DIET, FOOD, DRINKS AND LIFE-STYLE IN GLAUCOMA

Glaucoma is treated by drugs, through lasers or by surgery. However, research has shown that diet may have a positive or negative effect on the outcome of this potentially blinding condition.

Initially, elevated intra-ocular pressure (More than 21 mmHg) [IOP] was regarded as the main cause for glaucomatous optic nerve degeneration (GOND). However, later other mechanisms were presented in the etiopathogenesis of this disease. These include the vascular theory (which is based on altered ocular blood flow and other mechanisms), biochemical theory (which blames a number of biochemical mediators) and some other theories such as genetic, glymphatic and translaminar pressure difference (pressure between the eyeball and brain).

During metabolism there is continuous release of oxygen free radicals (OFRs) by the tissues in the body. These OFRs are responsible for damage to structures including retinal ganglion cells (RGCs), leading to progressive loss of vision. However, certain mechanisms are usually present in the body to take care of these excessive OFRs. These mechanisms include: anti-oxidant enzymes (such as= superoxide dismutase, catalase, glutathione peroxidase) and free radical scavengers (For e.g. = glutathione, alpha-tocopherol, betacarotene). A number of anti-oxidants also occur naturally in certain foods.

Intake of foods rich in anti-oxidants such as carotenoids may have a positive impact in slowing the rate of GOND. Certain foods which have been found to contain large amounts of carotenoids includes fruits and vegetables with red, yellow and orange hues. Thus, carrots, squash, grapefruits, oranges, apricots, cabbage, peaches, green beans, spinach, kale and beets have an important role in providing carotenoids. It has been found that consuming eggplants (10 gm/day) may reduce intra-ocular pressure (IOP) by 25%. Similarly, ≥2 servings per week of oranges and peaches are useful.

Eggplant

Vitamins with antioxidant property are Vitamin A, C and E. They are present in carrots, radishes, Brussels sprouts and celery. Some other anti-oxidant rich foods are: pomegranate, acai berries, cranberries and dark chocolate.  Vitamin E is available in eggs, wheat germ and nuts. 

Minerals such as zinc, manganese, magnesium and selenium also have anti-oxidant properties. Foods which contain these trace elements include: red meat, poultry and seafood (especially oysters). 

Blackcurrants contain anthocyanins which are neuroprotective and also normalize ocular blood flow. 

Docosahexaenoic fatty acids (DFA) and total omega-3 long-chain polyunsaturated fatty acid are useful in improving ocular blood flow, impaired systemic microcirculation and neuroprotection. Some of the excellent sources of these fatty acids are wild-caught salmon, tuna, herrings, sardines and mackerel. 

Salmon

Flavonoids are polyphenol compounds present in plants. They have antioxidant properties and are neuroprotective. Some good sources of flavonoids are: cocoa, green tea and red wine.

Green tea

Regular exercise is useful for glaucoma by improving blood flow. However, some of the postures in yoga should be avoided as they increase IOP. A slightly raised pillow (20⁰) is also advisable.

On the other hand, certain foods are damaging to the eye and worsen GOND. These are diets containing high levels of trans fatty acids such as baked goods such as cookies, cakes, donuts and also fried items such as French fries or stick margarine. Salt and caffeine should also be avoided as they may increase blood pressure (BP). Smoking also reduces ocular blood flow and may worsen the GOND.

Although evidence is mixed regarding the role of diet in glaucoma, yet a healthy lifestyle including proper nutrition, exercise and avoidance of harmful activities such as smoking or excessive alcohol consumption may have an overall positive impact on the body. As  Felix Lagrange (1922) said: “Glaucomatous optic nerve degeneration is a sick eye in a sick body”.

                 

Glaucomatous optic nerve degeneration