Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Johanna T. Dwyer is active.

Publication


Featured researches published by Johanna T. Dwyer.


Journal of Nutrition | 2011

Dietary Supplement Use in the United States, 2003–2006

Regan L. Bailey; Jaime J. Gahche; Cindy V. Lentino; Johanna T. Dwyer; Jody S. Engel; Paul R. Thomas; Joseph M. Betz; Christopher T. Sempos; Mary Frances Picciano

Dietary supplement use has steadily increased over time since the 1970s; however, no current data exist for the U.S. population. Therefore, the purpose of this analysis was to estimate dietary supplement use using the NHANES 2003-2006, a nationally representative, cross-sectional survey. Dietary supplement use was analyzed for the U.S. population (≥1 y of age) by the DRI age groupings. Supplement use was measured through a questionnaire and was reported by 49% of the U.S. population (44% of males, 53% of females). Multivitamin-multimineral use was the most frequently reported dietary supplement (33%). The majority of people reported taking only 1 dietary supplement and did so on a daily basis. Dietary supplement use was lowest in obese adults and highest among non-Hispanic whites, older adults, and those with more than a high-school education. Between 28 and 30% reported using dietary supplements containing vitamins B-6, B-12, C, A, and E; 18-19% reported using iron, selenium, and chromium; and 26-27% reported using zinc- and magnesium-containing supplements. Botanical supplement use was more common in older than in younger age groups and was lowest in those aged 1-13 y but was reported by ~20% of adults. About one-half of the U.S. population and 70% of adults ≥ 71 y use dietary supplements; one-third use multivitamin-multimineral dietary supplements. Given the widespread use of supplements, data should be included with nutrient intakes from foods to correctly determine total nutrient exposure.


Nutrition Research | 1998

Flavonoids : Dietary occurrence and biochemical activity

Julia Peterson; Johanna T. Dwyer

Flavonoids are plant phytochemicals that cannot be synthesized by humans. The six classes of flavonoids (flavanones, flavones, flavonols, isoflavonoids, anthocyanins, and flavans) vary in their structural characteristics around the heterocyclic oxygen ring. Flavanones occur predominantly in citrus fruits, flavones in herbs, isoflavonoids in legumes, anthocyanins and catechins in fruits and flavonols in all fruits and vegetables. Food preparation and processing of fresh fruits and vegetables may decrease flavonoid content by 50% owing to leaching into water or removal of portions of the plant that are rich in them. Grains and oils seeds have flavonoids, but processing removes or reduces them. Other plant food groups contain differing amounts of flavonoids. Honey, chocolate, and sweets that contain some plant constituents have flavonoids. Flavonoids are not present in animal foods. Dietary intake estimates vary from 23 mg/day to 1000 mg/day but the number of compounds and classes assessed vary, and all estimates currently are incomplete. In vitro and animal studies have demonstrated that flavonoids have antioxidant and antimutagenic activities. Case control studies suggest that flavonoids may reduce the risk of cardiovascular disease and stroke. Flavonoid classes vary in their absorption and their metabolism is still obscure. They are conjugated in the liver or kidney and excreted into bile or urine. Colonic bacteria split the heterocyclic ring and degrade the flavonoids to phenyl acids which may be absorbed, conjugated, and excreted or metabolized further by colonic bacteria.


Psychosomatic Medicine | 1998

Nonsurgical factors that influence the outcome of bariatric surgery: a review.

L. K. G. Hsu; Peter N. Benotti; Johanna T. Dwyer; Susan B. Roberts; Edward Saltzman; Scott A. Shikora; Barbara J. Rolls; William M. Rand

Objective Severe obesity (ie, at least 100% overweight or body mass index >or=to40 kg/m2) is associated with significant morbidity and increased mortality. It is apparently becoming more common in this country. Conventional weight-loss treatments are usually ineffective for severe obesity and bariatric surgery is recommended as a treatment option. However, longitudinal data on the long-term outcome of bariatric surgery are sparse. Available data indicate that the outcome of bariatric surgery, although usually favorable in the short term, is variable and weight regain sometimes occurs at 2 years after surgery. The objective of this study is to present a review of the outcome of bariatric surgery in three areas: weight loss and improvement in health status, changes in eating behavior, and psychosocial adjustment. The study will also review how eating behavior, energy metabolism, and psychosocial functioning may affect the outcome of bariatric surgery. Suggestions for additional research in these areas are made. Method Literature review. Results On average, most patients lose 60% of excess weight after gastric bypass and 40% after vertical banded gastroplasty. In about 30% of patients, weight regain occurs at 18 months to 2 years after surgery. Binge eating behavior, which is common among the morbidly obese, may recur after surgery and is associated with weight regain. Energy metabolism may affect the outcome of bariatric surgery, but it has not been systematically studied in this population. Presurgery psychosocial functioning does not seem to affect the outcome of surgery, and psychosocial outcome is generally encouraging over the short term, but there are reports of poor adjustment after weight loss, including alcohol abuse and suicide. Conclusions Factors leading to poor outcome of bariatric surgery, such as binge eating and lowered energy metabolism, should be studied to improve patient selection and outcome. Long-term outcome data on psychosocial functioning are lacking. Longitudinal studies to examine the long-term outcome of bariatric surgery and the prognostic indicators are needed.


The New England Journal of Medicine | 1982

Estrogen Excretion Patterns and Plasma Levels in Vegetarian and Omnivorous Women

Barry R. Goldin; Herman Adlercreutz; Sherwood L. Gorbach; James H. Warram; Johanna T. Dwyer; Linda Swenson; Margo N. Woods

We studied 10 vegetarian and 10 nonvegetarian premenopausal women on four occasions approximately four months apart. During each study period, the participants kept three-day dietary records, and estrogens were measured in plasma, urinary, and fecal samples. Vegetarians consumed less total fat than omnivores did (30 per cent of total calories, as compared with 40 per cent) and more dietary fiber (28 g per day, as compared with 12 g). There was a positive correlation between fecal weight and fecal excretion of estrogens in both groups (P less than 0.001), with vegetarians having higher fecal weight and increased fecal excretion of estrogens. Urinary excretion of estriol was lower in vegetarians (P less than 0.05), and their plasma levels of estrone and estradiol were negatively correlated with fecal excretion of estrogen (P = 0.005). Among the vegetarians the beta-glucuronidase activity of fecal bacteria was significantly reduced (P = 0.05). We conclude that vegetarian women have an increased fecal output, which leads to increased fecal excretion of estrogen and a decreased plasma concentration of estrogen.


Journal of Nutrition | 2010

Estimation of Total Usual Calcium and Vitamin D Intakes in the United States

Regan L. Bailey; Kevin W. Dodd; Joseph Goldman; Jaime J. Gahche; Johanna T. Dwyer; Alanna J. Moshfegh; Christopher T. Sempos; Mary Frances Picciano

Our objective in this study was to estimate calcium intakes from food, water, dietary supplements, and antacids for U.S. citizens aged >or=1 y using NHANES 2003-2006 data and the Dietary Reference Intake panel age groupings. Similar estimates were calculated for vitamin D intake from food and dietary supplements using NHANES 2005-2006. Diet was assessed with 2 24-h recalls; dietary supplement and antacid use were determined by questionnaire. The National Cancer Institute method was used to estimate usual nutrient intake from dietary sources. The mean daily nutrient intake from supplemental sources was added to the adjusted dietary intake estimates to produce total usual nutrient intakes for calcium and vitamin D. A total of 53% of the U.S. population reported using any dietary supplement (2003-2006), 43% used calcium (2003-2006), and 37% used vitamin D (2005-2006). For users, dietary supplements provided the adequate intake (AI) recommendation for calcium intake for approximately 12% of those >or=71 y. Males and females aged 1-3 y had the highest prevalence of meeting the AI from dietary and total calcium intakes. For total vitamin D intake, males and females >or=71, and females 14-18 y had the lowest prevalence of meeting the AI. Dietary supplement use is associated with higher prevalence of groups meeting the AI for calcium and vitamin D. Monitoring usual total nutrient intake is necessary to adequately characterize and evaluate the populations nutritional status and adherence to recommendations for nutrient intake.


The Lancet | 1982

EXCRETION OF THE LIGNANS ENTEROLACTONE AND ENTERODIOL AND OF EQUOL IN OMNIVOROUS AND VEGETARIAN POSTMENOPAUSAL WOMEN AND IN WOMEN WITH BREAST CANCER

Herman Adlercreutz; R. Heikkinen; M. Woods; Theodore Fotsis; Johanna T. Dwyer; Barry R. Goldin; Sherwood L. Gorbach

Dietary studies and assays of urinary lignans in postmenopausal women showed that lignan excretion is significantly lower in urine of women with breast cancer than in normal omnivorous and vegetarian women and confirmed that there is a significant correlation between fibre intake and lignan excretion. It is suggested that the precursors of the human lignans enterolactone and enterodiol formed by the intestinal microflora are to be found in fibre-rich foods such as grains, nuts, and legumes. Excretion of equol, which has antioestrogenic properties, was similar in all groups studied and did not correlate with fibre intake, but occasional high values were found in some subjects.


The American Journal of Clinical Nutrition | 2012

Flavonoid intake and cardiovascular disease mortality in a prospective cohort of US adults

Marjorie L. McCullough; Julia J. Peterson; Roshni Patel; Paul F. Jacques; Roma Shah; Johanna T. Dwyer

BACKGROUND Flavonoids are plant-based phytochemicals with cardiovascular protective properties. Few studies have comprehensively examined flavonoid classes in relation to cardiovascular disease mortality. OBJECTIVE We examined the association between flavonoid intake and cardiovascular disease (CVD) mortality among participants in a large, prospective US cohort. DESIGN In 1999, a total of 38,180 men and 60,289 women in the Cancer Prevention Study II Nutrition Cohort with a mean age of 70 and 69 y, respectively, completed questionnaires on medical history and lifestyle behaviors, including a 152-item food-frequency questionnaire. Cox proportional hazards modeling was used to calculate multivariate-adjusted hazard RRs and 95% CIs for associations between total flavonoids, 7 flavonoid classes, and CVD mortality. RESULTS During 7 y of follow-up, 1589 CVD deaths in men and 1182 CVD deaths in women occurred. Men and women with total flavonoid intakes in the top (compared with the bottom) quintile had a lower risk of fatal CVD (RR: 0.82; 95% CI: 0.73, 0.92; P-trend = 0.01). Five flavonoid classes-anthocyanidins, flavan-3-ols, flavones, flavonols, and proanthocyanidins-were individually associated with lower risk of fatal CVD (all P-trend < 0.05). In men, total flavonoid intakes were more strongly associated with stroke mortality (RR: 0.63; 95% CI: 0.44, 0.89; P-trend = 0.04) than with ischemic heart disease (RR: 0.90; 95% CI: 0.72, 1.13). Many associations appeared to be nonlinear, with lower risk at intakes above the referent category. CONCLUSIONS Flavonoid consumption was associated with lower risk of death from CVD. Most inverse associations appeared with intermediate intakes, suggesting that even relatively small amounts of flavonoid-rich foods may be beneficial.


Journal of Nutrition | 2011

Foods, Fortificants, and Supplements: Where Do Americans Get Their Nutrients?

Victor L. Fulgoni; Debra R. Keast; Regan L. Bailey; Johanna T. Dwyer

Limited data are available on the source of usual nutrient intakes in the United States. This analysis aimed to assess contributions of micronutrients to usual intakes derived from all sources (naturally occurring, fortified and enriched, and dietary supplements) and to compare usual intakes to the Dietary Reference Intake for U.S. residents aged ≥2 y according to NHANES 2003–2006 (n = 16,110). We used the National Cancer Institute method to assess usual intakes of 19 micronutrients by source. Only a small percentage of the population had total usual intakes (from dietary intakes and supplements) below the estimated average requirement (EAR) for the following: vitamin B-6 (8%), folate (8%), zinc (8%), thiamin, riboflavin, niacin, vitamin B-12, phosphorus, iron, copper, and selenium (<6% for all). However, more of the population had total usual intakes below the EAR for vitamins A, C, D, and E (34, 25, 70, and 60%, respectively), calcium (38%), and magnesium (45%). Only 3 and 35% had total usual intakes of potassium and vitamin K, respectively, greater than the adequate intake. Enrichment and/or fortification largely contributed to intakes of vitamins A, C, and D, thiamin, iron, and folate. Dietary supplements further reduced the percentage of the population consuming less than the EAR for all nutrients. The percentage of the population with total intakes greater than the tolerable upper intake level (UL) was very low for most nutrients, whereas 10.3 and 8.4% of the population had intakes greater than the UL for niacin and zinc, respectively. Without enrichment and/or fortification and supplementation, many Americans did not achieve the recommended micronutrient intake levels set forth in the Dietary Reference Intake.


International Journal of Obesity | 2002

Binge eating disorder in extreme obesity.

L. K. G. Hsu; B. Mulliken; B. Mcdonagh; S. Krupa Das; William M. Rand; C. G. Fairburn; Barbara J. Rolls; Megan A. McCrory; Edward Saltzman; Scott A. Shikora; Johanna T. Dwyer; Susan B. Roberts

OBJECTIVE: To determine whether extremely obese binge eating disorder (BED) subjects (BED defined by the Eating Disorder Examination) differ from their extremely obese non-BED counterparts in terms of their eating disturbances, psychiatric morbidity and health status.DESIGN: Prospective clinical comparison of BED and non-BED subjects undergoing gastric bypass surgery (GBP).SUBJECTS: Thirty seven extremely obese (defined as BMI ≥40 kg/m2) subjects (31 women, six men), aged 22–58 y.MEASUREMENTS: Eating Disorder Examination 12th Edition (EDE), Three Factor Eating Questionnaire (TFEQ), Structured Clinical Interview for the Diagnostic and Statistical Manual-IV (SCID-IV), Short-Form Health Status Survey (SF-36), and 24 h Feeding Paradigm.RESULTS: Twenty-five percent of subjects were classified as BED (11% met full and 14% partial BED criteria) and 75% of subjects were classified as non-BED. BED (full and partial) subjects had higher eating disturbance in terms of eating concern and shape concern (as found by the EDE), higher disinhibition (as found by the TFEQ), and they consumed more liquid meal during the 24 h feeding paradigm. No difference was found in psychiatric morbidity between BED and non-BED in terms of DSM-IV Axis I diagnosis. The health status scores of both BED and non-BED subjects were significantly lower than US norms on all subscales of the SF-36, particularly the BED group.CONCLUSION: Our findings support the validity of the category of BED within a population of extremely obese individuals before undergoing GBP. BED subjects differed from their non-BED counterparts in that they had a greater disturbance in eating attitudes and behavior, a poorer physical and mental health status, and a suggestion of impaired hunger/satiety control. However, in this population of extremely obese subjects, the stability of BED warrants further study.


Early Human Development | 2000

Dietary essential fatty acids, long-chain polyunsaturated fatty acids, and visual resolution acuity in healthy fullterm infants: a systematic review

John Paul SanGiovanni; Catherine S. Berkey; Johanna T. Dwyer; Graham A. Colditz

BACKGROUND Biologically active neural tissue is rich in docosahexaenoic acid (DHA), an omega-3 long-chain polyunsaturated fatty acid (LCPUFA). We conducted a systematic review to examine the nature of discordant results from studies designed to test the hypothesis that dietary DHA leads to better performance on visually-based tasks in healthy, fullterm infants. We also conducted a meta-analysis to derive combined estimates of behavioral- and electrophysiologic-based visual resolution acuity differences and sample sizes that would be useful in planning future research. STUDY DESIGN AND METHODS Twelve empirical studies on LCPUFA intake during infancy and visual resolution acuity were identified through bibliographic searches, examination of monograph and review article reference lists, and written requests to researchers in the field. Works were reviewed for quality and completeness of information. Study design and conduct information was extracted with a standardized protocol. Acuity differences between groups consuming a source of DHA and groups consuming DHA-free diets were calculated as a common outcome from individual studies; this difference score was evaluated against a null value of zero and then used, with the method of DerSimonian and Laird (Meta-analysis in clinical trials. Control Clin Trials 1986;7:177-188), to derive combined estimates of visual resolution acuity differences within seven age categories. RESULTS OF RANDOMIZED COMPARISONS: The combined visual resolution acuity difference measured with behaviorally based methods between DHA-supplemented formula fed groups and DHA-free formula fed groups is 0.32+/-0.09 octaves (combined difference+/-S.E.M., P=0.0003) at 2 months of age. The direction of this value indicates higher acuity in DHA-fed groups. RESULTS OF NON-RANDOMIZED STUDY DESIGNS: The combined visual resolution acuity difference measured with behaviorally based methods between human milk fed groups and DHA-free formula fed groups is 0.49+/-0.09 octaves (P< or =0.000001) at 2 months of age and 0.18+/-0.08 octaves (P=0.04) at 4 months of age. Acuity differences for electrophysiologic-based measures are also greater than zero at 4 months (0.37+/-0.16 octaves, P=0.02). CONCLUSION Some aspect of dietary n-3 intake is associated with performance on visual resolution acuity tasks at 2, and possibly, 4 months of age in healthy fullterm infants. Whether n-3 intake confers lasting advantage in the development of visually based processes is still in question.

Collaboration


Dive into the Johanna T. Dwyer's collaboration.

Top Co-Authors

Avatar

Leila G. Saldanha

National Institutes of Health

View shared research outputs
Top Co-Authors

Avatar

Mary Frances Picciano

National Institutes of Health

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Karen Andrews

United States Department of Agriculture

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Jaime J. Gahche

National Center for Health Statistics

View shared research outputs
Top Co-Authors

Avatar

Joseph M. Betz

National Institutes of Health

View shared research outputs
Top Co-Authors

Avatar

Joanne M. Holden

Agricultural Research Service

View shared research outputs
Top Co-Authors

Avatar

Elizabeth A. Yetley

National Institutes of Health

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge