Beetroot beneficial for athletes and heart failure patients, research finds
Football teams are claiming it improves their athletic performance, and according to new research from Kansas State University, it also benefits heart failure patients. The special ingredient: beetroot.
Recently, the Auburn University football team revealed its pregame ritual of taking beetroot concentrate, or beet juice, before each game. The juice may have contributed to the team's recent winning season — and one exercise physiologist who has been studying the supplement for several years says that may be the case.
"Our research, published in the journal Physiology in 2013, has shown that the nitrate found in beetroot concentrate increases blood flow to skeletal muscles during exercise," said David Poole, professor of exercise kinesiology and anatomy and physiology at Kansas State University. The journal Physiology is widely regarded as the world's premiere physiology journal.
The researchers' latest study, "Microvascular oxygen pressures in muscles comprised of different fiber types: Impact of dietary nitrate supplementation," was published in the Journal of Nitric Oxide, Biology and Chemistry. This work provides the basis for how beetroot juice may benefit football players by preferentially increasing blood flow to fast-twitch muscle fibers — the ones used for explosive running. This work was performed by Poole; Scott Ferguson, doctoral student in anatomy and physiology; and Timothy Musch, professor of exercise kinesiology and anatomy and physiology, all at Kansas State University.
In addition to improving athletic performance, the research also found that beetroot juice can improve the quality of life for heart failure patients.
"Remember, for every one football player in the United States, there are many thousands of heart failure patients that would benefit from this therapy," Poole said. "It's a big deal because even if you can only increase oxygen delivery by 10 percent, that can be the difference between a patient being wheelchair-bound versus getting up and walking around and interacting with his or her family."
The benefits of beetroot come from the nitrate found within it. The amount of nitrate in one 70-milliliter bottle of beetroot juice is about the same amount found in 100 grams of spinach.
"When consumed, nitrate is reduced in the mouth by bacteria into nitrite," Ferguson said. "The nitrite is swallowed again and then reduced to nitric oxide, which is a potent vasodilator. The nitric oxide dilates the blood vessels, similar to turning on a water faucet, and allows blood to go where it needs to go."
The beetroot juice consumption resulted in a 38 percent higher blood flow to the skeletal muscles during exercise and was preferential to the less-oxygenated, fast-twitch muscles.
"Heart failure is a disease where oxygen delivery to particular tissues, especially working skeletal muscles, is impaired, decreasing the capacity to move the arms or legs and be physically active," Poole said. "The best therapy for these patients is getting up and moving around. However, that is often difficult. Increasing the oxygen delivery to these muscles through beetroot can provide a therapeutic avenue to improve the quality of life for these patients."
Beets could lower risk of heart disease
New research from the University of Reading has shown that eating four slices of bread containing beetroot lowers blood pressure and improves the function of blood vessels, significantly improving heart health.
The researchers provided 24 participants with four slices (200g) of bread containing 100g of beetroot, or control bread with no beetroot enrichment once on two separate occasions. They found the diastolic¹ blood pressure of those who consumed ‘beetroot bread' was lowered by up to 7 mmHg when compared to the control group approximately 3 hours after consumption.
Evidence suggests that a reduction in diastolic blood pressure of 5-6 mmHg over a five year period could reduce the chances of a stroke by 38% and coronary heart disease by 23% less. In addition, prolonged high blood pressure is an important risk factor for the development of heart disease, which is the single biggest killer in the UK, causing nearly 179, 000 deaths per year.
The component of beetroot bread thought to be responsible for the beneficial effects on blood vessel function and blood pressure is dietary nitrate. Dietary nitrate is a natural component of beetroot and a number of other vegetables such as spinach, lettuce and rocket.
When dietary nitrate is eaten it produces nitric oxide in the blood vessel wall which causes relaxation of the vessel and increased blood flow. This ultimately results in lowering of blood pressure and an improvement in blood vessel function.
Julie Lovegrove, Professor of Human Nutrition, Head of the Hugh Sinclair Unit of Human Nutrition and the Deputy Director of the Institute for Cardiovascular and Metabolic Research (ICMR) at the University of Reading, who led the study said: "These exciting and novel findings show for the first time that bread containing beetroot improves blood vessel function. This is an important addition to the increasing body of evidence that suggests beneficial effects of dietary nitrate rich foods on the heart.
"This research also supports the findings of our previous study which was carried out last year and showed that beetroot in the form of juice or bread lowers blood pressure. Collectively, these studies suggest a potential role for foods rich in dietary nitrate in the management of high blood pressure."
The study, published in the Journal of Nutrition, was undertaken by Dr Ditte Hobbs in the University of Reading's Hugh Sinclair Human Nutrition Group, which has an international reputation for its research into the relationship between diet and the risk of chronic disease such as cardiovascular disease, diabetes, neurodegenerative disease and cancer.
Drinking Cup of Beetroot Juice Daily May Help Lower Blood Pressure
A cup of beetroot juice a day may help reduce your blood pressure, according to a small study in the American Heart Association journal Hypertension.
People with high blood pressure who drank about 8 ounces of beetroot juice experienced a decrease in blood pressure of about 10 mm Hg. But the preliminary findings don't yet suggest that supplementing your diet with beetroot juice benefits your health, researchers said.
"Our hope is that increasing one's intake of vegetables with a high dietary nitrate content, such as green leafy vegetables or beetroot, might be a lifestyle approach that one could easily employ to improve cardiovascular health," said Amrita Ahluwalia, Ph.D., lead author of the study and a professor of vascular pharmacology at The Barts and The London Medical School in London.
The beetroot juice contained about 0.2g of dietary nitrate, levels one might find in a large bowl of lettuce or perhaps two beetroots. In the body the nitrate is converted to a chemical called nitrite and then to nitric oxide in the blood. Nitric oxide is a gas that widens blood vessels and aids blood flow.
"We were surprised by how little nitrate was needed to see such a large effect," Ahluwalia said. "This study shows that compared to individuals with healthy blood pressure much less nitrate is needed to produce the kinds of decreases in blood pressure that might provide clinical benefits in people who need to lower their blood pressure. However, we are still uncertain as to whether this effect is maintained in the long term."
The study involved eight women and seven men who had a systolic blood pressure between 140 to 159 millimeters of mercury (mm Hg), did not have other medical complications and were not taking blood pressure medication. The study participants drank 250 mL of beetroot juice or water containing a low amount of nitrate, and had their blood pressure monitored over the next 24 hours.
Blood pressure is typically recorded as two numbers. Systolic blood pressure, which is the top number and the highest, measures the pressure in the arteries when the heart beats. Diastolic blood pressure, the bottom and lower number, measures blood pressure in the arteries between heart beats.
Compared with the placebo group, participants drinking beetroot juice had reduced systolic and diastolic blood pressure -- even after nitrite circulating in the blood had returned to their previous levels prior to drinking beetroot. The effect was most pronounced three to six hours after drinking the juice but still present even 24 hours later.
In the United States, more than 77 million adults have diagnosed high blood pressure, a major risk factor for heart diseases and stroke. Eating vegetables rich in dietary nitrate and other critical nutrients may be an accessible and inexpensive way to manage blood pressure, Ahluwalia said.
Getting people to eat more fruits and vegetables is challenging, but results of the study offer hope, she said. "In the U.K., the general public is told that they should be eating five portions of fruit or vegetables a day but this can be hard to do. Perhaps we should have a different approach to dietary advice. If one could eat just one (fruit or vegetable) a day, this is one more than nothing and should be viewed as positive."
The USDA recommends filling half your plate with fruits and vegetables, and the American Heart Association recommends eating eight or more fruit and vegetable servings every day.
Want more efficient muscles? Eat your beets and spinach
After taking a small dose of inorganic nitrate for three days, healthy people consume less oxygen while riding an exercise bike. A new study in the February, 2011 issue of Cell Metabolism traces that improved performance to increased efficiency of the mitochondria that power our cells.
The researchers aren't recommending anyone begin taking inorganic nitrate supplements based on the new findings. Rather, they say that the results may offer one explanation for the well-known health benefits of fruits and vegetables, and leafy green vegetables in particular.
"We're talking about an amount of nitrate equivalent to what is found in two or three red beets or a plate of spinach," said Eddie Weitzberg of the Karolinska Institutet in Sweden. "We know that diets rich in fruits and vegetables can help prevent cardiovascular disease and diabetes but the active nutrients haven't been clear. This shows inorganic nitrate as a candidate to explain those benefits."
In fact, up until recently nitrate wasn't thought to have any nutritional value at all. It has even been suggested that this component of vegetables might be toxic. But Weitzberg and his colleague Jon Lundberg earlier showed that dietary nitrate feeds into a pathway that produces nitric oxide with the help of friendly bacteria found in our mouths. Nitric oxide has been known for two decades as a physiologically important molecule. It opens up our blood vessels to lower blood pressure, for instance.
The new study offers yet another benefit of nitrate and the nitric oxides that stem from them. It appears that the increased mitochondrial efficiency is owed to lower levels of proteins that normally make the cellular powerhouses leaky. "Mitochondria normally aren't fully efficient," Weitzberg explained. "No machine is."
Questions do remain. The new results show that increased dietary nitrate can have a rather immediate effect. But it's not yet clear what might happen in people who consume higher levels of inorganic nitrate over longer periods of time. Weitzberg says it will be a natural next step to repeat the experiment in people with conditions linked to mitochondrial dysfunction, including diabetes and cardiovascular disease, to see if they too enjoy the benefits of nitrates.
"Among the more consistent findings from nutritional research are the beneficial effects of a high intake of fruit and vegetables in protection against major disorders such as cardiovascular disease and diabetes," the researchers concluded. "However, the underlying mechanism(s) responsible for these effects is still unclear, and trials with single nutrients have generally failed. It is tempting to speculate that boosting of the nitrate-nitrite-NO pathway may be one mechanism by which vegetables exert their protective effects."
As an interesting aside, Weitzberg says that the benefits of dietary nitrates suggest that powerful mouthwashes may have a downside. "We need oral bacteria for the first step in nitrate reduction," he says. "You could block the effects of inorganic nitrate if you use a strong mouthwash or spit [instead of swallowing your saliva]. In our view, strong mouthwashes are not good if you want this system to work."
The group has also recently shown that nitrate reduces the blood pressure of healthy individuals and that in laboratory animals it counteracts components of the metabolic syndrome, a pre-stage of diabetes. Other scientists have demonstrated protective effects of nitrate and nitrite in animal models against heart attack and stroke.