Scientific Report of the 2020 Dietary Guidelines Advisory Committee: Evidence on Diet and Health

 

Welcome back to our series on the Scientific Report of the 2020 Dietary Guidelines Advisory Committee! Today we're going to give an overview of the first part of part D, and boy is this one a roller coaster ride!

Before we start, have you caught up on the first few installments? If not, check them out...

  1. Executive Summary
  2. Setting the Stage and Integrating the Evidence
  3. Methodology

And now, on to the next section: Evidence on Diet and Health!

Actually, this one is so huge that we're going to break it down into several posts. Today we're going to talk about chapter one: Current Dietary Intakes Through the Life Course.

This section begins with a key reminder, "Diet is directly related to health, and most Americans suffer from health conditions or suboptimal nutritional status that have the potential to be prevented or ameliorated through diet." This chapter digs into individual nutrients and food elements, but with the reminder to look at the ways food components interact, as well as their total consumption. "This chapter focuses on summarizing existing dietary and health-related data from Federal resources."

But why look at what people are eating? The answer is simple, "Understanding the extent to which the entire population and various subgroups (e.g. age, sex, race and ethnic origin, food security status, income) achieve food group and food component intake recommendations is the foundation for tailoring powerful public health communication strategies." Right now, the typical American eating pattern doesn't come close to ideal dietary patterns. That's why this report explores where we are eating first -- so we can learn what we need to do in order to improve our eating patterns and, with them, our health.

Remember, this report is the first to use a lifespan approach, so in some cases, we can't compare current intakes and science to what came before, only because there is little to no data for "before" just yet.

This section of the report focuses on 5 questions. Let's see the highlights of each one...

Question 1: What is the current prevalence of nutrition-related chronic health conditions?

You guys, things are pretty rough. "Nutrition-related chronic health conditions are common across every life stage of the U.S. population; conditions for which an unhealthy diet is a risk factor, including overweight and obesity, remain highly prevalent among all age groups."

While incidence of high total blood cholesterol has decreased and HDL ("good") cholesterol levels have generally improved in adults ages 20 and up since the last edition of the guidelines, hypertension prevalence has increased in older adults. 23% of children between the ages of 12 and 19 have either diabetes or prediabetes, and 34% of adults (age 18+) have prediabetes. That percentage tends to increase with age, and it's important to remember that many cases of diabetes are as yet undiagnosed. Another stat that increases with age is metabolic syndrome. The overall age-adjusted prevalence of metabolic syndrome among adults (age 20+ this time) is 35%, which also increases with age. And let's not forget chronic liver disease. "The age-sex group with the highest mortality rate from chronic liver disease was males ages 55 to 64 years (45.9 per 100,000)."

Now let's break down some obesity stats...

  • 41% of children age 2-19 are overweight or obese
  • 71% of US adults are overweight or obese

(To get a more detailed look at the answers to this question, check out pages 10-25 of the Evidence on Diet and Health section of the report).

Question 2: What are the Current Intakes of Food Groups?

"For Americans ages 2 years and older, intakes of Fruit, Vegetables, Dairy, and Whole Grains are generally below recommended amounts, and intakes of total Grains and total Protein Foods generally meet or exceed recommended amounts for most age-sex groups. Intakes of solid fats and added sugars are above recommended levels for all age-sex groups. Patterns of food group intake have not changed over the last decade."

The committee also found that pregnant women's eating patterns are generally low in fruits, vegetables, whole grains, protein, and dairy, while being rather high in saturated fats and added sugars. The same seems to be true for women who are breastfeeding.

While babies tend to get mostly breastmilk in the first three months, "exclusive breastfeeding past age 3 months and any duration at age 6 months is 57 percent, with notable differences observed by race and ethnicity. Complementary foods and beverages are introduced before age 6 months for a majority of infants." Once the kids hit 12 months, their eating patterns generally mirror that of the US population above the age of 2.

Now let's look at the highlights from each food group...

  • Most Americans consume less than 1 cup of fruit per day
  • Roughly 90% of Americans average about 1.5 cups of vegetables per day, which is also below the minimum recommendation.
  • Approximately 20% of Americans eat more total grains than is recommended each day, yet "Whole Grain intakes are well below recommended levels in all age-sex groups, with only 2 percent of the population meeting recommendations."
  • 88% of Americans consume too little dairy.
  • "Mean intake of Protein Foods is within the range of recommended amounts for most groups except females ages 12 to 19 years and age 70 years and older."

(To get a more detailed look at the answers to this question, check out pages 25-51 of the Evidence on Diet and Health section of the report).

Question 3: What are the Current Patterns of Food and Beverage Intake?

What infants eat varies widely and is largely dependent on breastfeeding practices. According to the committee's report, "Patterns of food group intakes and category sources of food groups among those ages 12 to 24 months are similar to those of the U.S. population ages 2 years and older, although intake of Dairy is higher than in older Americans."

Fifty to sixty percent of total energy intake for people age 2 and up comes from mixed dishes, snacks and sweets, and drinks. In fact, "Beverages account for approximately 15 to 18 percent of total energy intake for Americans ages 2 years and older and for 30 to 60 percent of total added sugars intake."

(To get a more detailed look at the answers to this question, check out pages 52-61 of the Evidence on Diet and Health section of the report).

Question 4: Which nutrients present a substantial public health concern because of underconsumption or overconsumption?

Americans (age 1+) tend to underconsume...

  • Calcium
  • Dietary fiber
  • Potassium
  • Vitamin D

That same group also tends to overconsume...

  • Added sugars
  • Saturated fat
  • Sodium

Further, "The following food components are underconsumed by all Americans ages 1 year and older but do not appear to pose a public health concern, given the present lack of adverse clinical and health outcome data: vitamins A, C, E, and K; magnesium; and choline."

Now let's get more specific. Older infants, women between the ages of 12 and 19, and premenopausal women (between the ages of 20 and 49) do not appear to be consuming enough iron, while many pregnant and lactating women aren't getting enough iron or iodine. The report also states "folate/folic acid should remain of concern among premenopausal women in the first trimester of pregnancy." There is also concern about the proper nutrition for infants. According to the report, "Proposed nutrients or food components that pose public health challenges for all infants, based on low estimated mean nutrient intakes." There are a whole host of other nutrients of concern that have less of a health impact, but for now they don't require big dietary policy changes so much as continued monitoring.

(To get a more detailed look at the answers to this question, check out pages 61-77 of the Evidence on Diet and Health section of the report).

Question 5: How Does Dietary Intake, Particularly Dietary Patterns, Track Across Life Stages, from the Introduction of Foods, Into Childhood, and Through Older Adulthood?

Honestly, for this question, the conclusion statement supplies the best overview of this section, so I'm going to present it in its entirety here:

"Diet quality is higher among young children and older adults than other life stages but does not align with existing dietary guidance. Food category sources of food groups and nutrients differ across life-stage groups. Fluid milk as a beverage decreases starting in early childhood, while the intake of sweetened beverages increases. Fruit and vegetable intakes decline through adolescence and adulthood but increase among older adults. Intakes of burgers and sandwiches contribute to most food groups, nutrients, and food components that fall outside of recommended ranges."

(To get a more detailed look at the answers to this question, check out pages 77-81 of the Evidence on Diet and Health section of the report).

And that brings us to the end of the section on questions. But we're not done yet!

Next up in this section is the discussion, which reviews the key observations of the beginning of part D. The discussion section addresses the shape of the dietary landscape over time, new findings for infants and toddlers, dietary patterns through the entire lifespan, a closer look at the relationship between dietary patterns and food security, and the keys to "ensuring lifelong healthy dietary choices." You can find all the details of this section on pages 81-89 of the Evidence on Diet and Health portion of the report.

Now let's move on to the final section, the summary. This report re-emphasizes "Diet is a modifiable factor that is critically relevant to the primary and secondary prevention of most non-communicable chronic diseases that are the leading causes of disability and death affecting Americans. Dietary intake also is an important determinant of body weight and risk of overweight and obesity. Development of overweight and obesity begin early in life and trigger development of the risk factors that such as hypertension, elevated blood glucose, insulin resistance and dyslipidemia that remain public health problems in all age groups."

From there, the summary outlines the revelation that each life stage has unique implications for both dietary patterns and disease risk. For a closer look at each individual stage, check out pages 89-92 of the Evidence on Diet and Health portion of the report.

And there you have it -- an overview of the first chapter of Evidence on Diet and Health: Current Dietary Intakes Through the Life Course.

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Published on Categories dietary guidelines, nutrition, prevention, food and health, weight control, nutrition education resources, kids, nutrition basicTags , , , , , , ,