Position of the American Dietetic Association and Dietitians of Canada: women's health and nutrition

Effect of Non-Nutritive Sweeteners on the Gut Microbiota

The human gut microbiota, a complex community of microorganisms living in the digestive tract, consists of more than 1500 species distributed in more than 50 different phyla, with 99% of bacteria coming from about 30-40 species. The colon alone, which contains the largest population of the diverse human microbiota, can harbor up to 100 trillion bacteria. The gut microbiota is essential in maintaining normal gut physiology and health. Therefore, its disruption in humans is often associated with various pathological conditions. Different factors can influence the composition and function of the gut microbiota, including host genetics, age, antibiotic treatments, environment, and diet. The diet has a marked effect, impacting the gut microbiota composition, beneficially or detrimentally, by altering some bacterial species and adjusting the metabolites produced in the gut environment. With the widespread use of non-nutritive sweeteners (NNS) in the diet, recent investigations have focused on their effect on the gut microbiota as a mediator of the potential impact generated by gastrointestinal-related disturbances, such as insulin resistance, obesity, and inflammation. We summarized the results from pre-clinical and clinical studies published over the last ten years that examined the single effects of the most consumed NNS: aspartame, acesulfame-K, sucralose, and saccharin. Pre-clinical studies have given conflicting results for various reasons, including the administration method and the differences in metabolism of the same NNS among the different animal species. A dysbiotic effect of NNS was observed in some human trials, but many other randomized controlled trials reported a lack of significant impacts on gut microbiota composition. These studies differed in the number of subjects involved, their dietary habits, and their lifestyle; all factors related to the baseline composition of gut microbiota and their response to NNS. The scientific community still has no unanimous consensus on the appropriate outcomes and biomarkers that can accurately define the effects of NNS on the gut microbiota.

Soy isoflavones, estrogen therapy, and breast cancer risk: analysis and commentary

There has been considerable investigation of the potential for soyfoods to reduce risk of cancer, and in particular cancer of the breast. Most interest in this relationship is because soyfoods are essentially a unique dietary source of isoflavones, compounds which bind to estrogen receptors and exhibit weak estrogen-like effects under certain experimental conditions. In recent years the relationship between soyfoods and breast cancer has become controversial because of concerns – based mostly on in vitro and rodent data – that isoflavones may stimulate the growth of existing estrogen-sensitive breast tumors. This controversy carries considerable public health significance because of the increasing popularity of soyfoods and the commercial availability of isoflavone supplements. In this analysis and commentary we attempt to outline current concerns regarding the estrogen-like effects of isoflavones in the breast focusing primarily on the clinical trial data and place these concerns in the context of recent evidence regarding estrogen therapy use in postmenopausal women. Overall, there is little clinical evidence to suggest that isoflavones will increase breast cancer risk in healthy women or worsen the prognosis of breast cancer patients. Although relatively limited research has been conducted, and the clinical trials often involved small numbers of subjects, there is no evidence that isoflavone intake increases breast tissue density in pre- or postmenopausal women or increases breast cell proliferation in postmenopausal women with or without a history of breast cancer. The epidemiologic data are generally consistent with the clinical data, showing no indication of increased risk. Furthermore, these clinical and epidemiologic data are consistent with what appears to be a low overall breast cancer risk associated with pharmacologic unopposed estrogen exposure in postmenopausal women. While more research is required to definitively allay concerns, the existing data should provide some degree of assurance that isoflavone exposure at levels consistent with historical Asian soyfood intake does not result in adverse stimulatory effects on breast tissue.

Older Black Women Differ in Calcium Intake Source Compared to Age– and Socioeconomic Status–Matched White Women

Racial disparity in osteoporosis between older black and white women is well established; however, less is known regarding daily dietary and supplemental calcium intake in these populations. Moreover, racial differences in calcium intake are confounded by differences in socioeconomic status (SES). The objective of this study was to assess calcium intake and source in older black women (n=33) and white women (n=33), matched in age and SES. Calcium intake and source were evaluated by interview using a 46-item calcium food frequency questionnaire including all food groups and supplements. Black and white women were identical in SES and matched on age (black women 66.9+/-6.2 years vs white women 67.1+/-5.5 years [mean+/-standard deviation], P=0.85). No significant difference existed for dietary calcium intake between black and white women (974+/-524 vs 1,070+/-600 mg/day; P=0.65) or total calcium intake between black and white women (1,485+/-979 vs 1,791+/-887 mg/day; P=0.15). Dairy foods contributed most to dietary calcium intake in black and white women and differed by race (black women 402+/-269 mg/day, white women, 603+/-376 mg/day; P=0.02). Calcium intake from grains differed by race (black women 205+/-201 mg/day vs white women 130+/-234 mg/day; P=0.010) and fortified cereals were a major source of calcium for black women. Calcium supplementation contributed substantially to total calcium intake in both groups, with more white women (n=23, 70%) using supplements than black women did (n=19, 58%). However, no racial difference existed in supplemented calcium intake (black women, n=19; 889+/-605 vs white women, n=23; 1,034+/-460 mg/day; P=0.20). Our data suggest that total daily dietary and supplemental calcium intakes do not differ, but calcium intake from dairy foods and from grains differ in older black and white women matched in age and SES.

Models for nutrition education to increase consumption of calcium and dairy products among African Americans

Calcium and dairy consumption are documented to be low among African Americans and have demonstrated benefits to bone growth, overall nutritional status, and health throughout the life cycle. There is also an emerging relationship to the prevention of obesity. This low consumption has been attributed to both cultural and community/environmental barriers. Using a life course construct and an ecological model of health behavior, this paper will illustrate why nutrition education and food consumption behavior at one stage of the life cycle may influence health status at that stage as well as influence health and consumption of calcium and dairy products at subsequent stages. The life course construct recognizes that both past and present behavior and experiences (in this case food and nutrient intake) are shaped by the wider social, economic, and cultural context and therefore may provide clues to current patterns of health and disease. The ecological model, concerned with constructs of environmental change, behavior, and policies that may help people make choices in their daily life, complements the life course approach when examining the potential influence of nutrition education provided by federally funded food and nutrition programs on calcium and dairy consumption behavior across the life cycle. The "critical period model" within the life course construct is operative for calcium, a nutrient for which adequate intake is critically important during adolescence when peak bone density development, necessary for later protection against osteoporosis, is important.

Group parent training: a novel approach for the treatment of eating disorders

This paper describes the rationale, development, and implementation of a group parent training program designed to assist caregivers in the management of their child's eating disorder while facilitating the development of a healthy home environment for sustained change. The content of this program instructs caregivers in disorder management and capitalizes on caregivers as role models of adaptive behavior. Strategies are provided to address acute disorder management, features of caregivers that may impede task implementation, and environmental and attitudinal changes. The group format enhances social support, accountability, and self-efficacy. A preliminary qualitative evaluation and future directions are described to assist healthcare professionals in better meeting the needs of caregivers of these disorders.

Eating Disorders

HEALTH ISSUE: Eating disorders are an increasing public health problem among young women. Anorexia and bulimia may give rise to serious physical conditions such as hypothermia, hypotension, electrolyte imbalance, endocrine disorders, and kidney failure. KEY ISSUES: Eating disorders are primarily a problem among women. In Ontario in 1995, over 90% of reported hospitalized cases of anorexia and bulimia were women. In addition to eating disorders, preoccupation with weight, body image and self-concept disturbances, are more prevalent among women than men.Women with eating disorders are also at risk for long-term psychological and social problems, including depression, anxiety, substance abuse and suicide. For instance, in 2000, the prevalence of depression among women who were hospitalized with a diagnosis of anorexia (11.5%) or bulimia (15.4 %) was more than twice the rate of depression (5.7 %) among the general population of Canadian women. The highest incidence of depression was found in women aged 25 to 39 years for both anorexia and bulimia. DATA GAPS AND RECOMMENDATIONS: Hospitalization data are the most recent and accessible information available. However, this data captures only the more severe cases. It does not include the individuals with eating disorders who may visit clinics or family doctors, or use hospital outpatient services or no services at all. Currently, there is no process for collecting this information systematically across Canada; consequently, the number of cases obtained from hospitalization data is underestimated. Other limitations noted during the literature review include the overuse of clinical samples, lack of longitudinal data, appropriate comparison groups, large samples, and ethnic group analysis.

Nutrition expertise in eating disorders

Anorexia nervosa (AN) and bulimia nervosa (BN) dominate published reports on disordered eating, although they actually account for a small number of cases. Binge eating disorder (BED) and subclinical syndromes of disturbed eating and distress are far more prevalent. Medical nutrition therapy including education is a cornerstone of therapy, however there has been no evaluation of baseline knowledge of nutrition and diet composition in this population relative to individuals who do not exhibit pathological eating behavior. In addition, previous reports suggest that individuals with clinical eating disorders have above-average knowledge of nutrition. In the present investigation, individuals with subclinical eating disorders did not differ from control participants. Poor scores overall indicate that nutritional counseling may be a useful component of treatment. These results further suggest that nutrition expertise is not an early feature of the disorder and, therefore, does not likely contribute to its development.

Calcium intake trends and health consequences from childhood through adulthood

Issues involving low calcium intake and dairy product consumption are currently the focus of much debate and discussion at both the scientific and lay community levels. In this review, we examine the following major areas of interest: (1). the role of calcium intake and dairy product consumption in chronic diseases, (2). nutritional qualities of milk and other dairy products, (3). trends in calcium intake and dairy product consumption, (4). current status of calcium intakes and dairy product consumption in children, (5). tracking of calcium intake and diary product consumption, (6). the impact of school meal participation on calcium intake and dairy product consumption, (7). concerns related to calcium-fortified foods and beverages and (8). factors influencing children's milk consumption. To date, the findings indicate that calcium intake and dairy product consumption have beneficial roles in a variety of chronic diseases; dairy products provide an abundant source of vitamins and minerals; calcium intakes of children have increased over time, yet intakes are not meeting the current adequate intake (AI) calcium recommendations; dairy consumption has decreased, and soft drink consumption and, possibly, consumption of calcium-fortified products have increased; consumption of dairy products have a positive nutritional impact on diets of children, particularly from school meals, and there are many factors which influence children's milk consumption, all of which need to be considered in our efforts to promote adequate calcium intakes by children. Based on this review, areas that need immediate attention and future research imperatives are summarized in an effort to further our understanding on what we already know and what we need to know to promote healthier eating habits early in life.

After the Fall: Women's Views of Fractures in Relation to Bone Health at Midlife

Past research has established the link between low energy fractures and the risk for future fractures. These fractures are potential markers for investigation of bone health, and may be precursors for osteoporosis. In spite of its significant public health burden, including burden of illness and economic costs, many individuals are not aware of the risk factors for and consequences of osteoporosis. This is a study of women aged 40 and older who experienced low energy fractures (e.g., from non-trauma sources and falls from no higher than standing height). We gathered data, using focus group interviews, about their experiences and understanding of the fractures in relation to bone health. Women often attributed the fractures to particular situations and external events (e.g., slipping on ice, tripping on uneven ground), and viewed the fractures as accidents. Women often felt that others are at risk for poor bone health, but believed that they themselves are different from those really at risk. Although the fractures are potential triggers for preventive efforts, few women connected their fracture to future risk. What is perceived by women (and others) as random and an accident is often a predictable event if underlying risk factors are identified. Only when there is more awareness of poor bone health as a disease process and fractures as markers for bone fragility will women, men and health care providers take action to prevent future fractures and established bone disease.

Influences on adolescent eating patterns: the importance of family meals

PURPOSE

To provide national estimates of the frequency and determinants of adolescents' consumption of fruits, vegetables, and dairy foods.

METHODS

Analyses were based on 18,177 adolescents in the first interview of the National Longitudinal Study of Adolescent Health. Multivariate logistic regressions provide estimates of the unique contribution of sociodemographic characteristics, body weight perception, and parental influences on adolescent food consumption.

RESULTS

Almost one in five adolescents reported skipping breakfast the previous day. A large percentage of adolescents reported eating less than the recommended amount of vegetables (71%), fruits (55%), and dairy foods (47%). Adolescents with better-educated parents had better consumption patterns than those with less-educated parents. Consumption patterns differed significantly by race. Adolescents who perceived themselves to be overweight were significantly more likely to have poor consumption patterns. Parental presence at the evening meal was associated with a lower risk of poor consumption of fruits, vegetables, and diary foods as well as the likelihood of skipping breakfast.

CONCLUSION

Parental presence at the evening meal is positively associated with adolescents' higher consumption of fruits, vegetables, and dairy foods. Nutrition and health professionals should educate parents about the role of family mealtimes for healthy adolescent nutrition.

Soy for breast cancer survivors: a critical review of the literature

A variety of health benefits, including protection against breast cancer, have been attributed to soy food consumption, primarily because of the soybean isoflavones (genistein, daidzein, glycitein). Isoflavones are considered to be possible selective estrogen receptor modulators but possess nonhormonal properties that also may contribute to their effects. Concern has arisen over a possible detrimental effect of soy in breast cancer patients because of the estrogen-like effects of isoflavones. Genistein exhibits a biphasic effect on the growth of MCF-7 cells in vitro, stimulating proliferation at low concentrations but inhibiting it at high concentrations. In ovariectomized athymic mice implanted with MCF-7 cells, both genistein and soy protein stimulate tumor growth in a dose-dependent manner. In contrast, in intact mice fed estrogen, genistein inhibits tumor growth. Although two studies in premenopausal women suggested that soy exerts estrogenic-like effects on breast tissue, recently conducted year-long studies indicated that isoflavone supplements do not affect breast tissue density in premenopausal women and may decrease density in postmenopausal women. These latter effects are opposite to those of hormone replacement therapy (HRT). Importantly, substantial data suggest that the progestogen, not the estrogen, component of HRT increases risk of developing breast cancer. Furthermore, recently conducted studies have failed to find that even HRT reduces survival in breast cancer patients. Overall, the data are not impressive that the adult consumption of soy affects the risk of developing breast cancer or that soy consumption affects the survival of breast cancer patients. Consequently, if breast cancer patients enjoy soy products, it seems reasonable for them to continue to use them.

The Importance of Meeting Calcium Needs with Foods

Calcium can be obtained from foods naturally rich in calcium such as dairy foods, from calcium-fortified foods and beverages, from supplements or from a combination of these. Recognition of calcium's many health benefits, along with Americans' low calcium intake, has led to interest in how best to meet calcium needs. Foods are the preferred source of calcium. Milk and other dairy foods are the major source of calcium in the U.S. In addition, these foods provide substantial amounts of other essential nutrients. Consequently, intake of dairy foods improves the overall nutritional quality of the diet. Other foods such as some green leafy vegetables, legumes and cereals provide calcium, but generally in lower amounts per serving than do dairy foods. Also, some components such as phytates in cereals and oxalates in spinach reduce the bioavailability of calcium. Calcium-fortified foods and calcium supplements are an option for individuals who cannot meet their calcium needs from foods naturally containing this mineral. However, their intake cannot correct poor dietary patterns of food selection which underlie Americans' low calcium intake. Considering the adverse health and economic effects of low calcium intakes, strategies are needed to optimize calcium intake. A first step is to recognize factors influencing dietary calcium consumption. Substituting soft drinks for milk and eating away from home are among the barriers to adequate calcium intake. The American public needs to understand why consuming foods containing calcium is the best way to meet calcium needs and learn how to accomplish this objective.

Focus groups identified women's perceptions of dairy foods

Focus groups were conducted with 39 Caucasian women (ages 30-55 years) to gain insight regarding their thoughts and feelings toward dairy foods. Women resided in Virginia; all had at least a high school education. Themes characterizing the group discussions were identified. Women knew that dairy foods were a good source of calcium and discussed it in relation to osteoporosis. Although many knew the risk factors related to osteoporosis, most were confused about measures to prevent it. Many used calcium supplements or vitamin/mineral supplements to help meet calcium requirements. Most thought dairy foods were high in fat. Women also discussed the sensory attributes of dairy foods as well as convenience and cost of dairy foods in relation to their dairy food choices.

The health of women in transition from welfare to employment

Although numerous studies of welfare policy exist, studies of women's health within the context of U.S. welfare reform policy have been limited. From an ecological health perspective, welfare policy shapes the immediate environment in which women live. The environment has long been recognized by nursing as a major determinant of health status. Using data from the Washington State Family Income Study (FIS), this research examined women's psychosocial health when making the transition from welfare receipt to employment. No differences in psychosocial health were found between women leaving welfare for employment and those remaining on welfare (p > .05 on depression, self-esteem, self-efficacy, and emotional support). This finding is consistent with earlier qualitative research, which indicates the life circumstances of women leaving welfare for paid employment rarely improve. To better understand how public policies such as those related to welfare affect the lives and health of women, additional research is sorely needed.