IMPORTANCE Changes in the economy, nutrition policies, and food processing methods can affect dietary macronutrient intake and diet quality. It is essential to evaluate trends in dietary intake, food sources, and diet quality to inform policy makers.OBJECTIVE To investigate trends in dietary macronutrient intake, food sources, and diet quality among US adults.DESIGN, SETTING, AND PARTICIPANTS Serial cross-sectional analysis of the US nationally representative 24-hour dietary recall data from 9 National Health and Nutrition Examination Survey cycles (1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016) among adults aged 20 years or older. EXPOSURE Survey cycle.MAIN OUTCOMES AND MEASURES Dietary intake of macronutrients and their subtypes, food sources, and the Healthy Eating Index 2015 (range, 0-100; higher scores indicate better diet quality; a minimal clinically important difference has not been defined).RESULTS There were 43 996 respondents (weighted mean age, 46.9 years; 51.9% women). From 1999 to 2016, the estimated energy from total carbohydrates declined from 52.5% to 50.5% (difference, −2.02%; 95% CI, −2.41% to −1.63%), whereas that of total protein and total fat increased from 15.5% to 16.4% (difference, 0.82%; 95% CI, 0.67%-0.97%) and from 32.0% to 33.2% (difference, 1.20%; 95% CI, 0.84%-1.55%), respectively (all P < .001 for trend). Estimated energy from low-quality carbohydrates decreased by 3.25% (95% CI, 2.74%-3.75%; P < .001 for trend) from 45.1% to 41.8%. Increases were observed in estimated energy from high-quality carbohydrates (by 1.23% [95% CI, 0.84%-1.61%] from 7.42% to 8.65%), plant protein (by 0.38% [95% CI, 0.28%-0.49%] from 5.38% to 5.76%), saturated fatty acids (by 0.36% [95% CI, 0.20%-0.51%] from 11.5% to 11.9%), and polyunsaturated fatty acids (by 0.65% [95% CI, 0.56%-0.74%] from 7.58% to 8.23%) (all P < .001 for trend). The estimated overall Healthy Eating Index 2015 increased from 55.7 to 57.7 (difference, 2.01; 95% CI, 0.86-3.16; P < .001 for trend). Trends in high-and low-quality carbohydrates primarily reflected higher estimated energy from whole grains (0.65%) and reduced estimated energy from added sugars (−2.00%), respectively. Trends in plant protein were predominantly due to higher estimated intake of whole grains (0.12%) and nuts (0.09%).CONCLUSIONS AND RELEVANCE From 1999 to 2016, US adults experienced a significant decrease in percentage of energy intake from low-quality carbohydrates and significant increases in percentage of energy intake from high-quality carbohydrates, plant protein, and polyunsaturated fat. Despite improvements in macronutrient composition and diet quality, continued high intake of low-quality carbohydrates and saturated fat remained.

Upper reference limits for the serum total homocysteine concentration increased with age and were higher for male participants than for female participants at all ages. In most cases, high homocysteine concentrations were associated with low serum vitamin concentrations.

Background: The health benefits and risks of dietary supplementation use remain controversial. Objective: To evaluate the association between dietary supplement use, levels of nutrient intake from foods and supplements, and mortality among US adults. Design: Prospective cohort study. Setting: National Health and Nutrition Examination Survey (NHANES) 1999–2010 linked to National Death Index Mortality Data. Patients: 30,899 US adults aged 20+ years who answered questions on dietary supplement use. Measurements: Dietary supplement use in the past 30 days and nutrient intake from foods and supplements. Outcomes included mortality from all causes, cardiovascular disease (CVD), and cancer. Results: During a median follow-up of 6.1 years, a total of 3,613 total deaths occurred, including 945 CVD deaths and 805 cancer deaths. Ever use of dietary supplements was not associated with mortality outcomes. Adequate nutrient intake (≥ Estimated Average Requirement or Adequate Intake) of vitamin A, vitamin K, magnesium, and zinc was associated with reduced all-cause or CVD mortality, but the associations were confined to nutrient intake from foods not supplements. Excess nutrient intake (> Tolerable Upper Intake Level) of calcium was associated with an increased risk of cancer mortality (> vs. ≤ Tolerable Upper Intake Level: multivariable-adjusted mortality rate ratio = 1.62, 95% CI: 1.07, 2.45; multivariable-adjusted mortality rate difference = 1.7, 95% CI: −0.1, 3.5 per 1,000 person-years), and the association appeared to be related to calcium intake from supplements (≥1000 mg/d vs. non-users: multivariable-adjusted mortality rate ratio=1.53, 95% CI: 1.04, 2.25; multivariable-adjusted mortality rate difference = 1.5, 95% CI: −0.1, 3.1 per 1,000 person-years) not foods. Limitations: Results from observational data may be affected by residual confounding. Reporting of dietary supplement use is subject to recall bias. Conclusion: Use of dietary supplements is not associated with mortality benefits among US adults. Primary Funding Source: National Institutes of Health