Applying the concept of nutrient density

by Sharon Natoli

In Australia’s current food environment, many people consume excess kilojoules without reaching daily requirements for vitamins, minerals and other essential nutrients. Making poor food choices can lead to ill health and weight gain(1), so it is clear that people need guidance on the best foods to choose for optimal health now more than ever. In the past, ‘healthy’ foods have been classifi ed as such because they are low in negative nutrients such as total and saturated fat, sugar and salt, rather than by the amount of important nutrients such as fibre, vitamins, minerals and protein they contain(2). This is where the concept of nutrient density comes in. Nutrient-dense foods are defined as those with a high proportion of vitamins and minerals relative to the amount of energy (kilojoules) they contain(1). For instance, foods such as fruits and vegetables that are relatively low in kilojoules but high in vitamins and minerals are considered to have a high nutrient density.

This concept is increasing in interest among researchers, government and health professionals alike.

MEASURING NUTRIENT DENSITY

Although the concept of nutrient density has been used by dietitians for many years, it is not yet emphasised in Australian dietary guidelines. This may be because of a lack of agreement on how best to rank foods according to their nutrient content. This area has been addressed over the years and there are currently two main systems being trialled in the US. Once a ranking system is agreed upon, we’ll be able to direct clients to choose those foods that provide the most nutrients per kilojoule consumed. What we do know is that by eating a variety of foods from each of the major food groups every day, with an emphasis on nutrient-dense choices, individuals are more likely to be getting all the vitamins, minerals and other compounds needed by the body without the need for supplements.

NUTRIENT-DENSE FOODS IN PRACTICE
By applying the concept of nutrient density to a typical weight loss meal, choices within each of the food groups can make a signifi cant diff erence to nutrient intakes. Table 1 highlights the difference between a day’s food intake containing nutrient-dense food choices and one with fewer nutrient-dense food choices. Both of these are equivalent in kilojoules (~6,200kJ), yet the nutrient-dense day’s intake provides substantially more vitamin A, ribofl avin, folate, iron, zinc and fibre than the regular diet, as well as being lower in saturated fat (as a percentage of total fat) and sugar.

It is important to make the distinction between foods that are naturally nutrient-dense (such as fruits, vegetables, eggs, lean red meat, reduced fat dairy and wholegrains) and those that have been fortifi ed (such as many breakfast cereals, breads and fruit juices)4. Although these foods can assist in increasing an individual’s daily nutrient intake, naturally nutrient-dense food choices are recommended as the basis of any healthy diet. Fortifi ed foods and nutritional supplements, however, can offer additional benefits to the diets of individuals at risk of defi ciency such as vegetarians, children, the elderly and pregnant women.

CLIENTS WHO MAY BENEFIT FROM NUTRIENT-DENSE FOODS

WEIGHT LOSS CLIENTS
By choosing nutrient-dense foods from each group, individuals on weight loss diets can consume less food and still meet their daily nutrient requirements. Table 1 illustrates how individuals wanting to lose weight without sacrificing key nutrients can select nutrient-dense food options within a kilojoule-controlled eating plan.

PREGNANT CLIENTS
Pregnancy increases nutritional requirements for protein, omega-3 fatty acids and most vitamins and minerals including folate, iron and zinc, with only a moderate increase in total kilojoule requirements.

ATHLETES
Athletes often need to change their body weight to meet the demands of their sport, therefore being able to control kilojoule intake without sacrificing nutrient intake becomes all the more important.

By including a variety of nutrient-dense foods in the diet, clients focusing on sports performance are5:
• more likely to obtain all the nutrients required in a day
• less likely to eat too much of any one food
• more likely to lower their risk of developing common defi ciencies seen in athletes such as iron, zinc and calcium.

RECOMMENDATIONS FOR NUTRIENT-DENSE EATING

The concept of nutrient density is increasingly relevant as many people struggle to maintain a healthy body weight, while also maintaining optimal nutritional status. Many clients consuming what appears to be a healthy balanced diet may in fact be lacking in a number of key vitamins and minerals. Encouraging clients to consume nutrient-dense foods such as wholegrains, strongly coloured fruits and vegetables, lean meat, eggs, and low-fat dairy products (in place of refined grains, sugar, full-fat dairy products and processed meats) as part of a healthy, balanced eating plan can help ensure they meet macronutrient and micronutrient intakes without exceeding kilojoule recommendations.

References:  
(1) Backstrand, J.R., ‘Quantitative approaches to nutrient density for public health nutrition’. Public Health Nutr 6 (8), 829-837 (2003).

(2) Drewnowski, A., ‘Concept of a nutritious food: toward a nutrient density score’. Am J Clin Nutr 82 (4), 721-732 (2005).

(3) Food & Nutrition Australia, My Healthy Eating Guide. (2007).

(4) Pennington, J., Kandiah, J., Niklas, T., Pitman, S., & Stitzel, K., ‘Practice paper of the American dietetic association: nutrient density: meeting nutrient goals within calorie needs’. J Am Diet Assoc 107 (5), 860-869 (2007).

(5) American College of Sports Medicine, American Dietetic Association, & Dietitians of Canada, ‘Joint Position Statement: nutrition and athletic performance’. American College of Sports Medicine, American Dietetic Association, and Dietitians of Canada. Med Sci Sports Exerc 32 (12), 2130-2145 (2000).  

Acknowledgements: The Egg Nutrition Advisory Group, Australian Egg Corporation Limited, Megan Treby.

 

Sharon Natoli, BSc
An accredited practising dietitian with 20 years experience, Sharon is the founding director of Food and Nutrition Australia
(FNA), one of Australia’s most professional and progressive nutrition clinics and consultancies. She is the nutrition expert
for Women’s Health magazine, contributes a regular column to Australian Doctor magazine and regularly appears on
television programs including Channel 7’s ‘Today Tonight’ and ‘Sunrise’. For more information visit www.foodnut.com.au

NETWORK MAGAZINE • WINTER 2009
• PP35-37