Beets contain several compounds that appear to benefit eye health, though the evidence is stronger for some conditions than others. The most studied connection runs through dietary nitrate, a molecule found in high concentrations in beetroot, which the body converts into nitric oxide to relax blood vessels and improve circulation. Because the eye depends heavily on tiny blood vessels to deliver oxygen and nutrients, anything that supports vascular function has the potential to protect vision. The research so far is promising but comes with meaningful caveats worth understanding before you start drinking beet juice as an eye health strategy.
How Nitrate in Beets Affects Blood Vessels in the Eye
The retina is one of the most metabolically active tissues in the body, and it relies on a dense network of very small blood vessels to function. When those vessels narrow or stiffen, the retina gets less oxygen, and over time that can contribute to vision problems ranging from glaucoma to diabetic eye disease. This is where beets enter the picture. Beetroot is one of the richest dietary sources of inorganic nitrate, and when you eat it, bacteria on your tongue convert that nitrate into nitrite, which your body then turns into nitric oxide. Nitric oxide is a signaling molecule that relaxes the smooth muscle in blood vessel walls, widening them and improving blood flow.
A study of older Australian adults found that higher dietary nitrate intake was associated with measurably wider retinal arterioles. Specifically, each 10-unit increase in total nitrate or vegetable nitrate intake corresponded to roughly 0.09 micrometers of additional arteriolar width after adjusting for other factors like blood pressure and smoking.1PubMed. Association of dietary nitrate intake with retinal microvascular structure in older adults That sounds tiny, and it is in absolute terms, but in the context of retinal microvasculature, small caliber differences are clinically meaningful. Wider arterioles reflect healthier, more flexible vessels that deliver blood more efficiently to the retinal tissue.
It is worth noting that this study looked at dietary nitrate broadly, not beets alone. Green leafy vegetables like spinach and kale are actually the largest contributors to nitrate intake in most diets. But beetroot and beetroot juice are unusually concentrated sources, which is why they are so popular in research on nitrate’s vascular effects. A single cup of beet juice can contain more nitrate than several servings of leafy greens.
Beets and Glaucoma Risk
The connection between dietary nitrate and glaucoma has drawn serious research attention, and the findings are among the most compelling in the beet-eye health space. Glaucoma is a group of conditions that damage the optic nerve, often linked to elevated pressure inside the eye but also to poor blood flow to the nerve itself. Two large population studies have found that people who eat more nitrate-rich foods have a lower risk of developing open-angle glaucoma, the most common form.
The first combined data from the Nurses’ Health Study and the Health Professionals Follow-up Study, tracking over 1.6 million person-years of follow-up. Compared with people in the lowest fifth of dietary nitrate intake (around 80 milligrams per day), those in the highest fifth (around 240 milligrams per day) had a roughly 21 percent lower risk of developing primary open-angle glaucoma. The association was even stronger for a subtype of glaucoma involving visual field loss near the center of vision, where the risk reduction was close to 48 percent.2PubMed Central. Association of Dietary Nitrate Intake With Primary Open-Angle Glaucoma: A Prospective Analysis From the Nurses’ Health Study and Health Professionals Follow-up Study Green leafy vegetables accounted for over half of the variation in nitrate intake across participants, but beetroot would contribute to the same nitrate pool.
A second study, the Rotterdam Study from the Netherlands, found a similar pattern. For every additional 10 milligrams per day of dietary nitrate, the odds of developing open-angle glaucoma dropped by about 5 percent. This held for nitrate from both vegetables and non-vegetable food sources.3PubMed Central. Dietary Nitrate Intake Is Associated with Decreased Incidence of Open-Angle Glaucoma: The Rotterdam Study The consistency across two large, independent cohort studies in different countries makes the association harder to dismiss as a fluke, though neither study can prove that nitrate itself is the active ingredient rather than something else in the diets of people who eat more vegetables.
Betalains and Cell-Level Protection
Beets owe their deep red-purple color to pigments called betalains, which are distinct from the more familiar anthocyanins found in blueberries and red wine. Betalains are potent antioxidants, and a lab-based study explored whether they could protect eye cells against the kind of damage seen in glaucoma. Using ocular cells exposed to oxidative stress, researchers found that pre-treating the cells with betalain improved glutathione levels (a key internal antioxidant) and reduced the activity of an enzyme associated with inflammation. The levels of inflammatory markers and genes linked to glaucoma progression were also restored toward normal in the treated cells.4AMB Express. Betalain exerts a protective effect against glaucoma is majorly through the association of inflammatory cytokines
This is encouraging but comes with an important caveat: it was a cell-culture study, not a human trial. What happens in a petri dish does not always translate to what happens inside a living eye. The concentrations of betalain used in the lab may not be achievable through diet alone, and the compound has to survive digestion, enter the bloodstream, and reach the eye in sufficient amounts to matter. Still, the study adds a plausible biological mechanism for why beet consumption might be protective. The nitrate story is about blood flow; the betalain story is about direct antioxidant and anti-inflammatory action on eye tissue. They are two separate pathways that could potentially complement each other.
What Happens When You Actually Drink Beet Juice
While the population studies above tracked long-term dietary patterns, a smaller interventional study looked at what happens to your eyes shortly after drinking beetroot juice. In healthy adults, a single dose of beet juice lowered systolic blood pressure by about 4.8 mmHg and diastolic blood pressure by about 6.2 mmHg compared to water. However, intraocular pressure did not change compared to the water control. More surprisingly, the researchers observed that superficial vessel density in several regions of the macula actually decreased shortly after beet juice consumption.5The North African Journal of Food and Nutrition Research. Beetroot juice: effects on blood pressure, intraocular pressure, and ocular vessel density in healthy adults
This seems to contradict the idea that beets improve eye blood flow, and it is a fair concern. One explanation is that the acute drop in blood pressure may have temporarily reduced perfusion pressure to the eye, even as the nitric oxide effect was widening vessels elsewhere in the body. The retina’s blood supply is partly autoregulated, meaning it tries to maintain stable flow regardless of systemic blood pressure, but there are limits. Another possibility is that the measurement captured a transient snapshot that does not reflect what happens over weeks or months of regular consumption. Acute responses and long-term adaptations are often different animals.
The takeaway is that a single glass of beet juice is not going to immediately improve blood flow to your retina. The benefits seen in the large population studies reflect years of consistent dietary habits, not one-off meals. If you already have low blood pressure, a big slug of beetroot juice could theoretically reduce perfusion to the eye temporarily, which is something to be aware of rather than alarmed by.
Folate in Beets and Retinal Vascular Health
Beets are a meaningful dietary source of folate, one of the B vitamins, and this opens another potential pathway to eye health that gets less attention than the nitrate connection. Folate helps the body break down homocysteine, an amino acid that at elevated levels can damage the lining of blood vessels. A review of the evidence found that high plasma homocysteine and low folate status have been observed in many patients with retinal vascular diseases, including retinal vein occlusions, diabetic retinopathy, and age-related macular degeneration. The review concluded that folic acid supplementation might serve as a protective treatment for patients with retinal vascular conditions who have elevated homocysteine or blood sugar.6PubMed Central. Folate and retinal vascular diseases
This does not mean beets treat diabetic retinopathy. But if you’re building a diet that supports eye health from multiple angles, the folate in beets adds another layer beyond nitrate and betalains. A cup of cooked beets provides a decent portion of your daily folate needs, and unlike nitrate, the folate connection does not depend on bacteria in your mouth to activate it.
Why Your Mouthwash Matters
This is one of the stranger wrinkles in the beet-eye connection. The entire nitrate-to-nitric-oxide pathway depends on bacteria living on the back of your tongue. When you eat beets, the nitrate circulates through your blood, gets concentrated in your saliva, and is then converted to nitrite by these oral bacteria. From there, your stomach and tissues convert nitrite into nitric oxide. Kill the bacteria, and you break the chain.
Research has shown that using strong antibacterial mouthwash can disable the nitrate-to-nitrite conversion, with stepwise reductions in both plasma and salivary nitrite as mouthwash strength increased.7PubMed. A stepwise reduction in plasma and salivary nitrite with increasing strengths of mouthwash following a dietary nitrate load In practical terms, if you’re drinking beet juice for its cardiovascular or eye health benefits but also using chlorhexidine-based mouthwash twice a day, you may be undercutting the very mechanism you’re trying to harness. This does not mean you should stop caring about oral hygiene, but it is worth knowing that not all mouthwashes are equally aggressive. Alcohol-free rinses and those without strong antibacterial agents are less likely to wipe out the nitrate-reducing bacteria you actually want.
Does Cooking Destroy the Good Stuff?
A reasonable question, since many beneficial plant compounds break down with heat. Betalains are somewhat heat-sensitive, and prolonged cooking does reduce their concentration. However, research on heated beetroot preparations suggests that cooking does not severely diminish the beneficial effects. A study examining heat degradation of betanin (the primary betalain in red beets) found that even after cooking, the biological activity and antioxidant capacity remained substantial. The researchers specifically noted that traditional preparations like borscht still provide meaningful health benefits.8PubMed Central. Effects of heat degradation of betanin in red beetroot (Beta vulgaris L.) on biological activity and antioxidant capacity
As for nitrate, it is quite stable during cooking. Boiling beets does leach some nitrate into the cooking water, so if you discard that water, you lose some of the benefit. Roasting retains more. And of course, raw beet juice delivers the full nitrate load with no heat losses at all, which is part of why concentrated beetroot juice shots have become popular in research and among athletes. For eye health specifically, there is no study comparing raw versus cooked beets, so the practical advice is just to eat them however you enjoy them and not overthink the preparation method.
Oxalates and Who Should Be Careful
Beets are high in oxalates, and that matters if you’re prone to kidney stones. Oxalic acid binds to calcium in the urinary tract and can form calcium oxalate stones, the most common type. Beets are listed among a small group of foods that have been directly shown to increase urinary oxalate excretion, alongside spinach, rhubarb, nuts, tea, chocolate, strawberries, and wheat bran.9Journal of the American Dietetic Association. Effect of dietary oxalate and calcium on urinary oxalate and risk of formation of calcium oxalate kidney stones The risk is highest for people who absorb oxalate at above-average rates, which includes people with certain intestinal conditions as well as some individuals without obvious digestive issues.10Asia Pacific Journal of Clinical Nutrition. Oxalate content of foods and its effect on humans
If you have a history of kidney stones, adding large amounts of beet juice to your diet for eye health purposes without consulting a doctor would be unwise. For everyone else, the oxalate content of beets at normal dietary quantities is not a major concern. Drinking adequate water and consuming calcium alongside oxalate-rich foods (the calcium binds the oxalate in the gut before it reaches your kidneys) are practical steps that reduce the risk substantially. Beetroot greens, incidentally, are even higher in oxalates than the root itself, so the same caution applies more strongly to them.
Beets Versus Other Eye-Healthy Foods
Where do beets fit in the broader landscape of foods linked to eye health? The honest answer is that they are not the most studied food for vision. Lutein and zeaxanthin, the carotenoid pigments found in kale, spinach, and egg yolks, have far more evidence behind them for protecting the macula and reducing the risk of age-related macular degeneration. Omega-3 fatty acids from fish have been studied extensively for dry eye and retinal health. And the AREDS2 supplement formula (containing vitamins C and E, zinc, copper, lutein, and zeaxanthin) remains the most rigorously tested nutritional intervention for slowing macular degeneration progression.
Beets offer something different. Their strength is the nitrate-blood flow pathway, which is less about protecting retinal cells from oxidative damage and more about ensuring those cells get adequate blood supply in the first place. That makes beets potentially more relevant for conditions involving vascular compromise, like glaucoma and diabetic retinopathy, than for conditions driven primarily by oxidative damage to photoreceptors. The betalain antioxidant activity adds some cell-protection capability, but the human evidence for that specific pathway is still early-stage.
The most practical framing is that beets are a useful addition to an eye-healthy diet, not a replacement for the more established nutritional strategies. They bring something to the table that leafy greens and fish do not, namely a concentrated nitrate dose with unique antioxidant pigments. Combining them with lutein-rich greens and omega-3 sources gives you coverage across multiple biological mechanisms rather than relying on one.
How Much Beet Is Enough
The population studies that showed reduced glaucoma risk compared people eating roughly 240 milligrams of dietary nitrate per day with those eating around 80 milligrams per day.2PubMed Central. Association of Dietary Nitrate Intake With Primary Open-Angle Glaucoma: A Prospective Analysis From the Nurses’ Health Study and Health Professionals Follow-up Study A single 250-milliliter glass of beetroot juice typically contains somewhere in the range of 300 to 500 milligrams of nitrate, depending on the brand and concentration. So a modest daily serving of beet juice could easily place you in the higher intake bracket where the associations with eye health were strongest.
That said, nobody has run a randomized controlled trial giving one group beet juice and another a placebo and then tracking glaucoma outcomes over years. The evidence is observational, meaning we know that people who eat more nitrate tend to develop glaucoma less often, but we cannot be certain the nitrate is the cause. People who eat lots of vegetables tend to be healthier in many ways, and isolating one nutrient’s effect from the rest of a healthy lifestyle is genuinely difficult.
For most people, eating beets a few times a week or drinking a small glass of beet juice daily is a reasonable amount. There is no established clinical dose for eye health, and going overboard comes with diminishing returns and increased oxalate exposure. The beet juice used in blood pressure and exercise research is typically in the range of 70 to 140 milliliters of concentrated juice, taken once daily, which provides a standardized nitrate dose. That is a reasonable reference point, even though the eye-specific data does not yet specify an optimal amount.
Beeturia and Other Harmless Surprises
If you start eating beets regularly and notice that your urine turns pink or red, do not panic. This phenomenon, called beeturia, affects an estimated 10 to 14 percent of people and is completely harmless. It happens because betalain pigments pass through the digestive system without being fully broken down and end up coloring the urine. The same pigments can also turn stool reddish. People who are iron deficient or have lower stomach acid may be more likely to experience it, since these conditions reduce the breakdown of betalains during digestion.
The only real concern is the momentary alarm of seeing red in the toilet and wondering if something is seriously wrong. Knowing in advance that you have been eating beets eliminates that worry. It is unrelated to any eye health effect and does not indicate that your body is failing to absorb the beneficial compounds. If anything, it shows the betalains made it through your system in an intact enough form to retain their color, though the relationship between excreted pigment and absorbed antioxidant activity is not straightforward.