Foods for eye health: what the evidence says

Which nutrients play a role in vision?

The role of these six nutrients has been studied most extensively. None works alone, and they are all supplied by a varied diet.

• Vitamin A. It is part of the pigment that enables vision in low light and helps maintain normal vision [1].
• Lutein and zeaxanthin. These are yellow pigments in plants that accumulate in the macula, the centre of the retina.
• Omega-3 DHA. It is a structural fat in the retina and helps maintain normal vision [1].
• Zinc. Together with vitamins C and E, it is part of the formulas studied for macular degeneration.
• Vitamins C and E. They are antioxidants that protect cells from oxidative damage.
• Riboflavin, or vitamin B2. It also helps maintain normal vision [1].

European law takes a cautious approach to these nutrients. It allows claims that vitamin A, riboflavin and DHA maintain normal vision if the food contains a sufficient amount [1]. None of these claims promises better vision: they refer to maintaining what is already working.

Which foods contain them?

Leafy green vegetables and fish are the two food groups mentioned most often when it comes to looking after the macula [3]. The other nutrients are found in many everyday foods.

• Vitamin A is found in eggs and dairy products, and as beta-carotene in carrots, pumpkin, sweet potatoes, mangoes and spinach.
• Lutein and zeaxanthin are found in spinach, Swiss chard, turnip greens, kale, corn, orange peppers and egg yolks.
• DHA is found in sardines, mackerel, anchovies, salmon, tuna and trout.
• Zinc is found in mussels, cockles, meat, pulses, nuts and seeds.
• Vitamin C is found in peppers, kiwifruit, citrus fruits, strawberries and broccoli.
• Vitamin E is found in olive oil, almonds, hazelnuts and sunflower seeds.
• Riboflavin is found in dairy products, eggs, lean meat, pulses and leafy greens.

A practical idea: if your plate includes something green and something colourful, you will get almost all of these nutrients without counting anything. For fish and plant-based alternatives, see our guide to foods rich in omega-3.

Can diet slow macular degeneration?

Age-related macular degeneration (AMD) damages the macula, the area of the retina that lets you see fine detail. It is more common after the age of 55, in people with a family history, and in people who smoke [3].

When it comes to food, the evidence shows associations. An analysis of two large European studies in older adults found 41% less advanced AMD among those who followed the Mediterranean diet most closely [2]. This was an observational study, so it shows a relationship without proving the cause.

There have been trials of supplements. The AREDS and AREDS2 studies tested a formula containing vitamins C and E, zinc, copper and beta-carotene; beta-carotene was later replaced with lutein and zeaxanthin [4]. In people with intermediate AMD, or advanced AMD in one eye, this formula probably slows progression to the advanced stage [3] [5].

Three important points to bear in mind:

• For people who do not have AMD or have it at an early stage, the benefit is very small [5].
• Beta-carotene capsules increase the risk of lung cancer in people who smoke or used to smoke [4] [5].
• Lutein and zeaxanthin on their own make very little difference to how the condition progresses, and adding omega-3 did not provide any benefit [4] [5].

If you have AMD, discuss this decision with your ophthalmologist, with your retinal examination results available. Your doctor or dietitian-nutritionist will advise on any omega-3 supplement.

Does omega-3 help with dry eye?

The evidence is mixed. For dry eye, a review of trials found that omega-3 supplements may offer some benefit, but the results were inconsistent and the certainty of the evidence was low [6]. The largest trial, which involved one year of treatment, found no difference compared with a placebo made with olive oil [7].

Based on this evidence, we do not recommend omega-3 supplements for dry eye [6] [7]. If one is being considered, your doctor or dietitian-nutritionist should advise you. If you take anticoagulants or antiplatelet medicines, check with your doctor before taking it. It does make sense to include oily fish, walnuts and seeds, which offer other benefits too. Your ophthalmologist will advise you on artificial tears, eye drops and any other treatment.

How is diabetes connected to the retina?

Diabetes can damage the small blood vessels in the retina. This is called diabetic retinopathy, one of the leading causes of vision loss worldwide [9].

Keeping blood glucose, blood pressure and blood lipids within target ranges reduces the risk of retinopathy or slows its progression, according to the American Diabetes Association [8]. Your medical team will work with you on this management, and nutrition plays an important role.

If you have diabetes, our metabolic health nutrition team can help with your dietary plan, in line with the goals set by the professional treating you.

Do carrots improve short-sightedness?

No. Short-sightedness (myopia) is a refractive error in which the eye focuses an image in front of the retina. Refractive errors are corrected with glasses, contact lenses or surgery [9].

The myth has a real basis. Vitamin A deficiency causes night blindness and is associated with malnutrition. If you already get enough vitamin A, eating more carrots will not improve your vision.

The same applies to age-related long-sightedness (presbyopia), the difficulty focusing up close that develops with age. It is corrected with reading glasses. Data on vision worldwide are available in the WHO fact sheet on blindness and visual impairment.

What mistakes do we see in consultations?

• Taking an eye-health supplement without a diagnosis. Sometimes it contains beta-carotene, even though the person used to smoke.
• Looking for one wonder food. Carrots, blueberries and salmon can all contribute as part of a varied diet.
• Saving leafy greens for Sunday salad. It is a good idea to include leafy green vegetables in several meals throughout the week.

It is common for someone to come to a consultation with a bottle of capsules in their bag and very few vegetables on their plate. In most cases, the change that makes the biggest difference starts with the plate.