Scientific Report of the 2015 Dietary Guidelines Advisory Committee

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Part D. Chapter 1: Food and Nutrient Intakes, and Health: Current Status and Trends - Continued

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Nutrient Intake and Nutrients of Concern

An overarching premise of the DGAC is that that the Dietary Guidelines for Americans should provide food-based guidance for obtaining the nutrients needed for optimal reproductive health, growth and development, healthy aging, and well-being across the lifespan (ages 2 years and older). Specific nutrient intake requirements are established for each sex and life-stage group by the Food and Nutrition Board of the Institute of Medicine7 and as such, this DGAC report did not reevaluate IOM recommendations or make independent specific nutrient recommendations. Rather, the DGAC reviewed nutrient intake and biochemical measures of nutritional status and potential nutrient-related health outcomes to identify “shortfall nutrients” and “overconsumed nutrients”, and then determined whether these nutrients should be designated as “nutrients of public health concern.”

“Shortfall nutrients” are those that may be underconsumed either across the population or in specific groups relative to IOM-based standards, such as the Estimated Average Requirement (EAR) or the Adequate Intake (AI). The EAR is the best measure of population adequacy of nutrient intake as is it is “the average daily intake level estimated to meet the requirement of half of the healthy individuals in a particular life stage and gender group.”7 p.3 The EAR is used to estimate the prevalence of inadequate intakes within a group. The AI is “a recommended average daily nutrient intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate—used when an RDA cannot be determined.”7 p.3 A high prevalence of inadequate intake either across the U.S. population or in specific groups constitutes a shortfall nutrient.

Overconsumed nutrients are those that may be overconsumed either across the population or in specific groups related to IOM-based standards such as the Tolerable Upper Limit of Intake (UL) or other expert group standards. A high prevalence of excess intake either across the U.S. population or in specific group constitutes an overconsumed nutrient.

“Nutrients of concern” are those nutrients that may pose a substantial public health concern and the DGAC divided them into two categories—those of concern due to overconsumption and those of concern due to underconsumption. To be identified as a nutrient of concern, the DGAC used the totality of evidence, evaluating data on nutrient intake and corroborating it with biochemical markers of nutritional status, where available, and evidence for associations with health outcomes to establish nutrients of concern.

Designation as a nutrient of concern for either under- or overconsumption is intended to communicate some level of risk for which the U.S. population may need to modify eating habits. Dietary guidance can then be formulated to assist individuals in increasing or decreasing nutrients that are under- or overconsumed.

Question 1: What are current consumption patterns of nutrients from foods and beverages by the U.S. population?

Source of evidence: Data analysis

Conclusion

Nutrient intake data from a representative sample of the U.S. population ages 2 years and older indicate that: vitamin A, vitamin D, vitamin E, folate, vitamin C, calcium, and magnesium are underconsumed relative to the EAR. Iron is under-consumed by adolescent and premenopausal females, including women who are pregnant. Potassium and fiber are underconsumed relative to the AI. Sodium and saturated fat are overconsumed relative to the UL or other standards for maximal intake.

Implications

A dietary pattern emphasizing a variety of nutrient-dense foods will help shift individual and population consumption toward recommended intake levels for nutrients of public health concern.

The U.S. population should increase consumption of foods rich in vitamin A, vitamin D, vitamin E, folate, vitamin C, calcium, and magnesium. Adolescent and premenopausal females should increase consumption of foods rich in iron. Heme iron from lean meats is highly bioavailable, hence, an excellent source.8 A diet emphasizing a variety of nutrient-dense foods will help shift consumption toward the recommended intake levels of these shortfall nutrients. The U.S. population should increase consumption of foods rich in potassium and fiber. A diet emphasizing a variety of nutrient-dense foods will help ensure optimal intake of these shortfall nutrients. In particular, fruit, vegetables and whole grains are excellent sources of vitamin A, C, folate, fiber, magnesium and potassium. The U.S. population should make concerted and focused efforts to decrease consumption of sodium and saturated fat.

The USDA Food Patterns provide guidance for consumption of a nutrient-dense, energy-balanced diet. Implementation of eating a healthy diet that is energy balanced while providing sufficient intake of shortfall nutrients without exceeding intake of overconsumed nutrients can be achieved through a variety of successful behavioral approaches as described in Part D. Chapter 3: Individual Diet and Physical Activity Behavior Change. Environmental and policy approaches are also important in helping the U.S. population achieve a healthy diet (see also Part D. Chapter 4: Food Environment and Settings). Federal nutrition assistance programs are a key aspect of providing critical nutrients for growth, development and long-term health for children, those with limited income and older Americans.

Review of the Evidence

To determine nutritional adequacy, the DGAC used 2007-2010 NHANES/WWEIA data to examine the intake distributions for 11 vitamins (vitamin A, vitamin B6, vitamin B12, vitamin C, vitamin D, vitamin E, vitamin K, folate, thiamin, niacin, and riboflavin), nine minerals (calcium, copper, iron, magnesium, phosphorous, potassium, selenium, sodium, and zinc), energy, macronutrients (total fat, saturated fat, polyunsaturated fat [including 18:2 and 18:3], protein, carbohydrate), and other compounds or components (fiber, carotenoids [alpha-carotene, beta-carotene, lycopene, lutein + zeaxanthin], caffeine, cholesterol, and choline) (see Appendix E-2.1: Usual intake distributions, 2007-2010, by age/sex groups [PDF - 1 MB]). The DGAC compared the intake estimates across the population age distribution to the Dietary Reference Intakes. The committee used data from foods and beverages as well as foods and beverages plus dietary supplements when supplement data were available. For nutrients with an EAR, the DGAC considered shortfall nutrients to be those where a substantial proportion of either the total population or specific age and sex subgroups had intake estimates below the EAR. Although multiple approaches can be used to estimate the prevalence of nutrient inadequacy in a population, the DGAC used the EAR cut point method.7 Figure D1.1 shows the percent of the U.S. population with usual intakes below the EAR. From Figure D1.1, the DGAC determined that vitamin D, vitamin E, magnesium, calcium, vitamin A and vitamin C were shortfall nutrients and that there may be a high prevalence of inadequate dietary intake of these nutrients.

Of the nutrients with an AI (vitamin K, choline, dietary fiber, and potassium), the DGAC determined that a low proportion of the population had fiber and potassium intakes above the AI and so potassium and fiber were therefore considered to be underconsumed (Figure D1.2).

Sodium and saturated fat were examined as potentially overconsumed nutrients in relation to the UL (for sodium), and the maximum level from the 2010 Dietary Guidelines of less than 10 percent of calories from saturated fat (for saturated fat). From 63 percent to 91 percent of females and 81 percent to 97 percent of males consumed more than the UL for sodium (Figure D1.3). From 67 percent to 92 percent of females and from 57 percent to 84 percent of males consumed more than 10 percent of calories from saturated fat (Figure D1.4). Therefore, sodium and saturated fat were both determined to be overconsumed by the U.S. population (see Appendix E-2.1: Usual intake distributions, 2007-2010, by age/sex groups [PDf - 1 MB] and Appendix E-2.2: Usual intake distributions as a percent of energy for fatty acids and macronutrients, 2007-2010, by age/sex groups [PDF - 386 KB]).

The DGAC examined population intakes of specific nutrients by age, sex, race/ethnicity, pregnancy status, and acculturation status.

Age and Sex

In addition to the age groups shown in Figures D1.1 and D1.2, the DGAC was interested in understanding the intake of shortfall nutrients in older adults (71 to 79 years and 80 years and older). Calcium intake from foods and beverages did not meet the EAR for older persons, where 71 percent of males and 81 percent of females ages 71 years and older had intakes below the EAR. For these analyses calcium from dietary supplements was also considered. When total intake of foods + beverage + dietary supplements containing calcium was considered, then the proportion of the older adults below the EAR improved to 55 percent for men and 49 percent for women over the age of 71 years. For vitamin D intakes from food and beverages only, about 93 percent of older males and more than 97 percent of older females had intakes below the EAR. Similar to the findings for calcium, intakes improved when considering total intake from foods and beverages plus dietary supplements. The proportions of older adult below the EAR dropped to 52 percent for both males and females older than 71 years.

Fiber was a shortfall nutrient for older adults, where only 4 percent of men and 13 percent of women had a dietary intake of fiber above the AI. Potassium also was a shortfall nutrient for both older males and females, where less than 3 percent of both groups had intakes above the AI. Use of dietary supplements containing potassium did not change the proportion of the older adults with intakes above the AI.

Protein was not identified as a shortfall nutrient for the overall older adult population but it should be noted that 6 percent of men older than 80 years and 11 percent of women older than 80 years old had protein intakes that were below the protein EAR (g/kg/body weight).

The sample size for the older participants in WWEIA 2007-2010 is small compared to other age groupings in the survey sample and despite the excellent population weights used in the WWEIA dataset, the estimates should be viewed with caution because of the limited sample (see Appendix E-2.3 Usual nutrient intakes for individuals age 71 years and older).

Race/Ethnicity

The DGAC examined the shortfall nutrients by race/ethnicity using the following groups: non-Hispanic white, non-Hispanic Black, Mexican-American, and all Hispanic combined (other race/ethnic subgroups not available). For certain shortfall nutrients, non-Hispanic whites have the highest intakes. These include vitamin A, vitamin E, magnesium, folate, iron, potassium, vitamin D, and calcium. Mexican-Americans have the highest intakes of fiber, while all Hispanics combined have the highest intakes of vitamin C. Non-Hispanic Blacks have the lowest intake for most of the shortfall nutrients (Table D1.1). We note that evaluation of intakes relative to the EAR or AI are the most appropriate for assessment of populations, instead of the mean intakes, but for the race/ethnicity groups, only the mean data are available.

Pregnancy

Many of the shortfall nutrients in the general population also were shortfall nutrients among women who are pregnant. Among this group, 26 percent were below the EAR for vitamin A intake and 30 percent had vitamin C intakes below the EAR. For vitamin D, 90 percent had intakes below the EAR and for vitamin E, 94 percent had intakes below the EAR. Calcium intake was also low, where 24 percent had intakes below the EAR, and for folate, 29 percent had intakes below the EAR. Notably, 96 percent of women who were pregnant had iron intakes below the EAR (Table D1.2 and Appendix E-2.4: Usual intake distributions, 2007-2010, for pregnant and non-pregnant women in the U.S. ages 19-50 years).

Fiber was a shortfall nutrient for women who were pregnant, as only 8 percent had fiber intakes above the AI. For potassium only 3 percent had intakes above the AI (Table D1.2).

It is important to note that the sample size for women who were pregnant in WWEIA 2007-2010 is very small (n=133 respondents), so the estimates should be interpreted with caution and the generalizability of the data to all women in the United States who were pregnant is limited.

Acculturation

The U.S. population is highly diverse in terms of race, ethnicity, and cultural origin. Many people immigrate to the United States from all over the world and each comes with distinct dietary habits and cultural beliefs about food and food patterns.9 Acculturation is defined as the process by which immigrants adopt the attitudes, values, customs, beliefs, and behaviors of a new culture. Acculturation is the gradual exchange between immigrants’ original attitudes and behavior and those of the host culture. 10 11 The DGAC appreciates that many immigrants have difficulties purchasing and preparing foods familiar to them either because the ingredients are not available or the ingredients may be too expensive. A large and growing body of research suggests that the extent of an individual or family’s acculturation status may be a predictor of dietary intake and that together, diet and acculturation status may influence health status or disease risk.9 10 12 13 For this reason, the DGAC felt it was important to examine dietary intake by acculturation status, particularly for shortfall nutrients and nutrients of concern. Additional information on acculturation and diet appears in Part D. Chapter 3: Individual Diet and Physical Activity Behavior Change.

NHANES collects data on some of the variables that can be used to create an acculturation variable, including whether respondents were born outside the United States in a Spanish-speaking country or born outside the United States in a non-Spanish speaking country, their race/ethnicity, and number of years they have resided in the United States.14 Upon reviewing the data, however, the DGAC found that the sample size was far too small to create meaningful variables to indicate “low acculturation status” or “high acculturation status.” The DGAC views this lack of ability to analyze the WWEIA data by acculturation status as a limitation of the available data. It is a very important area that needs further research, particularly when informing nutrition programs for new residents of the United States.

Food Insecurity Status

Readers are referred to Part D. Chapter 3: Individual Diet and Physical Activity Behavior Change and Part D. Chapter 5: Food Sustainability and Safety for more detailed discussions of food insecurity and food security issues. For this section of the report, the DGAC determined that it was important to evaluate nutrient intake, particularly for the shortfall nutrients by income status, which can be a marker of food insecurity. For these data analyses, we used the standard cutpoints of less than 131 percent of the poverty index, 131 to 185 percent of the poverty index and more than 185 percent of the poverty index and examined calcium, potassium, fiber and vitamin D (Table D1.3). In general, respondents (all ages 2 years and older) from households with higher income (more than 185 percent of the poverty index) had higher intakes of calcium, potassium, fiber, and vitamin D. Notably, in some of the very young age groups (2 to 5 years), intakes of potassium, fiber, and vitamin D were comparable across income groups, while calcium was highest in those coming from households at the 131 to 185 percent of the poverty index ratio. It may be that many of the households of lower income with small children are receiving important benefits from federal nutrition assistance programs, which could be helping to generate comparability in the intake of shortfall nutrients across the income groups.

For additional details on this body of evidence, visit:

Question 2: Of the nutrients that are underconsumed or overconsumed, including over the Tolerable Upper Limit of Intake (UL), which present a substantial public health concern?

Source of evidence: Data analysis

Conclusion

Nutrient intake data, together with nutritional biomarker and health outcomes data indicate that vitamin D, calcium, potassium, and fiber are underconsumed and may pose a public health concern. Iron also is a nutrient of public health concern for adolescent and premenopausal females.

Nutrient intake data, together with nutritional biomarker and health outcomes data indicate that sodium and saturated fat are overconsumed and may pose a public health concern.

Implications

The DGAC recommends that strategies be developed and implemented at both the individual and the population level to improve intake of nutrients of public health concern.

Review of the Evidence

These conclusions were reached using a 3-pronged approach, including analysis of data from What We Eat in America, NHANES dietary survey (2007-2010) (see Appendix E-2.1: Usual intake distributions, 2007-2010, by age/sex groups [PDF - 1 MB]), the Second National Report on Biochemical Indices of Diet and Nutrition in the U.S. Population, Centers for Disease Control and Prevention, 2012,3 and data on the prevalence of health conditions, from the CDC. The DGAC used the totality of evidence from these sources.

Nutrients of Concern for Underconsumption

Vitamin D. Vitamin D is unequivocally essential for skeletal health.15 The 2010 IOM report on Dietary Reference Intakes for calcium and vitamin D15 established new DRIs for vitamin D based on established and consistent evidence for vitamin D’s role in skeletal health. Numerous other functions exist for vitamin D, including its role as a transcription factor for more than 200 genes, roles in apoptosis and cellular proliferation, and a growing body of evidence supporting vitamin D’s role in preventing cancer, cardiovascular disease, and other chronic diseases.16-25

The IOM’s rationale for setting the DRI was limited to vitamin D’s role in skeletal health, as the evidence for the other diseases was not sufficiently mature at the time of the committee’s evidence review. Therefore, any interpretations for vitamin D intake and its classification as a shortfall nutrient and a nutrient of public health concern are restricted to this role in skeletal health. Given the high prevalence of osteoporosis and low bone density, particularly in the older women (see Question 17, on health conditions, below) and due to vitamin D’s critical role in bone health, the Committee determined that vitamin D should be classified as an underconsumed nutrient of public health concern.

Vitamin D can be obtained from the diet by consuming fluid milk and some milk products (e.g., some yogurts), fortified juices, finfish, fortified breakfast cereals and some fortified grain products as well as dietary supplements (Table D1.4 and Appendix E-3.3: Meeting Vitamin D Recommended Intakes in USDA Food Patterns). Vitamin D also is synthesized endogenously through cutaneous exposure to ultraviolet-B sunlight. The primary biomarker to assess vitamin D status is serum/plasma 25(OH)D concentrations. This biomarker represents dietary intake plus endogenous synthesis.

Dietary intake of vitamin D in the United States is low and well below the EAR values (Figure D1.1) for all age and sex groups. In addition, independent evidence of nutrient shortfall comes from data demonstrating low serum/plasma 25-hydroxyvitamin D concentrations from the CDC biomarker data, particularly for young adults (ages 20 to 39 years), middle-aged adults (ages 40 to 59 years), non-Hispanic Blacks and Mexican-Americans (Table D1.5). The correlation of dietary intake with the serum measures of 25-hydroxyvitamin D) is modest. In addition several factors predict serum concentrations of nutrients in addition to dietary intake.19 The DGAC and other expert panels, including the IOM, acknowledge that while numerous variables, including sun exposure and endogenous synthesis, are strong predictors of serum vitamin D status, dietary intake of vitamin D is a critical contributor to vitamin D status.26 27 Further, while there is some degree of unexplained variation in serum/plasma 25-hydroxyvitamin D concentrations, the biomarker is still important for evaluating vitamin D inadequacy. Various statistical approaches have been used to evaluate and confirm population inadequacy using the biomarker data. 28 Of note, the CDC biomarker data reviewed by the DGAC should be interpreted knowing that the NHANES Mobile Examination Clinics do not sample residents of northern climates in winter months due to variable sunshine exposure and the possibility that high levels of sunshine exposure may be overrepresented in NHANES. In other words, higher values in the dataset may be over-represented due to the summer blood draws, when 25-OHD tends to be higher from sun exposure and deficiencies may be under represented. 15 p.471-473

The DGAC’s decision to classify vitamin D as a nutrient of concern is similar to the conclusion reached by the U.S. Food and Drug Administration (FDA), which designated vitamin D as a nutrient of “public health significance” in its recent review of evidence in publishing a Proposed Rule on the Nutrition Facts label.29 In addition, multiple national and international groups, including the American Academy of Pediatrics (AAP),30 the Endocrine Society31 and the National Osteoporosis Foundation 32 have recommended that strategies to achieve the RDA or higher levels of vitamin D intake could include consumption of fortified foods, broadening the range of dairy products that are fortified, and consideration, in some cases, of the use of a vitamin D supplement or a multivitamin including vitamin D. Such a use is especially appropriate where sunshine exposure is more limited due to climate or sunblock use.

Calcium. Calcium plays a major role in skeletal health and also is essential for proper functioning of the circulatory system, nerve transmission, muscle contractility, cell signaling pathways, and vascular integrity.15 Dietary calcium is obtained from fluid milk and milk products, fortified juices, and some plant foods, including soy and soy products and vegetables (see Table D1.6 and Appendix E-3.2: Food Group Contributions). However, the bioavailability of calcium from plant foods is lower than from animal foods, such as dairy.

The DGAC reviewed the dietary intake data from WWEIA. Intakes of calcium were often far below the EAR, especially among adolescent girls and adults (Figure D1.1). Even though a reliable biomarker for calcium does not exist, because of its strong link to health outcomes and the risks associated with osteoporosis (see Question 17 on health conditions, below), the DGAC designated calcium as a nutrient of public health concern for underconsumption. In addition, the DGAC also notes that calcium is an underconsumed nutrient of public health concern among pregnant women. This conclusion concurs with the FDA’s review that designated calcium as a nutrient of “public health significance” in its recent review of evidence in publishing a Proposed Rule on the Nutrition Facts label.29

Strategies to improve calcium intake include increased dairy or fortified products that are important sources of calcium. Concern about the safety of calcium supplements and a relative lack of data about the health benefits of such supplements limit recommendations to use supplementation as a strategy to meet the RDA for calcium, compared to using fortified foods.

The subgroups of particular concern with regard to intake are preadolescent and adolescent females, pregnant females, and middle aged and older females (see Question 1, above).

Potassium. Potassium is the major intracellular cation and it plays critical roles in muscle function, cardiac function, and regulation of blood pressure. Potassium adequacy is also critical for health, as deficiency adversely affects numerous organ systems including the musculoskeletal, renal, and cardiovascular systems. The primary biomarker to assess potassium intake is urinary potassium, and these data are not available in the CDC biomarker dataset. The DGAC designated potassium as a nutrient of public health concern due to its general under consumption relative to the AI across the U.S. population and its association with hypertension and cardiovascular diseases, two common adverse diet-related health outcomes in the United States (see Question 17 on health conditions, below). This conclusion concurs with the FDA’s review that designated potassium as a nutrient of “public health significance” in its recent review of evidence in publishing a Proposed Rule on the Nutrition Facts label.29 Even though underconsumption was evident across the population (see Question 1, above), there is a particular concern for middle-aged and older adults, who are at increased risk for cardiovascular diseases (see Question 17). Fruits, vegetables, and legumes are all important sources of potassium (Table D1.7).

Fiber. Dietary fibers are non-digestible carbohydrates, primarily from plant foods, such as whole grains, legumes, fruits and vegetables (Table D1.8). The most important and well-recognized role for fiber is in colonic health and maintenance of proper laxation, but a growing body of evidence also suggests that fiber may play a role in preventing coronary heart disease, colorectal and other cancers, type 2 diabetes, and obesity.33 The AI for fiber is based on an intake level associated with the greatest reduction in the risk of coronary heart disease. There are no available biomarkers for fiber intake, so the designation as a nutrient of public health concern is based on the very low dietary intakes across all sectors of the U.S. population and its important contribution to health. Because the average intake levels of dietary fiber are half the recommended levels, achieving the recommendation requires selecting high-fiber cereals and whole grains and -meeting current recommendations for fruits and vegetables.

Iron. Iron is an essential mineral whose primary function is to transport oxygen in the blood. Inadequate iron status in the form of iron deficiency anemia leads to poor growth and development and the potential for cognitive deficits in children. Excellent sources of heme iron include red meats, enriched cereal grains, and fortified breakfast cereals (Table D1.9). Dietary intake estimates, together with the CDC nutritional biomarker data indicate that iron is a nutrient of concern for children, premenopausal females, and during pregnancy. Among women who are pregnant, 96 percent are below the EAR for iron intake. Serum ferritin is the biochemical marker used by NHANES and the CDC to evaluate iron status in the U.S. population. These data show that children and women of childbearing age are at risk of iron deficiency anemia. Risk of iron deficiency anemia also is higher among Mexican-American and non-Hispanic Black women than among non-Hispanic white women.3 Taken together, the DGAC concluded that iron was an underconsumed nutrient of public health concern for adolescent and premenopausal women and women who are pregnant. This conclusion concurs with the FDA’s designated iron as a nutrient of “public health significance” in its recent review of evidence in publishing a Proposed Rule on the Nutrition Facts label.29

Nutrients of concern for overconsumption

Sodium. Sodium is the major cation in extracellular fluid that maintains extracelluar fluid volume and plasma volume. It also functions in membrane potential activation and active transport of molecules across cell membranes. In excess, sodium is associated with several adverse health events, particularly hypertension.34 The DGAC treated sodium as a cross-cutting topic for dietary intake and health outcomes, and a sodium working group was convened. Details on sodium, including dietary sources and health outcomes-related data are found in Part D. Chapter 6: Cross-Cutting Topics of Public Health Importance). Current sodium intakes of the U.S. population far exceed the UL for all age and sex groups (Figure D1.3). Due to the critical link of sodium intake to health and that intake exceed recommendations, sodium was designated as a nutrient of public health concern for overconsumption across the entire U.S. population.

Saturated fat. The DGAC used the 2013 American Heart Association/American College of Cardiology (AHA/ACC) report on lifestyle management to reduce CVD risk2 for its evaluation of saturated fat intake. The DGAC concurred with the AHA/ACC report that saturated fat intake exceeds current recommendations in the United States and that lower levels of consumption would further reduce the population level risk of CVD. The DGAC also convened a working group on saturated fat (see Part D. Chapter 6: Cross-Cutting Topics of Public Health Importance for details). In addition, the DGAC conducted food pattern modeling to demonstrate the dietary changes that would be necessary to have diets with various levels of saturated fat as a percent of total energy (see USDA Food Patterns Modeling Report in Appendix E-3.5: Reducing Saturated Fats in the USDA Food Patterns). It is important to note that the median intake of saturated fat in the United States was 11.1 percent of total energy for all age groups in the 2007-2010 WWEIA data. However, a large majority (71 percent) of the total population consumed more than 10 percent of calories from saturated fat, with a range by age group from 57 percent to 92 percent (Figure D1.4). Further, 65 percent to 69 percent of the age groups at highest risk of CVD (males and females older than age 50 years) had intakes more than 10 percent of total calories were from saturated fat, the DGAC concluded that the U.S. population should continue to monitor saturated fat intake. Saturated fat is still a nutrient of concern for overconsumption, particularly for those older than the age of 50 years.

Cholesterol. Previously, the Dietary Guidelines for Americans recommended that cholesterol intake be limited to no more than 300 mg/day. The 2015 DGAC will not bring forward this recommendation because available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol, consistent with the conclusions of the AHA/ACC report.2 35 Cholesterol is not a nutrient of concern for overconsumption.

For additional details on this body of evidence, visit:

Question 3: Is there evidence of overconsumption of any micronutrients from consumption of fortified foods and supplements?

Source of evidence: Data analysis

Conclusion

Dietary patterns among Americans, including typical use of fortified foods, rarely lead to overconsumption of folate, calcium, iron, or vitamin D. However, each of these nutrients, as well as other nutrients, are overconsumed in some supplement users, especially those taking high-dose supplements.

Implications

The public may safely use dietary supplements containing RDA level of nutrients, so long as total intake from diet plus supplements does not exceed the UL. Use of products with high doses of nutrients, such that total intake exceeds the UL, should be discussed with a Registered Dietitian or other qualified health care provider.

Supplement users should seek guidance about factors such as whether the amount of nutrients in supplements exceeds the UL for those nutrients. Monitoring of dietary patterns in supplement users should continue to be done, with attention paid to the highest risk groups, such as children and women who are pregnant.

Review of the Evidence

These conclusions were based on analysis of usual intake data for selected nutrients from foods and supplements from WWEIA, NHANES dietary survey (2007-2010) (see Appendix E-2.5: Usual intake distributions for supplement users for folate, folic acid, vitamin D, calcium, and iron, 2007-2010, by age/sex groups [PDF - 386 KB] and Appendix E-2.6: Usual intake distributions for non-supplement users for folate, folic acid, vitamin D, calcium, and iron, 2007-2010, by age/sex groups [PDF - 752 KB]). Nutrients were selected if the DGAC had identified them as a shortfall nutrient and if supplemental intake data were available in WWEIA (Figure D1.5). When possible the total nutrient exposure was considered (food + supplements). The overconsumed nutrients (saturated fat and sodium) are not contained in most dietary supplements so that overconsumed nutrients were not considered for this question.

Folate. The use of supplemental folic acid exceeds the established UL in a small proportion of children, especially those younger than age 9 years. However, this UL is not based on clinical toxicity data in this population and exceeding the UL is primarily associated with supplement use.36 The risk associated with usual folate intakes among children in the United States is considered low, but caution should be used in advising supplements for children younger than age 9 years.

Calcium. Dietary calcium intake greater than 2000 mg/day (UL) are seen in up to about 20 percent of females, and 15 percent of adult males older than age 50 years. These high intakes are driven primarily by a historical perspective that very high calcium supplement usage may decrease the risk of osteoporosis. Concern exists about the safety of such high intakes and the possible association with CVD risk and little, if any, current evidence supports intakes of calcium above the UL for the purpose of decreasing osteoporosis.15 Of note, the World Health Organization recommends high dose calcium supplementation (1.5-2 g/day) to prevent hypertensive disorders of pregnancy.37 This recommendation is not widely followed among low-risk women in the United States. However, use of calcium supplements does not appear to pose a health risk related to overconsumption of calcium.37

Iron. In adults of all ages, a small proportion of iron supplement users have intakes above the UL. Concerns related both to cardiovascular health and oxidant damage exist, but are not well-defined. Iron supplementation is very common during early childhood and pregnancy, but is unlikely to pose a health risk.8

Vitamin D. Overconsumption of vitamin D occurs when individuals take high dose supplements, usually over a long period of time.15 The UL of 4000 IU/day is commonly exceeded by individuals with or without the guidance of a physician.15 In general, it is unlikely that most supplement users, who limit themselves to 10,000 IU/day or less, will have any evidence of toxicity, but a greater risk may exist among some groups, including small children. Those who take high dose supplements often have their serum/plasma 25-hydroxyvitamin D concentrations monitored and this can be helpful although no clearly toxic level of 25-hydroxyvitamin D in the blood is known. Overall, the population risk of overconsumption of vitamin D leading to toxic effects, including hypercalcemia or other clinical symptoms, is uncommon.38

For additional details on this body of evidence, visit:

Question 4: What is the level of caffeine intake derived from foods and beverages on the basis of Institute of Medicine (IOM) Dietary Reference Intakes age and sex categories in the U.S. population?

Source of evidence: Data analysis

Conclusion

In general, intakes of caffeine do not exceed what is currently considered safe levels in any age group. Some young adults may have moderately high intakes. There is less certainty about the safe level of intake in children and adolescents. However, routine consumption patterns do not suggest that excessive intakes are common in these groups.

Implications

The public may safely consume caffeine-containing beverages, such as coffee and tea. However, children, adolescents, and women who are pregnant or considering pregnancy should not consume very high levels of caffeine from beverages or supplements (e.g., energy shots, fortified foods).

Monitoring of caffeine intake should be continued with special attention to high-risk groups, including children and women who are pregnant. Families should monitor caffeine intake in children, and high-dose caffeine supplementations should not be used.

For additional details on caffeine safety please see Part D. Chapter 5: Food Sustainability and Safety.

Review of the Evidence

These conclusions were reached based on analysis of usual intake data from the WWEIA, NHANES dietary survey (2007-2010). Data on intakes of caffeine show that intakes in adults (Figure D1.6) peak at ages 31 to 70 years, and that younger adults (ages 19 to 30 years), older adults (71 years and older), have lower intakes. Relatively few individuals (less than 10 percent) have intakes above 400 mg/day (see Appendix E-2.1: Usual intake distributions, 2007-2010, by age/sex groups [PDF - 1 MB]), which is a level set as a moderate intake by some groups, including Health Canada.

In children, caffeine intakes increase with age (Figure D1.7) with median intakes remaining below 100 mg/day in adolescents (14 to 18 years). Recommended intakes from Health Canada of no more than 2.5 mg/kg/day, or about 85 mg/day total in children ages 10 to 12 years 39 are not exceeded by most children and adolescents although recent data indicates that as many as 10 percent of children and adolescents ages 12 to 19 years exceed this intake level.40 These data demonstrate that caregivers should monitor caffeine intake in children and exercise caution with respect to time-dependent changes in caffeine intake.

For additional details on this body of evidence, visit:

Question 5: How well do updated USDA Food Patternsv meet IOM Dietary Reference Intakes and 2010 Dietary Guidelines recommendations? How do the recommended amounts of food groups compare to current distributions of usual intakes for the U.S. population?

Source of evidence: Food Pattern Modeling

Conclusion

USDA Food Patterns across a broad range of ages and energy intake meet most goals for nutrient adequacy. The nutrients of public health concern for which the patterns do not meet recommendations are potassium and vitamin D. Recommended amounts of food groups and their component subgroups fall within the broad range of usual food group intake distributions for the U.S. population.

Implications

The USDA Food Patterns provide guidance for consuming a nutrient-dense, energy-balanced diet. To achieve nutrient adequacy, the U.S. population should be advised to consume dietary patterns consistent with the USDA Food Patterns.

Continued vigilance is needed to ensure that food intake patterns meet but do not exceed DRI targets in all age groups. The Patterns meet recommended intake levels or limits for almost all nutrients, including the following nutrients of concern: calcium, fiber, iron, sodium, and saturated fat. Two nutrients of concern (potassium and vitamin D) are not provided in recommended levels by the Patterns. Therefore, potassium and vitamin D intakes require assessment both of individual intake and population intake patterns of foods or supplements to ensure that needs for physiological functioning are met. Meeting the needs for these nutrients may require careful attention to excellent natural sources, food enriched or fortified with the nutrients, or, in some cases, consideration of supplements.

Following the recommended food intake pattern increases intakes of whole grains, vegetables, fruits, and fat-free/low fat dairy and thus increases the likelihood of meeting recommendations for these food groups while decreasing intake of the food components refined grains, solid fats, and added sugars. Following the recommended pattern also decreases intake of the nutrients sodium and saturated fat.

In some situations, specific foods or dietary supplements may be used to increase underconsumed nutrient intakes not met through the USDA Food Patterns.

Review of the Evidence

These conclusions were reached based on the results of the Food Pattern Modeling Report on Adequacy of the USDA Food Patterns. The USDA Food Patterns are intended to represent the types and amounts of foods that will provide nutrients sufficient to meet IOM nutrient recommendations and Dietary Guidelines for Americans recommendations. The Food Patterns are updated every 5 years during the deliberations of the Dietary Guidelines Advisory Committee, and are presented to the Committee for their assessment of the Food Patterns’ adequacy. As part of the update, amounts recommended from each food group may be modified to reach all or most of the specified goals. In addition, the amounts from each food group are compared to usual dietary intake patterns of the U.S. population, and are kept within the normal range of consumption. The current analysis, using the 2010 USDA Food Patterns as a baseline, found that the recommended amounts of each food group met almost all nutrient goals and were within the normal range of consumption. Therefore, no updates to the food group amounts from 2010 were needed.

As shown in Figure D1.8, for many nutrients, amounts of a nutrient in the patterns are well above the RDA or AI. Protein, phosphorus, zinc, copper, selenium, manganese, vitamin C, thiamin, riboflavin, niacin, vitamin K, folate, vitamin B6, and vitamin B12 are above the goal amounts for all age/sex groups.

In contrast, some nutrients are just above the RDA or AI, or marginally below (90 to 100%) goal amounts for several age/sex groups. These include calcium, iron, and magnesium. The percents of the RDA shown in Figure D1.8 are for the lowest calorie level assigned to these age/sex groups—the level applicable for a sedentary/less active physical activity level.

The nutrients for which adequacy goals are not met in almost all patterns are potassium, vitamin D, vitamin E, and choline. Due to the new higher RDA for vitamin D that was recommended by the 2011 Committee to Review Dietary Reference Intakes for vitamin D and calcium,15 amounts in the patterns are a much smaller percentage of the RDA than previously, and no pattern meets the EAR for vitamin D. To determine if vitamin D recommendations could be met while following the food group recommendations of the USDA Food Patterns, thorough, careful selection of specific foods within each food group, an additional modeling analysis was conducted and reported below (see Question 6).

The USDA Food Intake patterns provide a healthy pattern of food choices and to accomplish this, these patterns deviate from typical food intakes in a number of ways. To ensure that the patterns do not deviate too far beyond the range of what the U.S. population could feasibly consume, the recommended intake amounts in the patterns from each food group or subgroup plus oils were compared to the median and either the 5th or 95th percentile of usual intakes of the population, from WWEIA/NHANES 2007-2010.41 Table A6 of the Adequacy of the USDA Food Patterns Modeling Report (see Appendix E-3.1, Table A6) shows the comparison of food group recommended intakes to median and 95th percentile intakes.

For underconsumed food groups, such as fruits and vegetables, recommended amounts in the patterns are generally between the median and 95th percentiles of usual intakes. (see Appendix E-3.1: Adequacy of the USDA Food Patterns, Table A6) This indicates that the Food Patterns recommend amounts within the broad intake range for the population. However, for some specific food groups and some age/sex groups, such as vegetables for males ages 14 to 18 years, food group amounts in the Patterns are somewhat above the 95th percentile of usual intake. One exception to this is whole grain recommendations in the Patterns, which are well above the 95th percentile of usual intakes for all age/sex groups. Conversely, refined grain recommendations in the patterns are very low compared to usual intakes—about the 5th percentile of intake for most age/sex groups. This indicates that a major shift from refined to whole grains is needed in order to meet recommendations.

For Food Pattern components that are overconsumed, the limits in the patterns for maximum solid fat and added sugars (see Questions 7 and 8 for more information on solid fats and added sugars) also are very low compared to usual intake amounts—at approximately the 5th percentile of usual intakes for most age/sex groups, and less than the 5th percentile of usual intakes for boys and girls ages 2 to 13 years. (see Appendix E-3.1: Adequacy of the USDA Food Patterns, Table A6)

An additional modeling analysis was conducted to answer the questions: How well do the USDA Food Patterns meet the nutritional needs of children ages 2 to 5 years and how do the recommended amounts compare to their current intakes? Given the relatively small empty calorie limit for this age group, how much flexibility is possible in food choices? (see Appendix E-3.4: USDA Food Patterns—Adequacy for Young Children)

The nutritional needs and the diets of young children are different in some important ways from the nutritional needs and diets of older children and adults. Therefore, this modeling analysis focused on the adequacy of the Patterns for young children, given these differences. Nutrient profiles for the Dairy and Fruit groups were adjusted to better reflect the food choices within these groups of young children. The adjusted Dairy group nutrient profile for young children is based on 70 percent fluid milk, 25 percent cheese, 3.5 percent yogurt, and 1.5 percent soymilk. In contrast, the profile for the overall population is based on 51 percent fluid milk, 45 percent cheese, 2.5 percent yogurt, and 1.5 percent soymilk. In addition, 1 percent milk rather than fat-free milk was used as the representative food for fluid milk. The adjusted Fruit group nutrient profile for young children is based on 42 percent fruit juice and 58 percent whole fruit. In contrast, overall population intake is about 33 percent juice and 67 percent whole fruit. With these adjustments, the adequacy of the Patterns did not change, but amounts of potassium, vitamins D, A, C, and folate increased slightly, and sodium decreased slightly. The amounts recommended in the USDA Food Patterns fall within the broad range of usual intakes by this age group for most food groups and subgroups (see Appendix E-3.1: Adequacy of the USDA Food Patterns, Table A6).

In addition, the young children’s nutrient profiles were higher in energy, mainly due to the use of 1 percent rather than fat-free milk. Therefore, the amount of calories that could be allowed from solid fats and added sugars was adjusted down to keep the Patterns isocaloric. This resulted in limited flexibility in food choices when following the Patterns, especially for children ages 4 and 5 years for whom 2½ cup equivalents (cup eqs) from the Dairy group is recommended (the Patterns for children ages 2 and 3 years recommend 2 cup eqs). Options tested to increase flexibility in food choices included a small reduction of 1/2 ounce eq in the amount of Protein Foods, or a change from 1 percent milk to fat-free milk at 4 years of age. These changes did not result in lower nutrient adequacy levels.

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Question 6: Can vitamin D Estimated Average Requirements and/or Recommended Dietary Allowances be met with careful food choices following recommended amounts from each food group in the USDA Food Patterns? How restricted would food choices be, and how much of the vitamin D would need to come from fortified dairy and other food products?

Source of evidence: Food Pattern Modeling

Conclusion

Through the use of a diet rich in seafood and fortified foods, EAR, but not RDA, levels of vitamin D can be achieved. Additional fortification or supplementation strategies would be needed to reach RDA levels of vitamin D intake consistently, especially in individuals with low intakes of fish/seafood or fortified dairy foods, other fortified foods (e.g. breakfast cereals) and beverages.

Implications

Diet is an important aspect of achieving vitamin D intake targets. The U.S. population should be encouraged to choose foods and beverages fortified with vitamin D. When needed, supplementation can be considered to achieve RDA intakes of vitamin D.

Review of the Evidence

These conclusions were reached based on the results of the Food Pattern Modeling Report titled “Meeting Vitamin D Recommended Intakes in USDA Food Patterns” (see Appendix E-3.3). It may be difficult for individuals to reach the RDA intake of vitamin D from food, including food as it is currently fortified in the United States. The RDA was established by the Institute of Medicine on the assumption of minimal or no sunshine exposure. This was done even though the majority (up to 80 to 90 percent in some parts of the United States) of vitamin D in the body is derived from conversion by solar radiation of pre-vitamin D in the skin. However, during the winter, in much of the United States, this conversion is minimal and furthermore, recommendations for sunscreen use have limited the degree to which one can safely ensure sunshine exposure as a source of vitamin D.

Vitamin D exposure, and likely status, is assessed generally through serum/plasma 25-hydroxyvitamin D concentrations. However, this test is not recommended for routine screening of the entire population30-32 42 43 due to costs and challenges in obtaining measurements throughout the year and interpreting results in populations, including those who are obese. Because many non-screened individuals will still need to reach the RDA for vitamin D, supplement use may be considered for this purpose.

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