Over 3 million Americans suffer from glaucoma, a group of eye diseases that damage the optic nerve. In fact, they’re some of the world’s leading causes of irreversible blindness.
But research shows there’s a close link between diet and glaucoma, meaning you have more control over your health than you may have previously thought.
Diet and glaucoma: What’s the connection?
What you eat has a tremendous impact on your health–including the pressure in your eyes, known as intraocular pressure (IOP).
IOP measures the balance between production and drainage of the aqueous humor (eye fluid). An imbalance in this fluid production and drainage can put excessive force on the optic nerve, causing serious damage (oxidative stress) and potentially vision loss.
Studies show inflammatory, cholesterol-raising foods promote this oxidative stress throughout the body while impairing blood flow–increasing your IOP. On the other hand, a diet rich in antioxidants and anti-inflammatory foods can help stabilize eye pressure and protect the optic nerve.
It’s also important to note that other health conditions can increase glaucoma risk. This is especially true with open-angle glaucoma–the most prevalent form of the disease–which involves obstructed drainage canals in the eye.
Some of these risk-elevating conditions include:
- Hypertension: High blood pressure can affect ocular blood flow.
- Obesity: Research has linked higher body mass index (BMI) to elevated IOP.
- Diabetes: Some studies suggest diabetes doubles your risk of glaucoma.
However, eating healthier foods that combat these conditions can also reduce the likelihood of developing glaucoma–and may even slow its progression.
Diet for Glaucoma Prevention:
1. Fresh fruits and vegetables
The ideal anti-glaucoma diet is full of fresh produce. In fact, according to one study, consuming three or more servings of fruit or fruit juice each day alone could slash your risk by as much as 79%.
That’s because fruits and veggies are packed with powerful nutrients that combat oxidative stress, helping prevent damage to the optic nerve. Some of the most important of these nutrients are:
- Vitamin A: This vitamin plays a critical role in both vision and immune function, and has a protective effect on vital organs. Research has highlighted a strong link between higher dietary vitamin A intake and a lower risk of open-angle glaucoma.
- Vitamin C: This potent antioxidant combats oxidative damage. Studies have linked low vitamin C levels with normal-tension glaucoma, a type of the disease that can damage the optic nerve while IOP stays within the normal range. Vitamin C also helps protect retinal ganglion cells (neurons that transmit visual information from the eyes to the brain).
- Lutein and zeaxanthin: These antioxidants support eye health by fighting oxidative stress and protecting the retina and optic nerve from damage. They optimize blood flow to the retina, reduce inflammation, and even filter blue light, which can damage eye tissue.
Leafy green vegetables are particularly beneficial. They’re packed with all of these nutrients, as well as dietary nitrates, which the body converts to nitric oxide (NO)–a powerful vasodilator.
Blood vessel dilation boosts circulation to the eyes, combating excess pressure. Regularly consuming leafy greens like kale and spinach may even reduce your risk of glaucoma by up to 30%.
2. Nuts and seeds
Nuts and seeds are exceptional sources of vitamin E, which is vital for:
- Combating free radical damage that can degrade retinal tissues
- Protecting the brain from damage, potentially benefiting the optic nerve
- Maintaining overall cell health
also contain magnesium and arginine, two nutrients known to boost blood flow and potentially even reduce IOP.
Certain varieties are also loaded with healthy fats–particularly omega-3 fatty acids, which combat inflammation and support healthy retinal function. Walnuts are richest in these crucial fats.
Other nuts and seeds provide lutein and zeaxanthin, as well. These include:
- Almonds
- Hazelnuts
- Pistachios
- Sunflower seeds
3. Fatty fish
Since omega-3 fatty acids are beneficial for glaucoma prevention and management, if you eat animal products, include fatty fish like salmon, tuna, and sardines in your diet.
Omega-3 fatty acids–particularly EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) found in these fatty fish–have shown promising results in reducing IOP by 25-30% in some studies. This reduction is comparable to the effects of many topical glaucoma medications.
Omega-3’s may decrease IOP by boosting aqueous outflow, or the rate at which the eye’s fluid drains. This is likely due to the activity of prostaglandins, or beneficial metabolites (breakdown products) created via enzymatic processes in the body.
4. Dark chocolate
That’s right, chocolate lovers; your favorite treat is actually one of the best foods to reduce eye pressure.
Some research found that adults who ate a bar of dark chocolate experienced a temporary improvement in vision–specifically, contrast sensitivity–about two hours after consumption.
Scientists attributed this effect to increased blood flow in the eyes, promoted by the flavanols (antioxidants) in dark chocolate.
While the improvement in eyesight was modest–and some studies have since questioned these results–enjoying chocolate in moderation can certainly offer some benefits.
Just make sure to indulge in varieties with at least 70% cacao.
5. Green tea
While not technically a food, tea–especially green tea–is a powerful ally against high IOP. One study found that drinking at least one cup daily reduced the risk of glaucoma by 74% compared to non-tea drinkers.
Researchers believe the antioxidants and anti-inflammatory properties in green tea–particularly catechins like epigallocatechin gallate (EGCG)–play a key role. These catechins:
- Combat oxidative stress
- Enhance ocular blood flow, stabilizing IOP
- Help maintain the function of the endothelium (inner linings of blood vessels)
6. Black beans
Black beans are excellent sources of magnesium, which can help combat glaucoma by improving ocular blood flow. But studies have also found this vital mineral to have neuroprotective effects.
It inhibits the release of glutamate, a compound that can lead to oxidative stress and damage the optic nerve. Furthermore, it may protect retinal ganglion cells, thereby helping preserve vision.
Beans are also packed with fiber, which is an essential part of any healthy diet. This nutrient supports gut health, combating several risk factors for glaucoma, including:
- Weight gain
- High blood pressure
- High blood sugar levels
They’re also rich in zinc, which helps combat oxidative stress throughout the body.
7. Chicken
Chicken–especially chicken breast–is rich in vitamin B3, also called niacin. This nutrient plays a pivotal role in protecting eye cells from oxidative damage.
It acts as a precursor to nicotinamide adenine dinucleotide (NAD+), a molecule involved in cells’ energy and health. NAD+ levels naturally decrease with age. But studies show consuming higher amounts of niacin can:
- Significantly preserve and even improve visual function
- Reduce damage to the optic nerve
- Protect retinal cells
- Boost ocular blood flow
Some studies on niacin involved participants taking high-dose supplements rather than eating vitamin-B3-rich foods. However, getting more of this nutrient through your diet still offers benefits.
If you don’t eat meat, you can get plenty of vitamin B3 from:
- Peanuts
- Mushrooms
- Green peas
- Potatoes
- Avocados
- Brown rice
What Foods to avoid if you have Glaucoma
While the above foods can help you prevent or manage glaucoma, there are other foods that can contribute to or exacerbate the disease. Research has linked high carbohydrate diets in particular to increased risk.
Here are some foods to limit or avoid with glaucoma:
- Coffee: Coffee is high in caffeine, which can significantly increase IOP after 60-90 minutes in those with glaucoma. Consider switching to lower-caffeine tea, such as green tea to tend to your ocular health.
- Excess sugar: Because high-sugar foods increase the risk of diabetes, it’s best to limit or avoid candies, baked goods, ice creams, and sweetened beverages.
- Refined carbohydrates: These include white bread, pasta, rice, processed cereals, and packaged snacks, which can contribute to metabolic syndrome and weight gain.
- Trans fats: Found in fried foods and baked goods, trans fats can heighten cholesterol levels and lead to cardiovascular issues, which affect blood vessel health.
There’s no known cure for glaucoma, but you can prevent or slow its progression by making healthy choices.
- A diet rich in antioxidants and anti-inflammatory foods can help stabilize IOP and protect the optic nerve.
- Conditions such as hypertension, obesity, and diabetes increase glaucoma risk, so preventing or managing these is essential.
- Eating foods like green leafy vegetables, fruits, and fatty fish that are high in vitamins and omega-3 fatty acids effectively combats oxidative stress and stabilizes eye pressure.
- Avoiding foods high in caffeine, refined sugars, and trans fats, can further reduce your risk, and may even slow the progression of glaucoma.
Remember, even small changes can lead to big benefits for your health. Focus on consistency rather than perfection, and in time, you might just see a world of difference.
References:
About Glaucoma | Vision and Eye Health | CDC.
Glaucoma: The ‘Black hole’ of irreversible blindness – PMC.
Aqueous Humor Dynamics: A Review – PMC.
The Role of Diet in Glaucoma: A Review of the Current Evidence – PMC
Intraocular Pressure, Glaucoma, and Dietary Caffeine Consumption – PMC
Dietary Patterns, Carbohydrates, and Age-Related Eye Diseases – PMC
Vitamin A and Carotenoids – Consumer.
Dietary Sources of Lutein and Zeaxanthin Carotenoids and Their Role in Eye Health – PMC.
The Effect of Vitamins on Glaucoma: A Systematic Review and Meta-Analysis – PMC
Vitamin intake and glaucoma risk: A systematic review and meta-analysis – ScienceDirect
Suppression of Oxidative Stress as Potential Therapeutic Approach for Normal Tension Glaucoma – PMC.
Dietary supplements for improving nitric-oxide synthesis – PMC
Nutritional modulation of cataract – PMC
Composition of Nuts and Their Potential Health Benefits—An Overview – PMC
Omega-3 Fatty Acids – Health Professional Fact Sheet
Oral Omega-3 Supplementation Lowers Intraocular Pressure in Normotensive Adults – PMC
Dietary Omega 3 Fatty Acids Decrease Intraocular Pressure with Age by Increasing Aqueous Outflow | IOVS
Effects of Milk vs Dark Chocolate Consumption on Visual Acuity and Contrast Sensitivity Within 2 Hours: A Randomized Clinical Trial
Green Tea Catechins as Therapeutic Antioxidants for Glaucoma Treatment – PMC
Green tea—a new perspective of glaucoma prevention – PMC
The Role of Magnesium in the Pathogenesis and Treatment of Glaucoma – PMC
Influence of Trace Elements on Neurodegenerative Diseases of The Eye—The Glaucoma Model – PMC
Niacinamide and Neuroprotection: The Glaucoma Holy Grail – PMC.
Improvement in inner retinal function in glaucoma with nicotinamide (vitamin B3) supplementation: A crossover randomized clinical trial – Hui – 2020 – Clinical & Experimental Ophthalmology – Wiley Online Library
Vitamin B3 modulates mitochondrial vulnerability and prevents glaucoma in aged mice – PMC
Niacin – Health Professional Fact Sheet
Role of excessive weight in intraocular pressure: a systematic review and meta-analysis – PMC
Obesity-induced ocular changes in children and adolescents: A review – PMC.
Targeting Diet and Exercise for Neuroprotection and Neurorecovery in Glaucoma – PMC
The Burden of Carbohydrates in Health and Disease – PMC
