Why is there so much buzz about beetroot?

Beetroot is a root vegetable that’s most often found in it’s purple/red variety. There are a few other varieties too, like yellow and orange. Beetroot is most often found in the UK in pickled form, added pre-cooked to salads, or used raw in juices. In the UK, beetroot gets its sweetness from being grown in the most fertile soul. Beetroot is ready to harvest around July and August, which makes it popular in summer dishes.

Beetroot has been said to have numerous health benefits. The three most common claims for beetroot are:

• It can lower blood pressure
• It can improve sports performance and recovery
• It can support the immune system

In this article, Katherine Kimber (Dietitian) gives an overview of the evidence for beetroot to bring clarity to these claims.

Beetroot and blood pressure

Blood pressure

Blood pressure is the force that blood is pushed around the body. High blood pressure (hypertension) is when this force is consistently high. This means the heart is being forced to work harder. High blood pressure is common in the UK, with 7 million people being affected (1).

Many people are not diagnosed because high blood pressure is often symptom-less. NICE Guidelines (evidence-based recommendations for health and care in England) encourage you to book an appointment with your GP if you have not had a check-up in a while (1). The usual treatment is a combination of medications and lifestyle modifications. These lifestyle modifications include reducing stress, dietary modifications including lowering salt intake, and frequent exercise. If high blood pressure goes untreated, it can increase risk of cardiovascular (heart) disease. This can lead to a higher risk of strokes and heart attacks (1).

Beetroot is often recommended for blood pressure by many sources, including health magazines. This is due to two features of beetroot; nitrates and fibre. After reviewing the evidence, there is some evidence that nitrates can help lower blood pressure. But, the role of fibre and blood pressure requires more research.

Nitrates and blood pressure

Nitrates are compounds found in some foods, like green vegetables and beetroot. The proposed reason nitrates lower blood pressure is because they increase blood flow thus reducing the heart’s work (2).

A 2014 study looked at the effect of nitrates in beetroot juice in people with hypertension. One group consumed 250ml of nitrate-containing beetroot juice daily. The other group had 250ml of nitrate-removed beetroot juice. Both groups self-recorded their blood pressure daily for 4 weeks (3). Those drinking the nitrate-containing juice had a reduction in blood pressure. Two weeks after the study people stopped drinking beetroot juice, blood pressure was re-measured. Those who consumed the nitrate-containing beetroot juice still had lowered blood pressure.

There were various limitations with this study. There was no follow-up past the final blood pressure measure. So it can’t be known if the results were long-lasting or if the study peoples’ blood pressure rose again. The results may also not be specific to beetroot, but for any other source of nitrate like cabbage or kale.

Fibre and blood pressure

Fibre is the indigestible part of carbohydrate-containing foods. The recommended intake is around 30g per day for adults (4). The investigation of fibre and health outcomes has increased in recent years. The effect that fibre has on blood pressure isn’t crystal clear.

There is only one known study on beetroot and blood pressure. This had older people (the average age was 67 years old) consume 150g of whole beetroot daily for 8 weeks. Those who consumed beetroot had decreased blood pressure, compared to the non-beetroot group (5). But more research is needed on a bigger scale, with more people. There is also a need to understand if these results are only applicable to older adults.

It’s also important to mention that 150g of beetroot every day is likely not realistic. That is around 2 large balls of beetroot. It’s also important to know that beetroot contains around 3g of fibre per 100g. Which means it’s a source of fibre, but not “high in fibre”. High in fibre means a food contains 6g of fibre per 100g. Higher fibre vegetables include potatoes, carrots, peas, and beans (4).

Beetroot and sports performance and recovery

Beetroot has become a popular suggestion in fitness websites and magazines. But the effectiveness of beetroot for sports performance and recovery is not clear.

A 2021 review investigated beetroot for exercise performance and recovery. This review found mixed results (6). In swimmers, beetroot supplements had no impact on performance. Similarly, there was no found effect on performance in a study on a kayaking team. The same outcome was also found with recreational cyclists and Olympic-level cyclists.

Another review, from 2020, found some evidence that beetroot did improve performance. Improved performance meant reduced feelings of fatigue in runners (7). More research is needed on more people before any recommendations are made.

There is no evidence that beetroot can delay muscle soreness post-exercise.

Beetroot and the immune system

There are claims around the internet that beetroot improves immunity. Yet, there is currently no evidence for this. One common claim is that beetroot increases white blood cell production in the body. But there is not one study that suggests this.

Beetroot does contain vitamin C. Which is often claimed to prevent colds and flus. But evidence suggests that vitamin C does not do this, but may reduce symptom severity. This is only around half a day, between those in studies who take vitamin C supplements versus those who didn’t (8).

Beetroot does not appear to be beneficial to the immune system. That being said, a balanced diet can support general health and wellbeing.

Summary of beetroot health claims

•  Beetroot is claimed to reduce blood pressure. This is thought to be because of the nitrate and fibre content of beetroot. There is some evidence that nitrate can reduce blood pressure, however more research is needed.
• Beetroot can improve sports performance and recovery. The current evidence shows mixed results. In the majority of studies, beetroot has no effect on sports performance. There is a small number of studies where beetroot has reduced feelings of fatigue in athletes, but larger studies are needed. Beetroot has no studies associated with recovery after exercise.
• Beetroot is claimed to support the immune system. There is no evidence to support this claim. This claim may come from the fact that beetroot contain vitamin C. However vitamin C, against popular belief, does not reduce the likelihood of colds and flus.

Cautions

There are a few reasons why beetroot supplements may not be appropriate for some people. These include:

• Those with kidney stones or metal-accumulating diseases
• People who are pregnant, breastfeeding, or trying to get pregnant. This is because there is a potential link that nitrates can lead to neural tube defects (9).

Beetroot side-effects

Beetroot intake, especially daily supplements, can lead to side-effects. These range from harmless to harmful to health. This includes:

• High levels of beetroot can lead to pink urine, which is harmless (1).
• Beetroot has potential links to lower blood pressure. People with low blood pressure are not recommended to supplement beetroot. This is because blood pressure can become even lower.
• There is a potential that high intake of nitrates can lead to kidney stones.