Foods consist of a large number of different nutrients that are contained in a complex structure. The nature of the food structure and the nutrients therein (i.e., the food matrix) will determine the nutrient digestion and absorption, thereby altering the overall nutritional properties of the food. Thus, the food matrix may exhibit a different relation with health indicators compared to single nutrients studied in isolation. The evidence for a dairy matrix effect was presented and discussed by an expert panel at a closed workshop, and the following consensus was reached: 1) Current evidence does not support a positive association between intake of dairy products and risk of cardiovascular disease (i.e., stroke and coronary heart disease) and type 2 diabetes. In contrast, fermented dairy products, such as cheese and yogurt, generally show inverse associations. 2) Intervention studies have indicated that the metabolic effects of whole dairy may be different than those of single dairy constituents when considering the effects on body weight, cardiometabolic disease risk, and bone health. 3) Different dairy products seem to be distinctly linked to health effects and disease risk markers. 4) Different dairy structures and common processing methods may enhance interactions between nutrients in the dairy matrix, which may modify the metabolic effects of dairy consumption. 5) In conclusion, the nutritional values of dairy products should not be considered equivalent to their nutrient contents but, rather, be considered on the basis of the biofunctionality of the nutrients within dairy food structures. 6) Further research on the health effects of whole dairy foods is warranted alongside the more traditional approach of studying the health effects of single nutrients. Future diet assessments and recommendations should carefully consider the evidence of the effects of whole foods alongside the evidence of the effects of individual nutrients. Current knowledge gaps and recommendations for priorities in future research on dairy were identified and presented.
Summary: Sex hormone binding globulin (SHBG) is a glycoprotein composed of two 373‐amino‐acid subunits. The SHBG gene and a promotor region have been identified. The SHBG receptor has yet to be cloned but is known to act through a G‐protein‐linked second‐messenger system following plasma membrane binding. The principal function of SHBG has traditionally been considered to be that of a transport protein for sex steroids, regulating circulating concentrations of free (unbound) hormones and their transport to target tissues. Recent research suggests that SHBG has functions in addition to the binding and transport of sex steroids. Observational studies have associated a low SHBG concentration with an increased incidence of type 2 diabetes mellitus (DM) independent of sex hormone levels in men and women. Genetic studies using Mendelian randomization analysis linking three single nucleotide polymorphisms of the SHBG gene to risk of developing type 2 DM suggest SHBG may have a role in the pathogenesis of type 2 DM. The correlation between SHBG and insulin resistance that is evident in a number of cross‐sectional studies is in keeping with the suggestion that the association between SHBG and incidence of type 2 DM is explained by insulin resistance. Several potential mechanisms may account for this association, including the identification of dietary factors that influence SHBG gene transcription. Further research to characterize the SHBG‐receptor and the SHBG second messenger system is required. An interventional study examining the effects on insulin resistance of altering SHBG concentrations may help in determining whether this association is causal.
14 January 2005 in International Journal of Dairy Technology
Aim: To explore the views of individuals recently diagnosed with type 2 diabetes in relation to self-management of dietary intake and physical activity, and to compare these with the views of health professionals (HPs). Background: Diabetes education has become a priority area in primary and secondary care, and many education programmes are now embedded within a patient's care package. There are few contemporaneous explorations of patients’ views about lifestyle self-management. Such research is vital in order to identify areas that require further support, refinement or enhancement in terms of patient education. Methods: Focus groups were held with patients recently diagnosed with type 2 diabetes ( n = 16, 38% female, aged 45–73 years). In-depth semi-structured interviews were conducted with HPs ( n = 7). Discussions focussed on self-management specifically in relation to making dietary and physical activity changes. All discussions were tape recorded, transcribed and analysed by emergent themes analysis using NVivo to manage the coded data. Findings: Barriers were divided into six main categories: difficulty changing well-established habits, negative perception of the ‘new’ or recommended regimen, barriers relating to social circumstances, lack of knowledge and understanding, lack of motivation and barriers relating to the practicalities of making lifestyle changes. HPs generally echoed the views of patients. In conclusion, even against a background of diabetes education, recently diagnosed patients with type 2 diabetes discussed a wide range of barriers to self-management of diet and physical activity. The findings could help to provide HPs with a deeper understanding of the needs of recently diagnosed patients and may help refine current diabetes education activities and inform the development of educational resources.
Background— Observational evidence has consistently linked increased fruit and vegetable consumption with reduced cardiovascular morbidity; however, there is little direct trial evidence to support the concept that fruit and vegetable consumption improves vascular function. This study assessed the dose-dependent effects of a fruit and vegetable intervention on arterial health in subjects with hypertension. Methods and Results— After a 4-week run-in period during which fruit and vegetable intake was limited to 1 portion per day, participants were randomized to consume either 1, 3, or 6 portions daily for the next 8 weeks. Endothelium-dependent and -independent arterial vasodilator responses were assessed by venous occlusion plethysmography in the brachial circulation before and after intervention. Compliance was monitored with serial contemporaneous 4-day food records and by measuring concentrations of circulating dietary biomarkers. A total of 117 volunteers completed the 12-week study. Participants in the 1-, 3-, and 6-portions/d groups reported consuming on average 1.1, 3.2, and 5.6 portions of fruit and vegetables, respectively, and serum concentrations of lutein and β-cryptoxanthin increased across the groups in a dose-dependent manner. For each 1-portion increase in reported fruit and vegetable consumption, there was a 6.2% improvement in forearm blood flow responses to intra-arterial administration of the endothelium-dependent vasodilator acetylcholine ( P =0.03). There was no association between increased fruit and vegetable consumption and vasodilator responses to sodium nitroprusside, an endothelium-independent vasodilator. Conclusions— The present study illustrates that among hypertensive volunteers, increased fruit and vegetable consumption produces significant improvements in an established marker of endothelial function and cardiovascular prognosis.