Scientific Report of the 2015 Dietary Guidelines Advisory Committee

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Part D. Chapter 2: Dietary Patterns, Foods and Nutrients, and Health Outcomes - Continued

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Chapter Summary

The dietary patterns approach captures the relationship between the overall diet and its constituent foods, beverages, and nutrients in relationship to outcomes of interest. Numerous dietary patterns were identified, with the most common ones defined using indices or scores such as the HEI-2010, the AHEI-2010, or various Mediterranean-style dietary patterns, the DASH pattern, vegetarian patterns, and data-driven approaches.

The Committee’s examination of the association between dietary patterns and various health outcomes revealed remarkable consistency in the findings and implications that are noteworthy. When looking at the dietary pattern conclusion statements across the various health outcomes, certain characteristics of the diet were consistently identified (see Table D2.3). Common characteristics of dietary patterns associated with positive health outcomes include higher intake of vegetables, fruits, whole grains, low- or non-fat dairy, seafood, legumes, and nuts; moderate intake of alcohol (among adults); lower consumption of red and processed meat, and low intake of sugar-sweetened foods and drinks, and refined grains. Vegetables and fruits are the only characteristics of the diet that were consistently identified in every conclusion statement across the health outcomes. Whole grains were identified slightly less consistently compared to vegetables and fruits, but were identified in every conclusion with moderate to strong evidence. For studies with limited evidence, grains were not as consistently defined and/or they were not identified as a key characteristic. Low- or non-fat dairy, seafood, legumes, nuts, and alcohol were identified as beneficial characteristics of the diet for some, but not all, outcomes. For conclusions with moderate to strong evidence, higher intake of red and processed meats was identified as detrimental compared to lower intake. Higher consumption of sugar-sweetened foods and beverages as well as refined grains were identified as detrimental in almost all conclusion statements with moderate to strong evidence.

Table D2.3. Description of the dietary patterns highlighted in the DGAC’s Conclusion Statements that are associated with benefit related to the health outcome of interest. (Note: The reader is directed to the full Conclusion Statement above for more information on the relationship between dietary patterns and the health outcome. In some cases, dietary components were associated with increased health risk and this is noted in the table.)

Health Outcome

DGAC Gradea

Description of the Dietary Pattern Associated with Beneficial Health Outcomes

Cardiovascular disease

Strong

Dietary patterns characterized by higher consumption of vegetables, fruits, whole grains, low-fat dairy, and seafood, and lower consumption of red and processed meat, and lower intakes of refined grains, and sugar-sweetened foods and beverages relative to less healthy patterns; regular consumption of nuts and legumes; moderate consumption of alcohol; lower in saturated fat, cholesterol, and sodium and richer in fiber, potassium, and unsaturated fats.

Measures of body weight or obesity

Moderate

Dietary patterns that are higher in vegetables, fruits, and whole grains; include seafood and legumes; are moderate in dairy products (particularly low and non-fat dairy) and alcohol; lower in meats (including red and processed meats), and low in sugar-sweetened foods and beverages, and refined grains; higher intakes of unsaturated fats and lower intakes of saturated fats, cholesterol, and sodium.

Limited

Dietary patterns in childhood or adolescence that are higher in energy-dense and low-fiber foods, such as sweets, refined grains, and processed meats, as well as sugar-sweetened beverages, whole milk, fried potatoes, certain fats and oils, and fast foods are associated with an increased risk.

Type 2 diabetes

Moderate

Dietary patterns higher in vegetables, fruits, and whole grains and lower in red and processed meats, high-fat dairy products, refined grains, and sweets/sugar-sweetened beverages.

Cancer

Moderate

Colon/Rectal Cancer: Dietary patterns that are higher in vegetables, fruits, legumes, whole grains, lean meats/seafood, and low-fat dairy and moderate in alcohol; and low in red and/or processed meats, saturated fat, and sodas/sweets. (Conversely, diets that are higher in red/processed meats, French fries/potatoes, and sources of sugars (i.e., sodas, sweets, and dessert foods) are associated with a greater risk.)

Moderate (post) / Limited (pre)

Breast Cancer: Dietary patterns rich in vegetables, fruit, and whole grains, and lower in animal products and refined carbohydrate.

Limited

Lung Cancer: Dietary patterns containing more frequent servings of vegetables, fruits, seafood, grains/cereals, and legumes, and lean versus higher fat meats and lower fat or non-fat dairy products.

Not assignable

Prostate Cancer: N/A

Congenital anomalies

Limited – Neural tube defects

Neural tube defects: Dietary patterns during the preconception period that are higher in vegetables, fruits, and grains, and lower in red and processed meats, and low in sweets. 

Not assignable

Congenital heart defects or cleft lip/palate: N/A

Neurological and psychological illnesses

Limited

Age-related cognitive impairment, dementia, and/or Alzheimer’s disease: Dietary patterns containing an array of vegetables, fruits, nuts, legumes and seafood. 

Limited

Depression: Dietary patterns emphasizing seafood, vegetables, fruits, nuts, and legumes. 

Bone health

Limited

Adults: Dietary patterns higher in vegetables, fruits, grains, nuts, and dairy products, and lower in meats and saturated fat.

Not assignable

Children: N/A

a The DGAC presented represents the grade the Committee provided for the conclusion statement with the dietary pattern components described. Some health outcomes had more than one graded conclusion. Only the conclusion statements that describe dietary pattern components are presented here. Post = Post-menopausal; Pre = Pre-menopausal

As alcohol is a unique aspect of the diet, the DGAC considered evidence from several sources to inform recommendations. As noted above, moderate alcohol intake among adults was identified as a component of a healthy dietary pattern associated with some health outcomes, which reaffirms conclusions related to moderate alcohol consumption by the 2010 DGAC. The Committee also concurs with the conclusions reached by the 2010 DGAC on the relationship between alcohol intake and unintentional injury and lactation.1 However, as noted in Table D2.1, evidence also suggests that alcoholic drinks are associated with increased risk for certain cancers, including pre- and post-menopausal breast cancer. After consideration of this collective evidence, the Committee concurs with the 2010 DGAC that if alcohol is consumed, it should be consumed in moderation, and only by adults. However, it is not recommended that anyone begin drinking or drink more frequently on the basis of potential health benefits because moderate alcohol intake also is associated with increased risk of violence, drowning, and injuries from falls and motor vehicle crashes. Women should be aware of a moderately increased risk of breast cancer even with moderate alcohol intake. There are many circumstances in which people should not drink alcohol:

  • Individuals who cannot restrict their drinking to moderate levels.
  • Anyone younger than the legal drinking age.
  • Women who are pregnant or who may be pregnant.
  • Individuals taking prescription or over-the-counter medications that can interact with alcohol.
  • Individuals with certain specific medical conditions (e.g., liver disease, hypertriglyceridemia, pancreatitis).
  • Individuals who plan to drive, operate machinery, or take part in other activities that require attention, skill, or coordination or in situations where impaired judgment could cause injury or death (e.g., swimming).

Finally, because of the substantial evidence clearly demonstrating the health benefits of breastfeeding, occasionally consuming an alcoholic drink does not warrant stopping breastfeeding. However, women who are breastfeeding should be very cautious about drinking alcohol, if they choose to drink at all.vii

The common characteristics of a healthy dietary pattern found in the conclusion statements across the outcomes examined implies that following a dietary pattern associated with reduced risk of CVD, overweight, and obesity will have positive health benefits beyond these categories of health outcomes. Thus, the U.S. population should be encouraged and guided to consume dietary patterns that are rich in vegetables, fruits, whole grains, seafood, legumes, and nuts; moderate in low- and non-fat dairy products and alcohol (among adults); lower in red and processed meat; and low in sugar-sweetened foods and beverages and refined grains. These dietary patterns can be achieved in many ways and should be tailored to the individual’s biological and medical needs as well as socio-cultural preferences. As described in the DGAC’s conceptual model, a multi-level process at individual and population levels is required to help achieve a healthy diet and other lifestyle behaviors so as to achieve chronic disease risk reduction and overall well-being. The Committee recommends the development and implementation of programs and services that facilitate the improvement in eating behaviors consistent with healthy dietary patterns in various settings, including preventive services in our healthcare and public health systems as well as those that reach populations in other settings of influence such as preschool and school settings and workplaces.

The dietary pattern characteristics being recommended by the 2015 DGAC reaffirms the dietary pattern characteristics recommended by the 2010 DGAC, despite the fact that different approaches were employed. Additionally, this dietary pattern aligns with recommendations from other groups, including AICR and AHA/ACC. The majority of evidence considered focuses on dietary patterns consumed in adulthood on health risks, primarily risks of chronic disease development and, in the case of pregnancy, birth defects. Very little evidence considered here was directed to dietary patterns in children, and risk reduction studies evaluating children’s diets and risk of overweight and obesity provided limited evidence. No conclusions on chronic disease apply directly to evidence developed in children. Recommendations based on adult studies have implications for children based on general nutritional principles but caution is warranted, considering the fact that children with developing bodies and neurocognitive capabilities present unique nutritional issues.

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