Does what you eat affect what you see? Generally, people are aware of foods that are not very good for overall health. But have you considered that some foods do not support healthy vision and may contribute to vision loss? The health of your eyes is directly connected to the health of your heart and blood vessels. This article explores the potential impact of the carnivore diet on eye health, considering both potential benefits and risks.
Understanding the Carnivore Diet
The carnivore diet is a highly restrictive dietary regimen that eliminates all plant-based foods, relying exclusively on animal products such as meat, fish, eggs, and dairy. Some Arctic populations have survived for generations on almost entirely animal-based diets. The carnivore diet seeks to replicate this way of eating.
Potential Benefits of the Carnivore Diet
Autoimmune Conditions
Some supporters of the carnivore diet suggest that eliminating plant-based foods may benefit individuals with autoimmune conditions by reducing exposure to potential dietary triggers, such as lectins and oxalates.
John's Experience: A Case Study
John, a 70-year-old, before his carnivore experience, had been suffering. He had developed macular degeneration and was concerned he would lose sight in his left eye. He also suffered with high blood pressure, chronic joint pain, skin problems and skin tags, being overweight, histamine and allergy issues, and food allergies, requiring steroid shots. This constellation of problems shows that John was clearly on the decline, and his immune system was going astray. Skin tags are also thought to be markers of metabolic disease, as is an expanding waistline. High blood pressure is a major risk factor, and combined with metabolic issues, this left John at an increased risk of heart disease.
John first learned about the carnivore diet when he was listening to Joe Rogan’s podcast, “especially when you [Dr. Shawn Baker] were on, and from Jordan Peterson and his daughter both.” John read what he could find about the carnivore diet and found information that could help his vision: “I read an article where this man who got his 78-year-old mother with macular degeneration, to go carnivore. She was blind in the left eye and the right eye was getting pretty useless. She ate carnivore and at six months most of her eyesight came back in her left eye, and her right eye is improving also. She can now read a book which she hasn’t been able to do in seven years. I’m gonna stick to meat and eggs only, been 100% on it and see what happens.” He found the carnivore diet to be a logical choice and one that could help him with the problems he was seeing throughout his body. “Makes sense to me, seems to help every aspect of your body and health.”
Read also: The Carnivore Diet: An Autoimmune Solution?
John is already seeing results after two months of his 100% carnivore diet. He has already lost 15 pounds and notes that “I have the flattest stomach I’ve ever had since I was 25 or so.” This shows that his initial weight loss is from his belly, and probably represents a loss of visceral fat. That’s important because visceral fat is what promotes metabolic disease and inflammation. The waist: height ratio is a validated formula for predicting visceral fat accumulation, and since people’s heights don’t change much, getting a flat belly is a great sign this ratio is improving! He has also seen his high blood pressure disappear, “my skin has improved and all the skin tags on my neck have dropped off,” and his joints are healing: “my joints are almost pain-free.” These changes also suggest less inflammation, which is great! John is ready for more life, not more aging, saying, “I just turned 70, and according to Joe Rogan, guys my age are supposed to be almost at death’s door, ha!… I’ve been working out since I was 22 and still going.
Potential Risks and Considerations
Nutritional Imbalances
Potential nutritional imbalances due to the carnivore diet could also present challenges to long-term adherence.
Limited Research
Existing research on the carnivore diet is limited, with most evidence being anecdotal or derived from broader studies on ketogenic and low-carbohydrate diets.
Impact on the Gut Microbiome
Dietary Fiber Intake and Gut Microbiota in Human Health is important. The gut microbiome links dietary fiber to inflammatory diseases. Interplay between diet and gut microbiome, and circulating concentrations of trimethylamine N-oxide: findings from a longitudinal cohort of US men.
Kidney Stone Development
You are what you eat-Should it be all meat?: Impact of the carnivore diet on the risk of kidney stone development.
Read also: The Carnivore Diet's Impact on Sleep
Eye Health and General Dietary Considerations
The Impact of Unhealthy Foods
Processed food purchased at the supermarket is high in saturated fat, an unhealthy fat, the type that raises blood cholesterol levels. Saturated fat found in red meat, dairy products, fried foods, and junk food causes plaque buildup in blood vessels. A diet high in saturated fat is a diet consisting of unhealthy food. Katherine Patton, Lead, Outpatient Dietician at the Cleveland Clinic said, “try to find a balance and add a bit of healthy fat back into the diet. We do not recommend completely avoiding saturated fat.” The American Heart Association recommends aiming for about 5 to 6% of daily calories from saturated fat. A healthy diet leads to healthy eyes; an unhealthy diet leads to unhealthy eyes.
Foods to Avoid for Eye Health
- While delicious, the carbs found in pasta and white bread have been linked to a higher risk of eye diseases. When broken down, simple carbs cause a spike in blood sugar. Blood sugar is used as energy to fuel your body, but spikes caused by a poor diet are a risk factor for diabetes. A diet rich in simple carbohydrates can also cause weight gain and increase the risk of high cholesterol and heart disease.
- A high sodium diet with frequent salt spikes can lead to high blood pressure (hypertension). Over time, hypertension causes profound damage in the eye including blood vessel damage, a buildup of fluid beneath the retina, and a blockage of blood flow that kills nerves.
- Health experts recommend staying away from food items that include hydrogenated oils and trans fats. Cooking oil with less than four grams of saturated fat per tablespoon is recommended. Margarine is considered a healthy alternative to butter but is full of trans fats that can increase blood cholesterol levels.
- Soda, sports drinks, energy drinks, and other sweetened drinks can contain up to 7 to 10 tablespoons of sugar per drink.
The Keto Diet and Eye Health
The keto diet is a high-fat, low-carbohydrate diet that forces the body to shift its primary energy source from carbohydrates to fat. This shift leads to the production of ketones, molecules the body uses for energy instead of glucose from carbs. The keto diet is often used for weight loss, as it promotes fat burning.
Blurry vision is a common, though usually temporary, side effect for individuals starting the keto diet. The keto diet has a diuretic effect, which can lead to dehydration if fluid intake isn't properly maintained. Fortunately, you can support your eye health while following a keto diet by incorporating nutrient-rich foods vital for maintaining healthy vision. Vitamin A is crucial for maintaining the retina's function, which is responsible for vision. Zinc is key in maintaining healthy vision and can help prevent night blindness.
If blurry vision persists or worsens while following the keto diet, seeking professional help is essential. Schedule an eye exam to rule out other causes of blurry vision, such as underlying conditions like macular degeneration or diabetes.
Specific Eye Conditions and Diet
- Cataracts: A cataract is when the eye’s natural lens becomes cloudy. Aging is the most common cause of cataracts. The eye’s lens swells if blood sugar remains consistently high. The lens also converts blood sugar to sorbitol, a substance that collects in the eye and may cause cataracts. A study published by the researchers at the University of Oxford found that eating less meat and more vegetables can lower the incidence of developing cataracts.
- Age-related Macular Degeneration (AMD): Age-related macular degeneration (AMD) is an eye disease that causes deterioration of the macula - the back layer of the eye that records images we see. These images are then sent to the brain via the optic nerve and that’s how we see! AMD is the leading cause of vision loss among people over 50. The macula is an environment where there is an abundance of cell-damaging free radicals. Vitamins and minerals high in antioxidants may play a role in preventing AMD, by neutralizing free radicals.
Primary Open Angle Glaucoma (POAG)
Following a long-term diet that’s low in carbohydrates and high in fat and protein from vegetables may lower the risk of the most common subtype of glaucoma. In a first-of-its-kind study, a researcher at New York Eye and Ear Infirmary of Mount Sinai (NYEE) helped discover that if at-risk groups adhere to these dietary restrictions, they may reduce their risk of developing primary open angle glaucoma with early paracentral visual loss by 20 percent.
Read also: Troubleshooting Carnivore Diet Diarrhea
POAG is the leading cause of optic nerve degeneration that is related to the pressure level inside the eye, but other factors also contribute to this condition. “A diet low in carbohydrates and higher in fats and proteins results in the generation of metabolites favorable for the mitochondrion-rich optic nerve head, which is the site of damage in POAG. This dietary pattern has already been shown to have favorable results for epilepsy and showed some promising results for Parkinson’s and Alzheimer’s diseases,” said co-corresponding author Louis R. Pasquale, MD, FARVO, Deputy Chair for Ophthalmology Research for the Mount Sinai Health System.
Ketone bodies (energy compounds produced as the body metabolizes fats) are substituted for glucose as a major energy source for the brain and using more of these under a ketogenic diet may improve function and slow down neuronal degeneration. Since glaucoma is a condition that may be associated with mitochondrial dysfunction, researchers wanted to find out if substituting protein and fat for carbohydrates in the diet would enhance mitochondrial activity, maintain optic nerve function, and prevent optic nerve degeneration in this blinding eye disease.
Patients in the low-carbohydrate intake group who followed a diet of increased plant-based fat and protein were associated with a 20 percent lower risk of developing POAG subtype with paracentral visual field loss compared to those in the high-carbohydrate intake group. However, the researchers did not find any association between POAG and a low-carbohydrate diet without accounting for the source protein or fat, and they did not find any association between glaucoma and an animal-based low-carbohydrate diet.