juice daily. The findings appear in the journal Frontiers in Nutrition.
The researchers recruited an initial 54 women at the postmenopausal stage from the local community, but the final analysis included only 24 women: 12 in early postmenopause and 12 in late postmenopause. The participants had a resting blood pressure of less than 130/80 millimeters of mercury (mmHg), body mass index (BMI) between 18.5 to 35 kilograms per square meter (kg/m2), fasting low-density lipoprotein (LDL) cholesterol below 160 milligrams per deciliter (mm/dL), a hemoglobin A1C below 6%, and normal fasting blood sugar. They were all nonsmokers, and were not taking any cardiovascular medications or hormones at the time of the study. Under otherwise strict dietary guidance, the participants consumed two 2.3-ounce bottles of concentrated beetroot juice at the start of the study, followed by one bottle daily for one week. Each bottle delivered the same level of nitrates as three large beets. A few weeks later, individuals received beetroot juice from which the nitrate had been removed, serving as a placebo. The study authors performed imaging via Doppler ultrasound to assess the effect of the beetroot juice on participants’ brachial artery blood flow — the brachial artery is on the inside of one’s upper arm — before and after consumption, and the same was done with the placebo. The authors concluded that blood flow was improved while the participants were consuming their daily nitrate-rich beetroot juice, but the effect faded within 24 hours of drinking their last bottle. Additionally, neither the nitrate-rich beetroot juice nor placebo prevented the decline in blood flow after ischemia-reperfusion (IR) injury in either group.
Jayne Morgan, MD, cardiologist and the Executive Director of Health and Community Education at the Piedmont Healthcare Corporation in Atlanta, GA, who was not involved in the study, spoke to Medical News Today about its findings. Morgan explained that in menopause, “[a]s estrogen levels decrease, there is loss of the cardioprotective effects of estrogen on the heart.” “The reduction of estrogen production during the menopausal transition accelerates development of heart disease risk factors, such as increased LDL cholesterol, vascular stiffening, and high blood pressure,” said the study’s senior author, Jocelyn M. Delgado Spicuzza, PhD, of Pennsylvania State University’s College of Nursing. This cluster of risk factors renders the vasculature vulnerable to cardiovascular diseases — atherosclerosis, stroke, heart attack, etc. — and therefore increases heart disease risk following menopause, Delgado Spicuzza explained. Compounding these effects, noted Morgan, is the fact that estrogen serves as both an antioxidant and anti-inflammatory agent, helping reduce the development of plaques that can lead to heart attacks. In addition, “vasomotor symptoms are increasingly being recognized as not the innocuous and prerequisite silent suffering of women, but rather decreased sleep is a risk factor for heart disease,” Morgan said.
“Consuming nitrate through plants is a secondary pathway to increase the availability of nitric oxide in the body,” said Delgado Spicuzza. “[This is] a molecule responsible for widening blood vessels to accommodate blood flow and oxygen delivery to organs such as the heart,” she explained. “Since estrogen is no longer sufficient to stimulate nitric oxide production in the body naturally following menopause, dietary nitrate can be converted to nitric oxide through the entero-salivary pathway to help maintain healthy blood vessel functioning,” said Delgado Spicuzza. It is important, the study author further asserted, to be clear regarding the types of nitrates that can help improve blood vessel function. “Since plants contain nitrate from the soil, there is technically only one type of ‘nitrate’ in these natural food sources,” she said. “However,” Delgado Spicuzza continued, “when talking about nitrate in terms of preservatives or additives in animal products, there can be several forms of nitrate, which some term as ‘nitrates.’ I think using the singular form of nitrate is more accurate for describing the benefits of beetroot juice and the results from my research.” A positive aspect of plant-sourced dietary nitrate is that, unlike heart medications such as nitroglycerin, it retains its effectiveness with continued use.
As for the best sources of nitrate, Delgado Spicuzza advised: “Leafy green vegetables (lettuce, arugula, cabbage, spinach), stem and shoot vegetables (celery, rhubarb), herbs (basil, cilantro), and root vegetables (radish, beet, turnip) are the highest sources of dietary nitrate.” She added that “further research is needed to investigate if consumption of these foods can improve blood vessel function in post-menopausal women.” Plant-based nitrate is preferable from a health perspective compared to meat-based nitrate. As Morgan put it, “overall dietary context matters. A plant-based lifestyle that may include nitrate-rich consumption of beets, is associated with a number of health benefits and outcomes, including a lower risk of heart disease, cancers, and other chronic disease processes.” On the other hand, cardiologist Cheng-Han Chen, MD, of Saddleback Medical Center, CA, also not involved in the study, cautioned: “A carnivorous diet that is high in processed meats. You will get some effects from the nitrate, but you’re taking on all the other parts of it, which are the high-fat part of the meat.”
There are plenty of other heart-healthy foods for women at the postmenopausal stage, said Morgan. She cited the following as beneficial for cardiovascular health: pomegranate juice, citrus fruits and juices, dark chocolate, leafy green vegetables, berries, olive oil, garlic, fish and omega-3 fatty acids, and green tea. “Although the premise of this study makes sense, the study by itself would not make me start recommending beets to postmenopausal women,” said Chen. “It would be important to see larger trials that look at clinical outcomes, whether these women have fewer cardiovascular events in the future if they continue a high-nitrate diet,” he noted. For now, Chen’s recommendations remain unchanged, meaning “a heart-healthy diet that involves plenty of whole grains, fruits and vegetables, low salt, avoiding saturated fats, avoiding highly processed foods, and avoiding lots of sugar.” Morgan said she is also unlikely to alter what she tells patients based on this study. “But it is something to consider from an allopathic and dietary purview,“ she nevertheless noted. “We are what we eat, and food is increasingly being recognized as medicine.”
