Beetroot, the Promising Purple Superfood to Support Blood Flow

We have accepted many symptoms of poor blood flow as a normal part of life. Symptoms like declining memory for example, or difficulty with concentration for a sustained duration, or poor recovery after aerobic exercise, or breathlessness doing light activities, or feeling permanently tired despite sleeping well. This article is about how blood flow may be the root cause of these symptoms you’re experiencing frequently, and how eating beetroot may improve your quality of life through alleviating these symptoms. 

Each cell in your body requires a sustained supply of oxygen and nutrients, and removal of metabolic waste products. This is the primary function of your circulatory system. Your heart drives blood flow by providing mere force. However, it doesn’t determine to which tissues the blood flows, in what quantity and at what rate. This responsibility falls on your blood vessels, and it is dependent on the tone of your blood vessels. 

The wall of a blood vessel is composed of an inner layer of endothelial cells, and a surrounding outer layer of smooth muscle cells which encircle the vessel. By contracting or relaxing, this smooth muscle controls the diameter of the blood vessel’s lumen, essentially controlling the distribution of blood flow across blood vessels. When the smooth muscle contracts (vasoconstriction), the vessel’s lumen diameter narrows, increasing the flow resistance and reducing the blood flow through the vessel. When the muscle relaxes, the vessel’s lumen widens (vasodilation), reducing the flow resistance and allowing more blood flow. At its resting state, the vascular smooth muscle is partially contracted, forming a baseline vessel tone which can then contract further or relax in response to being signalled. 

The endothelial cells are sensitive to the environment within the blood vessel. They detect the mechanical force of the frictional drag exerted on the vessel wall by the blood. They also sense the chemical composition of the blood flowing through the vessel, including oxygen concentration, nutrient concentrations, blood pH, carbon dioxide and hormones and other circulating signalling molecules. The endothelium acts on this information and consequently regulates the vascular tone by signalling the smooth muscle cells. When the endothelium detects that blood flow needs to be increased within this vessel, whether due to a high mechanical friction force on the vessel, or oxygen delivery is insufficient, or the surrounding tissue has a high metabolic demand, the endothelium will respond by producing and releasing nitric oxide (NO). NO diffuses from the endothelium to the surrounding smooth muscle, where it activates intracellular pathways, which cause the muscle to relax, the vessel to dilate, and allows more blood to pass through to the target tissue. The more bioavailable NO within the vessel walls, the more responsive the vasculature can be to the needs of the body tissues. 

Due to NO not being stored, and it being broken down within seconds, NO is continuously synthesised to maintain the vessel's tone. When there is insufficient availability of NO, the vessels remain in their baseline partially constricted resting state, and are unable to adequately dilate in response to the tissues’ demand. The consequences of this are not limited to disease, but can manifest as declining day-to-day functioning of tissues and organs within non-diseased otherwise healthy persons. 

Beetroot is one of the richest natural sources of inorganic nitrate, containing approximately 495 milligrams per 100 grams [1]. When beetroot is consumed, the dietary nitrate is absorbed into the bloodstream, is concentrated by the salivary glands, and is then secreted on the tongue where commensal oral bacteria convert it to nitrite. This nitrite re-enters the circulation, and under conditions of low oxygen and low pH, the exact conditions in which greater blood flow is needed, is converted to NO [2]. The NO produced enters the vessels walls and restores the vessel's ability to dilate and match the bloodflow to the tissues demand. 

Beyond beetroot's nitrate content, it contains a pigment compound called betalain, which is responsible for the purple colour, which is a potent antioxidant. This antioxidant reduces the breaking down of NO which happens naturally, thereby increase NO availability further. 

Optimal blood flow is the foundation upon which every organ and every tissue in your body performs. Due to beetroot's high nitrate content and antioxidant pigment, it is able to improve the availability of NO to vasculature, allowing blood vessels to respond to the requirements of the tissues and to distribute blood flow to exactly where it is most needed. 

References

[1] Bahadoran Z, Mirmiran P, Jeddi S, Azizi F, Ghasemi A, Hadaegh F. Nitrate and nitrite content of vegetables, fruits, grains, legumes, dairy products, meats and processed meats. J Food Compos Anal. 2016;51:93-105. Available from: https://doi.org/10.1016/j.jfca.2016.06.006 

[2] Lidder S, Webb AJ. Vascular effects of dietary nitrate (as found in green leafy vegetables and beetroot) via the nitrate-nitrite-nitric oxide pathway. Br J Clin Pharmacol. 2013 Mar;75(3):677-96. doi: 10.1111/j.1365-2125.2012.04420.x. PMID: 22882425; PMCID: PMC3575935. 

Written by Lila Cunningham

Assessed and Endorsed by the MedReport Medical Review Board