Diabetic Retinopathy & Diet: Seeing Clearer With Keto
Your eyes allow you to see and navigate the world around you, and maintaining good eye health is imperative. You’ve heard about the countless health benefits of following a ketogenic diet, but what about vision and eye health? How does going keto affect eye health? Let’s look at the research and what the keto professionals and advocates are saying about diabetic retinopathy and diet.
Diabetic Retinopathy
The thin layer of tissue at the back of the eye is essential for vision and often shows earlier signs of diabetic retinopathy.
With diabetic retinopathy, chronic high blood sugar levels, and uncontrolled high blood pressure damage the intricate blood vessels of the tissue at the back of the eye (retina). Diabetic damage can develop in anyone with type 1 or 2 diabetes, and it’s one of the leading causes of vision loss worldwide. [1] [2]
Undiagnosed diabetes is surprisingly common. Early diabetic retinopathy might cause little to no symptoms, and, over time, this condition can lead to blindness. You’re more likely to develop this complication if your blood sugar is chronically high.
Symptoms of diabetic retinopathy include:
- Blurred vision
- Dark or empty areas of vision
- Fluctuating vision
- Vision loss
- Dark spots or string floating in your vision (floaters)
It’s best to promptly visit your doctor or healthcare practitioner if you have diabetes or concerns about your blood sugar and eye health. Yearly eye exams with your eye doctor are also recommended, even if your vision seems fine.
Studies show people with diabetes are twice as likely to get cataracts. Cataracts refer to an eye condition causing a clouding of the lens of the eye. [3]
What Causes Diabetic Retinopathy?
The connection between eye health and blood sugar levels is becoming clearer as research grows.
Over time, excess sugar in the blood can lead to a blockage of the tiny blood vessels of the retina, cutting off nutrients and blood supply.
In advanced cases, the eye often tries to grow new blood vessels, but these vessels typically leak easily and don’t develop properly. Retinal blood vessel damage can lead to a buildup of fluid (edema) in the middle portion of the retina.
The growth of new blood vessels often causes scar tissue to form, which can detach the retina from the back of the eye. New blood vessels can also interfere with normal fluid flow out of the eye, resulting in a buildup of pressure and, in some cases, damage to the optic nerve that carries images from your eye to your brain (glaucoma).
How Does a Ketogenic Diet Affect Eye Health?
When it comes to protecting and improving vision, many doctors, ophthalmologists, optometrists, and other health professionals are advocating the use of a ketogenic diet. Particularly if eye damage and diabetic retinopathy are caught in the early or mid-stages, chances of improvement are higher. Some eye doctors have even reported patients reversing eye damage with lifestyle changes, including a ketogenic diet. While these stories are anecdotal, anecdotal stories are important to develop a pattern and picture of what could be happening and a direction for science to study.
Keeping blood sugar in normal ranges long-term is crucial. Research supports the use of a ketogenic diet to improve vision and various eye conditions. For example, one study concluded eating a high-fat keto diet could protect from glaucoma. [4]
Many doctors report patients’ eyesight worsening after starting insulin. Insulin is a digestive hormone your body uses to help safely store sugar in your cells. One theory is that insulin forcibly pushes glucose into delicate and damaged cells and contributes to the development of diabetic retinopathy. So far, studies confirm this hypothesis and highlight how the risk of diabetic retinopathy increases when insulin is added as a treatment for people with type 2 diabetes. [5]
Risk factors of diabetic retinopathy include poorly controlled blood sugar and blood pressure and high cholesterol. These factors are known to improve when switching to the metabolic state of ketosis.
Blood Sugar
The reduction in carbohydrates and high-fat content of the keto diet can alter how your body stores and uses energy, easing the symptoms of diabetes. With the exception of fiber, carbohydrates turn to sugar in the body, and certain carbs, such as refined and highly processed grain-based carbs, cause high blood sugar spikes. Instead of sugar, your body converts fat into energy, which improves and regulates blood sugar levels and reduces the need for insulin. Less sugar on keto means less need for insulin.
Studies show keto enhances glycemic and blood sugar control resulting in discontinued insulin requirements and medication reduction. [6] [7]
Blood Pressure
There’s an association between blood pressure and blood sugar. Low-carb nutrition has been shown to normalize and lower blood pressure within a few days, but it can also take months or even a year to be fully effective.
Research reveals a lower glycemic diet is correlated with lower levels of blood pressure. These results could be in part due to the reduction of insulin, which stimulates the sympathetic nervous system and the kidneys to reabsorb sodium, potentially leading to higher blood pressure.
Research reveals a lower glycemic diet is correlated with lower levels of blood pressure.
These results could be in part due to the reduction of insulin, which stimulates the sympathetic nervous system and the kidneys to reabsorb sodium, potentially leading to higher blood pressure.
Sugar might actually be more impactful on blood pressure than salt. A specific type of sugar called fructose might increase blood pressure, and the ketogenic diet is especially low in fructose and other sugars. Obesity is another risk factor for high blood pressure, and the keto diet is renowned for helping people crush their weight loss goals! [8] [9] [10] [11] [12] [13]
Cholesterol
Cholesterol is complicated, and people report different outcomes. Overall, when consuming a ketogenic diet, no significant or concerning serum-lipid changes take place. Most people experience better cholesterol, such as an increase in HDL and stable LDL, and improved quality of LDL. [13]
Research continues to highlight how keto diets reduce heart disease risk factors, even in those with diabetes and other insulin-resistant conditions. [14] [15]
Concluding Thoughts
Improving vision and eye health also appear to be on the long list of health benefits associated with a ketogenic, low-carb, high-fat diet.
Many eye complications like diabetic retinopathy might be connected to or exacerbated by blood sugar dysregulation, insulin, and other metabolic factors. By improving these metabolic factors, the keto diet could also improve vision and eye health.
References
Lee, R., Wong, T. Y., & Sabanayagam, C. (2015). Epidemiology of diabetic retinopathy, diabetic macular edema, and related vision loss. Eye Vis (Lond), DOI: 10.1186/s40662-015-0026-2
Mayo Clinic. Diabetic Retinopathy, Symptoms and Causes. Diabetic retinopathy - Symptoms and causes - Mayo Clinic
Kiziltoprak, H., Tekin, K., Inanc, M., & Goker, Y. S. (2019). Cataract in diabetes mellitus. World J Diabetes, 10(3), 140-153. DOI: 10.4239/wjd.v10.i3.140
Zarnowski, T., Tulidowicx-Bielak, M., Kosior-Jarecka, E., Zarnowska, I., Turski, W. A., & Gasior, M. (2012). A ketogenic diet may offer neuroprotection in glaucoma and mitochondrial diseases of the optic nerve. Med Hypothesis Discov Innov Ophthalmol, 1(3), 45-49.
Zhao, C., Wang, W., Xu, D., Li, H., Li, M., & Wang, F. (2014). Insulin and risk of diabetic retinopathy in patients with type 2 diabetes mellitus: Data from a meta-analysis of seven cohort studies. Diagn Pathol, DOI: 10.1186/1746-1596-9-130
Westman, E. C., Yancy Jr., W. S., Mavropoulos, J. C., Marquart, M., & McDuffie, J. R. (2008). The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus. Nutrition & Metabolism, 5(36),https://doi.org/10.1186/1743-7075-5-36
Paoli, A., Rubini, A., Volek, J. S., & Grimaldi, K. A. (2013). Beyond weight loss: A review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. European Journal of Clinical Nutrition, 67, 789-796.
Horita, S., Seki, G., Yamada, H., Suzuki, M., Koike, K., & Fujita, T. (2011). Insulin resistance, obesity, hypertension, and renal sodium transport. International Journal of Hypertension, https://doi.org/10.4061/2011/391762
Santos, F. L., Esteves, S. S., Pereira, A. C., Yancy Jr. W. S., & nunes, J. P. L. (2012). Systematic review and meta-analysis of clinical trials of the effects of low carbohydrate diets on cardiovascular risk factors. Obesity Reviews, 13(11), 1048-1066. DOI: 10.1111/j.1467-789X.2012.01021.x
DiNicolantonio, J. J., & Lucan, S. C.(2014). The wrong white crystals: Not salt but sugar as aetiological in hypertension and cardiometabolic disease. Cardiac Risk Factors and Prevention, http://dx.doi.org/10.1136/openhrt-2014-000167
Perez-Pozo, S. E., Schold, J., Nakagawa, T., Sanchez-Lozado, L. G., Johnson, R. J., & Lillo, J. L. (2010). Excessive fructose intake induces the features of metabolic syndrome in healthy adult men: Role of uric acid in the hypertensive response. Int J Obes (Lond), 34(3), 454-461. DOI: 10.1038/ijo.2009.259
United States Department of Health and Human Services. Your Guide to Lowering Blood Pressure. Your Guide to Lowering Blood Pressure (nih.gov)
Volek, J. S., Phinney, S. D., Forsythe, C. E., Quann, E. E., Wood, R. J., Puglisi, M. J., Kraemer, W. J., Bibus, D. M., Fernandez, M., & Feinman, R. D. (2009). Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low-fat diet. Lipids, 44(4), 297-309. DOI: 10.1007/s11745-008-3274-2
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