ENC Newsletter December 2013
Welcome to the final edition of The Good Egg for 2013! To wrap up the year, this issue of the newsletter provides an overview of trends in relation to food and nutrient intakes in older Australians, highlighting the significant role eggs can play toward meeting nutrient intakes in this growing segment of the population. Issues to consider in older people are not only the nutrient density of the foods selected, but the ease of preparation, convenience, texture and price of foods. Eggs tick the box in relation to all of these factors, being nutrient dense, easy to prepare, tasty and economical.
This issue also provides details on how the various nutrients found in eggs are distributed – which nutrients are predominant in the white and which are found mostly in the yolk? The answers may surprise you so turn the page to find out more!
Our research update includes studies on eggs and coronary risk, eggs and allergy and provides a summary of the key findings from the recently released Australian Diabetes, Obesity and Lifestyle (AusDiab) study twelve year follow up.
Enjoy this issue and please let us know if you have any feedback. Wishing you and your families a very Merry Christmas and a Happy New Year!
The Egg Nutrition Council
Published: 28 November 2013
Nutrient and Food Intake Trends in Older People
Optimal food and nutrient intakes are particularly important during aging as good nutrition can reduce or delay the progression of lifestyle related diseases. However, significant challenges exist in maintaining good nutritional status with age including decreased immune function, increased oxidative stress and changes in the gastrointestinal tract. Reduced salivary flow, difficulty in swallowing, poor dentition and reduced appetite can also impair the nutritional status of older adults due to affects on food intake. This article provides a brief overview of recent research on food and nutrient intakes in older Australians and highlights how eggs can make a significant contribution to improving nutritional status in this growing segment of the population.
Older Australians commonly have lower than ideal intakes of fibre, calcium, vitamins A, D, E, B6, B12, folate, vitamin C, iron, magnesium and zinc1,2. The Blue Mountains Eye Study, found almost 1 in 4 older Australians either have, or are at risk of, vitamin B12 deficiency3 . In addition, up to 80% of older women and 70% of men living in hostels or nursing homes in various states of Australia are deficient in vitamin D4.
Protein is another nutrient of concern as inadequate intakes contribute to increased skin fragility, decreased immune function, poor wound healing and longer recovery times5. Lower than optimal protein intakes can also increase the rate of age-related muscle loss6. Given this, protein requirements are 25% higher for adults aged 70 years and over7 .
Trends in Food Intake
Only 10% of adults aged 65 years and over consume the recommended 5 serves of vegetables and 2 serves of fruit each day8. Assessing food intakes from 1992-94 to 2002-04, the Blue Mountains Eye Study, 9 found an increase in consumption of fish, nuts, omega-3, eggs and folate in both older men and women while intakes of wholegrain bread decreased. In relation to eggs, older Australians increased their intake by an average of 10% of a standard serve to reach an intake of 22.2g per day for women and 24.6g per day for men, translating to around 3 eggs a week. The authors identified that an increase in egg intake in older Australians may reflect changes in food intake that occur with age, such as physical changes, poorer dentition, and convenience associated with ease of preparation.
Eggs contribute a significant variety of nutrients that are often lower than ideal in the diets of older Australians including vitamins A, D, E, B12, folate, protein, iron, iodine and long chain omega-3s. They also provide a source of lutein and zeaxanthin, beneficial for eye health.
Due to the variety of nutrients found in eggs, they are an ideal food to include the diets of older adults. They are also economical, easily prepared and soft in texture which makes them appropriate for people of this age group. Eggs are recommended as part of a healthy eating pattern that also includes adequate amounts of wholegrain breads and cereals, fruits, vegetables, dairy foods, lean meat, fish and poultry and sources of unsaturated fats.
Eggs Consumption Lowers Coronary Risk1
This observational study of 382 adults investigated the relationship between egg consumption and coronary risk factors. Participants had an average age of 60 years and 63% were male. Egg consumption was assessed using a food frequency questionnaire with subjects divided into 3 categories depending on their frequency of egg consumption 1) less than one egg per week, 2) one egg per week and 3) more than one egg per week. Coronary risk was assessed by a cardiologist. The results were adjusted for gender, age and blood pressure and showed a significant negative association between egg consumption and dyslipidemia with no change in other coronary risk factors. Those participants who ate more than one egg per week had a lower risk of heart disease.
AusDiab Twelve Year Follow Up Data Released2
The AusDiab study is the largest Australian longitudinal population-based study examining the natural history of diabetes, pre-diabetes, heart and kidney disease. The study commenced in 1999 with a cohort of 11,000 adults, a five year follow up was completed in December 2005 and the results of the twelve year follow-up completed in 2012 was recently released. Key findings from this survey indicate that over 12 years of follow-up, the average increase in waist circumference was 5.3cm and was greater in women than in men; people aged between 25 and 34 gained more weight and waist circumference compared to any other age group; participants were more likely to underestimate the amount of time they spent sitting in a day by more than half; and people with diabetes had a five fold increase in mortality compared to people with normal glucose tolerance. This survey provides useful information on health related trends in Australia over the past 12 years.
Cooked eggs in different forms and egg allergy3
This study examined the effect of varying the fat content of cooked-egg containing foods on the dose required to produce an allergic reaction and the reaction severity in egg allergic children undergoing double-blind, placebo-controlled food challenges (DBPCFC). Fifty-nine sensitised egg allergic children underwent DBPCFC with vanilla pudding, pancake and minced meat with these foods providing fat levels of 22.8%, 31.9% and 52.7% respectively. Each child received increasing doses of egg protein within the foods and challenges were terminated when a reaction was observed. The results showed no significant relationship between the dose of egg protein in the different types of food and the rate or severity of reaction. The authors concluded that the fat content of cooked-egg containing foods does not influence the dose of egg protein required to elicit a reaction or the severity of the allergic reaction in egg-allergic children.
White or yolk - which is the winner when it comes to nutritional value?
Most people know egg whites are a good source of protein however, often don’t release that almost half of the protein in eggs is found in the yolk. When it comes to good nutrition, both parts of the egg have their strengths. Here are some enlightening facts about how the nutrients in eggs are spread between the yolk and the white:
- The egg white contains more riboflavin and niacin than the yolk.
- The yolk contains a higher overall proportion of the vitamins found in eggs.
- Vitamins A, D and E are found in the fat of the yolk.
- The yolk makes up 33% of the liquid weight of the egg.
- The yolks content of phosphorus, manganese, iron, iodine, copper and calcium are higher than the white’s.
- All of the zinc in an egg is found in the yolk.
- 67% of the protein found in eggs is albumen.
- In addition to protein, niacin and riboflavin, egg white also contains chlorine, magnesium, potassium, sodium and sulphur.
- Egg white thins out with age because the protein changes in character.
- Lecithin found in egg yolk is responsible for the eggs emulsifying properties.
- The heat of cooking causes some minor nutrient losses of the B vitamins in the egg.
- Normal cooking denatures the egg protein, however it is still just as nutritious and contains all of the amino acids that make up the protein.
- Amino acids are destroyed only when an egg is severely overcooked e.g. the brown lacy edges of an overcooked fried egg.
Given the above, the Egg Nutrition Council encourages enjoyment of the whole egg to maximise the nutritional benefits of this versatile food.
Nutrient and Food Intake Trends in Older Adults - References:
1. McCarty, CA. et al Nutr Diet 59, 12-17 (2002).
2. National Nutrition Survey. ABS and Commonwealth Dept of Health & Aged Care, Canberra, 1998.
3. Flood, V. Sydney Nutrition Society Meeting (2005).
4. Med J Aust 182, 281-285 (2005).
5. Chernoff, R. J Am Coll Nutr 23, 627S-630S (2004).
6. Mithal, A. et al. Osteoporosis Int. 2013 May;24(5):1555-66
7. NHMRC Nutrient Reference Values for Aust & NZ including RDI’s (2006).
8. ABS. Australian Health Survey,. Report No. 4364.0.55.001 (ABS, 2012).
9. Flood, V. M. et al. Eur J Clin Nutr 64, 603-613 (2010).
Egg-Vestigator - References:
1Chagas P, et al. Atherosclerosis. 2013 Aug;229(2):381-4.
2AusDiab 2012. The Australian Diabetes, Obesity and Lifestyle Study. Baker IDI, Aug 2013
3 L. Libbers, B. M. et al. Clinical & Experimental Allergy,2013; (43) 1067–1070.
Masterclass - References:
Watson R ed. Eggs and Health Promotion, Iowa State Press, 2002.