Guidelines Dietary - Eat For Health

Table 2.1: Evidence statements for consuming ‘a wide variety of nutritious foods’Evidence statementThe evidence suggests that high quality diet is associated with a reduced risk of chronic disease and improvedhealth outcomes.The evidence suggests the consumption of a dietary intake pattern aligned with national dietary guidelines orrecommendations is associated with reduced morbidity and mortality.GradeCCNotes: Grades – A: convincing association, B: probable association, C: suggestive associationIncludes evidence statements and gradings from the Evidence Report (literature from years 2002–2009). Does not include evidence fromother sources, such as the 2003 edition of the dietary guidelines (in which individual studies were classified according to their design aslevel I, II or III but overall grades for relationships were not derived), although these sources have been used to inform these Guidelines.Grade C evidence statements showing no association and all Grade D statements can be found in Appendix E.2.1.3 How consuming a wide variety of nutritious foods may improvehealth outcomesNutritional science has traditionally characterised foods according to their macro- and micronutrient values, butthere is increasing evidence of the role that whole foods play in promoting health and wellbeing, and of the roleof food components other than nutrients in protecting against some communicable and non-communicablechronic diseases when consumed as part of a varied nutritious diet. 328,329 These non-nutrient components includephytochemicals, which are obtained from plants and are biologically active but not directly associated withdeficiency syndromes. They include carotenoids, flavonoids, isoflavonoids, polyphenols, isothiocyanates, indoles,sulphoraphanes, monoterpenes, xanthins and non-digestible oligosaccharides. It is not always known which foodconstituents are responsible for the protective effects of specific foods against specific chronic diseases, and it islikely that many other active constituents will be discovered in the future. Interactions between these compoundsare likely to be complex, either causing or masking effects, or acting synergistically with other compounds. 9Guideline 2Dietary variety has the benefit of diluting potential toxicants found naturally in foods. 330 Diversity in food intakecan reduce an individual’s exposure to any one group of toxicants. Other ways of minimising this risk includeappropriate and careful processing, cooking and storage of food (see Chapter 5).Another potential benefit of food variety comes from maximising the bioavailability of nutrients. 331 The many complexrelationships between foods, nutrients and food components (such as phytates) can influence the absorption,metabolism and retention of nutrients. When dietary patterns are varied and nutrients are in adequate supply,these interactions pose fewer problems than in restricted, monotonous dietary patterns.Clinical problems associated with excess intake of nutrients are nearly always associated with intakes ofsupplements. 8 It is also possible to develop symptoms of toxicity when dietary patterns concentrate onparticular foods, or if the same nutrient is consumed in different chemical forms. 8,332 Examples include excessiveconsumption of carrot juice or regularly eating very large quantities of liver, which may cause vitamin A toxicity. 3332.1.4 Practical considerations: enjoy a wide variety of nutritious foodsIt is important to consider this Guideline together with other Guidelines, particularly Guideline 3 on limiting intakesof specific foods high in saturated fats, added sugars and/or added salt and Guideline 1 on healthy weight. The word‘plenty’ is used judiciously to encourage increased consumption of vegetables (except those that are fried).For the other food groups, the Guidelines do not advocate plenty, but rather focus on an adequate amount ofthe preferred varieties within each food group, for example wholegrain, or lean, or lower fat and plain water,preferably from the tap. This serves to distinguish between eating a variety and overconsumption, as there issome evidence that there may be a link between eating a variety of energy-dense food and drinks and excessfood intakes (see Chapter 1). Variety refers to nutritious food, not discretionary foods.Different quantities of different types of foods from the five food groups are recommended for different ages,sexes, and those with different energy (kilojoule) intake requirements. These are based on dietary modelling toinform the revised Australian Guide to Healthy Eating 9 and companion resources. Discussion of dietary patternsand the environment is included in Appendix G.Enjoy a wide variety of nutritious foodsNational Health and Medical Research Council33