Perspective: School Meal Programs Require Higher Vitamin D Fortification Levels in Milk Products and Plant-Based Alternatives-Evidence from the National Health and Nutrition Examination Surveys (NHANES 2001-2018).

Poor vitamin D status impairs bone growth and immune defense in school-aged children and adolescents, particularly in minorities. Vitamin D insufficiency/deficiency increases the risk of acute viral respiratory infection, underscoring the need for adequate vitamin D intakes during school sessions when viral exposure may be greatest. We studied available vitamin D-related survey data and published findings based on NHANES (2001-2018) to assess the dependency of vitamin D status {25-hydroxyvitamin D [25(OH)D]; in nmol/L} on vitamin D intake (µg/d) in elementary school-aged children (4-8 y), middle school children (9-13 y), and high school adolescents (14-18 y). We sought evidence supporting the need for school programs to facilitate vitamin D adequacy. Usual vitamin D intakes from food and beverages by children/adolescents (NHANES 2015-2018) examined at the 50th percentile intake by race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic) showed all age groups consumed less than half of the Estimated Average Requirement (EAR) for vitamin D (10 µg/d), independent of race/ethnicity. NHANES (2001-2010) analyses show evidence of lower vitamin D status in school-aged children that is linked to lower intakes of fortified milk varying over race/ethnicity and age. Adolescents had lower vitamin D status and milk intake than younger children. A total of 22-44% of vitamin D intakes occurred away from home, with larger percentages of total intakes at breakfast and lunch, at times consistent with school meals. Ever-present inadequate vitamin D intakes with a large percentage consumed away from home together with well-established benefits to growth, bone, and immune defense from enriched vitamin D-fortified milk in school intervention trials provide strong justification to require enriched vitamin D-fortified foods in school meals. An easy to implement plan for improving vitamin D intakes is possible through the FDA's amendment allowing higher vitamin D fortification levels of dairy and plant-based milk alternatives that could increase vitamin D intakes beyond the EAR with just 2 daily servings.

Perspective: Plant-based Whole-Grain Foods for Chronic Kidney Disease: The Phytate-Phosphorus Conundrum.

Restriction of dietary phosphorus intake is an important component of good clinical practice in kidney failure patients, particularly after dialysis initiation. Greater consumption of predominantly plant-based diets, including phytate-rich foods, is increasingly recommended for health maintenance/disease prevention in this population, with the implicit assumption that phytate-phosphorus in whole-grain cereals, legumes, pulses, and nuts is poorly absorbed. Review of human interventions with diets high in phytate-phosphorus indeed suggests an absorption of at least 50%, still less than animal protein-bound phosphorus, but higher than the generally believed 10-30%. Factors largely ignored up to now, but of potential influence on phytate-phosphorus bioavailability, include effect of food processing in releasing phosphorus, action of colonic bacteria that are able to release inorganic phosphorus, and capacity of the colon to absorb phosphorus. These issues may become increasingly important as new plant-based alternatives to meats, all containing phytate, are being rapidly introduced in the market.

Dietary Phosphate and the Forgotten Kidney Patient: A Critical Need for FDA Regulatory Action.

Careful dietary management that reduces high phosphate intake is recommended to slow the progression of chronic kidney disease (CKD) and prevent complications of CKD and may help reduce chronic disease risks such as incident CKD associated with high phosphate intake in the healthy general population. For patients treated with maintenance dialysis, control of serum phosphorus levels is considered a marker of good care and requires a coordinated plan that limits dietary phosphate intake, uses oral phosphate binders, and provides an adequate dialysis prescription. Even with traditional thrice-weekly hemodialysis or peritoneal dialysis, use of phosphate binders, and a concerted effort to limit dietary phosphate intake, adequately controlled serum phosphorus levels are not possible in all dialysis patients. Efforts to limit phosphate intake are thwarted by the underestimated and unquantified phosphate content of processed foods and some medications due to the hidden presence of phosphate additives or excipients added during processing or drug formulation. Effectively limiting phosphate intake could potentially be achieved through simple US Food and Drug Administration regulatory actions. Mandatory labeling of phosphate content on all packaged foods and drugs would enable identification of healthy low-phosphate foods and medications and permit critically important control of total phosphate intake. Simple changes in regulatory policy and labeling are warranted and would enable better management of dietary intake of phosphate at all stages of kidney disease, as well as potentially reduced health risks in the general population.

Global prevalence and disease burden of vitamin D deficiency: a roadmap for action in low- and middle-income countries.

Vitamin D is an essential nutrient for bone health and may influence the risks of respiratory illness, adverse pregnancy outcomes, and chronic diseases of adulthood. Because many countries have a relatively low supply of foods rich in vitamin D and inadequate exposure to natural ultraviolet B (UVB) radiation from sunlight, an important proportion of the global population is at risk of vitamin D deficiency. There is general agreement that the minimum serum/plasma 25-hydroxyvitamin D concentration (25(OH)D) that protects against vitamin D deficiency-related bone disease is approximately 30 nmol/L; therefore, this threshold is suitable to define vitamin D deficiency in population surveys. However, efforts to assess the vitamin D status of populations in low- and middle-income countries have been hampered by limited availability of population-representative 25(OH)D data, particularly among population subgroups most vulnerable to the skeletal and potential extraskeletal consequences of low vitamin D status, namely exclusively breastfed infants, children, adolescents, pregnant and lactating women, and the elderly. In the absence of 25(OH)D data, identification of communities that would benefit from public health interventions to improve vitamin D status may require proxy indicators of the population risk of vitamin D deficiency, such as the prevalence of rickets or metrics of usual UVB exposure. If a high prevalence of vitamin D deficiency is identified (>20% prevalence of 25(OH)D < 30 nmol/L) or the risk for vitamin D deficiency is determined to be high based on proxy indicators (e.g., prevalence of rickets >1%), food fortification and/or targeted vitamin D supplementation policies can be implemented to reduce the burden of vitamin D deficiency-related conditions in vulnerable populations.

Rationale and Plan for Vitamin D Food Fortification: A Review and Guidance Paper.

Vitamin D deficiency can lead to musculoskeletal diseases such as rickets and osteomalacia, but vitamin D supplementation may also prevent extraskeletal diseases such as respiratory tract infections, asthma exacerbations, pregnancy complications and premature deaths. Vitamin D has a unique metabolism as it is mainly obtained through synthesis in the skin under the influence of sunlight (i.e., ultraviolet-B radiation) whereas intake by nutrition traditionally plays a relatively minor role. Dietary guidelines for vitamin D are based on a consensus that serum 25-hydroxyvitamin D (25[OH]D) concentrations are used to assess vitamin D status, with the recommended target concentrations ranging from ≥25 to ≥50 nmol/L (≥10-≥20 ng/mL), corresponding to a daily vitamin D intake of 10 to 20 µg (400-800 international units). Most populations fail to meet these recommended dietary vitamin D requirements. In Europe, 25(OH)D concentrations <30 nmol/L (12 ng/mL) and <50 nmol/L (20 ng/mL) are present in 13.0 and 40.4% of the general population, respectively. This substantial gap between officially recommended dietary reference intakes for vitamin D and the high prevalence of vitamin D deficiency in the general population requires action from health authorities. Promotion of a healthier lifestyle with more outdoor activities and optimal nutrition are definitely warranted but will not erase vitamin D deficiency and must, in the case of sunlight exposure, be well balanced with regard to potential adverse effects such as skin cancer. Intake of vitamin D supplements is limited by relatively poor adherence (in particular in individuals with low-socioeconomic status) and potential for overdosing. Systematic vitamin D food fortification is, however, an effective approach to improve vitamin D status in the general population, and this has already been introduced by countries such as the US, Canada, India, and Finland. Recent advances in our knowledge on the safety of vitamin D treatment, the dose-response relationship of vitamin D intake and 25(OH)D levels, as well as data on the effectiveness of vitamin D fortification in countries such as Finland provide a solid basis to introduce and modify vitamin D food fortification in order to improve public health with this likewise cost-effective approach.

Dietary phosphorus excess: a risk factor in chronic bone, kidney, and cardiovascular disease?

There is growing evidence in the nephrology literature supporting the deleterious health effect of excess dietary phosphorus intake. This issue has largely escaped the attention of nutrition experts until this symposium, which raised the question of whether the same health concerns should be extended to the general population. The potential hazard of a high phosphorus intake in the healthy population is illustrated by findings from acute and epidemiologic studies. Acute studies in healthy young adults demonstrate that phosphorus intakes in excess of nutrient needs may significantly disrupt the hormonal regulation of phosphorus contributing to disordered mineral metabolism, vascular calcification, bone loss, and impaired kidney function. One of the hormonal factors acutely affected by dietary phosphorus loading is fibroblast growth factor-23, which may be a key factor responsible for many of the cardiovascular disease (CVD) complications of high phosphorus intake. Increasingly, large epidemiological studies suggest that mild elevations of serum phosphorus within the normal range are associated with CVD risk in healthy populations. Few population studies link high dietary phosphorus intake to mild changes in serum phosphorus due to study design issues specific to phosphorus and inaccurate nutrient composition databases. The increasing phosphorus intake due to the use of phosphorus-containing ingredients in processed food and the growing consumption of processed convenience and fast foods is an important factor that needs to be emphasized.

Contributions to total phosphorus intake: all sources considered.

High serum phosphorus is linked to poor health outcome and mortality in chronic kidney disease (CKD) patients before or after the initiation of dialysis. Dietary intake of phosphorus, a major determinant of serum phosphorus, seems to be systematically underestimated using the available software tools and generalized nutrient content databases. Several sources of dietary phosphorus including the addition of phosphorus ingredients in food processing, and phosphorus content of vitamin and mineral supplements and commonly used over-the-counter or prescription medications are not fully accounted for by the nutrient content databases and software programs in current clinical use or used in large population studies. In this review, we explore the many unknown sources of phosphorus in the food supply to identify all possible contributors to total phosphorus intake of Americans that have escaped inclusion in past intake estimates. Our goal is to help delineate areas for future interventions that will enable tighter control of dietary phosphorus intake, a critical factor to maintaining health and quality of life in CKD and dialysis patients.

Survey of current vitamin D food fortification practices in the United States and Canada.

Widespread poor vitamin D status in all age and gender groups in the United States (USA) and Canada increases the need for new food sources. Currently ∼60% of the intake of vitamin D from foods is from fortified foods in these countries. Those groups in greatest need are consuming significantly lower amounts of commonly fortified foods such as milk. Both countries allow voluntary vitamin D fortification of some other foods, although in Canada this practice is only done on a case-by-case basis. Novel approaches to vitamin D fortification of food in both countries now include "bio-addition" in which food staples are fortified through the addition of another vitamin D-rich food to animal feed during production, or manipulation of food post-harvest or pre-processing. These bio-addition approaches provide a wider range of foods containing vitamin D, and thus appeal to differing preferences, cultures and possibly economic status. An example is the post-harvest exposure of edible mushrooms to ultraviolet light. However, further research into safety and efficacy of bio-addition needs to be established in different target populations. This article is part of a Special Issue entitled 'Vitamin D Workshop'.

Modern India and the vitamin D dilemma: evidence for the need of a national food fortification program.

India is located between 8.4 and 37.6 degrees N latitude with the majority of its population living in regions experiencing ample sunlight throughout the year. Historically, Indians obtained most of their vitamin D through adequate sun exposure; however, darker skin pigmentation and the changes which have accompanied India's modernization, including increased hours spent working indoors and pollution, limit sun exposure for many. Inadequate sun exposure results in reduced vitamin D synthesis and ultimately poor vitamin D status if not compensated by dietary intake. Dietary vitamin D intake is very low in India because of low consumption of vitamin D rich foods, absence of fortification and low use of supplements. All these factors contribute to poor vitamin D status as measured by low circulating levels of 25-hydroxy vitamin D. Our review searches the published literature specific to India for evidence that would confirm the need to fortify food staples with vitamin D or stimulate public health policies for vitamin D supplementation and dietary guidelines tailored to the Indian diet. This review documents findings of widespread vitamin D deficiency in Indian populations in higher and lower socioeconomic strata, in all age groups, in both genders and people in various professions. Moreover, poor vitamin D status in India is accompanied by increased bone disorders including osteoporosis, osteomalacia in adults and rickets and other bone deformities in children. Without a concerted national effort to screen for vitamin D status, to implement policies or guidelines for vitamin D fortification and/or supplementation and to re-assess recommended dietary intake guidelines, dramatic increase in the number of bone disorders and other diseases may lie ahead.

Correcting poor vitamin D status: do older adults need higher repletion doses of vitamin D3 than younger adults?

We conducted an examination of recent studies to determine whether older adults (>or=65 years) need higher levels of supplementary vitamin D than young adults when attempting to replete vitamin D status in deficient subjects, i.e. those with levels of 25-hydroxyvitamin D less than 75 nmol/L. As data on repletion with vitamin D(2) have recently been published, we restricted our discussion to the use of vitamin D(3) from dietary supplements, prescriptions for large oral doses, and bolus dosing or injections. Most published dosing regimens failed to achieve 75 nmol/L in most all subjects, whether young adults (<65 years) or older adults (>or=65 years). Whether as daily or bolus oral supplementation, elderly subjects appeared to need more vitamin D3 compared with younger adults, however, baseline levels, endpoints, study duration, compliance, and other factors were different among studies. To ensure most subjects are replete in vitamin D, a daily dose of more than 50 microg (2000 IU) in younger and 125 microg (5000 IU) is required. Other strategies including bolus and loading doses are described. No study reported adverse effects of using oral intakes about the current upper level of 50 microg (2000 IU).

Despite mandatory fortification of staple foods, vitamin D intakes of Canadian children and adults are inadequate.

Vitamin D is largely obtained through sun-induced skin synthesis and less from dietary sources, but during Canadian winters, skin synthesis is non-existent. The objective of this study was to estimate vitamin D intakes in Canadians from food sources. Data used in this study included food intakes of Canadians reported in the 2004 Canadian Community Health Survey Cycle 2.2 (CCHS 2.2), a nationally representative sample of 34,789 persons over the age of 1 year. The mean+/-SD dietary intake of vitamin D from food of Canadians was 5.8+/-0.1 microg/day, with males 9-18 years having the highest mean intakes (7.5+/-0.2 microg/day) and females 51-70 years having the lowest intakes (5.2+/-0.3 microg/day). Males in all age groups had higher intakes than females and White Canadians had higher vitamin D intakes than Non-Whites in most age sex groups. Milk products contributed 49% of dietary vitamin D followed by meat and meat-alternatives (31.1%). The majority of Canadians consume less than current recommended intake of vitamin D from food. Consideration should be given to strategies to improve vitamin D intake of Canadians by increasing both the amount of vitamin D added to foods and range of foods eligible for fortification.

Trends in mineral metabolism: Kidney Early Evaluation Program (KEEP) and the National Health and Nutrition Examination Survey (NHANES) 1999-2004.

BACKGROUND: Chronic kidney disease (CKD) is associated with mineral metabolism dysregulation, cardiovascular disease, and premature mortality. No study specifically examined mineral metabolism trends in a generalizable sample of patients at increased CKD risk. METHODS: This cross-sectional analysis from November 1, 2005, to December 31, 2006, of calcium, phosphorus, and parathyroid hormone (PTH) includes 2,646 individuals with estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m(2) in the National Kidney Foundation Kidney Early Evaluation Program (KEEP), a community-based health-screening program targeting individuals 18 years and older with diabetes, hypertension, or family history of kidney disease, diabetes, or hypertension. A parallel analysis of National Health and Nutrition Examination Survey (NHANES) 1999-2004 data was performed. RESULTS: In KEEP, as eGFR decreased from 55 to less than 60 mL/min/1.73 m(2) to less than 30 mL/min/1.73 m(2), calcium level decreased (9.55 +/- 0.47 to 9.34 +/- 0.62 mg/dL; P < 0.001), phosphorus level increased (3.70 +/- 0.59 to 4.15 +/- 0.80 mg/dL; P < 0.001), and PTH level increased (66.3 +/- 36.3 to 164 +/- 109 pg/mL; mean, 80.8 +/- 57.0 pg/mL; P < 0.001). NHANES 1999-2004 showed similar trends, with PTH values not as high. Individuals within opinion-based Kidney Disease Outcomes Quality Initiatives targets from the highest to the lowest eGFR group were as follows: calcium, 93.0% to 92.3% (KEEP) and 97.4% to 89.6% (NHANES); phosphorus, 90.4% to 90.3% (KEEP) and 91.6% to 87.1% (NHANES); and PTH, 46.1% to 31.2% (KEEP) and 56.4% to 36.1% (NHANES). CONCLUSIONS: In a community-based CKD screening population, increased PTH level occurs early in patients with stage 3, typically with normal calcium and phosphorus levels. These findings support the importance of including PTH with calcium and phosphorus monitoring for individuals with eGFR less than 60 mL/min/1.73 m(2).

Vitamin D intakes in North America and Asia-Pacific countries are not sufficient to prevent vitamin D insufficiency.

Worldwide, vitamin D status is suboptimal relative to circulating levels of 25-hydroxyvitamin D (25OHD) needed to prevent a variety of chronic conditions, however, it has long been assumed that dietary intake is sufficient to meet needs when sun exposure is limited. In the USA, mean vitamin D intake from foods is close to 5 microg, the Dietary Reference Intake (DRI) recommendation for persons up to 50 years; however, the amount of vitamin D needed to maintain a sufficient 25OHD level during winter is >12.5 microg, and that needed for darkly pigmented, veiled, or sun protected persons is >50 microg. In the USA, most vitamin D intake from foods is provided by fortification. Canada and New Zealand have fewer fortified choices, and intakes are correspondingly lower. Supplement use can increase mean intake to >12.5 microg but does not always reach those who need it most. Serum 25OHD levels in New Zealand reveal much more insufficiency than expected, especially for Pacific people and Mäori; low serum 25OHD concentrations are seen throughout the Asia-Pacific region. Fortification and supplementation may be effective to achieve intakes of 12.5 microg vitamin D in some of the population, but for many achieving the amount needed in the absence of skin synthesis requires intakes above the current upper level for vitamin D of 50 microg.

Public health strategies to overcome barriers to optimal vitamin D status in populations with special needs.

In North America, there is increasing public health awareness of the importance of adequate vitamin D intake to the maintenance of optimal vitamin D status and overall health. Experts now define this as circulating levels of 25-hydroxyvitamin D of 75-80 nmol/L. This serum level and high levels of dietary intake have been associated with significantly reduced risk of chronic diseases, such as osteoporosis, cardiovascular disease, diabetes, and some cancers. All of these diseases are more prevalent in the elderly of all races, and some are more prevalent and of greater severity among blacks than whites. Our objective is to review recent actions to increase public awareness of the health importance of maintaining optimal circulating 25(OH)D and potential strategies to increase vitamin D intake. Clinicians and educators are encouraged to promote improved vitamin D intake and status, particularly among the elderly and blacks. This will largely depend on combined efforts to judiciously fortify our food supply and to develop individual supplementation protocols for supplements or controlled use of UV light exposure to maintain optimal serum 25(OH)D, especially in high-risk groups. Growing evidence supports a low risk of toxicity with vitamin D use in fortification or supplementation, despite its past reputation of potential toxicity in excess. The cost to fortify food or supplements with vitamin D is relatively inexpensive compared with developing drugs used to treat or prevent chronic diseases; moreover, there is significant potential for broad health benefits in the reduced risk and prevention of multiple chronic diseases.

Dietary recommendations to meet both endocrine and autocrine needs of Vitamin D.

In the most recent revision of the dietary recommendations for Americans and Canadians in 1997, a recommended intake for Vitamin D was set in the absence of an estimation of mean requirements. There are now new data to estimate average requirements; however, there must be consideration of factors affecting need in populations and of total body tissue needs including the prevention and treatment of cancer. A recent study provides dietary dose-response data in the absence of sun exposure, and a mean requirement of 12.5microg (500IU) was found for Caucasian men. A seasonal build up (summer) and waning (winter) of Vitamin D stores implies that the requirement of Vitamin D in complete absence of yearly summertime sun exposure would approach levels of intake that mimic Vitamin D gained from sun exposure. High prevalence of Vitamin D insufficiency and the re-emergence of rickets have been observed worldwide. For many countries without mandatory staple food fortification, Vitamin D intake is often too low to sustain healthy circulating levels of 25 hydroxyvitamin D. Even in some countries that require (mandatory) or allow fortification (optional), Vitamin D intakes are low in some groups due to their unique dietary patterns, such as low milk consumption, vegetarian diet, limited or no use of dietary supplements, or changes away from traditional food consumption. Supplement use can significantly increase Vitamin D intakes across all age and gender groups but the benefit is primarily gained in persons whose intakes are close to adequate. African American men and women have greater prevalence of Vitamin D insufficiency, which may be a factor in their susceptibility to certain cancers. New recommendations for Vitamin D should be made for the otherwise healthy populations in greatest need of dietary Vitamin D due to lack of adequate sun exposure.