Chapters 1-2:
These chapters are commendable summaries of the vision, actions and resources necessary to achieve the goals outlined. In particular, the chapters emphasize the need to solve the unacceptably lingering nutrition problems of the 20th Century. All of the public health measures necessary to do so have been known for at least 100 years and all of the recognized essential nutrients have been known for more than 50 years. Likewise, ancillary aids such as antibiotics necessary to treat the common infectious agents associated with the malnourished state have also been available for nearly as long. In practice, the proof-of-principle experiments were completed long ago. Under-nutrition is largely non-existent in Nations that have been able to implement the public health foundations required for clean water and food and that have been able to provide diverse foods in amounts that allow adequate intakes of the essential nutrients in healthy diets. As such, then, the 20th Century’s lingering nutrition problems are not the result of a lingering deficit in nutrition science. They are the consequence of the lingering investment, financing, policy facilitation, and implementation deficits. Chapters 1 and 2 highlight the action elements necessary to turn these issues around. All are critically important, but explicit commitment to the knowledge and evidence-base is the foundation for effective conduct of all of the other recommendations.
Because the fundamental biological causes of under-nutrition are largely understood, final solution to the nutrition problems of the 20Th Century is achievable on a global scale. On the other hand, in Chapter 1, the draft aligns its commitment with the 66th WHA goal of reducing NCDs by 25% by 2025. While certainly commendable, this goal is potentially less tractable. First, on the whole, neither the knowledge nor evidence-base for NCDs are as complete or as convincingly clear and unambiguous as is the information on essential nutrient deficiencies. The pathophysiological bases of NCDs, the nutrition problems of the 21st Century, are not nearly as well understood as the biological causes of under-nutrition. Secondly, proof-of-principle experiments in developed countries have not been nearly as demonstrably effective for prevention of many NCDs, cancers for instance. Third, in NCDs where success has been achieved, it is plausible that these accomplishments were achievable because the overall environmental, societal, public health and economic problems that remain impediments to successful elimination of under-nutrition were corrected first. Fourth, in many NCDs medical/pharmaceutical preventive and therapeutic advances have been responsible for a significant fraction of the successes. The past and future scientific, technological and industrial contributions to medicine get little mention in the draft. Fifth, in large part, behavioral change underlies correction of most modifiable NCD risk factors and science and society have been remarkably poor at changing behaviors in almost any sphere of life. Finally, the large, 25% reduction in NCDs must be accompanied by a corresponding reduction in all-cause mortality. If not little net human benefit results. Thus, for instance, if reduction in cardiovascular deaths is accompanied by an increase in deaths from cancer and other causes (as has been the case in some cardiovascular disease trials), how does one measure success or recommend pubic health policies?
Chapter 3 (Section 3.1):
Chapter three provides insightful guidance by recognizing the critical interplay of food systems, supply chains, economic incentives, income growth, and food-system based policies as necessary elements in any overall action plan. Most importantly, the chapter explicitly recognizes that healthy diets and diverse diets are necessary for any nutritional success, either in eliminating under-nutrition or in reducing the risk of NCDs. The absolutely critical word here is “diets” and in whole diets, not individual foods. Despite regular and repeated forays into dietary and/or nutrient fads that have promised long-term beneficial returns, the field of nutrition has demonstrated over and over again that overall health maintenance is a function of an individuals whole diet pattern, not of any specific, individual food or class of foods.
More than fifty years ago, expert nutrition advice was that there are no good foods or bad foods, only good or bad diets. Nonetheless, in the intervening decades, various “bad food” hypotheses were tested repeatedly. Over time, the integrated results of these studies have provided proof that the overall diet pattern is what is critical to maintaining optimal nutritional health, not the presence or absence of specific nutrients in any individual food. Thus, for instance, egg were once vilified as a “bad food” by the American Heart Association because consumption of the cholesterol in eggs would lead to increased serum cholesterol and, consequently, to increased cardiovascular risk. Rather quietly when compared to the highly vocal AHA campaigns to reduce cholesterol intake, in its 2013 Guideline on Lifestyle Management to Reduce Cardiovascular Risk, the AHA now says in a single short sentence that “There is insufficient evidence to determine whether lowering dietary cholesterol reduces Low Density Lipoprotein Cholesterol” (1).
Likewise, in the current framework draft (bullet list, Section 3.1), simplified recommendations for reduction in salt, saturated fat and sugar intakes no longer adequately or transparently reflect the complexity of the current state of nutrition science in these areas.
Specifically:
· Intake of saturated fat is less than 10% of total energy intake: This item fails to address the accumulated evidence that the macronutrient replacements for the saturated fats removed from the diet are critical in regard to the overall health consequences, that there are profound differences in the health effects of individual saturated fatty acids, and that the consequent health risks are dependent on the individual fatty acids, not saturated fats as a class, and that effects of reducing saturated fats, per se, on heart disease risk may not be as profound as once suspected, once the effect of the presence of trans-fats in earlier studies is removed (1-24). Recently, published data led Dr. Frank Hu at Harvard to remark that, “The single macronutrient approach is outdated… I think future dietary guidelines will put more and more emphasis on real food rather than giving an absolute upper limit or cutoff point for certain macronutrients.” (25)
· Intake of free sugars is less than 10% of total energy or, preferably, less than 5%: This recommendation is just not supportable from current evidence. There are no direct human experimental data to support a 5% intake level. As far as I can determine, the 10% level is an arbitrary one based on the subjective opinion of a WHO Study Group that met in Geneva in 1989 when, without any systematic evidence-based assessment, the “Group judges that the upper limit of the population nutrient goal for free sugars should be about 10% of energy” (WHO Technical Report Series 797, page 113). Earlier this year, in response to the WHO draft sugars guideline, I submitted formal comments on the lack of evidence basis for this guideline. To my knowledge, this document remains a draft with recommendations that are not yet formally approved. Rather than duplicate in detail here the evidence I sent to the WHO in March, I have attached my earlier comments as an Appendix at the end of the current comments and supporting citations. Since my earlier comments to the WHO on this issue, an additional related meta-analysis has been published (26). This analysis demonstrated statistically significant increments in circulating triglycerides, LDL-Cholesterol and blood pressure as a function of dietary sugars intake. However, the changes in surrogate variables were quite small and their clinical significance is surely arguable without further data, especially hard clinical endpoints (26).
· Intake of Salt is less than 5 g per day: New data question the advisability of severe restrictions in dietary sodium intake based on risk/benefit ratio of salt restrictions beyond modest decrements in intake (27-33). These data continue to show that individuals who consume very high quantities of sodium as salt will have significant, beneficial effects on blood pressure and support the findings of the DASH diet study of hypertensive individuals. However, they question extrapolation of DASH data to populations as a whole since very low sodium intakes are not only associated with little additional benefit but the adverse risk profile increases. In an editorial accompanying the most recent reports in the New England Journal of Medicine, Dr. Susan Oparil discusses the new data and concludes that the articles “highlight the need to collect high-quality evidence on both the risks and benefits of low-sodium diets.” (33) Thus, the current Framework for Action draft needs to reconsider the absolute value chosen for its recommended salt intake.
Chapter 3 (Section 3.1.1):
Food Environments: Additionally, as a consequence of the necessary modifications of the Section 3.1 bullet items discussed above, there will be a corresponding need to reword the related bullet items in Section 3.1.1
Summary:
The current ICN2 Zero Draft Framework for Action represents a thoughtful document overall and one that provides comprehensive and inclusive recommendations on the whole. However, the draft overstates the level of the today’s evidence when it makes simplified recommendations about individual foods. Several of these specific restrictions are no longer supported convincingly by hard scientific data. Moreover, this negative approach fails to emphasize more positive approaches that focus on healthy dietary patterns as a whole. Not only are these more scientifically sound based on current evidence, healthy whole diet patterns will permit each of the 193 Nations in the U.N. to more readily adapt their individual dietary guidelines to local foods available within these Nations and to food patterns and consumption habits that continue to support the unique social and cultural contexts of the citizens of these countries.
Comments Submitted by
Dennis M, Bier, M.D.
Director, Children’s Nutrition Research Center
Baylor College of Medicine, Houston, TX, USA
Editor-in-Chief, The American Journal of Clinical Nutrition
Dennis M. Bier