PubMed Health⌕ Search

Biomedical subjects

Susan J Whiting

Publications and source records attributed to Susan J Whiting.

At least 19 recordsLinked to original sources
PubMed2007

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.

Asia↗
PubMed2006

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.

Aged↗
PubMed2006

Calcium supplementation trials and bone mass development in children, adolescents, and young adults.

The development of bone mass during childhood through young adulthood is an important determinant of bone health later in life, and calcium is the major building block. Most randomized, double-blind, placebo-controlled trials of calcium supplementation have been done in girls; however, calcium supplementation in boys has been investigated in recent studies. Positive short-term effects on bone measures during growth has been shown in boys and girls, particularly in weight-bearing appendicular bone, although the lifelong effect is not certain.

Adolescent↗
PubMed2006

Dietary Reference Intakes for the micronutrients: considerations for physical activity.

The Dietary Reference Intakes (DRIs) are a set of recommendations for healthy persons. For the most part, recommendations are determined experimentally under controlled conditions of light activity. During increased physical activity, it is expected that micronutrient requirements would increase relative to the inactive state. Micronutrients of interest to athletes are those associated with oxygen handling and delivery, such as iron, and vitamin D, a newly emerging function of which is to maintain muscle strength. The DRI report on electrolytes (including water) is the most recent set of recommendations. In addition to recommendations for intakes to meet needs, many micronutrients have an upper level that indicates caution in consuming a large amount. We illustrate the process of setting DRI values for the micronutrients (including electrolytes and water), and provide a summary of instances where physical activity needs were considered when DRI values were derived. Understanding the origin of DRI values for micronutrients will assist in understanding how to use the values in assessment and planning.

Diet↗
PubMed2006

Symposium overview. Dietary Reference Intakes: considerations for physical activity.

The following series of papers comprise a symposium on Dietary Reference Intakes (DRIs), which are the new dietary recommendations for North Americans, that was presented at the 2004 Annual Meeting of the Canadian Society for Exercise Physiology. The process of developing the DRIs has been an enormous undertaking resulting, thus far, in 12 book-length reports spanning from 1997 to 2004. It was therefore timely to review the recommendations, describe the considerations for physical activity that went into setting the recommendations, and, where possible, indicate how the DRIs may be applied to athletes.

Humans↗
PubMed2006

Dietary intakes of Canadians in the 1990s using population-weighted data derived from the provincial nutrition surveys.

Provincial nutrition surveys of adults were conducted between 1990 and 1999 in Canada. Eight reports have been issued, and one is forthcoming. The purpose of this study was to estimate the national dietary intake of adult Canadians, using the publicly available data. Group mean-nutrient-intake data from 16 915 adults, aged 18 to 84 years, from published provincial reports were collated by age and sex for each of 9 provinces (Manitoba data were unavailable). Using Canadian census data appropriate to the year of collection, intake data were weighted to provide 1 national intake value for each nutrient, by 8 age and sex categories. In general, the energy and nutrient intake of adults decreased with age. For every age group, with the exception of vitamin C, intake of nutrients by men was greater than that by women. On the basis of a comparison of recently recommended intakes (Dietary Reference Intakes), the nutrients that are of concern because of inadequate intake include dietary fibre, calcium, magnesium, and folate. The data demonstrate the impact of folate fortification on folate intake; the mean intake became twice that of prefortification levels. This study used group mean-intake data; therefore, we cannot make definitive conclusions about the prevalence of inadequacy for the nutrients. Because of limitations with some provincial response rates, our data should not be construed as representative of the Canadian population. However, because these surveys were completed between the 19701972 Nutrition Canada Survey and the 2004 Canadian Community Health Survey, these population-weighted data might be a useful point of comparison for monitoring trends in nutrient intake from food.

Adult↗
PubMed2006

Relationships of activity and sugar drink intake on fat mass development in youths.

PURPOSE: To determine whether a significant relationship exists between fat mass (FM) development and physical activity (PA) and/or sugar-sweetened drink (SD) consumption in healthy boys and girls aged 8-19 yr. METHODS: A total of 105 males and 103 females were assessed during childhood and adolescence for a maximum of 7 yr and a median of 5 yr. Height was measured biannually. Fat-free mass (FFM) and FM were assessed annually by dual x-ray absorptiometry (DXA). PA was evaluated two to three times annually using the PAQ-C/A. Energy intake and SD were assessed using a 24-h dietary intake questionnaire also completed two to three times per year. Years from peak height velocity were used as a biological maturity age indicator. Multilevel random effects models were used to test the relationship. RESULTS: When controlling for maturation, FFM, and energy intake adjusted for SD, PA level was negatively related to FM development in males (P<0.05) but not in females (P>0.05). In contrast, there was no relationship between SD and FM development of males or females (P>0.05). There was also no interaction effect between SD and PA (P>0.05) with FM development. CONCLUSION: This finding lends support to the idea that increasing PA in male youths aids in the control of FM development. Models employed showed no relationship between SD and FM in either gender.

Adipose Tissue↗
PubMed2005

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.

Autocrine Communication↗
PubMed2005

Effects of thickened beverages fortified with inulin on beverage acceptance, gastrointestinal function, and bone resorption in institutionalized adults.

OBJECTIVES: We wanted to develop thickened beverages that contain soluble fiber (inulin) with acceptable consistency, taste, and texture and to determine the effects of these beverages on bone resorption markers (to determine calcium retention), bowel frequency, and indicators of gastrointestinal function in institutionalized adults bound to wheelchairs. METHODS: A double-blind, 3-wk, cross-over study testing 13-g/d inulin-fortified versus isocaloric standard modified starch-thickened beverages was conducted in institutionalized adults who were bound to wheelchairs and had dysphagia or did not have dysphagia. Beverage acceptability, as assessed by discriminative and descriptive sensory testing, bowel frequency, fecal output, and laxative use, were determined by direct testing or by nursing charts. Bone resorption was measured by using the urinary excretion of fasting calcium and of cross-linked N-telopeptides of collagen. RESULTS: Sensory panelists were unable to detect a difference between beverages thickened with modified starch and those fortified with inulin. Few differences were found between the control and inulin-fortified beverages for sensory descriptors. No significant difference was found in frequency of bowel movements between treatments; however, weighted bowel movement frequency increased by 13% with inulin (P < 0.01), whereas enema and laxative administration decreased by 13% (P < 0.05). Bone resorption, as an indicator of calcium retention, remained unchanged. CONCLUSIONS: Inulin was incorporated into thickened beverages, with no decrease in acceptability; when consumed, perceived stool output increased in residents of long-term care facilities.

Adult↗
PubMed2005

Effects of flax fiber on laxation and glycemic response in healthy volunteers.

We investigated whether a flax supplement taken orally or baked in a bakery product would effect the physiological responses characteristic of soluble and insoluble fiber, i.e., laxation and glycemic response, respectively. In Study 1, 26 healthy young adults consumed up to 15 g of fiber from a proprietary flax fiber supplement or as a psyllium supplement for 2 weeks once usual fecal weights were established. Changes in dietary fiber intake and acceptability of both products were evaluated. An increase in fecal weight was found with both fiber treatments. Supplemental fiber at intakes of 9.0 g/day (flax) and 10.4 g/day (psyllium) gave fecal bulking capacity of about 2.9 and 4.8 g of fecal weight/g of fiber, respectively. In Study 2, the effect of flax bread versus control white bread on glycemic response was studied. Eleven fasting subjects completed four test periods (duplicate trials of each bread) under standardized glycemic testing conditions. Paired t tests were used to analyze test compared with control peak blood glucose values (6.6 +/- 0.9 mmol/L compared with 6.9 +/- 0.7 mmol/L, P < .05, respectively) and area under the curve (AUC) (669 +/- 53 compared with 693 +/- 57, P = .015, respectively). Peak blood glucose values and AUC were improved by ingestion of flax fiber in healthy subjects. In conclusion, a flax fiber supplement provides the benefits of soluble and insoluble fiber.

Adult↗
PubMed2005

Positive effects of vegetable and fruit consumption and calcium intake on bone mineral accrual in boys during growth from childhood to adolescence: the University of Saskatchewan Pediatric Bone Mineral Accrual Study.

BACKGROUND: Nutrition is an important modifiable factor in the development of bone mass during adolescence. Recent studies of children and adolescents examined the effects of foods such as milk products and fruit and vegetables on bone growth; however, few studies included both boys and girls. OBJECTIVE: The purpose was to ascertain the role of consumption of milk products and vegetables and fruit in the accrual of total-body bone mineral content (TBBMC) in boys and girls from childhood to late adolescence. DESIGN: Seven-year longitudinal data were obtained from 85 boys and 67 girls aged 8-20 y. Biological maturity was defined by the number of years from the age at peak height velocity. Dietary intake was assessed by serial 24-h recalls. Anthropometric measurements and physical activity were assessed every 6 mo. TBBMC assessed with dual-energy X-ray absorptiometry in the fall of each year was the indicator of bone mass. RESULTS: Most boys (87.8%) met Canadian recommendations for milk product intake. Few subjects (<30%) consumed vegetables and fruit in recommended amounts. Using a multilevel modeling statistical approach containing important biological and environmental factors, we found that vegetable and fruit intakes, calcium intake, and physical activity were significant independent environmental predictors of TBBMC in boys but not in girls. CONCLUSIONS: In addition to adequate dietary calcium intake, appropriate intakes of vegetables and fruit have a beneficial effect on TBBMC in boys aged 8-20 y. Underreporting of dietary intake by girls may explain why this effect was not apparent in girls.

Absorptiometry, Photon↗
PubMed2005

Season and ethnicity are determinants of serum 25-hydroxyvitamin D concentrations in New Zealand children aged 5-14 y.

New Zealand children, particularly those of Māori and Pacific ethnicity, may be at risk for low vitamin D status because of low vitamin D intakes, the country's latitude (35-46 degrees S), and skin color. The aim of this study was to determine 25-hydroxyvitamin D concentrations and their determinants in a national sample of New Zealand children aged 5-14 y. The 2002 National Children's Nutrition Survey was designed to survey New Zealand children, including oversampling of Māori and Pacific children to allow ethnic-specific analyses. A 2-stage recruitment process occurred using a random selection of schools, and children within each school. Serum 25-hydroxyvitamin D concentration [mean (99% CI) nmol/L] in Māori children (n = 456) was 43 (38,49), in Pacific (n = 646) 36 (31,42), and in New Zealand European and Others (NZEO) (n = 483) 53 (47,59). Among Māori, Pacific, and NZEO, the prevalence (%, 99% CI) of serum 25-hydroxyvitamin D deficiency (<17.5 nmol/L) was 5 (2,12), 8 (5,14), and 3 (1,7), respectively. The prevalence of insufficiency (<37.5 nmol/L) was 41 (29,53), 59 (42,75), and 25 (15,35), respectively. Multiple regression analysis found that 25-hydroxyvitamin D concentrations were lower in winter than summer [adjusted mean difference (99% CI) nmol/L; 15 (8,22)], lower in girls than boys [5 (1,10)], and lower in obese children than in those of "normal" weight [6 (1,11)]. Relative to NZEO, 25-hydroxyvitamin D concentrations were lower in Māori [9 (3,15)] and Pacific children [16 (10,22)]. Ethnicity and season are major determinants of serum 25-hydroxyvitamin D. There is a high prevalence of vitamin D insufficiency in New Zealand children, which may or may not contribute to increased risk of osteoporosis and other chronic disease. There is a pressing need for more convincing evidence concerning the health risks associated with the low vitamin D status in New Zealand children.

Adolescent↗
PubMed2005

Dietary recommendations for vitamin D: a critical need for functional end points to establish an estimated average requirement.

From its inaugural value in 1941, the Recommended Dietary Allowance (RDA) for adults for vitamin D has remained close to 400 IU (10 microg) level. This original recommended intake was based on the observation that the amount of vitamin D activity in a teaspoon of cod liver oil was sufficient to prevent rickets in infants. Since that time until 1997, determination of vitamin D requirements and status was more conjecture than science. In 1997, when the recommended intake level of vitamin D was set as an adequate intake value rather than an RDA, much has been learned about metabolism of vitamin D. The circulating metabolite 25-hydroxyvitamin D is the major static indicator of vitamin D status. Using its response to diet in the absence of sun exposure, a dose-response study suggests a mean requirement of at least 500 IU (12.5 microg) from which an RDA could be set. Other factors may need adjustment, such as sun exposure and body fat. However, functional indicators of status are needed. The role of vitamin D in calcium metabolism (i.e., calciotropic functions) is better understood; bone turnover and parathyroid hormone are potential indicators. Vitamin D has noncalciotropic functions arising from extrarenal synthesis of the active metabolite 1,25 dihydroxyvitamin D involving cell proliferation and immunity, from which function indicators of status may be derived. Despite gaps in our knowledge, there are data from which new dietary reference intake values for vitamin D may be set.

Canada↗
PubMed2005

Vitamin D intake: a global perspective of current status.

Global high prevalence of vitamin D insufficiency and re-emergence of rickets and the growing scientific evidence linking low circulating 25-hydroxyvitamin D to increased risk of osteoporosis, diabetes, cancer, and autoimmune disorders have stimulated recommendations to increase sunlight (UVB) exposure as a source of vitamin D. However, concern over increased risk of melanoma with unprotected UVB exposure has led to the alternative recommendation that sufficient vitamin D should be supplied through dietary sources alone. Here, we examine the adequacy of vitamin D intake worldwide and evaluate the ability of current fortification policies and supplement use practices among various countries to meet this recommendation. It is evident from our review that vitamin D intake is often too low to sustain healthy circulating levels of 25-hydroxyvitamin D in countries without mandatory staple food fortification, such as with milk and margarine. Even in countries that do fortify, vitamin D intakes are low in some groups due to their unique dietary patterns, such as low milk consumption, vegetarian diet, limited use of dietary supplements, or loss of traditional high fish intakes. Our global review indicates that dietary supplement use may contribute 6-47% of the average vitamin D intake in some countries. Recent studies demonstrate safety and efficacy of community-based vitamin D supplementation trials and food staple fortification introduced in countries without fortification policies. Reliance on the world food supply as an alternative to UVB exposure will necessitate greater availability of fortified food staples, dietary supplement use, and/or change in dietary patterns to consume more fish.

Chronic Disease↗
PubMed2004

The canadian health claim for calcium, vitamin d and osteoporosis.

To provide evidence for or against allowing a health claim for calcium in Canada, we undertook a review of the current U.S. health claim for calcium and osteoporosis, and also reviewed the scientific literature published since that health claim was first proposed and reviewed by the U.S. Food and Drug Administration in 1991 and adopted in 1993. Our objectives were 1) to determine if the science behind the claim was still valid, and if so, 2) to recommend any new wording to the claim, if warranted, prior to implementation in Canada. Based on a review of the evidence (to May 2000) related to the various claim elements, the following health claim for calcium has been established in Canada: A healthy diet with adequate calcium and vitamin D, and regular physical activity, help to achieve strong bones and may reduce the risk of osteoporosis. The compositional criteria for foods bearing this claim are that the food must provide at least 200 mg calcium per serving and that the phosphorus content (excluding that provided by phytate) must be less than the calcium content.

Calcium, Dietary↗
PubMed2004

Vitamin D fortification in the United States and Canada: current status and data needs.

Most circulating 25-hydroxyvitamin D originates from exposure to sunlight; nevertheless, many factors can impair this process, necessitating periodic reliance on dietary sources to maintain adequate serum concentrations. The US and Canadian populations are largely dependent on fortified foods and dietary supplements to meet these needs, because foods naturally rich in vitamin D are limited. Fluid milk and breakfast cereals are the predominant vehicles for vitamin D in the United States, whereas Canada fortifies fluid milk and margarine. Reports of a high prevalence of hypovitaminosis D and its association with increased risks of chronic diseases have raised concerns regarding the adequacy of current intake levels and the safest and most effective way to increase vitamin D intake in the general population and in vulnerable groups. The usual daily intakes of vitamin D from food alone and from food and supplements combined, as estimated from the US third National Health and Nutrition Examination Survey, 1988-1994, show median values above the adequate intake of 5 microg/d for children 6-11 y of age; however, median intakes are generally below the adequate intake for female subjects > 12 y of age and men > 50 y. In Canada, there are no national survey data for estimation of intake. Cross-sectional studies suggest that current US/Canadian fortification practices are not effective in preventing hypovitaminosis D, particularly among vulnerable populations during the winter, whereas supplement use shows more promise. Recent prospective intervention studies with higher vitamin D concentrations provided evidence of safety and efficacy for fortification of specific foods and use of supplements.

Adolescent↗