Our arteries are lined by tile-like endothelial cells, collectively known as the endothelium. These cells play a key role in regulating blood flow and maintaining artery health by releasing chemical messengers such as nitric oxide (NO). Nitric oxide relaxes arterial smooth muscle, increasing arterial diameter and allowing more blood to flow to working muscles, erectile structures, and anywhere there is increased demand for blood oxygen. Small changes in diameter lead to big changes in blood flow (Poiseuille’s law). Therefore, small improvements in endothelial cell health and function can make a big difference in blood flow, particularly when upstream narrowing of larger arteries already compromises flow. This explains why angina on exertion can resolve within weeks of starting a whole foods, plant-based diet.
Food can enhance or impair artery function within hours. In flow-mediated dilatation studies, a single high-fat meal can reduce blood flow for hours. The effect is strongest with meat and other animal products high in saturated fats, but also apparent with vegetable oils. It is attenuated by concurrent or prior consumption of antioxidant-rich whole plant foods. Many animal products and some processed food have pro-oxidant (e.g. Haeme iron, oxidised fats) and inflammatory (e.g. endotoxins) components which impair endothelial cells.
The nitrates in vegetables (esp. leafy greens, broccoli, beetroot) provide endothelial cells with an easier metabolic pathway for NO synthesis. The increase in NO results in a subtle relaxation of arteries which increases blood flow and lowers blood pressure. A clinical trial comparing beetroot juice (high in nitrates) to a nitrate-reduced beetroot juice placebo showed a reduction in blood pressure within 2-3 hours. However, the effect lasted for less than 24 hours, suggesting that for the best results, nitrate-rich plants, such as green leafy vegetables, may need to be consumed several times a day (Dr Caldwell Esselstyn recommends patients eat them 6 times per day).
The nitric oxide produced by endothelial cells also helps prevent artery walls from stiffening, inhibits plaque progression and reduces the stickiness of blood cells. The Teflon-like effect of NO on endothelium and blood cells helps prevent cholesterol from being deposited in artery walls and allows red blood cells to flow smoothly through capillaries that may be smaller than the cells’ diameter. High saturated-fat meals can turn blood into a sticky sludge that flows poorly through smaller vessels. Some research suggests that unsaturated plant fats can have similar effects.
Atherosclerosis (cholesterol plaque) begins when LDL cholesterol particles attach to the inside of arteries and deposit cholesterol into the subendothelial space (on the artery side of the endothelial cells). Healthy endothelial cells resist this process. Cardiovascular risk factors tend to damage or impair endothelial cells. For example: the physical effect of high blood pressure, high blood insulin and glucose levels in diabetes, and chemical damage from TMAO or oxidative stress.
While we may like to think our endothelium looks like the beautiful, symmetrical tiling we see in health documentaries, if you are an older adult who has followed a Western diet, your endothelium is more likely to look like a patchy, poor-quality tiling job. The good news is that we can nurture our endothelial cells by reducing risk factors that harm them, bathing them in protective phytonutrients, and turbocharging them with dietary nitrates. Endothelial cells can also be replenished by progenitor cells from bone marrow.
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Page created 13th January 2013
Last updated 31st October 2026