Food & eyes, what’s the link between them? Direct one!
What do your eyes need?
Did your mother give you a carrot when you were a child and say how healthy it was for your eye? She wasn’t wrong though.
Carrots contain vitamin A that is indeed good for your eyesight, but the eye is such a complex organ that it needs different nutrients – from vitamin C to omega-3.
The vitamins mentioned below may help to protect the eyes against cataracts and the early stages of age-related macular degeneration (AMD) (1), as the latter is the leading cause of permanent vision loss among 60+ Americans.
The link between diet and correction of basic vision problems such as nearsightedness or farsightedness are not discussed here.
Which foods contain it? Sweet potatoes, carrots, pumpkin, cantaloupe, peppers, mangoes.
How much do you need? 900 mcg for men, 700 mcg for women daily.
Beta carotene is an orange pigment that belongs to a class of nutrients called carotenoids. It is directly relevant to vitamin A as our body easily produces vitamin A out of beta carotene as needed.
The retina is a thin layer of tissue that lines the back of the eye on the inside. Vitamin A helps it to convert light into signals to be processed by the brain, that’s why it’s considered essential for good vision. Taken together with vitamins C and E and the mineral zinc, beta carotene may slow the progression of AMD.
Lutein and zeaxanthin
Which foods contain it? Kale, spinach, broccoli, Brussels sprouts, collard greens.
How much do you need? No set RDA, but from 6 to 12 mg of the two nutrients daily recommended.
Other two essential carotenoids are lutein and zeaxanthin. They are only carotenoids found in the retina and are known for protecting the macula — the part of the retina that's responsible for clear central vision. The macula deteriorates in people with AMD. One study (2) found that women who got the most lutein and zeaxanthin through their diets lowered their risk of needing surgery to remove a cataract (the clouding of the normally clear lens of the eye) by 22% compared with women who got the least.
Which foods contain it? Papaya, strawberries, grapefruit, oranges, lemon, kiwifruit, red and green peppers, tomatoes, potatoes, cabbage, cauliflower, green peas, etc.
How much do you need? 90 mg for men, 75 mg for women daily. Another 35 mg for smokers.
Eye tissue and fluid that nourishes the lens and protects it from clouding contain large amounts of vitamin C. To prove the point that eyes also need vitamin C, some studies (3) suggest that it may help to ward off cataracts, although there is no consensus view so far.
For example, one study (3) found that people who consume about 8 to 10 times the RDA of vitamin C were less likely to develop cataracts than people who consumed the RDA. Further randomized clinical trials of thousands of people found no association between vitamin C intake and the incidence of cataracts.
On the other hand, Swedish study (3) that followed more than 24,000 women for about 8 years showed that taking 1,000 mg of vitamin C supplements on a regular basis were more likely to develop cataracts. In women ages 65+ the risk was even 38% more than that of women who didn’t take vitamin C supplements. So following the RDA recommendations and diverse diet may be the key.
Which foods contain it? Salmon, anchovy, albacore tuna, cod, oysters, sardines. Non-fish sources: chia seeds, walnuts, flaxseeds and flaxseed oil, soybeans, or algae supplements.
How much do you need? 250–500 mg (you may either eat oily fish twice a week or take omega-3 fatty acid supplements daily).
One of three forms of omega-3 fatty acids is DHA and makes up about 30% of brain matter. A study published in Investigative Ophthalmology & Visual Science (4) found that DHA prevented age-related vision loss in lab mice. According to Dr. Ann Bajart, a corneal specialist and clinical instructor in ophthalmology at Harvard Medical School (5), the vision study likely applies to humans.
The mechanics behind diet supplemented with DHA is that it prevents a buildup of the toxic molecule A2E in the retinal pigment epithelial cells. While DHA will not reverse retinal damage, it may help to preserve vision, says Dr. Bajart (5). DHA rich diet also helps to relieve dry eye and chronic inflammation of the eyelids as well as correlates with lower rates of heart disease, cognitive decline, and arthritis.
Vitamin E & Zinc
Which foods contain vitamin E? Nuts, seeds, avocado, and vegetable oils.
How much vitamin E do you need? 15 mg daily.
Which foods contain zinc? Seafood, cereal, poultry, and dairy aisles.
How much zinc do you need? 11 mg for men, 8 mg for women daily.
Vitamin E is a powerful antioxidant that protects eyes against the damaging effects of free radicals. Combined with beta carotene and vitamin C it may reduce AMD risk.
As to zinc, it’s considered to preserve retinal health. It helps to transport vitamin A to the retina so should be taken along with it for good vision.
First of all, nothing is better than a balanced diet with all foods mentioned above for your eyes, especially vegetables. Researchers found (6) that people who ate 100 to 142 mg of vegetable nitrates each day had a 35% lower risk of developing early AMD in comparison to people who ate less than 69 mg of vegetable nitrates daily. Two of the top nitrate sources are spinach and beets. Nitrates are thought to help as they are the precursors to nitric oxide which for its part helps to increase blood flow to the retina.
Secondly, supplements with high-dose combinations of antioxidant vitamins and minerals may lower the risk of wet AMD by 25% (1). However, supplements don’t seem to benefit people who either do not have AMD or who have early AMD. Nevertheless, ask the doctor whether antioxidant-zinc supplements are needed for you.
What vegetables are you going to add to your diet first?
- The Aging Eye Preventing and treating eye disease, A HARVARD MEDICAL SCHOOL, 2019
- Nutritional Supplementation, Cataracts and Age-related Macular Degeneration, Current Topics in Nutraceutical Research Vol. 3, No. 4, pp. 219-230, 2005
- Eating for good vision, Harvard Women's Health Watch, A HARVARD MEDICAL SCHOOL, 2013
- Dietary Docosahexaenoic Acid Supplementation Prevents Age-Related Functional Losses and A2E Accumulation in the Retina, Investigative Ophthalmology & Visual Science April 2012, Vol.53, 2256-2265
- Omega-3 for your eyes, Harvard Health Letter, A HARVARD MEDICAL SCHOOL, 2012
- Nitrates from vegetables may lower age-related macular degeneration risk, Harvard Men's Health Watch, A HARVARD MEDICAL SCHOOL, 2019
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