Good vision is essential for good health and sporting performance especially when athletes are involved in precision sports that require good hand and eye co-ordination such as tennis, archery, pistol shooting, cricket, golf etc.
There are a number of eye conditions that are now being linked with nutrition and although the evidence in some incidences is inconclusive it is interesting to learn more about our sight, which is a valuable sense we so often take for granted.
This disease is seen in developing countries and is an extreme example where eye health and nutrition are linked. Xerophthalmia can cause blindness in children and is a direct result of vitamin A deficiency. Changes in the conjunctiva and cornea of the eye result in a loss of tears; Bitot’s spots that are silvery grey in colour appearing on the eyeball; corneal ulceration and scarring all of which results in a shrunken eyeball.
Generally cataracts develop when changes occur in the chemistry of the eye resulting in the lens becoming cloudy and hard. This can result in painless blurring and dimming of vision and a heightened sensitivity to light and glare. The changes can be the result of natural aging, exposure to ultraviolet light, smoking, medications (steroids, gout medications), injury and certain diseases such as diabetes.
Cataracts affect most people after the age of 75 years so veteran athletes are the group most likely to be affected. Cataracts can also affect younger people, particularly those who smoke, are diabetic or have sustained some eye trauma e.g. as a result of a sporting injury.
Any dietary changes that reduce the risk of gout and diabetes will obviously also help improve eye health through the control of blood sugars, fat and protein intake. Athletes who spend long periods out door’s in the summer such as cricketers are advised to wear wide-brimmed hats and sunglasses.
The macular disc is a part of the retina responsible for processing the details of the central part of vision. Two types of degeneration, “wet” and “dry” have been defined.
In the “dry” form the macular becomes pigmented and thin while in the more severe “wet”form, abnormal blood vessels form in the macular causing leakage of fluid and blood that ultimately results in scarring. Age is one of the main risk factors for developing this eye disease which also appears to affect more women than men and may affect smokers. This disease also appears to be associated with hypertension, elevated blood cholesterol and obesity and so any dietary changes that alleviate these diseases will also benefit eye health.
Glaucoma is the second leading cause of blindness, after cataracts, in western societies. It occurs due to an increase in fluid pressure within the eye (aqueous humor) causing damage to the optic nerve. Treatment focuses on reducing the production or aqueous humor or increasing its drainage. Risk factors for developing glaucoma include: genetics, advancing age,ethnicity, medications such as the prolonged use of steroids and diseases that restrict blood flow to the eye such as diabetes retinopathy.
Xerophthalmia causing night blindness and dry eyes can be prevented by eating Vitamin A and Beta carotene rich foods such as:
- Fresh vegetables particularly yellow/orange/red vegetables such as kumara, pumpkin, carrots, tomatoes etc.
- Fat found in animals and plants
- Protein found in meat, fish, egg, dairy, nuts, seeds, pulses and grains.
While it may be tempting to want to take Vitamin A supplements a word of caution. Fat soluble vitamins such as A and D can be accumulated by the liver to toxic levels. Symptoms may include headache, bone and muscle pain, visual impairment, alopecia and elevated blood lipids. It is far safer to eat Vitamin A rich foods rather than taking dietary supplements unless these are prescribed and monitored by your doctor.
Several nutrients are believed to boost the body’s natural defense system that protects tissues from the oxidative damage of free radicals. In the eye, oxidation affects proteins and fats in the lens to the extent that the lens becomes damaged and cloudy. This oxidative damage can create a cataract and other eye diseases such as night blindness, dry eyes and advanced macular degeneration. The following anti-oxidant nutrients are being studied in relation to the treatment of eye disease.
- Vitamins C: found in all raw fruits and vegetables
- Vitamin E: found in wheat germ, soy bean oil, margarines, nuts, kumara and whole grain cereals.,
- Lutein: found in yellow peppers, mango, berries and green leafy vegetables such as kale, spinach, cabbage and broccoli.
- Zeaxanthin can be found in kumara, orange peppers, broccoli, corn, lettuce, spinach, tangerines, oranges and eggs.
- Zinc: is found in oysters, crab, mussels, red meat and liver
- Copper: is widely distributed in oysters, other shell-fish, liver, kidney, nuts, cereals, dried fruit and legumes.
- Selenium: Fish, red meats, grains and dairy products.
- Manganese: is present in whole grain cereals and legumes.
While it may be tempting to try many of the new supplements branded as eye treatments caution is advised with antioxidants as in excess they can increase the risk of some forms of cancer.
Essential Fatty Acids (EFA’s)
Two types of EFAs are omega-3 fatty acids and omega-6 fatty acids. Studies have found that omega-3 fatty acids, in particular, may reduce the incidence of macular degeneration and “dry” eyes.
Omega-3 fatty acids include docosahexaenoic acid (DHA), eicoapentaenoic acid (EPA) and alpha-linolenic acid (ALA). Good food sources include salmon, tuna, sardines and herrings. Fish oil supplements are also useful for people who are not “fish lovers”.
To reduce your intake of omega-6s, avoid fried and highly processed foods that may contain trans fats as these interfere with the body’s absorption of omega-3 fatty acids reducing immunity and contributing to diseases such as hypertension, diabetes, some forms of cancer.
Hand and Eye Co-ordination
In order to grasp something our eye needs to track an object, co-ordinate that hand and eye movement, anticipate the shape and size of the object and degree of force required by our fingertips to make contact and grasp the object and continue to hold it.
Good co-ordination is assisted by the following nutrients:
- Iron: Poor eye and hand co-ordination has been found in iron deficient infants and children. Good food sources of iron include, red meat, green leafy vegetables and grains.
- Zinc: Studies have found that improved zinc intake can increase hand and eye co-ordination in children while in adults, memory, muscle strength and endurance can be improved.
- Folate: A lack of folate can result in reduced hand and eye co-ordination in children. Folate is also important for prevention of Alzheimer’s disease which results in a steady loss of hand and eye co-ordination. Good food sources include; green vegetables, bran and whole grain cereals, eggs, beetroot and bananas
- Hydration: As little as 2-5 percent of dehydration will result in a loss of co-ordination, loss of patience and concentration. So build a hydration plan into your training.
- Alcohol: As little as 0.06-0.10g/dL is enough to reduce reaction times, hand and eye co-ordination, accuracy and balance. So leave any celebrating until after you have re-hydrated following important events.
Dietary recommendations for good eye health
- Eat plenty of fresh fruit and vegetables
- Ensure that you include at least 2 yellow/red/orange vegetables into your diet each day.
- Choose lean meats, fish and poultry regularly and keep portion sizes small.
- Choose whole grain breads and cereals.
- While it may be tempting to take dietary supplements only do so only on the advice of your doctor.
- Keep well hydrated
- Avoid alcohol 2-3 days before an important event.
- Regular exercise can help you to maintain a healthy body weight.
- Monitor your blood pressure and blood sugar to prevent diabetes and hypertension.
If you would like to ensure that you are eating enough of these essential nutrients for eye health then contact us today for a nutritional assessment.