Jule Klotter

“Displacing Foods” as Primary Cause of Age-Related Macular Degeneration?

In late 2013, ophthalmologist Chris A. Knobbe, MD, began investigating the connection between processed food consumption and age-related macular degeneration (AMD).^1,2 His research resulted in an article for Medical Hypotheses,³ published November 2017, and co-authored with Marija Stojanoska, MSc, and a book, Cure AMD – Ancestral Dietary Strategy to Prevent & Reverse Macular Degeneration, published September 2016.

Knobbe and Stojanoska gathered information about AMD prevalence and processed food consumption from 25 countries. They used sugar and ‘harmful’ vegetable oil as markers for processed food, defining ‘harmful’ oil as those with high polyunsaturated content, commonly used in processed foods (soybean, corn, canola, cottonseed, sunflower, safflower, rapeseed, grapeseed, and rice bran oils). They found that AMD was “a medical rarity worldwide” from 1851, when the first ophthalmoscopes permitted doctors to view the optic nerve, until the 1930s.

According to Knobbe’s research, the first reports of patients with AMD characteristics appeared in an 1874 report concerning four English patients. Twenty-one years later, a German ophthalmologist “determined that macular degeneration was as rare as maculopathy and traumatic maculopathy” in his review of 50,000 patient medical records. Dr. Knobbe says maculopathy and traumatic maculopathy continue to be rare today, based on his 24 years of clinical practice, having “witnessed less than a handful of the latter two conditions combined.” The incidence of AMD grew during the 1930s; it was acknowledged in the 1940 edition of Sir Stewart Duke-Elder’s comprehensive textbook of ophthalmology to be “a common cause of failure in central vision in old people.” By 1975, AMD had risen to “epidemic” proportions in the US and UK – but not in Japan and some other countries.

Dr. Knobbe points out that food quality changed in the 1880s. Refined white wheat flour became commonplace with the use of roller mill technology, instead of stone mill grinding. The new technology removed the most nutritious parts of the wheat grain (the bran and germ), which contain B vitamins, vitamin E, essential fatty acids, and minerals. In addition, 1880 saw the introduction of seed oils, aka vegetable oils, such as cottonseed oil. Food manufacturers used hydrogenation and partial hydrogenation to create cooking oils, like Crisco, as cheaper alternatives for traditionally used animal fats, like butter, lard, and beef tallow.

While poverty or the consequences of war or drought could result in malnourishment, traditional diets consumed before widespread food processing in the late 1880s afforded protection against many diseases common today. “History is very clear that all of the chronic metabolic diseases, ie. ‘Westernized’ disease, such as heart disease, cancer, type 2 diabetes, and obesity, all of which are so prevalent today, were medical rarities at the turn of the 20^th century,” says Knobb.

The Japanese people were presumed to have ‘genetic protection’ against AMD. As late as 1979 at Japan’s Nagoy University Hospital, about 0.2 percent of the eye patients had AMD. But as their diet became increasingly “Westernized,” and the consumption of sugar and harmful oils rose, AMD incidence rose. The 2007 Hisayama study reported that 10% of Japanese residents age 50 and older had early AMD and 1.4% had late AMD. 

Meanwhile, Pacific Island nations of Samoa, Solomon Islands, and Kiribati, which continue to maintain traditional diets (seafood, taro, yams, and other roots and tubers, and a variety of tropical fruits) with few processed foods, have AMD incidence of 0.2% or less—including populations age 60 and older. In looking at data from the Pacific Island nations, Knobbe and Stojanoska found that sugar consumption was extremely low in the Solomon Islands, moderately low in Samoa, and moderately high in Kiribati.

All three countries, however, had extremely low consumption of ‘harmful’ vegetable oils (“essentially zero”), according to the Food and Agriculture Organization of the United Nations (FAO). “The correlative data…demonstrates that, when consumption of sugar is moderate, but ‘harmful vegetable oil’ consumption remains extremely low or absent, the prevalence of AMD remains rare,” the authors conclude.

Interestingly, the harmful vegetable oils decrease absorption of eye-protective carotenoids, found in leafy greens like kale, collards, and spinach. Diets rich in these pro-vitamin A precursors were associated with low risk of developing AMD, according to the 1971-1972 National Health and Nutrition Examination Survey (NHANES). “These oils literally cause destruction of the carotenoids, unless significant antioxidants are present, which is often not the case,” says Knobbe.

Knobbe contends that nutrient supplements, such as those tested in the Age-Related Eye Disease Study (AREDS), do not make up for the inadequacies of the Western diet dominated by processed foods. He points out that the probability of progression to advanced AMD in people with intermediate AMD who took part in the AREDS placebo group was 28 percent over five years. In comparison, it was 20 percent for those who received vitamins E, C, beta-carotene, and zinc. Adding lutein, zeaxanthin, DHA, and EPA (AREDS 2) did not reduce the progression risk further.

Recent studies by Carl Awh, MD, et al, and a 2016 study by Johanna M. Seddon and colleagues indicate that the effectiveness of supplementation may depend upon genetic make-up.⁴ Some genotypes of the CFH and ARMS2 genes (both implicated in genetic risk for AMD) were benefited by supplements while other genotypes actually showed increased progression.

For guidance on what constitutes a traditional diet, Knobbe refers to the findings of Weston A. Price, DDS, who traveled the world in the 1920s and 30s to observe the dietary habits and health of isolated populations. Price discovered that health declined as processed and canned foods became part of the diet. All healthy societies included nutrition from animal sources—even though that meant eating insects, instead of cows, chickens, or fish, in some cases. Other valued traditional foods include whole, raw milk, butter oil from pasture-raised animals, organ meats, seafood, and fish eggs. Fresh fruits and vegetables, nuts, and seeds are also part of nutrition-rich diets.

In their study, Knobbe and Stojanoska conclude “that macular degeneration is entirely preventable, through ancestral dietary strategy and avoidance of processed foods. Finally, this research has implications for patients with existing early and intermediate stages of AMD.”³

Blue Light and Retinal Damage

In 2018, researchers at University of Toledo (Ohio) reportedly discovered how blue light emitted by digital devices damages the retina and promotes age-related macular degeneration (AMD).⁵ Photoreceptor cells in the retina sense light, signaling the brain, but only in the presence of retinal molecules within the cells.

Unlike red or yellow light, blue light “excites” retinal (a polyene chromophore) in a way that “irreversibly changes and distorts” the phospholipid (PIP2) bound to the cell’s plasma membrane.⁶ This disruption leads to an increase in calcium within the cell, excessive cell shape change, and cell death. Interestingly, the combination of retinal and blue light proved to be toxic to non-photoreceptor cells (eg, HeLa cells) as well. Adding alpha-tocopherol, a lipid-soluble antioxidant, to incubated cells lessened damage to PIP2.

Blue light filters are being investigated as a way to lessen damage. Spanish researchers tested the protective effect of a filter using three groups of young albino mice (unexposed, exposed to filtered light, exposed to light without filter).⁷ The filter removed 94% of the blue component emitted by a cold light fluorescent emission lamp (400-820 nm). The mice, whose pupils were dilated with atropine, were exposed to continuous bright light (5000 lux) for seven days.

Even though the filter removed this high percentage of blue light, the researchers found retinal damage in both groups exposed to the high-intensity light: “the number of photoreceptors in the unexposed groups of mice was significantly higher than in the unprotected or the protected groups.” Among the light-exposed mice, photoreceptor cell survival was significantly better in the central areas of the retina in the filter group. The authors suggest that blue-blocking filters may be an effective way to decrease, albeit not totally prevent, retinal damage.

Benefits of Solar Ultraviolet Radiation

Because of the association between ultraviolet radiation (UV) and skin cancers, people have been encouraged to use sunscreen and limit sun exposure. Yet, as Michael F. Holick explains in a 2016 article, sunlight exposure is associated with lower incidence of autoimmune illnesses such as multiple sclerosis and reduced mortality from a wide variety of disease, including cardiac disease, cancers, and infectious disease.⁸ Holick points out that melanoma, the deadliest skin cancer, “is often found on the least sun-exposed areas” and that “occupational sun exposure has been associated with a reduced risk” for this disease.

Sunlight’s health benefits have been primarily ascribed to vitamin D whose production is dependent upon ultraviolet B (UVB). The active form of vitamin D [1,25(OH)2D] is necessary to prevent skeletal deformity (rickets). Vitamin D also takes part in many metabolic processes, including DNA repair, antioxidant activity, and regulating cellular proliferation and differentiation—actions that provide protection against cancer. Vitamin D receptors are found in cells throughout the body.

Vitamin D is not the only beneficial result from UV exposure. UV radiation prompts melanocytes in the epidermal-dermal junction to produce melanin, a compound that absorbs UVB and ultraviolet A (UVA).⁹ Melanin acts like a protective shield for epidermal cells. In addition to its role as a natural sunscreen, melanin is an antioxidant and free radical scavenger.

UV radiation also stimulates nitric oxide production in the skin. Nitric oxide is a vasodilator, reducing blood pressure, and is cardioprotective. The compound also upregulates protein 53, which suppresses tumor formation.

And UV radiation increases expression of the proopiomelanocortin (POMC) gene, resulting in production of beta-endorphin (producing feelings of well-being) and production of ACTH (adrenocorticotropin hormone), which increases production of the immune modulator cortisol.

Both solar-derived and dietary/supplemental vitamin D are stored in fat cells until needed, says Holick. Sunlight, however, provides more benefits than vitamin D alone. The question is how to reap the benefits without causing skin cancers. The answer depends on many factors, including skin pigment, geographic location, time of day, and exposure time. Avoiding sunburn is the primary consideration. Information about sun exposure and vitamin D production is available at www.vitamindfoundation.org. A free app called dminder.info is another resource.

Yoga Practices and Glaucoma

Researchers in India want to investigate Tratak kriya, a yoga practice that includes eye exercises, as a way to lower intraocular pressure (IOP) in people with glaucoma.¹⁰ Glaucoma, the most common cause of blindness, affects over 65 million people worldwide. Above-normal IOP, characteristic of glaucoma, damages the optic nerve.

Tratak kriya is a technique for maintaining eye health, according to Ayurveda, India’s ancient traditional medicine system. Tratak is simply the practice of gazing steadily at a small object without blinking for as long as possible or until the eyes fill with tears. In their 2018 article, the authors say that this exercise causes contraction and relaxation of ciliary muscles in the eyes. These same muscles are involved in the outflow of the aqueous humor. Increasing outflow reduces IOP. The Indian team hopes that restoring ciliary muscle movement will reduce IOP and, thereby, prevent the development of glaucoma in high-risk people or slow its progression. After testing Traka kriya’s effect on IOP, they propose clinical studies in people with glaucoma, using the technique as an ‘add-on’ to standard care, and other studies to investigate its use as a preventive measure in people without glaucoma.

Another yoga practice, forced unilateral nostril breathing, has already been shown to affect IOP in clinical studies.¹¹ Back in 1990, an Israeli team  found that breathing through the right nostril (the left was packed with cotton), for 20 minutes decreased IOP an average of 27% in the right eyes and 22.5% in the left in 46 patients with open and closed angle glaucoma, bringing the pressure to normal range. Previous studies found that forced left nostril breathing increased IOP. Not all participants in the 1990 study benefited from right nostril breathing; IOP increased significantly in three people with neovascular glaucoma, one with juvenile glaucoma, and one with closed angle glaucoma.

Yoga breathing exercises are known to affect the autonomic nervous system, which is a factor in regulating intraocular pressure. Although the effect of the breathing exercise was nearly immediate, the Israeli team did not view it as a potential clinical intervention because the effect lasted just two to three hours. However, the study’s results suggest that chronic blockage in the right nostril, due to nasal polyps or septal deviation, may be a contributor to the development of high IOP and glaucoma.

This column was originally published in Townsend Letter, April 2019.

References

1. Knobbe CA. Is Age-Related Macular Degeneration (AMD) Preventable – and Treatable – with Diet? Introduction.  Cure AMD Foundation.  www.cureamd.org
2. Knobbe CA. What Are the Best ‘Eye Vitamins’ for Macular Degeneration?  www.cureamd.org
3. Knobbe CA, Stojanoska M. The ‘Displacing Foods of Modern Commerce’ Are the Primary and Proximate Cause of Age-Related Macular Degeneration: A Unifying singular Hypothesis (abstract).  Medical Hypotheses. November 2017;109:184-196.
4. Seddon JM, Silver RE, Rosner B. Response to AREDS supplements according to genetic factors: survival analysis approach using the eye as the unit of analysis. Brit J Ophthal. 2016;100(12):1731-1737.
5. Chemists discover how blue light from digital devices speeds blindness. Science Daily. August 8, 2018.
6. Ratnayake K, et al. Blue light excited retinal intercepts cellular signaling. Scientific Reports. 2018;8:10207.
7. Vicente-Tejedor J, et al. Removal of the blue component of light significantly decreases retinal damage after high intensity exposure. PLOS. March 15, 2018.
8. Holick MF. Biological Effects of Sunlight, Ultraviolet Radiation, Visible Light, Infrared Radiation and Vitamin D for Health. Anticancer Research.  2016;36:1345-1356.
9. Islam MT. Beneficial Aspects of Ultraviolet Rays in Protective and Sound Health. EC Pharmacology and Toxicology. December 18, 2017.
10. Sankalp TD, Yada RK, Faiq MA. Effect of Yoga-Based Ocular Exercises in Lowering of Intraocular Pressure in Glaucoma Patients: An Affirmative Proposition. Int J Yoga. September-December 2018;11(3):239-241.
11. Backon J, et al. A functional vagotomy induced by unilateral forced right nostril breathing decreases intraocular pressure in open and closed angle glaucoma. Brit J Ophthal. 1990;74:607-609.

Published July 29, 2023

About the Author

Jule Klotter has a master’s in professional writing from the University of Southern California. She joined Townsend Letter’s staff in 1990. Over the years, she has written abstract articles for “Shorts” and many book reviews that provide information for busy practitioners. She became Townsend Letter’s editor near the end of 2016.