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Impact of Changing Scientific Recommendations on Nutrition Policies

Posted 17 July 2018 | By Barbara O. Schneeman, PhD 

Impact of Changing Scientific Recommendations on Nutrition Policies

This article reviews the evolution of nutrition recommendations and how they are reflected in current policy decisions. A special focus is placed on fat and carbohydrate recommendations and their associated risks for non-communicable diseases.

Introduction

In the first half of the twentieth century, the primary focus in nutrition was on the prevention of undernutrition through adequate intake of micronutrients, energy and protein. However, by the second half of the century, observational data indicated associations between certain dietary factors and the prevalence of Non-Communicable Diseases (NCDs), such as cardiovascular disease (CVD), cancers and type 2 diabetes. NCDs were becoming the major cause of morbidity and mortality in developed countries.1 A result of a better understanding the relationships between foods and diseases was to develop and promote policies aimed at modifying peoples’ dietary behaviors to reduce health risks. Policies and public health strategies developed in the 1990s were based on nutrition recommendations from previous decades. However, since then, several countries have updated nutrition recommendations based on more recent science and subsequently developed new approaches to systematically review evidence.2,3

The Evolution of Fat and Carbohydrate Recommendations

The evolution of recommendations regarding the dietary intake of fats and carbohydrates in the US parallels many of the changes in recommendations internationally. In the US, the earliest Recommended Dietary Allowances (RDA), developed by the Food and Nutrition Board of the National Academy of Sciences, focused on fat and carbohydrate as energy sources as well as roughage provided by crude fiber in the American diet.4 This same emphasis was also evident in the early work of the World Health Organization (WHO) and the Food and Agricultural Organization (FAO) in development of their recommendations.5 The 1968 RDA recommended carbohydrate intakes should emphasize complex carbohydrates (cellulose and hemicelluloses) as the preferred source rather than refined carbohydrates, such as sugars that may be associated with dental caries. It was also recognized that some small amount of carbohydrate in the diet was needed to prevent ketosis, a condition in which the body does not have enough carbohydrates to burn for energy and instead burns fat.6 In 1989, the RDAs were linked to recommendations from two seminal reports, the Surgeon General’s Report on Diet and Health and the National Research Council’s report on Diet and Health. Both reports were more specific and quantitative in providing recommendations for components of fats and carbohydrates.7,8,9 A similar transition occurred in WHO/FAO recommendations in Technical Report 916, published in 2003.10 The Food and Nutrition Board introduced a new process in 1998 for developing recommendations, referred to as the Dietary Reference Intakes (DRIs); this approach was used for the 2005 recommendations on fats and carbohydrates.11-13 Likewise, between 2010 and 2017, the European Food Safety Authority (EFSA) reviewed and updated the 1993 advice of the Scientific Committee for Food (SCF) on Dietary Reference Values (DRVs) for Europe as requested by the European Commission.14,15 In addition, WHO implemented the Grading of Recommendations Assessment, Development and Evaluation (GRADE) process to develop new guidelines, including the recommendations for fats and carbohydrates.16

How have the recommendations evolved?

Recommendations regarding fractions of fats and carbohydrates have become more quantitative and specific. Within the fat category, Saturated Fatty Acids (SFA), trans fatty acids and cholesterol have become associated with increasing risk of CVD; sugars have been associated with increased risk of dental caries and dietary fiber has been associated with improved bowel function and decreased risk of cardiovascular disease (CVD). Between the 1989 RDA and the 2005 DRI, the quantitative recommendations for energy from fats and carbohydrates shifted from specific numbers (30% and 50% of total daily energy intake (%E), respectively) to a range or Acceptable Macronutrient Distribution Range (AMDR) (20-35% and 45-65% energy, respectively).17,18 In 1989, RDA recommendations for SFAs were to consume less than 10% of energy and, in the 2005 DRI, no quantitative recommendations were established for SFAs, cholesterol or trans fatty acids. The scientific review could not establish an Adequate Intake (AI) nor a tolerable Upper Level (UL) because these fats are not essential and, too, there is a positive linear relationship between intake of these fats and coronary heart disease risk. Thus, the recommendations developed from the scientific analysis are that intakes of trans fats should be as low as possible. As a consequence, food pattern modeling is needed to estimate what can be considered ‘as low as possible’ in recommended dietary patterns, rather than determining a specific adverse event. 

Over time, the RDA and DRI process has been consistent in recommending that complex carbohydrates are preferable to refined carbohydrates, which includes refined starches and sugars. Among the various carbohydrate fractions, dietary fiber has a specific quantitative recommendation; however, specific quantitative recommendations were not developed for sugars. The 2005 DRI based the recommended intake for fiber on the intake levels associated with reduced risk of CVD and also recommended that what is included in dietary fiber should occur naturally, as part of the plant matrix or if isolated or synthetic, demonstrated to have a health benefit.19 The DRI report estimated that no more than 25% of energy as sugar should be added to the diet without diluting the overall nutritional quality of the diet; however, the report did not establish an upper level of intake or an adequate intake level for sugars.

Current recommendations from EFSA are comparable to the DRIs, but establish the RI range for energy from carbohydrate as between 45-60%. The recommended range for total fat is between 20-35% of energy for adults. The recommended intake for saturated fatty acids and trans fatty acids should be “as low as possible.” EFSA did not establish an AI or UL for sugars. Fiber intake of 25 g/day was recommended based on normal laxation in adults.20

The 2003 technical report from WHO and FAO acknowledged on a global basis the dual burden of malnutrition due to nutrient inadequacy as well as dietary factors that increased risk for NCDs. In this context, the report recommended population targets for fats and carbohydrates to promote health and reduce risk of NCDs.21 These recommendations were updated in 2008 and 2010 and have been under review by WHO.22,23 Updated guidelines for free sugars have been published and draft guidelines for saturated fats and trans fat are available online.24,25 To strengthen the guideline process, WHO adopted the GRADE methodology for systematic evaluation of the scientific evidence.26 For example, in evaluating its recommendations on the intake of free sugars, two systematic reviews were developed: one to evaluate the effects of free sugars on dental caries, and the other to evaluate their effect on weight gain.27,28 The recommendation of less than 10% of energy intake from free sugars was based on the association between intake of sugars and dental caries.

Using Dietary Recommendations for Policy Development.

One of the most well-established uses of the RDAs and DRIs is the development of food guidelines or recommended dietary patterns that are nutritionally adequate and avoid excess consumption of food components. As a part of the DRI process, a report outlined the use of DRIs in dietary planning, including the types of planning at an individual level, for institutions that plan and serve meals and for government programs involving food assistance and other nutrition-related programs.29

In the US, the first food guidelines, emphasizing nutrient adequacy, were established in the early 1900s.  The original RDAs, published in 1941, were developed to assist with planning nutritionally adequate rations for the military.30 Once the relationship between diet and NCDs emerged, food guidelines needed to reflect limitations on nutrients or food substances as well as sufficient nutrient intake. These measures eventually resulted in a process to establish Food-Based Dietary Guidelines (FBDG). The first set of Dietary Guidelines for Americans (DGA) was published by USDA and DHHS (i.e., the Department of Health and Human Services) in 1980.31 The DGA has been reviewed and updated every five years.32,33 The DGA are science-based recommendations used by the federal government to inform policy regarding food and nutrition. For example, they are used to evaluate programs, such as Women, Infants and Children (WIC) or the school feeding assistance programs. They were also factored into regulations to update nutrition labeling.

The US was among the first countries to implement mandatory nutrition labeling for foods. Following enactment of the National Nutrition Labeling and Education Act (NLEA) in 1990, the US Food and Drug Administration (FDA) developed regulations based on scientific recommendations in the diet and health reports from the Surgeon General and the National Research Council and linked to the 1989 RDAs.34-37 In addition, FDA referenced the 1990 Dietary Guidelines for Americans.38 These science-based recommendations were essential for establishing the Daily Values used in Nutrition Facts so that consumers could estimate a food’s contribution to their daily dietary intake and decide whether a food was either high or low in a particular nutrient. 

The Daily Values (DVs) include two types of reference values—the Reference Daily Intakes (RDIs), which primarily include reference values for nutrients for which an RDA is established, and Daily Reference Values (DRVs), established for fats and carbohydrates. The National Academies of Sciences, Engineering and Medicine considers age and sex in determining DRIs; however, for labeling purposes, a single value must be chosen across the various categories, which vary by nutrient, but is typically the highest RDA value among the various populations. 

In 2016, FDA finalized regulations to update nutrition labeling 39 and comprehensively reviewed the 2005 DRI reports and the 2010 and 2015 DGAs to determine what updates, if any, were needed in labeling for fats and carbohydrates.40-42 As a result of this review and evaluation, FDA determined that the DRV for energy from fat should be changed from 30% to 35%, or based on a 2000 kcal diet from 65 to 78 g/day. The energy from carbohydrates was changed from 60% to 55%, or from 300 to 275 g/day in a 2000 kcal diet. In addition, “added sugar” was incorporated into mandatory nutrition labeling and a DRV of 50 g/day was established (i.e., 10% of energy). The development of a DRV for added sugars was not based on a recommendation from the DRI process, but instead, derived from food modeling of recommended dietary patterns that provide 2000 kcals used by the 2015 DGA.43 Because the DRI process had recommended an AI for dietary fiber (14 g/1000 kcals), this value was used for the DRV. FDA has since proposed a scientific review process to determine if isolated or synthetic fibers can be counted toward a product’s total dietary fiber content. DVs are a useful tool for evaluating how a food fits into a daily pattern. To assist consumers in using the DV for planning a healthful diet Canada, for example, has included a statement in the nutrition label that “5% or less of the DV is a little; 15% or more of the DV is a lot.”44 Both Canada and the EU have established reference values for labeling purposes comparable to the DVs used in the US (Table 1).45,46 The most significant difference among these countries is for sugars. Both Canada and the EU established a reference value for total sugars that includes added sugars while the US established a reference value only for added sugars and not for total sugars. The EU and Canadian approach is enforceable through analysis of sugars in the product; the US approach will require access to manufacturer records to verify values for added sugars.

Table 1. Daily Reference Intakes Used for Nutrition Labeling in a Diet of 2000 kcal (8400kJ)
  EU US Canada
Total Fat, g 70 78 75
Saturated fats, g 20 20 20*
Total carbohydrates, g 260 275 --
Total sugars, g 90 -- 100
Added sugars, g -- 50 --
Dietary fiber, g --† 28 28
* Daily reference intake for saturated and trans fats.
--Indicates that no value is provided.
†A daily reference values for fiber was not included in the EC regulations; EFSA recommended 25g/day.

Where does policy need to evolve to reflect science?

Following the implementation of mandatory nutrition labeling in 1994, the US has had almost 25 years of experience with food labeling policies emphasizing nutrient content of foods to guide consumer behavior. Because nutrient content cannot be discerned independently of this declaration, providing such information is informative for consumers educated to select foods based on a nutrient profile. However, a trend clearly evident over multiple cycles of the recommendations in the Dietary Guidelines is the greater emphasis on food choices and dietary patterns as important elements in recommendations to promote health and reduce risk of NCDs. In the 2005, DGA’s Dietary Approaches to Stop Hypertension (DASH) Eating Plan was included as a dietary pattern demonstrated to reduce hypertension risk.47

In subsequent versions of the DGA, references have been added to the Mediterranean eating plan and vegetarian eating patterns as additional examples of overall patterns associated with reducing risk for NCDs.48 The DASH and Mediterranean Eating Plans are of particular interest because of the evidence demonstrating modification of risk factors for NCDs when such eating plans are implemented. Common elements in these eating plans include inclusion of whole grains, fruits and vegetables, nutrient-dense foods (such as seeds and nuts), use of dairy products, eating fish and seafood in place of some meats and poultry, as well as the more traditional recommendations to limit dietary factors such as saturated fats, cholesterol, and sugars, and to maintain energy balance. Dietary patterns or eating plans can be constructed to encourage food choices reflecting limiting intake of saturated fats, trans fatty acids, cholesterol, sugars and refined carbohydrates while selecting foods providing fiber and foods meeting the needs for required nutrients. Such an approach emphasizes dietary patterns that will result in the desired changes to the intake of specific food components. In other words, recommendations are increasingly focusing on food choices rather than specific nutrients, thus emphasizing a complete dietary strategy rather than a reductionist strategy focused on specific nutrients.49,50

Although recommendations emphasize dietary patterns or eating plans, policy options regarding dietary patterns continue to emerge. For example, for a product promoted as containing whole grains, the question remains what is a meaningful amount of whole grain for the product to contribute effectively to a recommended dietary pattern? A similar question can be raised for all food groups recommended as part of a healthful dietary pattern and also suggest that some policy guidance is needed for claims about the contribution that ingredients in packaged foods, such as fruits, vegetables, whole grains, and oils, make to achieve recommended dietary patterns. With regard to foods to limit, current policies focus on the food component or ingredient to limit, such as added sugars, trans fatty acids, saturated fatty acids, rather than food choices within a dietary pattern, such as beverages sweetened with sugars, sweets, bakery products, or salty snacks.

In updating nutrition labeling, FDA has included added sugars in the list of mandatory nutrients. Their justification is based on concern of excess calorie intake contributing to overweight and obesity. However, foods that contribute to added sugars intake, such as certain beverages, snacks and sweets51 may contain energy from other macronutrients. Too, products with added sugars can be reformulated to reduce their added sugars content, but not necessarily reduce their contribution to energy intake. Some countries have proposed to address this issue by using front-of-pack labeling (FOP) to score foods based on their content of nutrients to limit as well as recommended food groups.52 However, many FOP approaches are nutrient-focused rather than focused on encouraging intake of food groups as part of a recommended dietary pattern relevant to a population.53 As countries develop systems, such as FOP labeling and labeling claims to highlight ingredients that contribute positively to recommended dietary patterns, data will be needed to determine if these approaches provide sufficient dietary guidance to improve food selection among consumers so that effective policies can be established.

Conclusion

Because recommendations for total fat, saturated fats, trans fats and carbohydrates have not changed markedly since the 1990s, most policies are reasonably consistent with current recommendations. The most noticeable shift has been a recognition that 35% rather than 30% energy from fat is more reflective of moderate fat intake and that the intake of trans fatty acids should be as low as possible. One of the most important changes is that the process to establish recommendations has become more systematic in evaluating the scientific evidence supporting the recommendations. In terms of public health, the progress since the 1990s has illustrated that while understanding the role of specific components of foods for NCD risk is necessary, it may not be sufficient to fully understand the importance of diets in reducing risk. The orientation toward single nutrients or food components (e.g., sugars, saturated fatty acids, trans fatty acids) tends to emphasize one component of the diet in managing risk for NCDs rather than recognizing the importance of interactions among dietary factors and disease risk reduction, especially for macronutrients. The next phase of recommendation and policy development will require a greater understanding of and focus on dietary patterns related to modulating risk.

References

  1. US Department of Health and Human Services. The Surgeon General’s Report on Nutrition and Health. Washington DC DHHS, 1988.
  2. European Food Safety Authority (EFSA), 2017. Dietary Reference Values for Nutrients: Summary Report. EFSA supporting publication 2017:e15121. 92 pp.
  3. Institute of Medicine. Dietary Reference Intakes: the Essential Guide to Nutrient Requirements. National Academy Press; 2006.
  4. National Academy of Sciences. Recommended Dietary Allowances. National Academy Press; 1941.
  5. Joint FAO/WHO/UNU Expert Consultation. Energy and Protein Requirements. World Health Organization, 1985. http://www.fao.org/docrep/003/AA040E/AA040E00.htm. Accessed 6 July 2018.
  6. Food and Nutrition Board. Recommended Dietary Allowances, 7th edition. National Academy Press, Washington DC. 1968.
  7. Op cit 1.
  8. Food and Nutrition Board. Recommended Dietary Allowances. 10th edition. National Academy Press, Washington DC. 1989.
  9. National Research Council. Diet and Health: Implications for Reducing Chronic Disease Risk. Washington DC, National Academies Press, 1989.
  10. Food and Agriculture Organization and the World Health Organization. Diet, Nutrition and the Prevention of Chronic Diseases. WHO Technical Report 916, WHO 2003.
  11. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press, Washington DC 2002/2005.
  12. Murphy SP, Yates AA, Atkinson SA, Barr S I and Dwyer J. “History of Nutrition: the Long Road Leading to the Dietary Reference Intakes for the United States and Canada.” Adv Nutr 7:157-68, 2016.
  13. The DRIs can include an Estimated Average Requirement (EAR), a recommended dietary allowance (RDA), an Acceptable Macronutrient Distribution Range (AMDR), an Adequate Intake (AI), and a tolerable Upper Level (UL).
  14. The Dietary Reference Values (DRVs) include the Population Reference Intakes (PRI), Average Requirements (ARs), Adequate Intakes (AIs), and Reference Intakes (RIs) ranges for macronutrients as well as tolerable upper intake levels (ULs).
  15. Op cit 2.
  16. World Health Organization. WHO Handbook for Guideline Development. World Health Organization 2014.
  17. Op cit 8.
  18. Op cit 11.
  19. Op cit 11.
  20. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA). Scientific Opinion on Dietary Reference Values for Carbohydrates and Dietary Fibre. EFSA Journal 8:1462-1539. 2010.
  21. Op cit 10.
  22. Food and Agricultural Organization. Fats and Fatty Acids in Human Nutrition; Report of an Expert Consultation. FAO 2010.
  23. Mann J, Cummings JH, Englyst HN, Key T, Liu S, Riccardi G, Summerbell C, Uauy R, van Dam, RM, Venn B, Vorster HH and Wiseman M. FAO/WHO Scientific Update on Carbohydrates in Human Nutrition: Conclusions. Eur. J. Clin. Nutr. 61 (Suppl1): S132-S137. 2007.
  24. Guideline: Sugars Intake for Adults and Children. Geneva: World Health Organization 2015.
  25. Draft WHO Guidelines for SFA and TFA. http://www.who.int/nutrition/topics/sfa-tfa-public-consultation-4may2018/en/. Accessed 6 July 2018.
  26. Op cit 16.
  27. TeMorenga L, Mallard S, Mann J. “Dietary Sugars and Body Weight: Systematic Review and Meta-analysis of Randomized Controlled Trials and Cohort Studies.” BMJ 345:e7492-7517, 2012.
  28. Moynihan PJ and Kelly SAM. “Effects on Caries of Sugars Intake: Systematic Review to Inform WHO Guidelines.” J Dent Res 93:8-18, 2014.
  29. Institute of Medicine. Dietary Reference Intakes: Applications in Dietary Planning. Washington DC. The National Academies Press; 2003.
  30. Op cit 4.
  31. Department of Agriculture and Department of Health and Human Services. The Dietary Guidelines for Americans. Home and Garden Bulletin No. 232. U.S. Government Printing Office, Washington DC 1980.
  32. A report from NASEM provides background on the process for establishing the DGA and more details on their use in policy development.
  33. National Academies of Sciences, Engineering, and Medicine. Redesigning the Process for Establishing the Dietary Guidelines for Americans. Washington, DC: The National Academies Press. 2017.
  34. Op cit 1.
  35. Op cit 2.
  36. Op cit 3.
  37. Department of Health and Human Services, Food and Drug Administration. Food Labeling: Mandatory Status of Nutrition Labeling and Nutrient Content Revision, Format for Nutrition Label. Federal Register 58(3): 2079-2205, 1993.
  38. Department of Agriculture and Department of Health and Human Services. The Dietary Guidelines for Americans. US Government Printing Office, Washington DC, 1990.
  39. Department of Health and Human Services, Food and Drug Administration. Food Labeling: Revision of the Nutrition and supplement Facts Labels. Final rule. Fed Reg 81(103):33742-33999, 2016.
  40. Op cit 11.
  41. Department of Agriculture and Department of Health and Human Services. The Dietary Guidelines for Americans. US Government Printing Office, Washington DC 2010.
  42. Department of Agriculture and Department of Health and Human Services. The Dietary Guidelines for Americans for 2015-2020. U.S. Government Printing Office, Washington DC 2015.
  43. Ibid.
  44. Health Canada. Food labeling Changes. https://www.canada.ca/en/health-canada/services/food-labelling-changes.html?_ga=1.241989700.795923089.1481549645. Accessed 6 July 2018.
  45. Health Canada. Nutrition Labelling; Table of Daily Values. Her Majesty the Queen in Right of Canada; 2016.
  46. European Union. Regulation (EU) No 1169/2011 of the European Parliament and of the Council. Official Journal of the European Union: L 304/61 Annex XIII Reference Intakes, 22.11.2011.
  47. Department of Agriculture and Department of Health and Human Services. The Dietary Guidelines for Americans. US Government Printing Office, Washington DC 2005.
  48. Op cit 42.
  49. Tapsell LC, Neale EP, Satija A, and Hu FB. “Foods, Nutrients, and Dietary Patterns: Interconnections and Implications for Dietary Guidelines.” Adv Nutr 7:445-54, 2016.
  50. Mozaffarian D. “Dietary and Policy Priorities for Cardiovascular Disease, Diabetes, and Obesity: a Comprehensive Review.” Circulation 133: 187-225, 2016.
  51. The 2015-2020 Dietary Guidelines for Americans identified beverages sweetened with sugars, snacks and sweets as the major sources of added sugars in the diet of Americans. For many beverages such as sodas and juices, sugars are the only component that contributes energy in the food.
  52. Australian Government. Healthy Star Rating System, Commonwealth of Australia. http://healthstarrating.gov.au/internet/healthstarrating/publishing.nsf/content/home. Accessed 6 July 2018.
  53. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Establishing Food-Based Dietary Guidelines. EFSA Journal 2010; 8(3):1460. 42 pp.

About the Author

Barbara O. Schneeman, PhD, is Professor Emerita of Nutrition at the University of California, Davis. She was a faculty member and administrator at the University for 28 years. From 2004-2013, she served as the director of the Office of Nutrition, Labeling and Dietary Supplements at the US Food and Drug Administration (FDA) and as higher education coordinator at USAID from 2015-2016. She may be contacted at boschneeman@ucdavis.edu.

Cite as: Schneeman BO. “Impact of Changing Scientific Recommendations on Nutrition Policies.” Regulatory Focus. July 2018.Regulatory Affairs Professionals Society.


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