In today’s digital world, however, most vision problems are often the result of poor eye care and bad habits. Poor eyesight can be caused by many factors including genetics, age, environment, habits and nutrition.
Why diet is important?
Diet is thought to be important because certain nutrients protect the body from damaging substances called oxidants. Oxidants, including free radicals, are thought to be partly responsible for the ageing process.
Antioxidants reduce this harmful effect. Vitamins A, C and E are antioxidants.
Carotenoids are also effective against oxidants.
Lutein and zeaxanthin are important carotenoids. Many of these substances can only be obtained from food. Lutein and zeaxanthin are yellow plant pigments which give certain foods their colour. Lutein and zeaxanthin are found in high concentrations in the macula.
Another carotenoid, mesozeaxanthin, is formed in the body from lutein.
These three carotenoids are known as ‘macular pigment’.
They are thought to play an important role in absorbing damaging blue wavelengths of light. They act as a natural sunblock for the macula and can counteract the effects of free radicals.
Some studies have suggested that people with low levels of macular pigment may be more likely to develop age-related macular degeneration. Some people may have naturally low levels of macular pigment but weight and diet may also be factors. The human body cannot make lutein or zeaxanthin. They have to be eaten.
Several studies suggest that eating at least 10mg of lutein a day has the most beneficial effect on macular pigment levels.
While it is important to eat a wide range of foods, the vegetables have the highest amount of lutein are:
Lutein in vegetables milligrams (mg)/100g (fresh)
Kale 11.4 mg
Red pepper 8.5 mg
Spinach 7.9 mg
Lettuce 4.7 mg
Leek 3.6 mg
Broccoli 3.3 mg
Peas 1.7 mg
Some studies suggest very light cooking may increase the bio-availability of lutein; that is the ease with which the body can absorb the lutein. It is thought too much cooking may destroy it.
Cooking with oil or fat may help with absorption into the body. However, research is ongoing. Kale is the best source of lutein and has good bio availability, even when raw.
Both lutein and zeaxanthin have unique skills and abilities that give them eye-protecting powers unlike any other nutrients.
Eggs contain high levels of lutein and zeaxanthin, and they may be easily absorbed by the body because they are eaten with the fat contained in the egg. Zeaxanthin is also found in orange and yellow fruits and vegetables.