Diet influences inflammation, hormone balance, cell membrane composition, and gland function — all of which are relevant to dry eye disease. It's not the whole picture, but it's a meaningful part of it.

Omega-3 fatty acids — the most important dietary factor

The strongest dietary evidence in dry eye centres on omega-3 fatty acids — specifically EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), the long-chain omega-3s found primarily in oily fish.

Omega-3s have well-documented anti-inflammatory properties and play a role in the composition of meibomian gland secretions. Several studies have shown that omega-3 supplementation improves meibomian gland function, tear film stability, and dry eye symptoms — though the evidence is not uniformly positive across all study designs and populations.

The most useful practical conclusion from the evidence is that omega-3 supplementation is a reasonable, low-risk adjunct to dry eye management for most patients — particularly those with MGD-driven dry eye. It won't replace in-clinic treatment for significant disease, but it supports it.

Dietary sources of omega-3 The best dietary sources of EPA and DHA are oily fish — salmon, mackerel, sardines, herring, and anchovies. Current UK guidance suggests eating two portions of fish per week, one of which should be oily. For most dry eye patients this is a floor rather than a ceiling.

Omega-3 supplements For patients who don't eat fish regularly, or who want to achieve higher intake than diet alone provides, supplementation is appropriate. Fish oil capsules are the most common form. We'd advise looking for products with a high combined EPA and DHA content — the total omega-3 figure on the label is less important than the active component breakdown.

Algae-based omega-3 supplements provide EPA and DHA without fish and are a good option for vegetarian and vegan patients.

Omega-6 and the inflammatory balance

The ratio of omega-6 to omega-3 in the diet matters as well as absolute omega-3 intake. Omega-6 fatty acids — found in abundance in vegetable oils, processed foods, and many cooking oils — are pro-inflammatory in excess. The modern Western diet tends to be heavily weighted towards omega-6.

Reducing omega-6 intake — primarily by reducing processed food consumption and switching to olive oil for cooking — while increasing omega-3 intake improves the overall inflammatory balance. This is relevant to dry eye because chronic low-grade inflammation is central to the disease process.

Hydration

The tear film is largely water. Chronic mild dehydration affects tear volume and tear film stability. Staying well hydrated — plain water rather than caffeinated or alcoholic drinks — is a simple and underrated component of dry eye management.

There's no precise prescription here, but patients who increase their daily water intake often notice a modest improvement in eye comfort alongside other benefits.

Vitamin D

Vitamin D deficiency is extremely common in the UK given our latitude and the amount of time most people spend indoors. There is emerging evidence of an association between vitamin D deficiency and dry eye disease, with some studies suggesting that correcting deficiency improves symptoms.

Given how common deficiency is in the UK population, checking vitamin D status through your GP and supplementing if deficient is sensible for general health reasons regardless of the dry eye connection.

Foods to be cautious about

Some dietary factors appear to worsen dry eye or drive the underlying inflammation:

Alcohol — reduces tear production and has pro-inflammatory effects. See our dedicated page on Alcohol & Dry Eye.

High sugar and refined carbohydrates — drive systemic inflammation through several mechanisms and are associated with worsened inflammatory conditions generally.

Trans fats — found in some processed and fried foods, trans fats are pro-inflammatory and have no nutritional benefit. Most major food manufacturers have removed them but they persist in some products.

Excessive caffeine — has a mild diuretic effect and may contribute to dehydration at high intake, though moderate coffee and tea consumption is unlikely to be significant for most patients.

What about supplements beyond omega-3?

Several other supplements are sometimes recommended for dry eye. The evidence varies:

GLA (gamma-linolenic acid) — found in evening primrose oil and starflower oil, GLA has some evidence of benefit in dry eye, possibly through its effect on meibomian gland secretion. It's often combined with omega-3 in specialist dry eye supplements.

Lutein and zeaxanthin — primarily known for their role in macular health, these carotenoids have antioxidant properties relevant to ocular surface health. Found in leafy green vegetables, eggs, and certain nuts including pistachios.

Vitamin A — essential for conjunctival goblet cell health and mucin production. Severe deficiency causes significant ocular surface disease. Frank deficiency is uncommon in the UK but suboptimal intake may be relevant in some patients.

We'll advise on appropriate supplementation as part of your treatment plan rather than recommending a blanket supplement protocol — what's appropriate depends on your specific presentation and dietary history.

Diet as part of the bigger picture

Diet alone won't resolve significant dry eye disease — particularly where meibomian gland dysfunction or lid disease is the primary driver. But it's a meaningful supporting factor, and patients who optimise their diet alongside in-clinic treatment consistently do better than those who don't.

Small, sustained changes — increasing oily fish intake, improving hydration, reducing processed food — are more useful than chasing the latest supplement trend.

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