Prevalence of Age-Related Macular Degenerative Disorder Due to Poor Dietary Habits

AMD in Relation to Diet

Diet is a vital factor that affects the modality of AMD risk either it took it towards a positive sideways or towards late AMD i.e., severe stage of AMD. The data of detailed studies showed that a diet which is rich in antioxidants (ascorbic acid, vitamin E, lutein, zeaxanthin) and micronutrients is a contributing factor in lowering the risk of AMD while the food containing a high percentage of trans fat also has to boost factor in AMD risks development [5]. Nowadays, people didn’t get stick to one diet and it is rarely found that they were using one food in isolation for a long while. Different approaches have been examined to study a well- characterized dietary pattern by scoring mechanism. The Mediterranean diet is one of such approaches it contains fruits, vegetables, vitamins and micronutrient-rich food with no red meat which is a potentially protective factor in lowering AMD risks [6]. Although the trend of the Mediterranean diet has been extended to a vast level to AMD to confirm its impact but still no analytical trials confirmed. It is just preferred because anti-oxidant in the diet prevents the damage due to oxidation and the nutrients in food have more health impact that helps in combating the degenerative AMD disease. However, more clinical trials are needed for the conformity of MD towards the prevention of AMD [5].

Carotenoids

Carotenoids are fat soluble pigments that are found in living sources such as fungi, algae, fruits, vegetables and also in humans. There are more than six hundred carotenoids are reported with having variant structures and split into carotenes xanthophyll’s and lycopene [7]. Each class of the above-mentioned carotenoid carries their particular pigment due to the fact of belonging to tetra terpene family basic chemical structure of carotenoids contain a core carbon chain with single and double, cyclic or acyclic altering bonds and these changing bonds are accountable for their coloring and antioxidant property [8]. Carotenoids are responsible for red, green, or orange hues in plants that can be naturally occurring or can be produced by various biotechnological methods in the laboratories due to their high market in food sector [8].

Carotenoids associated with the human diet are lutein, zeaxanthin, α-carotene, β-carotene. During the research, experts found lutein and zeaxanthin are the most dominating macular pigments as observed under High Performance Liquid Chromatography (HPLC) and UV spectra [9]. Lutein and zeaxanthin are antioxidant carotenoids that are crucial in preserving cell membrane to stabilize it, snuffing out free radicals as they absorb the blue light that lowers the risk of age-related macular degeneration. Some other carotenoids such as α-carotene, β-carotene are also beneficial in reducing the threats of diseases relating to age as aging results in biological and cognitive degradation [7].

Hence, their dietary intake or supplementation would be the key to overcoming this increasing worldwide issue as AMD contributes 8.7% of world’s blindness diseases that researches also reported that this rate has been evolved that the average percentage will get doubled in 2050 [2]. Therefore, it is very important to adequately balance the diet of people by their natural food rich with functional nutrients or supplemented food with carotenoids. Analytical data have given the results of carotene content that is commonly available in fruits and vegetables such as apples contain 100- 140 µg/100g lutein and spinach 2047-20300 µg/100 g) [10].

Role of carotenoid in the prevention of AMD’s

In older people, antioxidants’ effectiveness gets retarded as a matter of fact that the biological activity, functioning of the brain and organs get lowered with age due to its ability to fight against the external environment that gets very low [11]. A recent database has reported that an average age of 72 years with a healthy life of 63 years globally [12]. Antioxidant carotenoids have been proved to lower the risk of AMD due to their antioxidant activity as they are more efficient than carotene and alpha-tocopherol and they can fight more effectively and rapidly to oxidative stress and protect from auto-oxidation [13].

Age related macular degeneration can result due to aging but have not the only reasons excessive smoking, diet with low carotenoid contents as well as oxidative stress due to environmental oxidative by-products can also be a reason for this disease [14]. Nevertheless, blue lights of high wavelengths from electronic devices can have worst effects on the retinal cells and cause this disease when a person get excessively exposed to it [15]. As the epithelial cells and photoreceptors don’t spread due to their post mitosis, hence they don’t contain the DNA detection systems as other cells that are more oxygen sensitive [16]. The sensitivity can damage the cell membrane and natural macular carotenoid which absorb blue light and guard against environmental light induced oxidation the damage causes severe problems and result in blurred vision [17]. Hence, the role of these carotenoids is crucial in AMD as research suggests that there is an inverse relationship among both if there is a decrease in the diet of carotenoids there will be an increased risk of AMD vice versa [18]. Carotenoids that have been identified as optical therapy agents and studies have shown the significant beneficial effects as zeaxanthin/lutein (2 mg/10 mg/day/ year). It also improves the person’s visual performance by a year other health benefits by lowering oxidative stress. Research suggests that lutein and other provitamin nutrients could be a high chance of effective therapy against age- related illness [19, 20]. Carotenoids especially lutein has a role in the prevention of AMD that improves the content of these carotenoids in the patients diagnosed with the disease as compared to normal people its means that these are being damaged due to the illness [21, 22]. Moreover, these carotenoids are anti- inflammatory and prevent visual disorders like AMDs that caused severe damage. Various epidemiological studies have proved that in age-related eye diseases controlled macular carotenoid supplemented diets have significant control potential, a multicenter approach [23, 24]. Another research evidence reported shows 32% reduced risk of AMD in people who took high content of zeaxanthin and lutein as compared to those who consumed less amount [25]. Mechanism of action of carotenoids in controlling AMDs.

The macular pigment contains carotenoids mainly the Xanthophylls that are situated right in the inner and outer layer of plexiform from where they get attached to the binders of protein. They are usually present in variant proportions. These are also present in the most sensitive region of the eyes as they absorb the blue UV light up to 460 nm their adequate presence and are crucial for visual health [26]. They filter the blue light across the retina that aid in visualizing distant image from the eyes. Macular pigment density is also directly related to the performance of eyes and visual health [27]. Thus, age related macular degenerative problems are due to the loss of macular pigments and carotenoids that aid in building macula pigments and controlling its losses. These carotenoids provide that optimal density and protect the macula from getting damaged hence helping in controlling AMDs.

Prevalence of AMD

Particular research is not conducted on the prevalence of AMD in the people following poor dietary patterns but the various available data shows that the ratio of prevalence of AMD is increasing especially in European countries and the number of patients suffering from any kind of AMD all over the world is elevating day by day that is being controlled by the intake of medicines but it can be suppressed by the use of healthy diet on daily basis. About 196 million are getting affected by it all over the world. It can be controlled with the healthy alteration in diet and lifestyle [28, 29].

The onset of AMD and its progression in the body is directly linked with the intake of the diet containing low levels of vitamins, carotenoids, and fatty acid i.e. omega-3. The diet that has a portion of carbohydrates like cereals is refined after processing and loses some of its beneficial constituents that are needed by the body that making the body deficient of those nutrients. Processing vegetables beyond a certain limit results in the destruction of the essential vitamins in them, which will have made it much better to consume the leafy vegetables in raw form. Eating food having high level of sugar like sweets over a certain limit is bad for health similarly consuming food rich in fats and oils adds into the category of unhealthy diet [28]. Poor dietary habits, like consumption of a lot of energy bars, drinks, junk food and fried food, lead to high prevalence of Age-related macular disorders. Therefore, the frequency of AMD is directly proportional to the poor or unhealthy diet. It has been proved through studies that intake of carotenoids mainly lutein and zeaxanthin, vitamin A & C and minerals like Cu, Zn through the intake of fruits, vegetables and meat of fish [28, 30].

Control of AMDs

Diet includes any food item having macro & micro nutrients that should be consumed in daily recommended proportions. People of different areas have different dietary patterns consisting of different nutrients and the nutritional level differs a lot. People consuming a diet consisting of cereal grains, fruits, vegetables, poultry, fish etc. are less likely to diagnose with AMD [31].

Food material having a prominent amount of Vitamin A, B6 & C found an association with the lower risk of AMD at the intermediate level [32]. Plant-based diet including nuts and spices etc. is proven beneficial against AMD and reduces oxidative stress. A diet containing refined cereals, red meat, fried products and other such products is not favorable in reducing the chances of AMD. From the category of oils, olive oil is found to help decrease the AMD level in body [31].

Numerous experimental studies have that food containing carotenoids play an effective role against AMDs and cataracts. From the category of carotenoids, lutein and zeaxanthin are present in spinach, kale, asparagus, pistachio, egg, and in many other products. Lutein and Zeaxanthin are the important constituents of Macular pigment in the retina [33]. It plays a vital role in maintaining eye health, improvising the functioning of the eye and preventing macula from harmful rays and other free radicals. A diet that has these natural lutein sources in it, increased the efficacy against AMD in its preventive formula. Therefore, to control AMD, it is significant to add the food categories such as leafy vegetables, eggs and nuts in your daily dietary pattern. Such food will defend the body against the early and late effects of AMD [3].