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The requirements for vitamin D were last set in 1997 by the Food and Nutrition Board of the Institute of Medicine. Intakes were assumed to come from diet, and values were based on achievement of adequate vitamin D status and on observed values to prevent seasonal variations in parathyroid hormone concentrations. Serum 25-hydroxyvitamin D concentrations were considered the best indicator of vitamin D adequacy, because the production of 25-hydroxyvitamin D is not regulated. Normal ranges were obtained from reference populations, but the values varied widely with age and geographic region. Revised recommendations should take into consideration appropriate functional measures for multiple tissues and disease risks. Vitamin D-calcium interdependencies must be taken into account. Higher intakes of both vitamin D and calcium can reduce bone resorption, and higher concentrations of one nutrient might compensate for insufficiency in the other. Better ways to assess vitamin D (and calcium) inputs are needed. Food composition databases are incomplete for both vitamin D and calcium, especially in this era of food fortification, and are complicated by the poor quality control for vitamin D fortification. Upper levels of vitamin D intake were set at 50 microg/d (2000 IU/d) for all ages. Some individuals would require higher levels than these to achieve serum 25-hydroxyvitamin D concentrations for optimal calcium absorption. So much new information on vitamin D and health has been collected since the requirements were set in 1997 that this nutrient is likely the most in need of revised requirements.

Dramatic increases in obesity and diabetes have occurred worldwide over the past 30 years. Some investigators have suggested that these increases may be due, in part, to increased added sugars consumption. Several scientific organizations, including the World Health Organization, the Scientific Advisory Council on Nutrition, the Dietary Guidelines Advisory Committee 2015, and the American Heart Association, have recommended significant restrictions on upper limits of sugars consumption. In this review, the scientific evidence related to sugars consumption and its putative link to various chronic conditions such as obesity, diabetes, heart disease, nonalcoholic fatty liver disease, and the metabolic syndrome is examined. While it appears prudent to avoid excessive calories from sugars, the scientific basis for restrictive guidelines is far from settled. [ABSTRACT FROM AUTHOR]

Background: The maximal calcium absorption in response to vitamin D has been proposed as a biomarker for vitamin D sufficiency. Objective: The objective was to determine whether there is a threshold beyond which increasing doses of vitamin D, or concentrations of serum 25-hydroxyvitamin D [25(OH)D], no longer increase calcium absorption. Design: This was a placebo-controlled, dose-response, randomized, double-blind study of the effect of vitamin D on calcium absorption in healthy postmenopausal women. Seventy-six healthy postmenopausal women were randomly assigned to placebo or 800 IU (20 mg), 2000 IU (50 µg), or 4000 IU (100 µg) vitamin D3 for 8 wk. The technique of dual isotopes of stable calcium was used with a calcium carrier to measure calcium absorption at baseline and after 8 wk. Results: Seventy-one women with a mean ± SD age of 58.8 ± 4.9 y completed the study. The mean calcium intake was 1142 6 509 mg/d and serum 25(OH)D was 63 ± 14 nmol/L at baseline. A statistically significant linear trend of an increase in calcium absorption adjusted for age and body mass index with increasing vitamin D3 dose or serum 25(OH)D concentration was observed. A 6.7% absolute increase in calcium absorption was found in the highest vitamin D3 group (100 µg). No evidence of nonlinearity was observed in the dose-response curve. Conclusions: No evidence of a threshold of calcium absorption was found with a serum 25(OH)D range from 40 to 130 nmol/L. Calcium absorption in this range is not a useful biomarker to determine nutritional recommendations for vitamin D. This trial was registered at clinicaltrials. gov as NCT01119378. [ABSTRACT FROM AUTHOR]

The article offers updates on various studies related to nutrition. It states that the calcium absorption efficiency was not associated with 25(OH)D concentrations alone in menopausal women. It discusses the study which aims to estimate the proportion of U.S. populations who do not meet federal dietary requirements using the National Cancer Institute (NCI) method. Meanwhile, it explores the study on the relationship between weight gains and serum levels of persistent organic pollutants (POPs).