DHA and its role in maintaining eyesight
In today’s post we will talk about docosahexaenoic acid (DHA), which is an omega-3 fatty acid and plays a crucial role in maintaining vision. In this article we will review the existing scientific literature and the most recent clinical trials looking at the impact of DHA on vision maintenance. So, without further ado, we dive right into exploring this very interesting topic.
Understanding a little more about DHA
The study of the physiological significance and effects of omega-3 polyunsaturated fatty acids, particularly DHA, remains a relatively unexplored field in the human health sciences. The idea that this fatty acid in photoreceptor membranes has no other function than to contribute to their fluidity is probably an oversimplification.
DHA is a key component of cell membranes, particularly in neural and ocular tissues. Thus, the brain and eye have high contents compared to other organs. Within the visual system, DHA is found in high concentrations in the retina, especially in photoreceptors, where its presence is essential for the proper functioning of vision. Being part of a complex collaborative system, in the brain, DHA participates in neuronal signaling, while in the eye it participates in the quality of vision.
DHA is transported into the bloodstream as a component of lipoproteins within triglycerides, phospholipids, and cholesterol esters or as a free non-esterified fatty acid, largely due to the release of adipose tissue deposits or lipase-mediated hydrolysis of circulating lipoproteins. This fatty acid accumulates in the brain and eye in late pregnancy and early childhood, and a lower content is linked to poorer cognitive development and visual function. In addition, it is of particular interest in the context of nutrition and disease prevention, due to its ability to maintain the integrity of visual cells and protect against degeneration processes. https://doi.org/10.1159/000448262
A journey from embryology
DHA is incorporated into the retina during fetal development and plays a critical role in maintaining the structure of photoreceptors. Studies in animal models and in humans suggest that the high concentration of DHA in the retina is critical for synaptic plasticity and visual signal transmission. It has the ability to modulate the processes involved in the pathogenesis of age-related macular degeneration (AMD). Some research has shown that it is essential in the biology of retinal cells, especially in rods and cones that allow visual perception in low and high light conditions, respectively. In addition, DHA is efficiently absorbed in the diet through the consumption of fatty fish and omega-3 supplements, which facilitates its distribution in visual tissues, where it acts to improve retinal function. DOI: 10.1001/archopht.126.9.1274
A double-edged sword
1. Reactive Oxygen Species (ROS) and their Role in the Retina
Reactive oxygen species (ROS) generated by biological systems as metabolic byproducts include superoxide radicals, hydrogen peroxide, hydroxyl radicals, and singlet oxygen. Mitochondria under both physiological and pathological conditions are a major source of ROS. Superoxide radicals are produced by cellular respiration, by cyclooxygenases (COX) during the metabolism of arachidonic acid, and by lipoxygenases (LOX), as well as by endothelial cells and inflammatory cells. Nitrosylated oxidation products linked to ROS reduce biological activity with loss of important functions in energy metabolism, transport, cell signaling and a wide variety of detrimental effects. https://doi.org/10.3390/antiox10030386
2. Oxidative Stress in Aging and the Retina
The fact that aging increases oxidative stress in cells and that visual cells are enriched in DHA can lead to functional alterations. DHA peroxidation can deplete crucial phospholipids from their sites in specific membrane domains. In addition, the peroxidation of DHA generates toxic products that can damage the detachment of the discs from the photoreceptors or their phagocytosis by the retinal pigment epithelium.
In the human body, the retina boasts the highest consumption of oxygen per gram of tissue, requiring large amounts of ATP to support cellular functions. This high metabolism makes the retina especially vulnerable to damage from oxidative stress. Numerous studies have shown that ROS contribute to vascular endothelial dysfunction and neuronal degeneration of the retina. https://doi.org/10.3390/antiox9100920
3. DHA as a Preventive Agent in Ocular Pathologies
However, current research suggests that DHA has a preventive role in several visual pathologies. In macular degeneration, one of the leading causes of blindness in older adults, the AREDS2 study evaluated the effect of supplementation with DHA and other nutrients and concluded that those individuals with adequate DHA intake showed a lower risk of disease progression. DOI: 10.1016/j.ophtha.2004.10.047
4. DHA and Diabetic Retinopathy
In addition, other studies indicate that DHA contributes to reducing eye inflammation and oxidative stress, key factors in the progression of AMD. As for dry eye syndrome, evidence suggests that DHA supplementation might improve eye lubrication and reduce tear evaporation, providing relief in symptoms of chronic dry eyes.
Another relevant aspect is the potential of DHA in diabetic retinopathy, a common ocular complication in people with diabetes. Some studies have shown that DHA helps maintain the integrity of blood vessels in the retina, reducing the risk of hyperglycemia-induced vascular damage. This effect is largely attributed to the ability to reduce inflammation and oxidative stress in ocular tissues, as well as its influence on the regulation of angiogenic factors. https://doi.org/10.1186/1743-7075-8-39
5. Mechanisms of Action of DHA on Eye Health
The mechanisms of action of DHA on eye health are diverse and complex. DHA is known to contribute to the fluidity of cell membranes in photoreceptors, allowing efficient regeneration of visual pigments. In addition, DHA has antioxidant and anti-inflammatory properties, which protects retinal cells from damage associated with aging and free radicals. However, current research has certain limitations, such as the lack of large-scale longitudinal studies confirming the effects of DHA on the prevention of eye diseases in the long term.
Taking Action: DHA-Rich Food Supplements
Because fatty fish are the richest dietary source of DHA, their intake is strongly influenced by fish consumption. From a clinical point of view, DHA could be considered as an important supplement in the diet to maintain eye health and prevent degenerative diseases of the retina. Active Omega 3 DHA is a dietary supplement designed to provide a high dose of this essential fatty acid that the body cannot synthesize efficiently. Each pearl contains 1000 mg of fish oil, of which 760 mg is DHA. The oil in this product is obtained by a cold extraction process, concentrated in the form of triglycerides, which favors better absorption and bioavailability.
Active Omega 3 DHA, developed by Salengei, helps maintain visual and brain function and has been formulated to meet recommended daily needs, particularly important in populations with high demand for DHA, such as pregnant women and adults at risk of eye diseases. Being enriched with vitamin E as an antioxidant, Active Omega 3 DHA It also protects retinal cells from oxidative damage, supporting its use as a preventive supplement in eye health and proper visual development, especially in critical stages such as pregnancy and lactation.
Conclusion
The scientific evidence we have consulted supports the role of DHA as an essential component in visual health, thanks to its contribution to the structure and function of the retina and its potential effects in the prevention of eye diseases. Not only is DHA critical for visual development in childhood, but it can also play a protective role in older adults, particularly against conditions such as AMD and dry eye syndrome.
Despite the limitations of some studies, DHA is a promising ally in the prevention and management of various ocular pathologies. Future research should focus on long-term controlled trials to confirm these findings and provide more specific recommendations on DHA supplementation for the maintenance of eye health.
