What foods to eat to prevent age-related macular degeneration (AMD)?

Age-related macular degeneration results from progressive deterioration of the center of the retina : the macula. It often does not lead to total blindness, because the periphery of the retina remains intact. This pathology affects more than a million people in France, half of whom are people over 80 years old. It's here leading cause of low vision among people over 50 in industrialized countries. Its progression is more or less rapid, but it quickly becomes disabling for daily tasks.

There are two types of AMD:

• Dry AMD results in an accumulation of colored proteins in the center of the retina and a shrinkage of the latter.
• Wet AMD which corresponds to a scar lesion of the retina in response to a proliferation of choroidal new vessels. The transition from one form to another is possible.

The symptoms between these two types of AMD may be slightly different. Overall, AMD causes difficulty observing details, a distortion of straight lines (metamorphopsia), a dark spot in the center of the field of vision (scotoma), a reduction in the perception of contrasts, a modification of color vision, visual blur, etc.

Before the age of 50, certain signs can be precursors of AMD, such as a need for more intense lighting or a loss of visual acuity. These symptoms describe Age-Related Maculopathy (AML).

AMD is a multifactorial condition whose causes and mechanisms are not fully understood. Several risk factors are known to play a role in the progression and appearance of AMD: age, sex (women are more exposed), genetic predisposition, exposure to light, smoking (smoking increases risks by 4 to 6), certain pathologies (obesity, diabetes or high blood pressure, etc.).

The goal of nutrition is toimprove retinal protection. Indeed, a suitable diet warns and slows the progression of AMD. This diet focuses on the following nutrients:

• Lutein, Zeaxanthin and Mesozeaxanthin : these compounds are xanthophyll carotenoids (non-provitamin A). They are exclusively provided by food. Indeed, our body is incapable of synthesizing them. Their concentration is extremely high in the retina and particularly in the macula. Numerous studies reveal that a high concentration of lutein and zeaxanthin in plasma reduces the risk of developing an advanced form of AMD. Indeed, their role for vision is multiple. Among these roles, a large percentage is reserved for protection. They filter blue light by absorption of this light, which reduces the production of singlet oxygen, which is strongly oxidizing (singlet oxygen is formed from UV in the retina and lens). Additionally, like many carotenoids, they are antioxidants. Thus, they trap singlet oxygens and detoxify by rearrangement of their components (the conjugated double bonds of their isoprene units). Some sources even provide them with an anti-inflammatory effect. All of these factors contribute to the protection of vision.

• Omega-3 : these belong to the family of polyunsaturated fatty acids. They are known for their anti-inflammatory properties. It appears that a deficiency of omega-3, particularly DHA, leads to a drop in their concentration in the retina. This decrease seems to disrupt the normal functioning necessary for vision (visual transduction). It therefore seems necessary to ensure their contributions to preserve the effectiveness of the vision. In addition, omega-3s are constituents of retinal photoreceptors. DHA also participates in the neuroprotection of the optic nerve: it is the precursor of neuroprotectin D1. Finally, EPA is vasoregulatory. Leads are proposed on its anti-vasoproliferative potential (cause of wet AMD). Namely, omega-3s of animal origin can claim contribute to the maintenance of normal brain functions and normal vision if and only if they contain at least 40 mg of DHA per 100 g and 100 kcal of product, and if the person ingests at least 250 mg per days, according to EFSA. 

• THE Zinc : zinc is a trace element. It contributes to maintaining vision by being involved in the metabolism of vitamin A. Indeed, it is necessary for the synthesis of the vitamin A transport protein. Vitamin A is essential for vision. In addition, zinc contributes to antioxidant protection via several mechanisms: it introduces the synthesis of metallothionein (antioxidant enzyme), it contributes to the activity of superoxide dismutase (antioxidant enzyme), finally, it competes with copper and iron (trace elements capable of producing excess free radicals). It also appears that its presence reduces the risk of advanced AMD, as studies show that low zinc intake increases the risk of developing AMD.

• Antioxidants : Many studies suggest that antioxidants have beneficial effects on AMD. Indeed, oxidative stress is harmful to photoreceptor cells, which accelerates their death. Antioxidant nutrients work either by contributing to the functioning of antioxidant enzymes or by neutralizing free radicals. There are many antioxidant nutrients: vitamins (E, B2 and C), trace elements (copper, iron, zinc, manganese and selenium), phytonutrients (carotenoids, polyphenols, terpenes, isocyanates, phytic acid, etc.), cysteine , etc. It appears that sufficient intake of antioxidants associated with zinc is beneficial. However, antioxidants alone do not slow down the progression of AMD.

• There Vitamin D : some studies suggest that vitamin D helps prevent AMD. However, the mechanisms of action are not elucidated; further studies are necessary to confirm its benefit.

• There Vitamin A and the Beta carotene : Vitamin A is a fat-soluble vitamin essential for vision. Indeed, it is essential for the functioning of rods and cones (specialized cells of the eye) and for the renewal of the ocular epithelium. In addition, they contribute to protection against ultraviolet radiation. Beta-carotene is a carotenoid capable of forming retinol (we speak of provitamin A). Through its anti-oxidant action and its provitamin ability, beta-carotene is also an essential ally against AMD.

• A low glycemic load: it seems that a diet with a low glycemic load helps to limit oxidative stress. Oxidative stress increases the risk of developing AMD.

Berries (or red fruits) are particularly interesting for AMD. They are rich in antioxidants, particularly lutein, zeaxanthin, and mesozeaxanthin. For the richest plants, their lutein and zeaxanthin content is estimated at approximately 200 µg per 100 g. These carotenoids are the only ones, to date, to have sufficiently substantiated research to support their benefits. Indeed, their antioxidant and photoprotective capacity slows the progression of age-related macular degeneration.

Berries also contribute to antioxidant intake: vitamin C (on average 15 mg per 100 g), the vitamin B2 (on average 0.04 mg per 100 g) and phytonutrients (including resveratrol, polyphenols, carotenoids, etc.).

We recommend you :

• to consume a portion of berries per day: blueberries, blackberries, currants, physalis, blackcurrants, etc.

• to consume 25 g of dried berries per day, such as Aronia berries, THE Goji berries where the Dried blueberries.

Egg yolk is extremely rich in lutein and zeaxanthin: the two photoprotective carotenoids. There is an average of 504 μg for 2 eggs (a recommended serving for a meal). This is more than double the richest plants. In addition, eggs are vectors of vitamin A (2 eggs provide approximately 25% of the daily requirement for vitamin A), antioxidant trace elements (zinc, selenium, copper, manganese, etc.), vitamin B2 and vitamin E.

We recommend you :

• to consume at least 4 to 5 eggs per week.

• to choose eggs from the Bleu-Blanc coeur sector. The Bleu-Blanc-Cœur label certifies that the chickens' feed has been enriched with omega-3. As a result, eggs have a better omega-6/omega-3 ratio.

Lutein and zeaxanthin reduce the harmful effects of sunlight on the eye, particularly on the foveal photoreceptors. They are found in various foods, particularly in colorful plants: yellow, red, orange fruits, green, red, yellow vegetables, etc.

We recommend you :

• consume 1 portion (approximately 150 g) of vegetables rich in lutein and zeaxanthin per day: spinach, cabbage, chard, avocado, kale, peppers, dandelions, etc.

• to consume 1 serving (approximately 150 g) of fruits rich in lutein and zeaxanthin per day: apricots (or 25 g ofDried apricots), oranges, mangoes, persimmons, etc.

• to take a cure Camu-camu powder. Camu-camu powder would be a vector of trans-lutein and zeaxanthin. 

• to make colorful plates.

• to sprinkle your preparations with spices and aromatic herbs: cayenne pepper, basil, parsley, red pepper, oregano, cumin and black pepper are vectors of lutein and zeaxanthin.

Oily fish are known for their nutritional richness. In prevention of AMD, almost their entire composition is interesting:

• Omega-3: they are rich in alpha-linolenic acid (on average 0.2 g per 100 g of fatty fish). Additionally, these are our only sources of EPA and DHA: 2.5g per 100g.

• Vitamin D: there is an average of 10 µg of vitamin D in 100 g of fatty fish. It is one of the foods richest in vitamin D.

• Zinc: 100 g of fatty fish meets approximately 10% of zinc needs.

• Antioxidants: the vitamin E content of fatty fish is significant: 1 mg per 100 g. In addition, iron, copper, manganese and even selenium are present. All these trace elements contribute to oxidative protection.

We recommend you :

• to consume 2 fatty fish per week: mackerel, sardines, bluefin tuna, salmon, trout, herring, etc.

• to think about fish oil cures: 5 g of poison oil per day, for 2 weeks. This treatment can be repeated several times a year. Fish liver oils are extremely rich in vitamin A (1 tsp meets the daily vitamin A requirement). Caution, vitamin A is teratogenic, pregnant women should not consume fish liver oil on a regular basis.

A vitamin A deficiency disrupts vision and reduces the eye's protection against UV rays. Our vitamin A intake depends on animals and plants through beta-carotene. Beta-carotene is the main carotenoid with vitamin A activity. In fact, in humans, 6 mg of beta-carotene has the same activity as 1 mg of retinol. In addition, it protects against free radicals: the latter accelerate the destruction of eye cells. Therefore, regular intake of vitamin A and beta-carotene contributes to the functioning and protection of the eyes.

We recommend you :

• regularly consume foods rich in retinol: cod liver oils, liver (maximum two servings per month), butter (20 g maximum per day), eggs, fatty fish, etc.

• to favor cheeses rich in retinol: dry goat's cheese, mascarpone, parmesan, Munster, gorgonzola, Tome de Savoie, Comté.

• to favor vegetables rich in beta-carotene: sweet potato, carrot, pumpkin, cabbage, spinach, salad, pumpkin, etc.

• to favor fruits rich in beta-carotene: melon, apricot, mango, pepper, tomato, morello cherry, etc.

• a cure of Urucum : urucum (or achiote) contains red seeds extremely rich in beta-carotene: approximately 1305 mg per 100 g. Less than one gram of Urucum powder covers the daily beta-carotene requirement.

Nuts are beneficial against AMD due to several of their components: omega-3 (alpha-linolenic acid, the precursor of EPA and DHA), antioxidants (vitamin E, zinc, etc.).

We recommend you to consume 15 g of nuts or seeds per day. THE Walnut kernels, THE linseed and the chia seeds are richest in omega-3. THE Pistachios are vectors of lutein and zeaxanthin.

Vegetable oils should not be neglected in the face of AMD. These contribute to the intake of vitamin E: an antioxidant vitamin. Additionally, some oils are full of omega-3 (alpha-linolenic acid). Finally, thanks to their lipid composition, they improve the absorption of carotenoids (including lutein, zeaxanthin and mesozeaxanthin).

We recommend you :

• consume 1 to 2 tablespoons of vegetable oil per day.

• vegetable oils rich in omega-3 are: rapeseed oil,nut oil, l’linseed oil, l’hemp oil, l’soya oil, l’Chia oil, etc.

• vegetable oils rich in vitamin E are:wheat germ oil, Sunflower oil,avocado oil, l'sweet almond oil, l'safflower oil, etc.

Zinc is present in many foods, especially animal products and pulses.

Moreover, dried vegetables have a low glycemic index: estimated at 20. For a normal portion (around 60 g per meal), they also have a low glycemic load: estimated at 2. Thus, they fight against hypervariations in blood sugar. and these harmful consequences for the body, including the ocular system.

We recommend you :

• to consume three to five portions of meat or seafood (shellfish, fish, molluscs) per week.

• to consume dried vegetables at least two meals per week: lentils, split peas, chickpeas, red beans, mogettes, etc.

• Protect your eyes from the sun: obviously, Adequate sun protection is essential. UV rays from the sun are risk factors for developing AMD.

• Stop smoking  : smoking greatly increases the risks of developing AMD.

• Supervise the evolution of related pathologies: obesity, cholesterol and high blood pressure could increase the risk of developing AMD. It would therefore be necessary to stabilize these pathologies to improve the progression of AMD. Please contact your doctor and a dietitian nutritionist.

• Consume local and seasonal : local and seasonal products have a more interesting nutritional density. Indeed, export inevitably leads to a micronutritional loss. The seasonality of plants modulates their micronutrient composition: we observe a vitamin and mineral peak when the plants are picked in season.

• Carry out a cure Blueberry bud macerate : Blueberry bud macerate is the reference macerate for eye disorders. As a preventative measure, its presence could be interesting: 5 to 15 drops per day in a glass of water, 15 minutes before a meal, for three weeks. Start with five drops and increase gradually.