STI: Egg role

April 9, 2009

Eggs get a break - Cover story

Egg role

Despite its solid nutritional credentials - eggs contain essential vitamins and minerals and are a good source of protein - dietitians tell MYB why they should be consumed in moderation

By June Cheong 

 

The controversy over the humble egg - and its effects on health - has not yet been laid to rest.

 

Last April, a study published in The American Journal Of Clinical Nutrition found that older men who ate seven or more eggs every week were 23per cent more likely to die of any cause during the study, which followed 21,300 male doctors over 20 years. This was especially so for diabetics.

 

The study also reported that men and women who ate seven or more eggs every week were 58 per cent and 77per cent respectively more likely to develop Type 2 diabetes compared to those who did not eat a single egg.

 

However, the same study concluded that there was no relation between eating eggs and increased risk of heart attack or stroke.

 

Then, in February this year, British researchers from the University of Surrey concluded that most people could eat as many eggs as they liked without wrecking their health.

 

So are eggs friend or foe?

 

Ms Pauline Chan, a dietitian and managing director of The Nutrition Place, said: 'Eggs have high nutritional value, are an excellent source of protein, contain only 70 to 80 calories each and are not high in fat.

 

'However, eggs are quite high in cholesterol and average 210mg per egg while our daily cholesterol allowance is only 300mg.'

 

The debate over eggs' health benefits has ramifications, given Singaporeans' appetite for them.

 

Last year, Agri-food and Veterinary Authority of Singapore figures show that more than 1.1 billion hen's eggs, 10.5 million preserved duck's eggs, 19.1 tonnes of caviar and 169.7 tonnes of fish roe were imported to be consumed.

 

These figures exclude the number of eggs sold by egg farms here for local consumption. For example, Seng Choon Farm estimates it sells 180 million hen's eggs every year.

 

Eggs are a good source of high quality protein and contain 13 vitamins and minerals including vitamins A and B, lutein, zinc and magnesium.

 

Protein is needed for essential functions like growth, tissue repair, making hormones and enzymes.

 

Vitamin A is essential for maintaining good vision while the range of B vitamins from eggs is important in energy production.

 

Ms June Liew, a dietitian at the department of dietetics and nutrition services at Singapore General Hospital, said lutein is related to eye health and may be important in preventing age-related blindness.

 

Some studies suggest that lutein from eggs is more easily absorbed by the body than other lutein-rich sources, she added.

 

Magnesium helps to maintain normal muscle and nerve function and heart rhythm while zinc is required to maintain a healthy immune system and our sense of taste and smell.

 

Despite eggs' solid nutritional credentials, dietitians are not very much in favour of eggs being eaten too often.

 

Ms Lydia Tan, a nutritionist at the youth health division of the Health Promotion Board, said it would be prudent to limit the intake of egg yolks to four or fewer a week.

 

The main beef that dietitians Mind Your Body spoke to have against eggs is their cholesterol content.

 

The Singapore Heart Foundation recommends that our daily cholesterol intake should be capped at 300mg a day. As an egg has about 210mg of cholesterol, healthy adults should eat only three to five eggs a week while those with high cholesterol levels should eat not more than two or three eggs a week.

 

Although studies have found that only a third of the cholesterol in the body comes from one's diet, the total amount of fat, saturated fat and cholesterol consumed can affect blood cholesterol levels.

 

'The debate on dietary cholesterol's effect on blood cholesterol is ongoing. However, most health authorities still recommend that daily intake of cholesterol be less than 300mg,' said Ms Chan.

 

In response to growing public concern over eggs' cholesterol content, egg farmers have come up with new-fangled, health-conscious variants of normal hen's eggs.

 

For example, Seng Choon Farm developed lower cholesterol eggs in 1991. Such eggs normally have between 80 and 170mg of cholesterol. Its other designer eggs - engineered to serve certain purposes - include carrot eggs, enhanced with lutein (a compound usually found in vegetables which helps to protect the eyes).

 

Asked how such designer eggs came about, MsChan said: 'They are produced by feeding egg-laying hens with a special diet rich in certain vitamins and other nutrients.

 

'The special diet usually includes kelp, flax seeds, canola oil and marigold extract.'

 

Ms Koh Chern Peng, a farm manager at Seng Choon Farm, said: 'Eggs are a great vehicle to carry extra nutrients in easily digestible form. It is amazing how hens can transform crude grains, which humans can't digest easily, into something as wonderful and versatile as the egg.

 

'Some nutrients may be more easily absorbed from eggs than vegetables, such as in the case of lutein.'

 

While designer eggs address certain health concerns, the fact is that egg yolks have the most concentrated amount of cholesterol in any food.

 

Ms Liew said: 'It is important to understand that there is no good or bad food per se. Whether a food does more harm to than benefits the body depends on the amount consumed and our current health condition.'

 

Ms Chan concluded: 'While designer eggs may contain extra nutrients such as omega-3 fatty acids, you can also get these from other food sources such as fish.

 

'The key to a healthy diet is always balance, moderation and variety.'

 

EGGS UNSCRAMBLED

 

Ever wondered why some egg yolks are burnished orange and others are a pale shadow of yellow?

 

Mind Your Body unscrambles five mysteries about eggs.

 

1: What causes the variations in egg yolk colour?

 

Ms Pauline Chan, a dietitian and the managing director of The Nutrition Place, said the colour of the egg yolk is dependent on the hen's feed.

 

A diet of wheat and white corn meal would produce an almost colourless yolk. If the hen is fed a diet that includes yellow corn meal, marigolds or carotene, the egg yolk would have a deep yellow colour, she said.

 

2: Are brown eggs better than white eggs or vice versa?

 

Ms June Liew, a dietitian at the department of dietetics and nutrition services at Singapore General Hospital, said brown eggs are produced by hens with red ear lobes and feathers while white eggs are produced by hens with white ear lobes and feathers. There is no significant link between shell colour and the nutritional value of an egg.

 

3: Can eggs be used for facials or hair masks?

 

Egg whites can be used for facials and can be applied directly on the face or together with other ingredients.

 

Ms Liew said that albumin in the egg is said to have a drying effect, thereby tightening pores and firming the skin.

 

She added that some people claim that eggs promote soft and healthy hair by nourishing the hair follicles with essential proteins, sulphur content and its wide array of vitamins and minerals. For these reasons, eggs are used to make shampoos and conditioners.

 

'But more scientific studies are needed to prove the efficacy of eggs on skin and hair health,' she said.

 

4: Are eggs good for children and why?

 

Ms Lydia Tan, a nutritionist at the youth health division of the Health Promotion Board, said eggs are a good source of choline, a nutrient essential for normal functioning of cells and brain development in infants. Eggs are also a good source of riboflavin, zinc and vitamin A, which are essential for growth and eye health.

 

5: When and how should a young child start eating eggs?

 

Ms Tan said egg allergy is more common in children under two years. Tolerance of eggs usually develops in children after that. The egg white, which is mainly protein, is the main source of allergens.

 

However, cooked egg yolks can be introduced to infants at six months.

 

Ms Chan cautioned: 'Whether or not you yourself have a history of egg allergy, the first time you introduce eggs to your young child, be sure to watch for signs of an allergic reaction such as rashes, asthma symptoms, swelling of the mouth or throat, vomiting or diarrhoea and loss of consciousness.'

 

A study found men and women who ate seven or more eggs every week were 58 and 77% more likely to develop Type 2 diabetes, compared to those who did not eat any

 

What's in that shell?

 

Hen's egg (50g)

Calorie: 72kcal

Protein: 6.3g

Carbohydrate: 0.4g

Total fat: 5g

Saturated fat: 1.6g

Monounsaturated fat: 1.9g

Polyunsaturated fat: 0.7g

Cholesterol: 212mg

Omega 3: 37mg

Omega 6: 573mg

Sodium: 70mg

Choline: 125.6mg

Vitamin E: 0.5mg

Lutein: 166mcg

Vitamin A: 70mcg

 

Duck's egg (70g)

Calorie: 130kcal

Protein: 9g

Carbohydrate: 1g

Total fat: 9.6g

Saturated fat: 2.6g

Monounsaturated fat: 4.6g

Polyunsaturated fat: 0.9g

Cholesterol: 619mg

Omega 3: 71.4mg

Omega 6: 391mg

Sodium: 102mg

Choline: 182mg

Vitamin E: 0.9mg

Lutein: 321mcg

Vitamin A: 136mcg

 

Quail's egg (9g)

Calorie: 13kcal

Protein: 1g

Carbohydrate: 0g

Total fat: 1g

Saturated fat: 0.3g

Monounsaturated fat: 0.4g

Polyunsaturated fat: 0.1g

Cholesterol: 76mg

Omega 3: 4mg

Omega 6: 84.6mg

Sodium: 13mg

Choline: 23.7mg

Vitamin E: 0.1mg

Lutein: 33mcg

Vitamin A: 14mcg

 

Caviar (28g)

Calorie: 71kcal

Protein: 7g

Carbohydrate: 1g

Total fat: 5g

Saturated fat: 1.1g

Monounsaturated fat: 1.3g

Polyunsaturated fat: 2.1g

Cholesterol: 165mg

Omega 3: 1,901mg

Omega 6: 22.7mg

Sodium: 420mg

Choline: 137mg

Vitamin E: 0.5mg

Lutein: 184mcg

Vitamin A: 75.9mcg

 

Fish roe (28g)

Calorie: 40kcal

Protein: 6g

Carbohydrate: 0.4g

Total fat: 1.8g

Saturated fat: 0.4g

Monounsaturated fat: 0.5g

Polyunsaturated fat: 0.8g

Cholesterol: 105mg

Omega 3: 682mg

Omega 6: 8.1mg

Sodium: 25mg

Choline: 95.1mg

Vitamin E: 2mg

Lutein: 59.9mcg

Vitamin A: 25.2mcg

 

Salted duck's egg (97g)

Calorie: 93kcal

Protein: 6.8g

Carbohydrate: 1g

Total fat: 6.9g

Cholesterol: 395mg

Sodium: 249mg

Vitamin A: 97mcg

 

Century egg (115g)

Calorie: 97kcal

Protein: 8.2g

Carbohydrate: 3.8g

Total fat: 5.5g

Cholesterol: 191mg

Sodium: 226mg

Vitamin A: 96mcg

 

WHAT'S WHAT

 

Saturated fat: Comes mainly from animal foods and tends to raise cholesterol level.

Monounsaturated fat: Commonly thought of as healthy as they help lower the risk of heart disease and stroke.

Polyunsaturated fat: Also thought of as healthy as it is associated with low blood cholesterol.

Omega 3: A form of polyunsaturated fat that protects against heart disease and stroke. They are not made by the body and thus must be obtained from food.

Omega 6: A form of polyunsaturated fat that is critical for heart and brain health.

Choline: An important nutrient for the development of the brain and is essential for pregnant and nursing women to ensure healthy foetal brain development.

Lutein: A nutrient essential for eye health and preventing age-related blindness.

 

Recipe - Layered steamed egg with lemongrass sauce

 

Dietitians Mind Your Body spoke to said poaching, steaming and boiling are the healthiest ways to cook an egg.

 

Ms June Liew, a dietitian at the department of dietetics and nutrition services at Singapore General Hospital, said: 'If you do use fat, limit the amount and use unsaturated fat like olive, canola and sunflower oil.'

 

Below is a good way to cook eggs, suggested by The Orange Lantern Vietnamese Restaurant.

 

LAYERED STEAMED EGG WITH LEMONGRASS SAUCE

4 eggs

200g shredded woodear mushroom

200g shredded carrot

100g rice vermicelli

1 tbs plain flour

Sugar

Salt

Black Pepper

 

Sauce:

1 stalk lemongrass

1 green lime

3 tbs lime juice

1 tbs honey

3 tbs fish sauce

1 tbs grounded chilli

3 tbs sugar

 

Garnishing:

1 stalk lemongrass

1 cherry tomato

1 stalk mint leaves

 

Method:

 

Separate the egg whites from the yolks. Beat the egg whites and add a small amount of flour to thicken.

 

Place the egg whites on dish in a steam container and steam for two minutes.

 

Beat the egg yolks with a small amount of salt and pepper.

 

Coat shredded carrot with a small amount of egg yolk and steam for two minutes.

 

Do the same with shredded wood ear mushroom and with rice vermicelli.

 

Mix sugar and lime with the remaining egg yolk and steam for two minutes.

 

Stack interspersing vegetable and egg layers. Trim sides and steam for a further two minutes.

 

Place on a plate and pour sauce over before serving.

 

Sauce:

 

Bring fish sauce and water to a boil. Add rest of ingredients and allow to boil for a further two minutes.