Perspective: The Glycemic Index Falls Short as a Carbohydrate Food Quality Indicator to Improve Diet Quality.

This perspective examines the utility of the glycemic index (GI) as a carbohydrate quality indicator to improve Dietary Guidelines for Americans (DGA) adherence and diet quality. Achieving affordable, high-quality dietary patterns can address multiple nutrition and health priorities. Carbohydrate-containing foods make important energy, macronutrient, micronutrient, phytochemical, and bioactive contributions to dietary patterns, thus improving carbohydrate food quality may improve diet quality. Following DGA guidance helps meet nutrient needs, achieve good health, and reduce risk for diet-related non-communicable diseases in healthy people, yet adherence by Americans is low. A simple indicator that identifies high-quality carbohydrate foods and improves food choice may improve DGA adherence, but there is no consensus on a definition. The GI is a measure of the ability of the available carbohydrate in a food to increase blood glucose. The GI is well established in research literature and popular resources, and some have called for including the GI on food labels and in food-based dietary guidelines. The GI has increased understanding about physiological responses to carbohydrate-containing foods, yet its role in food-based dietary guidance and diet quality is unresolved. A one-dimensional indicator like the GI runs the risk of being interpreted to mean foods are "good" or "bad," and it does not characterize the multiple contributions of carbohydrate-containing foods to diet quality, including nutrient density, a core concept in the DGA. New ways to define and communicate carbohydrate food quality shown to help improve adherence to high-quality dietary patterns such as described in the DGA would benefit public health.

The prevalence of self-reported lactose intolerance and the consumption of dairy foods among African American adults are less than expected.

OBJECTIVE: To determine the self-reported incidence of lactose intolerance and its influence on dairy choices among African American adults. DESIGN, SETTING, AND PARTICIPANTS: An online survey closely matched to the 2000 US Census was administered to a nationally representative sample of African Americans (2016 adults) and a comparison sample of the general population (1084 adults). Statistical analyses performed included pairwise t tests for proportion conducted on percent responses at the 95% confidence level. RESULTS: African Americans were more likely to eat fewer dairy foods, experience physical discomfort after consumption, and believe they were lactose intolerant. While 49% of African Americans had ever experienced "some type of physical discomfort" after eating dairy foods, 24% believed they were lactose intolerant. Within this group, 85% of African Americans would be willing to consume more dairy products if they could avoid lactose intolerance symptoms. CONCLUSIONS AND IMPLICATIONS: Dairy food, calcium, and vitamin D intake in African Americans and the general population are below US recommendations. Deficiencies of these nutrients are associated with chronic diseases that disproportionately affect African Americans. In the United States, dairy foods are the primary source of calcium and vitamin D, and lactose intolerance can be a significant barrier to dairy food intake. However, self-described lactose intolerance is less than commonly reported in African American populations. Low dairy intake may reflect concerns about lactose intolerance, other factors such as learned food habits and cultural preferences. Nutrition recommendations for African Americans and the general population should focus on the health benefits of dairy foods, provide culturally sensitive dietary options, and strategies to increase tolerance.

Putting the nutrient-rich foods index into practice.

With approximately 2 out of 3 Americans currently overweight or obese, many continue to come up short on recommendations for certain nutrients such as calcium, magnesium, potassium, vitamin A, vitamin C, vitamin E, and fiber in their diet. Numerous attempts have been made to provide consumers with nutrient-profiling tools, such as manufacturer-specific symbols, to improve dietary selections, but many of the tools have focused on assisting consumers in making single food selections and do not provide guidance about planning total diets. In response to the 2005 Dietary Guidelines Advisory Committee's recommendation for research to define nutrient density, the Nutrient Rich Foods Coalition (NRFC) embarked on the development of a scientifically valid definition of nutrient density and consumer-driven educational tools to communicate the concept of nutrient-rich foods (NRF) to consumers. The science-based, consumer-driven NRF approach to eating may help Americans make multiple small changes in their diet that ultimately lead to better diet quality and significant improvements in public health.

Dairy consumption and related nutrient intake in African-American adults and children in the United States: continuing survey of food intakes by individuals 1994-1996, 1998, and the National Health And Nutrition Examination Survey 1999-2000.

OBJECTIVE: To establish the first baseline of dairy and related nutrient intake in African Americans, an at-risk population of public health concern in the United States. To document dairy consumption in African Americans by age and sex during 1994-1998 and 1999-2000 and compare it with concomitant dairy, calcium, and related nutrient intakes in non-African-American adults and children. DESIGN: Duplicate and single 24-hour recalls were analyzed to determine dietary intake during the Continuing Survey of Food Intakes by Individuals 1994-1996, 1998 (CSFII), and the National Health and Nutrition Examination Survey 1999-2000 (NHANES), respectively. SUBJECTS: African Americans and non-African Americans of all ages who participated in CSFII 1994-1996, 1998, and in NHANES 1999-2000; both surveys are a stratified random sample of the total civilian, noninstitutionalized US population. STATISTICAL ANALYSIS: Dairy food and nutrient intake per day were quantified according to age, sex, and ethnicity/race from CSFII 1994-1996, 1998, and NHANES 1999-2000. For NHANES, mean intakes from 1-day food records were sample-weighted, and standard errors estimated by the Taylor linearization method of SUDAAN (version 9.0, 2004, RTI International, Research Triangle Park, NC). Usual daily intakes of calcium, magnesium, and phosphorus were based on 2-day intake data from CSFII 1994-1996, 1998, and calculated using Software for Intake Distribution from Iowa State University. The percentage of individuals categorized as not meeting the Estimated Average Requirement for magnesium and phosphorus were calculated in the same way. RESULTS: CSFII 1994-1996, 1998, and NHANES 1999-2000 data both show that African Americans in all age groups consume fewer mean servings per day of total dairy, milk, cheese, and yogurt than non-African Americans, and have lower mean intakes of calcium, magnesium, and phosphorus. Significant differences were seen for men and women. CONCLUSIONS: In this analysis, young African-American women did not meet Dietary Reference Intakes for phosphorus, and all African Americans did not meet Dietary Reference Intakes for calcium and magnesium. African Americans in all age groups did not meet dairy recommendations from the 2005 US Dietary Guidelines and the 2004 National Medical Association Consensus Report on the role of dairy and dairy nutrients in the diet of African Americans.

Effect of a Nutrient Rich Foods consumer education program: results from the nutrition advice study.

BACKGROUND: The Nutrient Rich Foods (NRF) approach to eating uses the NRF Index, a nutrient profiling metric to help consumers choose foods that contain more vitamins, minerals, and other nutrients per kilocalorie. Research is needed to test the efficacy of dietary guidance using nutrient profiling systems to rank foods. OBJECTIVE: To examine whether nutrition education and supporting materials would increase understanding of the NRF approach and improve food shopping, meal planning, consumption of nutrient-rich foods, and diet quality. DESIGN: Unbalanced randomized controlled trial conducted in February to May 2009 with participants assigned to NRF education group (n=128) or control group receiving standard nutrition education (n=61). PARTICIPANTS/SETTING: Adult primary food shoppers and preparers with at least one child in the household aged 3 to 17 years. INTERVENTION: Group education session and support tools (pocket guide, shopping list, refrigerator magnet, weekly e-mail messages, and biweekly mailings). MAIN OUTCOME MEASURES: Surveys of knowledge, attitudes, and behaviors and two 24-hour telephone dietary recalls at baseline and after an 8-week intervention period. STATISTICAL ANALYSES: Examined time-by-treatment interactions in outcome measures. RESULTS: Compared to controls, NRF participants increased meal planning (+24.2% vs ?4.9%; P<0.01), ability to identify nutrient-rich foods (+60.2% vs +24.6%; P<0.001), and use of shopping lists (+14.1% vs +3.3%; nonsignificant trend), and consumed more vegetables and fruits (P<0.05). NRF participants improved overall diet quality as shown by their scores on the Healthy Eating Index (P=0.04) and NRF scale scores (nonsignificant trend). Significant improvements were observed in Healthy Eating Index component scores for total fruit; whole fruit; whole grains; saturated fat; and energy from solid fats, alcohol, and added sugars. CONCLUSIONS: Findings of this study showed that a consumer education program increased participants' use of the NRF approach and improved diet quality. Larger and longer-term studies are needed to confirm the findings and better understand processes of change.

Effects of soy consumption on gonadotropin secretion and acute pituitary responses to gonadotropin-releasing hormone in women.

Soy contains the isoflavone phytoestrogens, genistein and daidzein. These isoflavones are partial estrogen agonists in cell and animal models, but effects from dietary soy in humans are unclear. Experiments were conducted in pre- and postmenopausal women to examine whether dietary isoflavones from soy behave as estrogen agonists, antagonists or have no effect on the estrogen-sensitive pituitary. Pituitary sensitivity to gonadotropin-releasing hormone (GnRH), an estrogen-sensitive endpoint, was measured during GnRH challenge tests administered before, during and after dietary soy consumption. The response to an isoflavone-rich soy food diet was examined in five premenopausal and seven postmenopausal women using transdermal estrogen replacement therapy. Estrogen agonists suppress gonadotropin concentrations and enhance GnRH priming (enhanced gonadotropin secretion in response to repeated doses of GnRH), whereas antagonists elevate gonadotropin concentrations and have no effect on GnRH priming. Each subject consumed 50 g textured soy protein containing 60 mg total isoflavones daily for 10-14 d. Baseline estradiol concentrations were consistent among study periods. In both pre- and postmenopausal women, soy consumption did not affect mean baseline or peak luteinizing hormone (LH) concentrations, indicating a lack of estrogen-like effect at the level of the pituitary. However, in postmenopausal subjects, mean LH secretion decreased after discontinuing soy, suggesting a residual estrogenic effect. In one premenopausal woman, enhanced LH secretion was observed after soy treatment, suggesting there may be subpopulations of women who are highly sensitive to isoflavones.