Dietary Interventions for Type 2 Diabetes in South Asian Populations-A Systematic Review.

PURPOSE: South Asians face a high burden of type 2 diabetes (T2D). We systematically summarized current research on the efficacy, cultural relevance, and research gaps of nutrition interventions that could be used for treatment in this population. FINDINGS: We identified 18 articles published since 2010. Dietary pattern interventions have focused on low-glycemic index (GI) solutions and consistently reported improvement in glycemic management. Trials of nutrition education and counselling had diverse approaches, with those utilizing more intensive interventions generally eliciting better glycemic outcomes. Many studies developed interventions with cultural relevance by including traditional foods, providing materials in the local language, and acknowledging important food-related customs. These adaptations were seen in South Asian countries as well as Western countries hosting immigrants. Data from South Asian countries support low-GI and intensive counselling approaches for the treatment of T2D. Given the high prevalence of T2D in these populous countries, approaches that can reach large numbers of people are needed. In Western countries, more emphasis on providing culturally relevant nutrition therapy is needed.

Graduate Student Literature Review: A scoping review on the impact of consumption of dairy products on phosphatidylcholine and lysophosphatidylcholine in circulation and the liver in human studies and animal models.

Dairy consumption is inversely related to the risk of developing type 2 diabetes in epidemiological research. One proposed hypothesis is that phospholipid (PL) species associated with dairy consumption mediate this relationship. This scoping review aimed to identify the existing literature in animal and human trials investigating the impact of dairy products, including milk, yogurt, and cheese as well as dairy-derived PL supplementation on PL and its species in the circulation, summarizing the characteristics of these studies and identifying research gaps. A systematic search was conducted across 3 databases (PubMed, Scopus, and Web of Science) in March 2021. Of 2,427 identified references, 15 studies (7 humans and 8 animal studies) met the eligibility criteria and were included in the final narrative synthesis. The evidence base was heterogeneous, involving a variety of clinical and preclinical studies, metabolically healthy or obese/diabetic participants or animal models, and displayed mixed findings. Circulating postprandial concentrations of total PL were elevated acutely but unchanged after longer intervention with dairy products. The PL concentration remained stable even after a high dosage of milk supplemented with dairy-derived PL, which may be related to increased fecal excretion; however, certain phosphatidylcholine (PC) or lysophosphatidylcholine species were increased in circulation by interventions. These include several PC species with 32 to 38 total carbons in addition to the dairy biomarkers C15:0 and C17:0. The results of this scoping review demonstrate a small body of literature indicating that dairy products can influence blood concentrations of PC and lysophosphatidylcholine species in both rodents and humans without alteration of total PL and PC. There is a lack of well-designed trials in humans and animals that explore the potential differences between individual dairy foods on PL species. In addition, trials to understand the bioactive properties of PC and lysophosphatidylcholine species on cardiometabolic risk are needed.

Barriers and Mitigating Strategies to Healthcare Access in Indigenous Communities of Canada: A Narrative Review.

The objective of this review is to document contemporary barriers to accessing healthcare faced by Indigenous people of Canada and approaches taken to mitigate these concerns. A narrative review of the literature was conducted. Barriers to healthcare access and mitigating strategies were aligned into three categories: proximal, intermediate, and distal barriers. Proximal barriers include geography, education attainment, and negative bias among healthcare professionals resulting in a lack of or inadequate immediate care in Indigenous communities. Intermediate barriers comprise of employment and income inequities and health education systems that are not accessible to Indigenous people. Distal barriers include colonialism, racism and social exclusion, resulting in limited involvement of Indigenous people in policy making and planning to address community healthcare needs. Several mitigation strategies initiated across Canada to address the inequitable health concerns include allocation of financial support for infrastructure development in Indigenous communities, increases in Indigenous education and employment, development of culturally sensitive education and medical systems and involvement of Indigenous communities and elders in the policy-making system. Indigenous people in Canada face systemic/policy barriers to equitable healthcare access. Addressing these barriers by strengthening services and building capacity within communities while integrating input from Indigenous communities is essential to improve accessibility.

Pea polyphenolics and hydrolysis processing alter microbial community structure and early pathogen colonization in mice.

Health benefits associated with pea consumption have been attributed to the fiber and polyphenolic content concentrated within the pea seed coat. However, the amount of pea polyphenols can vary between cultivars, and it has yet to be studied whether pea polyphenols impact the intestinal microbiota. We hypothesized that pea polyphenols promote a healthy microbiome that supports intestinal integrity and pathogen colonization resistance. To investigate the effects of pea polyphenols, pea cultivars rich and poor in proanthocyanidins were supplemented in raw or acid hydrolyzed form to an isocaloric diet in mice. Acid hydrolysis increases the absorption of pea polyphenols by cleaving polymeric proanthocyanidins to their readily absorbable anthocyanidin monomers. After 3 weeks of diet, mice were challenged with Citrobacter rodentium and pathogen colonization and inflammation were assessed. Counter to our hypothesis, pea seed coat fraction supplementation, especially the non-hydrolyzed proanthocyanidin-rich fraction diet adversely increased C. rodentium pathogen load and inflammation. Ileal, cecal and colon microbial communities were notably distinct between pea seed cultivar and hydrolysis processing. The consumption of intact proanthocyanidins decreased microbial diversity indicating that proanthocyanidins have antimicrobial properties. Together our results indicate supplementation of raw pea seed coat rich in proanthocyanidins adversely affect intestinal integrity. However, acid hydrolysis processing restored community structure and colonization resistance, and the anthocyanidin-rich fractions reduced weight gain on a high fat diet. Establishing a clear understanding of the effects of pea fiber and polyphenolic form on health will help to develop research-based pea products and dietary recommendations.

Dietary Pea Fiber Supplementation Improves Glycemia and Induces Changes in the Composition of Gut Microbiota, Serum Short Chain Fatty Acid Profile and Expression of Mucins in Glucose Intolerant Rats.

Several studies have demonstrated the beneficial impact of dried peas and their components on glucose tolerance; however, the role of gut microbiota as a potential mediator is not fully examined. In this study, we investigated the effect of dietary supplementation with raw and cooked pea seed coats (PSC) on glucose tolerance, microbial composition of the gut, select markers of intestinal barrier function, and short chain fatty acid profile in glucose intolerant rats. Male Sprague Dawley rats were fed high fat diet (HFD) for six weeks to induce glucose intolerance, followed by four weeks of feeding PSC-supplemented diets. Cooked PSC improved glucose tolerance by approximately 30% (p < 0.05), and raw and cooked PSC diets reduced insulin response by 53% and 56% respectively (p < 0.05 and p < 0.01), compared to HFD (containing cellulose as the source of dietary fiber). 16S rRNA gene sequencing on fecal samples showed a significant shift in the overall microbial composition of PSC groups when compared to HFD and low fat diet (LFD) controls. At the family level, PSC increased the abundance of Lachnospiraceae and Prevotellaceae (p < 0.001), and decreased Porphyromonadaceae (p < 0.01) compared with HFD. This was accompanied by increased mRNA expression of mucin genes Muc1, Muc2, and Muc4 in ileal epithelium (p < 0.05). Serum levels of acetate and propionate increased with raw PSC diet (p < 0.01). These results indicate that supplementation of HFD with PSC fractions can improve glycemia and may have a protective role against HFD-induced alterations in gut microbiota and mucus layer.

Trans-11 vaccenic acid improves insulin secretion in models of type 2 diabetes in vivo and in vitro.

SCOPE: Trans-11 vaccenic acid (VA) is a fatty acid produced by ruminants entering the human food supply through meat and dairy products, which appears not to have the health risks associated with industrially produced trans-fatty acids. In this study, we investigated the effect of VA on insulin secretion in vivo in rats and in vitro in human and rat islets after diabetogenic insult. METHODS AND RESULTS: Hyperglycemic clamp showed that VA dietary supplementation for 8 weeks significantly increased glucose turnover in rats with type 2 diabetes (T2D), accompanied by an elevated plasma C-peptide concentration, indicating improved insulin secretion. The ß-cell area and proliferation rate were higher in T2D+VA than T2D group. Isolated islets from T2D+VA rats had higher glucose-stimulated insulin secretion (GSIS) than T2D group. In vitro, VA treatment for 24 and 48 h significantly enhanced GSIS in rat and human islets after diabetogenic challenges. The mRNA expression of G-protein-coupled receptor 40 (GPR40) and regenerating islet-derived 1α (REG-1α) were consistently increased by VA in both rat and human islets. CONCLUSION: These results indicate that VA may improve insulin secretion and growth of islets in T2D, at least partly by altering GPR40 and REG-1α mRNA expression.

Isoferulic acid prevents methylglyoxal-induced protein glycation and DNA damage by free radical scavenging activity.

BACKGROUND: Isoferulic acid (IFA), a naturally occurring cinnamic acid derivative, is a main active ingredient of the rhizoma of Cimicifuga dahurica. It has been shown various pharmacological activities. The aim of the study was to investigate the effect of IFA against MG-induced protein glycation and oxidative DNA damage. Free radical scavenging activity and the MGO-trapping abilities of IFA were also investigated. METHODS: The fluorescent MG-derived AGEs and non-fluorescent N(ε)-(carboxymethyl) lysine (N(ε)-CML) was measured using a spectrofluorometer and an enzyme linked immunosorbant assay (ELISA). Protein carbonyl content was used to detect protein oxidation. Gel electrophoresis was used to determine DNA damage. Superoxide anion radicals and hydroxyl radicals were determined using cytochrome c reduction assay and thiobarbituric acid reactive 2-deoxy-D-ribose oxidation products, respectively. The MG-trapping capacity was performed by HPLC. RESULTS: IFA (1.25-5 mM) inhibited the formation of fluorescent MG-derived AGEs, and N(ε)-CML, and protein carbonyl in bovine serum albumin. In addition, IFA (0.1-1 mM) also prevented MG/lysine-mediated oxidative DNA damage in the presence and absence of copper ion. The protective ability of IFA was directly correlated to inhibition of hydroxyl and superoxide anion radical generation during the reaction of MG and lysine. Most notably, IFA had no the directly trapping ability to MG. CONCLUSIONS: The present results highlighted that free radical scavenging activity, but not the MG-trapping ability, is the mechanism of IFA for preventing MG-induced protein glycation and DNA damage.

Hydrolysis enhances bioavailability of proanthocyanidin-derived metabolites and improves ß-cell function in glucose intolerant rats.

Proanthocyanidins (PAC) are a highly consumed class of flavonoids and their consumption has been linked to beneficial effects in type 2 diabetes. However, limited gastrointestinal absorption occurs due to the polymeric structure of PAC. We hypothesized that hydrolysis of the PAC polymer would increase bioavailability, thus leading to enhanced beneficial effects on glucose homeostasis and pancreatic ß-cell function. PAC-rich pea seed coats (PSC) were supplemented to a high-fat diet (HFD) either in native (PAC) or hydrolyzed (HPAC) form fed to rats for 4 weeks. HFD or low-fat diet groups were controls. PAC-derived compounds were characterized in both PSC and serum. Glucose and insulin tolerance tests were conducted. Pancreatic α-cell and ß-cell areas and glucose-stimulated insulin secretion (GSIS) from isolated islets were measured. Increased PAC-derived metabolites were detected in the serum of HPAC-fed rats compared to PAC-fed rats, suggesting hydrolysis of PSC-enhanced PAC bioavailability. This was associated with ~18% less (P<.05) weight gain compared to HFD without affecting food intake, as well as improvement in glucose disposal in vivo. There was a 2-fold decrease of α/ß-cell area ratio and a 2.5-fold increase in GSIS from isolated islets of HPAC-fed rats. These results demonstrate that hydrolysis of PSC-derived PAC increased the bioavailability of PAC-derived products, which is critical for enhancing beneficial effects on glucose homeostasis and pancreatic ß-cell function.