The United States Department of Agriculture (USDA) has posted the 2020 Dietary Guidelines Advisory Committee report, an overview on the latest nutrition science which will inform the department’s Dietary Guidelines for Americans. Already, the 835-page document has opened up a floodgate of deliberations from academia, the nutritional science community, food, beverage, and dietary supplements industries, and more.
 
The Dietary Guidelines for Americans will be updated by officials from the USDA and the U.S. Department of Health and Human Services for the years 2020-2025. It is anticipated that the Dietary Guidelines for Americans will be finalized by December.
 
“Science-based dietary guidance is critical to ensuring a healthy future for America,” Brandon Lipps, USDA Food, Nutrition, and Consumer Services Deputy Under Secretary, said. “USDA greatly appreciates the high-quality work done by this committee comprised of our nation’s leading scientists and dietary experts. We look forward to thoroughly reviewing the report and leveraging their scientific advice as we partner with HHS to develop the next edition of the Dietary Guidelines for Americans.”
 
The USDA and HHS are accepting written public comments on the committee’s final report through Aug. 13. The public will also have an opportunity to provide oral comments on the scientific report to the departments at a public meeting on Aug. 11.  
 
The advisory committee also hosted a webinar to publicly present its draft conclusions. Additionally, the topics and questions the committee examined were made public prior to scientific review.
 
Thus far, the committee has received more than 62,000 public comments. For comparison, prior committees received an average of about 450 comments. To date, the public has had more than 18 months to provide comments to help shape the committee’s review and the forthcoming dietary guidelines.
 
In addition to co-developing the Dietary Guidelines for Americans, USDA’s Food and Nutrition Service administers 15 nutrition assistance programs.
 
Key Takeaways
While the report affirmed much of the long-standing scientific groundwork that has been clinically substantiated to reduce the rates of nutrition-effected diseases, there were a number of key takeaways unique to the report posted by this committee.
 
Rather than analyzing the more base nutritional intakes of Americans, the committee believes that new dietary guidelines should take into account dietary patterns, in order to implement a broader perspective on quantity, frequency, and types of meals Americans may consume depending on culture, preference, and more.
 
The concept of dietary pattern analysis in guideline development was first introduced by the 2010 committee, and since, the DGA committee has begun incorporating observational data sourced from the What We Eat In America (WWEIA) and the National Health and Nutrition Examination Survey (NHANES).
 
Five working principles that can be incorporated from looking at dietary patterns involve establishing metrics for modifying recommendations across different stages of life, focusing on variety and nutrient density, limiting calories from added sugars, saturated fats, and sodium intake, shifting to healthier choices with a better nutrient-to-energy ratio, and supporting healthy eating patterns for all demographic subgroups.
 
One broad finding is that, on the whole, Americans need to increase their intake of fruits, vegetables, dairy products, and whole grains. Additionally, dietary pattern analysis found that Americans have a sub-optimal diversity in their sources of protein. Of nutrients presenting a public health concern because of either overconsumption or underconsumption, the committee reported that it was most concerned with low intakes of vitamin D, calcium, dietary fiber, and potassium. Underconsumption of vitamins A, C, E, and K, magnesium, and choline, did not appear to pose a public health concern due to “a lack of adverse clinical and health outcome data” in people with low status in these nutrients, the committee reported.
 
The evidence gathered by the committee, further emphasizing the importance of an approach rooted in dietary patterns rather than nutrient intake, is a number of population-based studies suggesting that healthful diets tend to decline as we age, and the incorporation of healthy eating patterns at any stage of life can lead to lasting improvements. Declines in healthy eating patterns observed in adolescent females were of particular concern to the committee.
 
Edging out Added Sugars and Alcohol
The committee took major issue this year with the overconsumption of added sugars (predominantly from sweetened beverages), solid fats, and sodium. In fact, added sugars are over twice as highly consumed by Americans as they should be, the committee reported. The risks associated with sugar-sweetened beverages is most acute in children, the committee reported, indicating that a sizeable amount of added sugars are from these beverages, which can lead to poor diet quality throughout life. For this reason, the committee concluded that all sugar-sweetened beverages should be avoided by children entirely.  
 
Additionally, due to a rise in binge drinking and general consumption of alcohol, and further evidence suggesting that no abstinent person would benefit if they began drinking, the committee urged USDA and HHS to consider tightening recommendations on adult alcohol consumption to a mere one drink per day, on days when alcohol is consumed.
 
In adults, one sixth of all calories consumed came from beverages, which, while composing more than half of added sugars intake, were also a substantial source of vitamins C and D, calcium, and magnesium.
 
Life Stages
A number of recommendations that the committee intends to bring up for consideration have to do with the early stages of life. The committee reports evidence that women who are pregnant and/or lactating should be consuming 8-12 ounces of various seafood types to increase their omega-3 status, as it has been shown to benefit the cognitive and social development of infants and reduce the risk of gestational diabetes and hypertension. However, they did not have enough concurrent evidence specific to dosages, therefore, they could not advise a specific recommendation on omega-3 intake other than the long-standing 8-12 ounces.
 
Additionally, they believe that folate supplementation should be recommended due to mounting evidence that it may reduce the risk of hypertensive disorders among pregnant women. Additionally, the committee believes that Americans cease breastfeeding and begin introducing complementary foods and beverages too early, prior to 4 months old. Additionally, the introduction of peanuts and eggs in the second six months of life may prevent the development of allergies to these foods later in childhood, the committee said.
 
The committee reported it they will not be increasing recommended supplementation of more than 400 IU vitamin D for infants, as observational studies evaluated have shown that there are no developmental benefits, while negative effects may occur with increased vitamin D supplementation.
 
The committee reported concerns with young children between the ages of 1 and 3 and overconsumption of retinol, zinc, selenium, and copper, relative to their tolerable upper intake levels. For adolescents between 9 and 14, girls have low intakes of protein, iron, folate, vitamin B6 and vitamin B12, and both boys and girls have low intakes of phosphorous, magnesium, and choline. Older adults may be at risk for low intakes related to protein and vitamin B12. Additionally, choline and magnesium are underconsumed in the diets of women who are pregnant or lactating.
 
Falling Short
There are a plethora of nutritional metrics observed by the committee’s meta-analysis indicating key areas in which Americans are falling short of dietary recommendations.
 
According to the committee, 6 in 10 Americans have a chronic disease, and 4 in 10 Americans have two or more chronic diseases in which poor nutrition, lack of physical activity, and excessive alcohol use can be contributing factors. The most abundant nutritional deficiencies were in vitamin D, calcium, dietary fiber, and potassium. Another contributing factor may be a lack of diversity in sources of protein, and a major underrepresentation in non-animal sources of protein including legumes, nuts, and seeds. The committee reported that whole grain consumption is also too low. Additionally, dietary patterns show that Americans favor red and processed meat too highly over lean meat, fish, and high-protein dairy.
 
The analysis utilized NHANES data to determine how different demographic subgroups scored on the Healthy Eating Index, which assesses how well a set of foods aligns with the Dietary Guidelines for Americans. Those between the ages of 12 and 17 generally had the worst HEI scores, and there were notable differences in HEI scores between sexes, ages, and income levels.
 
Hypertension prevalence alarmingly increased in older age groups by 7.5% in adults ages 18 to 39 years, 33.2% in adults 40-59 years old, and 63.1% in adults 60 and older since 2007-2008. However, the prevalence of LDL cholesterol in adults ages 20 years and older has decreased from 22.2 % to 18.4% in that same time period. The prevalence of prediabetes and diabetes has mostly been stable since 1999. Currently, the proportion of adults in the U.S. with overweight or obesity is 71.2%, the committee reported. Average waistlines have increased, despite the fact that height has remained stable. Additionally, reductions in muscle mass were observed for adults above the age of 60, along with a trend in reduced bone mass for all adults 50 years and older.
 
Researchers Push for Sustainability Discussion
On the same day that the USDA advisory committee released its guidelines report, a team of researchers from several universities found that most national dietary guidelines are incompatible with the global environmental targets highlighted by the Paris Climate Accord, and that further epidemiological health benefits and reduced premature mortality rates could be achieved with more comprehensive and ambitious recommendations.
 
Interestingly, the advisory committee requested that the USDA and HHS take the environmental impact of the food supply into consideration when it comes to making future nutritional guidelines, something that remains largely unprecedented by most governmental dietary guidance policies. Research makes it clear that industrialized agriculture plays a large part in greenhouse gas emissions, soil erosion, and many other troubling ecological phenomena.
 
The team of researchers found that approximately 98% of all national dietary guidelines fell short of one standard global target pertaining to either health or the environment. It found that guidelines established by Australia’s EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems would achieve the greatest health benefit; these guidelines were associated with a third greater reduction in premature mortality, more than three times greater reductions in greenhouse gas emissions, and a general attainment of global health and environmental targets compared to the WHO recommendations, which researchers considered to be more comprehensive and ambitious than the national dietary guidelines of the U.S.  
 
“This analysis suggests that national guidelines could be both healthier and more sustainable,” the researchers wrote. “Providing clearer advice on limiting in most contexts the consumption of animal source foods, in particular beef and dairy, was found to have the greatest potential for increasing the environmental sustainability of dietary guidelines, whereas increasing the intake of whole grains, fruits and vegetables, nuts and seeds, and legumes, reducing the intake of red and processed meat, and highlighting the importance of attaining balanced energy intake and weight levels were associated with most of the additional health benefits. The health results were based on observational data and assuming a causal relation between dietary risk factors and health outcomes. The certainty of evidence for these relations is mostly graded as moderate in existing meta-analyses.”
 
However, guidelines are not a solution in themselves, the researchers found, indicating that less than half of all countries with national food based dietary guidelines actually fulfilled any of their recommendations.