When I was a child, the TV commercial jingle 'Rise and shine, go to work on an egg' was heard most days, as was the catchphrase 'look out for the little lion'. This was in the days when eggs were universally regarded as being 'good for you' Things started to change when cholesterol became a hot topic, and then along came Edwina Currie.
In 1988, whilst serving as Junior Health Minister, she made a bold statement saying that most of the UK's eggs were infected with salmonella, following which, sales of eggs fell by 60% overnight, and many egg-producers went out of business. Mrs Currie was forced to resign. So what is the truth about eggs?
The good bits
Eggs are a widely available and relatively cheap food source and can make a significant contribution to a healthy diet. They are a good source of:
Protein A medium egg provides 6.5g of protein. This is 14% of a woman's and 12% of a man's recommended daily intake of protein. The protein in eggs is of a high biological value, as it contains all the essential amino acids needed by the human body, and egg protein is the yardstick against which all other proteins are measured. Protein is found in both the yolk and the egg white (albumen), and makes up 12.5% of the weight of the egg.
Vitamins Eggs are an important source of vitamin A, vitamin D, vitamin E, niacin (vitamin B3), biotin and vitamin B12.
Minerals, including iodine, zinc, magnesium, calcium, phosphorus and iron.
Antioxidants Eggs contain the anti-oxidant mineral selenium and another type of anti-oxidant called carotenoids. Anti-oxidants have an important role in protecting against heart disease and certain cancers.
Folic acid and choline These are nutrients that help to prevent neural tube defects such as spina bifida in unborn babies.
A medium egg contains about 86 calories and 6.4g of fat (of which only 1.8g is saturated fat). The fat is located almost entirely in the yolk. Albumen contains less than 0.05% fat. The nutritional value of certain eggs has been enhanced by manipulating the feed of the hens, to produce eggs that are rich in Omega-3 fatty acids, or rich in vitamin E. Omega-3 fatty acids are thought to reduce heart disease risk. These eggs also contain increased amounts of vitamins D, E and B12, folic acid, iodine and selenium.
A recent study at Harvard Medical School found evidence to suggest that teenage girls who regularly eat eggs are less likely to develop breast cancer. Further research is necessary to clarify this finding. Researchers in Boston have concluded that the carotenoids in egg yolks could help to prevent loss of vision caused by age-related macular degeneration (AMD) and cataracts.
The bad bits
Egg allergy is fairly common in children. It usually begins in infancy, soon after eggs are introduced into the diet, but it usually disappears by age 5-7 years. Occasionally it can be lifelong. Eggs can cause two types of allergic response, either eczema, or the more serious food allergy response. This usually begins within a few minutes of eating eggs or egg containing products. Symptoms may include a rash, hives (wheals), runny nose, sneezing, itchy, watery eyes, coughing, choking, wheezing, breathing difficulties, vomiting and diarrhoea. In extreme cases, a severe, acute allergic reaction (anaphylaxis) can occur, which may be fatal. Children with mild egg allergy can often eat food prepared with small amounts of egg, eg cakes, but generally speaking, children with egg allergy should avoid all egg-containing foods.
The controversial bits
Cholesterol Egg yolks are loaded with cholesterol, and this led to a view that eggs were bad for you if eaten daily. Many cholesterol-lowering diet sheets advise no more than 3 eggs a week. This view is challenged by some doctors, who say that for most people, an egg a day is an acceptable intake. They point out that the liver from dietary saturated fat manufactures the majority of the cholesterol circulating in the bloodstream, and that dietary cholesterol makes no great contribution to blood cholesterol levels.
Salmonella Since the 1988 salmonella-in-eggs crisis, a major programme to vaccinate chickens against salmonella has been undertaken by British egg producers. More than 80% of UK eggs are produced under the industry's voluntary 'Lion' code of practice, which includes salmonella vaccination and a 'best before' date stamped on every egg. The Lion Quality mark on egg shells and egg boxes means that the eggs have been produced to the highest standards of food safety in the world. Last year, there were 30,000 reported cases of salmonella in England and Wales, many of which were shown to derive from eggs used in catering. The Health Protection Agency has investigated 80 outbreaks of salmonella in the last 2 years. They concluded that some caterers may not be following advice re the safe use of eggs, and also that the use by the catering trade of Spanish eggs was a major source of infection. Spain is a major source of imported eggs in the UK, and they do not have a satisfactory salmonella containment programme in place. Foods containing raw eggs (such as home-made mayonnaise) or lightly cooked eggs pose the greatest salmonella risk.
Using eggs safely
A few simple measures can reduce the risk of contracting salmonella from eggs used in the home.
Look for the Lion Quality mark (or the words Lion Quality) on the egg shell and egg box
Buy eggs from a reputable retailer. They are more likely to have been transported and stored at the recommended temperature (less than 20degrees Centigrade)
Throw away any eggs with cracked shells
Store eggs separately from other foodstuff
Store eggs in their box in the fridge, and make sure you use them before the 'best by' date on the box
Always wash your hands after you have handled eggs—it is possible for salmonella bacteria to be on the egg shell as well as inside the egg.
