An analysis of the recent US dietary guidelines process in light of its federal mandate and a National Academies report.

The US Dietary Guidelines for Americans is an enormously influential policy that has guided US nutrition programs since 1980. During these last 40 years, some researchers have expressed concern that the guidelines are based on an insufficiently rigorous assessment of the scientific evidence, a view that was largely substantiated by a Congressionally mandated 2017 report by the National Academies of Sciences, Engineering, and Medicine, which identified a need for enhanced transparency, greater scientific rigor, and updates to the scientific methodology for the DGA process. This paper traces the history of these ideas and contextualizes the DGA within the law and regulations that govern its process.

Dietary Saturated Fats and Health: Are the U.S. Guidelines Evidence-Based?

The last decade has seen nearly 20 papers reviewing the totality of the data on saturated fats and cardiovascular outcomes, which, altogether, have demonstrated a lack of rigorous evidence to support continued recommendations either to limit the consumption of saturated fatty acids or to replace them with polyunsaturated fatty acids. These papers were unfortunately not considered by the process leading to the most recent U.S.

Subchronic Tolerance Trials of Graded Oral Supplementation with Phenylalanine or Serine in Healthy Adults.

Phenylalanine and serine are amino acids used in dietary supplements and nutritional products consumed by healthy consumers; however, the safe level of phenylalanine or serine supplementation is unknown. The objective of this study was to conduct two 4-week clinical trials to evaluate the safety and tolerability of graded dosages of oral phenylalanine and oral serine. Healthy male adults ( = 60, 38.

Dietary Sugars: Not as Sour as They Are Made Out to Be.

Over the course of evolution, Mother Nature preserved the ability of humans to make every sugar they need for metabolic functions. Glucose is the almost exclusive fuel preferred by the human brain. Human infants are born with sweet taste receptors, sugars are a significant energy source in human milk, and mammals have a direct gut-to-brain sugar-sensing system that enhances development of a preference for sugars.

Proposals for Upper Limits of Safe Intake for Methionine, Histidine, and Lysine in Healthy Humans.

Based on research presented during the 10th Amino Acid Assessment Workshop, no observed adverse effect levels (NOAELs) for supplemental methionine at 46 mg/(kg·d) (∼3.2 g/d), for supplemental histidine at 8.0 g/d, and for supplemental lysine at 6.

Saturated Fats and Health: A Reassessment and Proposal for Food-Based Recommendations: JACC State-of-the-Art Review.

The recommendation to limit dietary saturated fatty acid (SFA) intake has persisted despite mounting evidence to the contrary. Most recent meta-analyses of randomized trials and observational studies found no beneficial effects of reducing SFA intake on cardiovascular disease (CVD) and total mortality, and instead found protective effects against stroke. Although SFAs increase low-density lipoprotein (LDL) cholesterol, in most individuals, this is not due to increasing levels of small, dense LDL particles, but rather larger LDL particles, which are much less strongly related to CVD risk.

Science dialogue mapping of knowledge and knowledge gaps related to the effects of dairy intake on human cardiovascular health and disease.

Dairy has been described as everything from a superfood to a poison; yet, arguments, assumptions, and data justifying these labels are not always clear. We used an issue-based information system, "dialogue mapping™," to summarize scientific points of a live panel discussion on the putative effects of dairy on cardiovascular diseases (CVD) from a day-long session among experts in nutrition and CVD. Dialogue mapping captures relations among ideas to explicitly, logically, and visually connect issues/questions, ideas, pro/con arguments, and agreements, even if discussed at different times.

The Philosophy of Evidence-Based Principles and Practice in Nutrition.

The practice of evidence-based nutrition involves using the best available nutrition evidence, together with clinical experience, to conscientiously work with patients' values and preferences to help them prevent (sometimes), resolve (sometimes), or cope with (often) problems related to their physical, mental, and social health. This article outlines the 3 fundamental principles of evidence-based practice as applied to the field of clinical nutrition. First, optimal clinical decision making requires awareness of the best available evidence, which ideally will come from unbiased systematic summaries of that evidence.

Nutrition from the Inside Out.

Nearly 50 years ago, I set out to investigate the clinical problem of hypoglycemia in children with illnesses that limited their food intake. My goal was to gather accurate and precise measurable data. At the time, I wasn't interested in nutrition as a discipline defined in its more general or popular sense.

Perspective: Improving Nutritional Guidelines for Sustainable Health Policies: Current Status and Perspectives.

A large body of evidence supports the notion that incorrect or insufficient nutrition contributes to disease development. A pivotal goal is thus to understand what exactly is appropriate and what is inappropriate in food ingestion and the consequent nutritional status and health. The effective application of these concepts requires the translation of scientific information into practical approaches that have a tangible and measurable impact at both individual and population levels.

Proposals for Upper Limits of Safe Intake for Arginine and Tryptophan in Young Adults and an Upper Limit of Safe Intake for Leucine in the Elderly.

On the basis of research presented during the 9th Amino Acid Assessment Workshop, a No Observed Adverse Effect Level (NOAEL) for diet-added arginine (added mostly in the form of dietary supplements) of 30 g/d and an upper limit of safe intake (ULSI) for diet-added tryptophan (added mostly in the form of dietary supplements) of 4.5 g/d have been proposed. Both recommendations apply to healthy young adults.

Options for basing Dietary Reference Intakes (DRIs) on chronic disease endpoints: report from a joint US-/Canadian-sponsored working group.

Dietary Reference Intakes (DRIs) are used in Canada and the United States in planning and assessing diets of apparently healthy individuals and population groups. The approaches used to establish DRIs on the basis of classical nutrient deficiencies and/or toxicities have worked well. However, it has proved to be more challenging to base DRI values on chronic disease endpoints; deviations from the traditional framework were often required, and in some cases, DRI values were not established for intakes that affected chronic disease outcomes despite evidence that supported a relation.

Saturated Fats and Cardiovascular Disease: Interpretations Not as Simple as They Once Were.

Historically, the so-called "lipid hypothesis" has focused on the detrimental role of saturated fats per se in enhancing the risks of cardiovascular disease. Recently, a body of new information and systematic analyses of available data have questioned simple interpretation of the relationship of dietary saturated fats and of individual saturated fatty acids to CVD risk. Thus, current assessments of risks due to dietary fat consumption that emphasize the confounding nature of the dietary macronutrients substituted for dietary saturated fats and give broader recognition to the effect of patterns of food intake as a whole are the most productive approach to an overall healthy diet.

Unscientific beliefs about scientific topics in nutrition.

Humans interact with food daily. Such repeated exposure creates a widespread, superficial familiarity with nutrition. Personal familiarity with nutrition from individual and cultural perspectives may give rise to beliefs about food not grounded in scientific evidence.

History and impact of nutritional epidemiology.

The real and important role of epidemiology was discussed, noting heretofore unknown associations that led to improved understanding of the cause and prevention of individual nutritional deficiencies. However, epidemiology has been less successful in linking individual nutrients to the cause of chronic diseases, such as cancer and cardiovascular disease. Dietary changes, such as decreasing caloric intake to prevent cancer and the Mediterranean diet to prevent diabetes, were confirmed as successful approaches to modifying the incidence of chronic diseases.

A proposal for an upper limit of leucine safe intake in healthy adults.

Based on recent research, an upper limit of safe intake (ULSI) for leucine is proposed for healthy adults: 0.53 g/(kg·d). Because leucine has been used as a dietary supplement for many years in people practicing exercise and sport, further study with long-term exposure to leucine in this specific subpopulation should be performed to eventually adjust the ULSI.

Summary of workshop discussions on establishing upper limits for amino acids with specific attention to available data for the essential amino acids leucine and tryptophan.

The morning of the first day of the 8th Amino Acid Assessment Workshop was organized and co-sponsored by the International Council on Amino Acid Science (ICAAS) and the International Life Sciences Institute Research Foundation and was focused on the International Life Sciences Institute Research Foundation's approach to establishing upper limits of nutrients. The remainder of d 1 and all of d 2 were focused on the safety of leucine and tryptophan, with special emphasis on determining the upper level of the safe range of intake. It was recognized that some toxicological frameworks, mainly the key-events dose response framework, might be applicable to amino acids and provide appropriate assistance to regulators in establishing upper limits for amino acids as a group of nutrients used in dietary supplements.

Safety standards in infant nutrition: a United States perspective.

In the United States, the general standard for food safety is reasonable certainty of causing no harm under the intended conditions of use. In contrast to food safety policy in some other countries, the United States treats foods for infants and children no differently than foods for adults, other than requiring additional standards for infant formulas. In the United States, food safety falls under the regulatory control of more than a dozen government agencies.

Promoting innovation in pediatric nutrition.

Truly impactful innovation can only be recognized in retrospect. Moreover, almost by definition, developing algorithmic paths on roadmaps for innovation are likely to be unsuccessful because innovators do not generally follow established routes. Nonetheless, environments can be established within Departments of Pediatrics that promote innovating thinking.

beta-Cell function and insulin sensitivity in adolescents from an OGTT.

Given the increase in the incidence of insulin resistance, obesity, and type 2 diabetes in children and adolescents, it would be of paramount importance to assess quantitative indices of insulin secretion and action during a physiological perturbation, such as a meal or an oral glucose-tolerance test (OGTT). A minimal model method is proposed to measure quantitative indices of insulin secretion and action in adolescents from an oral test. A 7 h, 21-sample OGTT was performed in 11 adolescents.

The phenotype of human obesity: the scope of the problem.

The prevention and treatment of childhood obesity have proven to be extremely difficult problems. Since the equation for maintaining energy balance is an extremely simple one, having only two terms, 'energy in' and 'energy out', the difficulties encountered in its application for obesity management are not immediately obvious. Among the problems that make practical application of the energy balance equation more difficult than expected are: (1) the precise feedback control system that is designed to maintain weight within a given range; (2) the aggressive resistance of the system to attempts to exceed its boundaries; (3) inaccurate assessment of energy intake in practice; (4) the dominant role of genes in determining body weight; (5) the polygenic nature of obesity and the fact that any single gene accounts for a small fraction of the genetic variation in weight; (6) underestimation of the genetic contribution to the current 'epidemic' of obesity; (7) the fact that 'modifiable' risk factors may be less modifiable than expected; (8) appreciation that family role modeling may be less influential than anticipated, and (9) the realization that our knowledge about the development of physical activity behaviors in childhood is extremely limited.