12 Weeks of Beetroot Nitrate Reverses Postmenopausal Carotid Stiffness

Twenty postmenopausal women, ages 60 to 85. After 12 weeks, their carotid arteries became measurably more elastic.

Published April 1, 2025 in the American Journal of Physiology - Heart and Circulatory Physiology, the randomized double-blind placebo-controlled parallel-design trial by Pinheiro, Proctor, Soares, and Alvares offers the longest-duration clinical evidence to date that dietary nitrate from beetroot can reverse the vascular stiffening that accelerates after menopause.

What Menopause Does to Arteries

Estrogen activates endothelial nitric oxide synthase (eNOS), the enzyme that produces nitric oxide (NO) in blood vessel walls. NO signals vascular smooth muscle to relax, keeping arteries compliant and responsive to blood flow changes.

When estrogen drops sharply at menopause, that chain breaks. Reduced eNOS activity means less NO, and less NO means arteries progressively lose their elasticity. The carotid arteries, which carry blood from the heart to the brain, are particularly important: stiffening there impairs cerebral blood flow regulation and increases the pulsatile load on the brain’s microvasculature.

Arterial stiffness is not just an abstract biomarker. It is an independent predictor of cardiovascular events. Within a decade of menopause, women’s cardiovascular risk approaches that of men the same age.

How Beetroot Creates a Bypass

Dietary nitrate does not rely on eNOS. It uses a different route.

Nitrate-rich foods like beetroot and spinach deliver inorganic nitrate (NO3) to the gut, where it is absorbed into the bloodstream. The circulation carries some of it back to the salivary glands, which concentrate and secrete it into saliva. Symbiotic bacteria living on the tongue and between the teeth then reduce nitrate to nitrite (NO2). After swallowing, that nitrite is converted to NO in the stomach and blood vessel walls.

This enterosalivary circuit completely bypasses estrogen and eNOS, which is why postmenopausal women are considered a particularly relevant population for dietary nitrate research.

In the trial, serum nitrate rose five to sixfold and serum nitrite rose 1.5- to twofold in the nitrate group, peaking around week 8. That sustained elevation means a persistent supply of NO precursors circulating throughout the study period.

One practical note: antibacterial mouthwash kills the oral bacteria that drive this conversion. Daily use of antibacterial oral rinses can significantly blunt the cardiovascular benefit of dietary nitrate.

What the 12-Week Numbers Show

Participants received 8.8 mmol of nitrate per day via a nitrate-rich beetroot extract (NR-BEETx). The placebo group received a nitrate-depleted version (ND-BEETx). Both supplements were identical in appearance, taste, and packaging.

Four measures of carotid artery stiffness all improved significantly in the nitrate group across weeks 4, 8, and 12:

• PWVβ (pulse wave velocity beta): How fast a pressure wave travels through the artery wall. Lower means more compliant.
• Beta stiffness index: The elastic rebound of the arterial wall per unit of pressure change. Lower means more flexible.
• Pressure-strain elastic modulus: How stiff the wall is relative to the pressure it bears. Lower means more pliable.
• Augmentation Index (AIx): The extra load on the heart created by reflected pressure waves. Lower means less cardiac strain.

Arterial compliance, the artery’s ability to accommodate blood volume changes, increased at the 12-week mark.

Blood pressure did not change in either group. That may seem counterintuitive, but it shows the study was sensitive enough to detect beneficial structural changes in arterial walls before they manifest as measurable shifts in systolic or diastolic pressure.

Microcirculation in the Legs and Feet

The carotid artery is a large central vessel. An ancillary finding pointed toward smaller vessels.

An in vitro angiogenesis assay showed that cells from the nitrate group formed new blood vessels at 1.8 times the rate of cells from the placebo group. Angiogenesis, the growth of new capillaries from existing vessels, is directly relevant to peripheral microcirculation in the legs and feet, skin regeneration, and wound healing.

Cold extremities and impaired peripheral circulation are common in postmenopausal women. This finding raises the possibility that beetroot nitrate may reach beyond large arteries to influence capillary-level blood flow. Because this was an in vitro result rather than a direct clinical measurement, drawing firm conclusions about peripheral circulation in living participants requires caution.

How to Get Beetroot Nitrate into Daily Life

The study dose of 8.8 mmol nitrate translates to practical food and supplement options:

• Beetroot juice, 250–350 mL: Concentrated beetroot juice typically delivers 6–8 mmol per 250 mL. One to one-and-a-half glasses per day approximates the study dose. Nitrate content varies considerably between brands, so look for products that list nitrate content explicitly.
• Beetroot powder, 1–2 teaspoons: High-concentration powders can deliver 4–6 mmol per 5 g serving. Easy to blend into smoothies or mix into water.
• NR-BEETx-style capsules: The same form used in the trial. Look for a label that specifies nitrate content in mmol, aiming for 8–9 mmol per day.
• Fresh beetroot: A medium beet (roughly 80 g) contains about 2–3 mmol of nitrate. Three beets a day reaches a comparable dose. Raw or juiced beetroot retains more nitrate than roasted or boiled.

If beetroot is not appealing, spinach, arugula, and celery are also high-nitrate vegetables. Combining them through the day can build a meaningful daily intake.

Who Should Take Note, and Who Should Be Careful

Most relevant for: Postmenopausal women over 50 who are interested in cardiovascular and vascular health but are not on blood pressure medication. Especially those experiencing peripheral coldness, slow skin healing, or general concern about vascular aging.

Approach with caution:

• Blood pressure medication: Dietary nitrate acts as a vasodilator. If you take calcium channel blockers, ACE inhibitors, or ARBs, speak with your doctor before adding high-dose beetroot supplements. This trial showed no blood pressure change, but individual pharmacological interactions can vary.
• PDE5 inhibitors: Concurrent use with sildenafil (Viagra) or tadalafil (Cialis) can cause a dangerous drop in blood pressure. This combination should be avoided.
• Reduced kidney function: Nitrate metabolism may differ in those with chronic kidney disease. Medical consultation is advised.
• Gout or kidney stone history: Beetroot is high in oxalate. High-dose, long-term intake warrants a conversation with a healthcare provider before starting.

The trial enrolled 20 participants, which is small. The results are meaningful but should be interpreted as early evidence rather than definitive proof. Larger, longer studies with diverse populations will be needed to confirm these findings. For most people, the most sustainable path is not a supplement protocol but a diet with more beetroot, spinach, and leafy greens woven into regular meals.