Month: June 2018

Hot topic – Fruit may save your sight

Eating fruit has been found to reduce the risk of losing your eyesight in later life. In a study published in Archives of Ophthalmology, people who ate at least three servings of fruit per day were found to have more than one-third lower risk of developing an eye condition called age-related macular degeneration.

Below we look at the issue in more depth.

What is age-related macular degeneration?

Age-related macular degeneration is the most common cause of sight loss in people aged 60 years and older.

The macula is a small area at the centre of the retina, the area at the back of the eye that converts light into images. This area is responsible for seeing fine details, for example when reading or recognising people’s faces.1

Macular degeneration (also known as maculopathy) is when the cells of the macula become damaged and stop working. People with macular degeneration have blurry or distorted central vision, and sometimes see shapes and colours that are not there. Peripheral vision (vision at the outer edges of the eye) is not affected, and it does not result in complete blindness.1

What causes age-related macular degeneration?

There are two types of macular degeneration.

In 90 percent of people with macular degeneration the cells of their macula slowly stop working, due to wear and tear. It usually develops slowly, affects both eyes equally and is known as “dry” macular degeneration.1

In the other 10 percent of people with macular degeneration, the disease develops when small blood vessels behind the eye bleed, causing build up of fluid and scarring. This form of the disease can progress quickly, leading to severe and rapid loss of vision. It tends to affect one eye first, although the other is often affected later. This form is known as “wet” or neovascular macular degeneration.1

Who gets age-related macular degeneration?

Age-related macular degeneration is common in people aged 60 years and older.1 It accounts for almost 50 percent of people registered blind or partially sighted in the UK, and up to a third of UK people aged more than 70 have it.5

People are more at risk of developing age-related macular degeneration if they smoke, have high blood pressure or have close relatives with the condition.2

What can be done to treat age-related macular degeneration?

Unfortunately, there are no cures for the dry form of age-related macular degeneration currently available. However, there are lots of ways to make the best of the remaining peripheral vision. The RNIB can offer more advice about this.

The wet form of macular degeneration can be treated by laser if it is detected at an early stage. Laser treatment may prevent vision from getting worse, slow down the progression of the condition and sometimes bring back sight that has already been lost.1

Because there are no effective treatments for late-stage age-related macular degeneration, prevention is important. For more on prevention, please see the final question and answer of this hot topic.

Does eating fruit help to reduce the risk of age-related macular degeneration?

Yes. People who ate three or more servings of fruit per day had 36 percent lower risk of developing the wet form of age-related macular degeneration than people who ate less than one and a half servings per day.

The results were similar for men and women.

Did fruit reduce the risk of all types of macular degeneration

No. The protective effect of eating fruit was only seen for the wet form of macular degeneration.

Which fruits are best?

Oranges and bananas were associated with the greatest reduction in risk of age-related macular degeneration. Other fruits were not so good at lowering the risk.

Do vegetables help to reduce the risk of age-related macular degeneration?

No. The researchers found that eating vegetables did not seem to have a effect on lowering age-related macular degeneration.

What else did the study look at?

The study also looked at dietary intake of antioxidant vitamins and carotenes (yellow or orange substances that are converted into vitamin A). A previous study showed high doses of antioxidants vitamins C and E, beta carotene and zinc delayed the progression of age-related macular degeneration.4

However, this study failed to show that antioxidant vitamins and carotenes had a protective effect.

Why does fruit reduce the risk of age-related macular degeneration?

Although it is not known for certain how fruit helps to protect against age-related macular degeneration, there is a theory that may offer an explanation. It is thought that the antioxidants in fruit may help protect macular cells in the retina by mopping up free radical molecules. These free radical molecules, which are produced by the body’s normal chemical reactions, are thought to attack cells and cause irreparable damage. By neutralising free radicals before they can attack macular cells, antioxidants can help to protect a person’s sight. However, because the antioxidant vitamins and carotenes did not contribute to the prevention in age-related macular degeneration, it is possible that other molecules in fruit may be playing a role.

Other constituents of fruits that may be beneficial to health include potassium, folic acid, fibre, flavonoids and other chemicals. At the moment it is not known how these may help prevent age-related macular degeneration.

Could the reduced risk be due to anything else?

Often, people who eat lots of fruit also lead more healthy lifestyles than people who don’t eat fruit. Another key factor is that fruit eaters tend not to smoke. It’s possible that the apparent benefits of fruit were due to not smoking. However, the researchers controlled for this and found that there was still a protective benefit in eating fruit.

How was the study conducted?

The study looked at the eating habits and lifestyles of 77,562 women and 40,866 men over the age of fifty. The participants were followed for up to 18 years for the women and 12 years for the men. They did not have macular degeneration at the start of the study.

During the course of the study 316 people developed age-related macular degeneration. The researchers looked at how much fruit these people ate. This was done by using up to five questionnaires to assess their diet, including the number of servings of fruit and vegetables they ate each day.

The study was published in the journal Archives of Opthalmology (Cho E, Seddon JM, Rosner B, Willett WC, Hankinson SE. Prospective Study of Intake of Fruits, Vegetables, Vitamins and Carotenoids and Age-related Maculopathy. Arch Ophthalmol. 2004; 122: 883-892).

What can I do to lower my risk of age-related macular degeneration?

You can reduce the risk of developing age-related macular degeneration by:3

  • eating at least five portions of fruit and vegetables a day, including three servings of fruit (preferably including bananas and oranges) (see what is a portion)
  • not smoking (see the smoking section)
  • eating a low fat diet
  • keeping physically active – the Government recommends at least 30 of moderate level physical minutes five times a week (see exercise section)
  • maintaining a healthy weight for you height (use our BMI calculator to find out your healthy weight range)