Are There Health Benefits of Beetroot Juice for Athletes?

Written by Dr. Steve Chaney on . Posted in current health articles, Exercise, Food and Health

Should You Add Beetroot Juice To Your Training Diet?

Author: Dr. Stephen Chaney

 

health benefits of beetroot juiceWhen I saw the headline “Beetroot Juice May Boost Aerobic Fitness For Swimmers” I did a double take. Could something as simple as eating more beets actually improve exercise performance? Are there real health benefits of beetroot juice for athletes?  So I looked up recent papers on the topic.  But, before I review those I should give you a little science behind the idea that beetroot juice might affect performance.

The Science Behind Beetroot Juice And Exercise

Nitric oxide is a colorless, odorless gas that serves as an important signaling molecule in the human body. Among its many beneficial effects is increased blood flow to muscle. This increased blood flow appears to be preferentially distributed to the type 2 muscle fibers which support moderate to high intensity exercise. Thus, nutrients that enhance nitric oxide levels might be expected to improve moderate to high intensity exercise.

There are two naturally occurring pathways for producing nitric oxide in the body. The first pathway utilizes arginine, an amino acid found in dietary protein. The second pathway utilizes nitrates, which are found in fruits and vegetables. The best dietary sources of nitrates are beetroot, spinach and other leafy green vegetables.

Arginine has been widely used in sports supplements for some time to enhance performance. However, clinical studies on arginine have been mixed, with some showing small enhancements in performance and others showing no significant effect. Most experts now think that the benefits of arginine are primarily seen with untrained or moderately trained athletes (people like you and me) – not for highly trained or elite athletes.

It is logical that natural sources of nitrates, such as beetroot juice, would have a similar beneficial effect on exercise, but it is only in the last couple of years that scientists have started to evaluate that possibility. I looked up six recent publications for this review.

Does Beetroot Juice Improve Exercise Performance?

Study # 1: In this study (Bailey et al, J. Appl. Physiol., 107: 1144-1155, 2009) untrained men (aged 19-38) were given beetroot juice or a placebo for 6 days and then put through a series moderate-intensity and severe-intensity step exercise tests on days 4-6. The amount of oxygen required to support the moderate intensity exercise was decreased by 19% in the beetroot juice group. For severe intensity exercise, the amount of oxygen needed to support the exercise was decreased by 23% and the time to exhaustion was increased by 16% in the beetroot juice group. Those effects were statistically significant.

Study # 2: In this study (Kelly et al, Am. J. Physiol. Regul. Integr. Comp. Physiol., 304: R73-83, 2013) untrained older adults (aged 60-70) were given beetroot juice or a placebo for 3 days and then put through a treadmill exercise test. Resting blood pressure and oxygen uptake kinetics during exercise were significantly improved in the beetroot group.

Study # 3: In this study (Breese et al, Am. J. Physiol. Regul. Integr. Comp. Physiol., 305: R1441-14505, 2013) physically active subjects were given beetroot juice or a placebo for 6 days and then put through a double step exercise protocol involving a transition from stationary to moderate intensity exercise followed immediately by a transition from moderate intensity to severe intensity exercise. No significant differences were observed between the beetroot juice group and the placebo group during the transition from stationary to moderate intensity exercise. However, for the transition from moderate intensity to high intensity exercise both efficiency of oxygen utilization and endurance were increased by 22% in the beetroot juice group.

does beetroot juice improve exercise performance

Study # 4: In this study (Pinna et al, Nutrients, 6: 605-615, 2014) moderately trained male master swimmers were given beetroot juice for 6 days. Swimming tests were conducted at the beginning and end of the 6 day period. After 6 days of beetroot juice supplementation, the workload was increased by 6% and the energy cost was decreased by 12% when the swimmers were performing at their maximal capacity.

Studies # 5 & 6: These studies (Lanceley et al, British Journal of Sports Medicine, 47: doi: 10.1136/bjsports-2013-093073.8; Hoon et al, Int. J. Sports Physiol. Perform., 9: 615-620, 2014) were both done with highly trained athletes and no significant improvement in performance was observed. This is fully consistent with previous studies utilizing arginine supplements.

In short, these studies suggest that beetroot juice is similar to arginine supplements in that:

  • It improves exercise performance at moderate to severe exercise levels, but not at low exercise levels.
  • It improves exercise performance for untrained or moderately trained athletes, but not for highly trained athletes.
  • The effects are modest. However, you should keep in mind that even a 20% increase in endurance during high intensity exercise can result in a significant incremental increase in muscle mass if the exercise is repeated on a regular basis.

What Are The Strengths & Weaknesses Of These Studies?

Strengths: The strengths of these studies are:

  • Most of the studies were double-blind, placebo controlled studies
  • The studies were internally consistent and were consistent with previous studies done with arginine supplements.

Weaknesses: The weaknesses of these studies are:

  • The studies were all very small and were of short duration. Larger, longer term studies are needed to validate the results of these studies.

So, are there health benefits of beetroot juice for athletes?

The Bottom Line:

  1. Nitrates and arginine are both converted to nitric oxide in the body, so it is plausible that they will have similar effects.
  1. Arginine supplements have been around for years and appear to have a modest affect on exercise performance with untrained and moderately trained athletes, but not with highly trained athletes. This is most likely because one of the effects of training is to increase blood supply to the muscles. Thus, highly trained athletes already have enhanced blood flow to the muscles, and the effect of arginine supplementation on blood flow is less noticeable.
  1. Nitrate supplements are just starting to be evaluated for their effects on exercise performance. Most of the research so far has been with beetroot juice, but the results should be similar for any naturally sourced nitrate supplement.
  1. The clinical studies published so far suggest that nitrate supplements are similar to arginine supplements in that they have a modest effect on high intensity exercise in untrained and moderate trained athletes (people like most of us). They appear to have little or no effect for highly trained athletes. Thus, the effect of nitrate supplements on exercise appears to be very similar to the effect of arginine supplements on exercise.
  1. Most of the studies performed to date have been small, short duration studies. They need to be validated by larger, longer term studies.
  1. If the effects of nitrate supplementation published to date are accurate they should be most beneficial for weight training and high intensity exercise because even modest increases in exercise endurance can result in an incremental increase in muscle mass and strength over time.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Do Omega-3s Lower Blood Pressure in Young, Healthy Adults?

Posted August 14, 2018 by Dr. Steve Chaney

What Is The Omega-3 Index And Why Is It Important?

Author: Dr. Stephen Chaney

 

Do omega-3s lower blood pressure in healthy adults?

omega-3s lower blood pressure young adultsThe literature on the potential health benefits of omega-3s is very confusing. That’s because a lot of bad studies have been published. Many of them never determined the omega-3 status of their subjects prior to omega-3 supplementation. Others relied on dietary recalls of fish consumption, which can be inaccurate.

Fortunately, a much more accurate measure of omega-3 status has been developed and validated in recent years. It’s called the Omega-3 Index. Simply put, the Omega-3 Index is the percentage of EPA and DHA compared to 26 other fatty acids found in cellular membranes. Using modern technology, it can be determined from a single finger prick blood sample. It is a very accurate reflection of omega-3 intake relative to other fats in the diet over the past few months. More importantly, it is a measure of the omega-3 content of your cell membranes, which is a direct measure of your omega-3 nutritional status.

A recent extension of the Framingham Heart Study reported that participants with an Omega-3 Index >6.8% had a 39% lower risk of cardiovascular disease than those with an Omega-3 Index <4.2% (WS Harris et al, Journal of Clinical Lipidology, 12: 718-724, 2018 ). Although more work needs to be done, an Omega-3 Index of 4% or less is generally considered indicative of high cardiovascular risk, while 8% or better is considered indicative of low cardiovascular risk. For reference, the average American has an Omega-3 Index in the 4-5% range. In Japan, where fish consumption is much higher and cardiovascular risk much lower, the Omega-3 Index is in the 9-11% range.

Previous studies have suggested that omega-3 fatty acids lower blood pressure to a modest extent. Thus, it is not surprising that more recent studies have shown an inverse correlation between Omega-3 Index and blood pressure. However, those studies have been done with older populations, many of whom had already developed high blood pressure.

From a public health point of view, it is much more interesting to investigate whether it might be possible to prevent high blood pressure in older adults by optimizing omega-3 intake in a young, healthy population, most of whom had not yet developed high blood pressure. Unfortunately, there were no studies looking at that population. The current study was designed to fill that gap.

 

How Was The Study Done?

omega-3s lower blood pressure young healthy adultsThe current study (M.G. Filipovic et al, Journal of Hypertension, 36: 1548-1554, 2018 ) was based on data collected from 2036 healthy adults, aged 25-41, from Liechtenstein. They were participants in the GAPP (Genetic and Phenotypic Determinants of Blood Pressure) study. Participants were excluded from the study if they had been diagnosed with high blood pressure and were taking medication to lower their blood pressure. They were also excluded if they had heart disease, chronic kidney disease, other severe illnesses, obesity, sleep apnea, or daily use of non-steroidal anti-inflammatory medications.

Blood samples were collected at the time of their enrollment in the study and frozen for subsequent determination of Omega-3 Index. Blood pressure was also measured at their time of enrollment in two different ways. The first was a standard blood pressure measurement in a doctor’s office.

For the second measurement they were given a wearable blood pressure monitor that recorded their blood pressure over 24 hours every 15 minutes during the day and every 30 minutes while they were sleeping. This is considered more accurate than a resting blood pressure measurement in a doctor’s office because it records the variation in blood pressure, while you are sleeping, while you are exercising, and while you go about your everyday activities.

 

Do Omega-3s Lower Blood Pressure In Young, Healthy Adults?

omega-3s lower blood pressure young adults equipmentNone of the participants in the study had significantly elevated blood pressure. The mean systolic and diastolic office blood pressures were 120±13 and 78±9 respectively. The average Omega-3 Index in this population was 4.6%, which is similar to the average Omega-3 Index in the United States.

When they compared the group with the highest Omega-3 Index (average = 5.8%) with the group with the lowest Omega-3 Index (average = 4.6%):

  • The office measurement of systolic and diastolic blood pressure was decreased by 3.3% and 2.6% respectively
  • While those numbers appear small, the differences were highly significant.
  • The 24-hour blood pressure measurements showed a similar decrease.
  • Blood pressure measurements decreased linearly with increasing Omega-3 Index. [In studies of this kind, a linear dose-response is considered an internal validation of the differences observed between the group with the highest Omega-3 Index and the group with the lowest Omega-3 Index.]

The authors concluded: “A higher Omega-3 Index is associated with statistically significant, clinically relevant, lower systolic and diastolic blood pressure in normotensive, young and healthy individuals. Diets rich omega-3 fatty acids may be a strategy for primary prevention of hypertension.”

 

What Does This Mean For You?

omega-3s lower blood pressure young adults questionPerhaps I should first comment on the significance of the relatively small decrease in blood pressure observed in this study.

  • These were young adults, all of whom had normal or near normal blood pressure.
  • The difference in Omega-3 Index was rather small (5.8% to 4.6%). None of the participants in the study were at the 8% or above that is considered optimal.
  • Liechtenstein is a small country located between Switzerland and Spain. Fish consumption is low and omega-3 supplement consumption is rare.

Under these conditions, even a small, but statistically significant, decrease in blood pressure is remarkable.

We should think of this study as the start of the investigation of the relationship between omega-3 status and blood pressure. Its weakness is that it only shows an association between high Omega-3 Index and low blood pressure. It does not prove cause and effect.

Its strength is that it is consistent with many other studies showing omega-3 fatty acids lower blood pressure. Furthermore, it suggests that the effect of omega-3s on blood pressure may also be seen in young, healthy adults who have not yet developed high blood pressure.

Finally, the authors suggested that a diet rich in omega-3s might reduce the incidence of high blood pressure by slowing the age-related increase in blood pressure that most Americans experience. This idea is logical, but speculative at present.

However, the GAPP study is designed to provide the answer to that question. It is a long-term study with follow-up examinations scheduled every 3-5 years. It will be interesting to see whether the author’s prediction holds true, and a higher Omega-3 Index is associated with a slower increase in blood pressure as the participants age.

 

Why Is The Omega-3 Index Important?

 

The authors of this study said: “The Omega-3 Index is very robust to short-term intake of omega-3 fatty acids and reliably reflects an individual’s long-term omega-3 status and tissue omega-3 content. Therefore, the Omega-3 Index has the potential to become a cardiovascular risk factor as much as the HbA1c is for people with diabetes…” That is a bit of an overstatement. HbA1c is a measure of disease progression for diabetes because it is a direct measure of blood sugar control.

In contrast, Omega-3 Index is merely a risk factor for cardiovascular disease. However, if it is further validated by future studies, it is likely to be as important for predicting cardiovascular risk as are cholesterol levels and markers of inflammation.

However, to me the most important role of Omega-3 Index is in the design of future clinical studies. If anyone really wants to determine whether omega-3 supplementation reduces cardiovascular risk, high blood pressure, diabetes or any other health outcome they should:

  • Start with a population group with an Omega-3 Index in the deficient (4-5%) range.
  • Supplement with omega-3 fatty acids in a double blind, placebo-controlled manner.
  • Show that supplementation brought participants up to an optimal Omega-3 Index of 8% or greater.
  • Look at health outcomes such as heart attacks, cardiovascular deaths, hypertension, stroke, or depression.
  • Continue the study long enough for the beneficial effects of omega-3 supplementation to be measurable. For cardiovascular outcomes the American Heart Association has stated that at least two years are required to obtain meaningful results.

These are the kind of experiments that will be required to give definitive, reproducible results and resolve the confusion about the health effects of omega-3 fatty acids.

 

The Bottom Line

 

An accurate measure of omega-3 status has been developed and validated in recent years. It’s called the Omega-3 Index. Simply put, the Omega-3 Index is the percentage of EPA and DHA compared to 26 other fatty acids found in cellular membranes.

Although more work needs to be done, an Omega-3 Index of 4% or less is generally considered indicative of high cardiovascular risk while 8% or better is considered indicative of low cardiovascular risk.

Previous studies have shown an inverse correlation between Omega-3 Index and blood pressure. However, these studies have been done with older populations, many of whom had already developed high blood pressure.

From a public health point of view, it is much more interesting to investigate whether it might be possible to prevent high blood pressure in older adults by optimizing omega-3 intake in a young, healthy population, most of whom had not yet developed high blood pressure. Until now, there have been no studies looking at that population.

The study described in this article was designed to fill that gap. The participants in this study were ages 25-41, were healthy, and none of them had elevated blood pressure.

When the group with the highest Omega-3 Index (average = 5.8%) was compared with the group with the lowest Omega-3 Index (average = 4.6%):

  • Both systolic and diastolic blood pressure were decreased
  • Blood pressure measurements decreased linearly with increasing Omega-3 Index.

The authors concluded: “A higher Omega-3 Index is associated with statistically significant, clinically relevant, lower systolic and diastolic blood pressure in normotensive, young and healthy individuals. Diets rich omega-3 fatty acids may be a strategy for primary prevention of hypertension.”

Let me translate that last sentence into plain English for you. The authors were saying that optimizing omega-3 intake in young adults may slow the age-related increase in blood pressure and reduce the risk of them developing high blood pressure as they age. This may begin to answer the question “Do omega-3s lower blood pressure in young, healthy adults?”

Or even more simply put: Aging is inevitable. Becoming unhealthy is not.

For more details, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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