Diabetic retinopathy is a serious complication of diabetes that can lead to vision loss and blindness. It occurs when high blood sugar levels damage the tiny blood vessels in the retina, the light-sensitive tissue at the back of the eye. Managing diabetes and its effects on your vision often requires lifestyle adjustments, including changes to your diet. This article delves into the role of diet in managing diabetic retinopathy, exploring whether certain foods can help reverse or mitigate its effects.
Understanding Diabetic Retinopathy
Diabetic retinopathy develops when prolonged periods of high blood sugar cause damage to the retina's delicate blood vessels. This damage can lead to the vessels leaking fluid or bleeding. In response, the eyes may grow new blood vessels that are weak and prone to leaking. Over time, this can result in symptoms such as:
- Floating spots
- Blurred vision
- Empty areas of vision
- Vision loss
More than half of people with diabetes will develop retinopathy at some point. The longer you've lived with the condition, the higher your risk. However, keeping blood sugars in your target range and A1C levels around 7% can significantly reduce your risk of complications, including retinopathy.
The Role of Diet in Managing Diabetic Retinopathy
While there's no known way to completely prevent diabetic retinopathy, food is a key part of managing diabetes and potentially mitigating its effects. Eating patterns recommended by diabetes experts are essentially the same for diabetic retinopathy as they are for overall diabetes management. The American Diabetes Association (ADA) emphasizes eating more fruits and vegetables, high-fiber whole grains, lean protein, and healthy fats while minimizing processed foods and added sugars.
The eating guidelines for both diabetes and diabetes-related eye health are tied to stable blood sugars, ensuring glucose levels stay within target ranges and don't dramatically fluctuate. As a result, experts emphasize lower A1C levels, which are proven to reduce the risk of diabetes-related complications.
Read also: Vegan Diet for Diabetes Management
Foods That May Benefit Eye Health and Diabetes Management
Certain foods may have benefits for your eyes and diabetes management overall. Fish, leafy green vegetables, the Mediterranean diet, and foods with vitamin A or omega-3 may be most beneficial. In a 2018 systematic review of clinical studies dating back to 1967, researchers analyzed over 4,200 studies about the link between dietary habits and diabetic retinopathy. They determined that foods higher in fiber, oily fish, and reduced calories, and the Mediterranean diet were most associated with a lower risk of diabetic retinopathy. An update in 2022 included many more studies in the subsequent years and reached the same conclusion.
Fish and Omega-3 Fatty Acids
Numerous studies show that a higher intake of fish has benefits relating to diabetic retinopathy. Fish oil is a rich source of long-chain omega-3 polyunsaturated fatty acids (PUFA), which reduces the risk of diabetes and has a protective effect against diabetic retinopathy. A 2016 study of people with type 2 diabetes found that eating at least 500 mg/d of dietary omega-3 fatty acids can help decrease the risk of sight-threatening diabetic retinopathy. This translates to eating two or more weekly servings of oily fish, which researchers noted was associated with a nearly 60% reduction in the risk of retinopathy.
Examples of oily fish include:
- Trout
- Kippers
- Eels
- Whitebait
- Herring
- Tuna
- Salmon
- Mackerel
- Swordfish
- Sardines
- Bluefish
Another study found that eating 85 to 141 grams of dark oily fish at least once a week could also protect against diabetic retinopathy, reducing retinopathy risk by 70% compared with those who never eat this fish.
Omega-3 fatty acids have numerous benefits for your body and brain, and many health organizations (including the ADA) recommend that adults eat at least 250 to 500 milligrams (mg) of omega-3 each day. While fatty fish is a primary source for omega-3, you can also find it in algae, seeds, and high-fat plant foods, such as:
Read also: Foods for Pre-Diabetes
- Chia seeds: Full of manganese, selenium, magnesium, and other nutrients. A standard 1-ounce (28-gram) serving contains 5 grams of protein, including all eight essential amino acids.
- Flaxseed: A good source of fiber, magnesium, and other nutrients, including a lot of omega-3 fatty acids.
- Walnuts: Contain fiber and high amounts of copper, manganese, and vitamin E, as well as important plant compounds.
- Eggs
- Yogurt
- Soy beverages
Fruits Rich in Lutein and Zeaxanthin
Foods rich in lutein and zeaxanthin - two carotenoid molecules that color food - have antioxidant properties and are known to help protect your eyes, in particular the macula and retina. An older study cited in 2022 research notes that lutein can delay diabetic retinopathy progression by 5 years. Adding just 10 mg of lutein each day could improve sensitivity to contrast, glare, and visual acuity in those in the early stages of diabetic retinopathy, according to research. You can find these in orange, red, yellow, and purple fruits that might include:
- Oranges
- Bananas (including red bananas)
- Berries
- Honeydew melon
- Mangoes
- Prunes
- Kiwis
An older research from 2013 surveyed nearly 1,000 people with type 2 diabetes who shared details about their fruit consumption and how it might have affected their diabetic retinopathy and eyesight. The study concluded that increased fruit intake was associated with reduced risk of diabetic retinopathy for those who ate a low fat, energy-restricted diet.
A 2021 study noted that “fruits are known to be low-glycemic-index foods rich in dietary fiber, which can slow down the conversion of carbohydrates into glucose after ingestion.” That research cited older research from 2014 that had concluded “more frequent consumption of foods rich in flavonoid particularly fruits like citrus fruit, apples, berries… was associated with reduced odds of developing diabetic retinopathy.” Still, the research supports the general link between better eating - which includes fruits - and improved blood sugars and diabetes management. This in turn can help lower A1C levels and overall reduced risk of diabetes-related complications.
Vegetables Rich in Lutein and Zeaxanthin
As with fruit, vegetables containing lutein and zeaxanthin are recommended for eye health. These may include both green leafy vegetables as well as highly pigmented ones, such as:
- Kale
- Broccoli
- Lettuce
- Parsley
- Peas
- Spinach
- Turnip greens
- Corn
- Carrots
- Pumpkin
- Red and orange peppers
- Squash
These green leafy vegetables that are high in nutrients and antioxidants can delay diabetic retinopathy progression by 5 years.
Read also: Manage Diabetes with This Indian Diet
Vitamins
Different vitamins play a role in your diabetes management, including how you may be affected by diabetic retinopathy. People with diabetic retinopathy tend to have lower levels of these vitamins, according to research. A 2020 research review explored the diabetes eye affects related to several vitamins, minerals, and other nutrients including vitamins A, B, C, D, and E. The study also mentions zinc, copper, and others that are more beneficial. This research also points out certain vitamins can be important in preventing retinopathy.
In particular, vitamin A helps protect the surface of the eyes and is beneficial for night vision. This vitamin can be found in carrots, sweet potatoes, spinach, kale, and cantaloupe. However, the ADA’s yearly guidelines note that there’s no clear evidence that supplements alone can improve your blood sugar levels or other long-term outlooks, such as the development of retinopathy - not unless a vitamin or mineral deficiency already exists. This means you shouldn’t take vitamin or mineral supplements and expect they’ll have an effect on your diabetes management or diabetic retinopathy. Consult your diabetes care team before making any changes or taking new medications or supplements.
The Mediterranean Diet
Many of the food items mentioned here share many of the same nutrient and vitamin benefits. A number of the foods contain properties that are beneficial for your diabetes management and eye health. Many of those foods are also part of the Mediterranean diet, which is based on the traditional foods that people eat in countries bordering the Mediterranean Sea (France, Spain, Greece, Italy). The diet focuses on fruits, vegetables, whole grains, legumes, nuts, seeds, olive oil, and heart-healthy fats.
Several studies have shown that the Mediterranean diet can promote weight loss and help prevent heart attacks, strokes, and premature death. It’s also helpful for the prevention of type 2 diabetes and may improve blood sugar levels for those with other types of diabetes. Specific to diabetes eye health, the Mediterranean diet contains anti-inflammatory and antioxidant compounds. These indirectly improve the peripheral uptake of glucose and reduce insulin resistance, which can, in turn, have a protective effect in reducing risk for diabetes complications. Olive oil provides oleic acid, which may help prevent diabetic retinopathy. A 2015 research that involved over 3,600 people with type 2 diabetes also found that Mediterranean diets enriched with extra virgin olive oil may protect against diabetic retinopathy.
The Diabetes Plate Method
A person may wish to try the Diabetes Plate Method. This is a simple guide for helping people plan portioned meals of balanced, nutritious foods. This strategy involves dividing a plate and filling half with vegetables low in starch, a quarter with lean proteins, and a quarter with carbohydrates.
- Non-starchy vegetables: These include asparagus, broccoli, Brussels sprouts, carrots, cucumber, mushrooms, peppers, spinach, and zucchini.
- Lean proteins: These include chicken, turkey, eggs, salmon, shrimp, lentils, hummus, nuts, tofu, and tempeh.
- Carbohydrates: These include brown rice, oats, bulgur, quinoa, potato, pumpkin, sweet potato, and fruit.
Foods to Limit or Avoid
Experts advise that people with diabetes manage their blood sugar levels and take steps to keep them within suitable ranges to help prevent eye complications. One way of doing this is by maintaining a balanced, nutritious diet and avoiding or limiting certain foods, such as:
- Foods high in salt, such as chips, crackers, and pizza
- Fried foods and other foods high in saturated fat and trans fat, such as fries, burgers, and cakes
- Sweets, such as baked goods, candy, and ice cream
- Beverages with added sugars, such as regular soda, juice, and regular sports or energy drinks
- Highly refined or processed foods, such as white bread, white pasta, and cured meats
Can Diabetic Retinopathy Be Reversed?
It’s long been known that diabetic complications, such as diabetic retinopathy, can be slowed by taking severe control of blood sugar levels and making healthy lifestyle changes. However, there’s also evidence to suggest that complications can actually be reversed. It appears that as long as the right conditions are met, the body can heal some of the damage.
While we typically cannot reverse the condition itself, we can eliminate the complications caused by diabetic retinopathy through effective treatments. For example, if diabetic retinopathy causes blurry vision due to swelling or bleeding, medications can often resolve these issues. However, in advanced stages, where the blood vessels have sealed off and retinal tissue has died, reversing the damage becomes much more challenging. This is why early detection and treatment are essential. The earlier diabetic retinopathy is caught, the better the outcomes.
For patients with type 1 diabetes, if blood sugar is kept under strict control, it may be possible to reverse the effects of diabetic retinopathy. With type 2 diabetes, however, the condition cannot be reversed. In both cases, lifestyle changes play a significant role in managing the condition. Keeping blood sugar levels within the target range through diet, exercise, and medication can prevent further damage to the eyes and slow the progression of diabetic retinopathy.
The Kempner Diet
The most famous diet-based therapy for reversing serious chronic disease is credited to Dr. Walter Kempner, physician of the ophthalmology department at Duke University, who pioneered the approach with his recommendations for eating mostly rice and fruit. Kempner’s diet was plant-based and ultra-low in sodium, fat, cholesterol and protein. Kempner conducted a patient study in which he took “eyegrounds photographs”, which captured a view of the back of the eye. By tracking changes in these images, he demonstrated that diet could actually reverse damage. In fact, he found some patients who had suffered extreme vision loss due to diabetic retinopathy were later able to read fine print again. Of the 44 patients in his study who had diabetic retinopathy, 30% of them saw improvement in their vision. While Kempner’s food plan is not recommended as a stand-alone approach, it does show that what you eat can be very powerful for preserving your eye health!
The Keto Diet
A 40-year-old woman, known type 2 diabetes mellitus, obese (100 kg), on insulin (80 units), was under treatment for unstable proliferative diabetic retinopathy with extramacular tractional retinal detachment (TRD) in the left eye. At 1-year follow-up, she developed progression of TRD involving the macula in the left eye for which she was advised surgery. She did not follow-up for 6 months during which time she had adopted a coconut oil-rich ketogenic diet. She reported losing 25 kg body weight along with reversal of diabetes (Glycosylated Haemglobin (HbA1C) of 5.3% without insulin) in the interim. During this 2-year follow-up visit, it was found that there was complete resolution of macular detachment due to TRD in the left eye with stable vision.
The ketogenic diet, which is high in fat, adequate in protein and low in carbohydrates, results in a greater circulation of ketone bodies by a process of ketogenesis. This, in turn, facilitates energy utilisation by burning fat and causing weight loss. The keto diet considerably reduces glycosylated Haemoglobin (HbA1c) levels, thereby helping to delay the microvascular and neurogenic complications of diabetes.
Other Lifestyle Modifications
In addition to diet, other lifestyle modifications can help manage diabetic retinopathy:
- Exercise Regularly: Engaging in more physical activity has been shown to delay the onset and progression of diabetic retinopathy, protecting the retina and reducing inflammation. It’s advised that people with diabetes get at least 150 minutes per week of moderate-intensity physical activity, such as swimming or bicycling.
- Manage Blood Pressure: Control hypertension
- Avoid Smoking and Alcohol: Don’t smoke and avoid alcohol
- Regular Eye Exams: Don’t miss routine eye exams that enable your eye doctor to monitor your condition and change treatment, as necessary. Patients with diabetes and high blood pressure should have a comprehensive dilated eye exam at least once a year. Regular annual diabetic eye exams make it much more likely that diabetic retinopathy is caught in its earliest stages, making treatment more likely to be effective.
Treatments for Diabetic Retinopathy
There are several treatments available to manage the complications and symptoms of diabetic retinopathy:
- Medication Injections: Medications are injected into the eye to stop blood vessels from leaking and to prevent abnormal blood vessel growth.
- Laser Therapy: Laser treatments can help manage bleeding in the eye and reduce swelling. They can be used in conjunction with medication to control the more severe symptoms of diabetic retinopathy. During both scatter and focal photocoagulation, the doctor will use lasers to help alleviate the condition. The lasers make small burns on the retina aimed at the blood vessels. When using scatter photocoagulation, hundreds of small burns are made in a specific pattern during two additional appointments. Focal photocoagulation specifically targets the leaking blood vessels that are in the macula. Unfortunately, this procedure is not aimed at correcting the blurry vision associated with diabetic retinopathy, but it does stop it from progressing further.
- Vitrectomy: Vitrectomy is a surgery that helps to remove scar tissue and/or the fluid that is clouded with blood that has been leaked into the eye. This operation is the most successful when performed before the disease has progressed too far. When the operation only targets removing the fluid, success rates are very high for the procedure.
- Cataract Surgery: Diabetes can accelerate cataract growth, leading to early-onset cataracts. Cataract surgery can improve vision, but it does not reverse diabetic retinopathy itself. Additionally, patients with diabetic retinopathy are at a higher risk for complications like retinal swelling after cataract surgery, which makes managing both conditions important.