The following three research papers have been selected by our Scientific Affairs Analyst at Nestlé, Jean Kim (PhD). They are designed to provide a topline overview and summary of the relevant research paper – they are not a full scientific review. For further details of the research paper, click through to the abstracts in the links provided.
1. What is the glycaemic index and load of the diets of Australian adults?
A recent analysis of the 2011-2012 Australian Health Survey.
Louie JCY, Jones M, Barclay AW and Brand-Miller JC (2017). Dietary glycaemic index and glycaemic load among Australian adults – results from the 2011-2012 Australian Health Survey. Scientific Reports, 7:43882.
Evidence from recent meta-analyses suggest that a low glycaemic index (GI) or low glycaemic load (GL) eating pattern is associated with a reduced risk of type 2 diabetes, coronary heart disease, gallbladder disease and breast cancer.(1-4)
Glycaemic load, the product of carbohydrate quantity and GI, has been shown to be the best predictor of postprandial glycaemia and insulinaemia, two factors that are intrinsically involved in the development of chronic disease.(5) Despite this, no previous attempt has been made to examine the dietary GI and GL of the general Australian adult population using national nutrition survey data. The study aimed to describe the current dietary GI and GL, and explore the main food sources contributing to the dietary GL, of a nationally representative sample of Australian adults.
METHODOLOGY / STUDY DESIGN
A weighted sample of 6326 adult respondents (52% male) of the National Nutrition and Physical Activity Survey component of the 2011-12 AHS was analysed. A previously published method was used to estimate glycaemic index (GI) values to individual food items in AUSNUT 2011-2013.(6)
SUMMARY OF FINDINGS
Overall, the mean dietary GI and GL was 54 (SD 7) and 135 (SD 59) respectively, with higher GI and GL in younger age groups. The top 3 contributors to dietary GL were breads (14.4%), cereal-based dishes (10.3%) and breakfast cereals (ready to eat) (6.6%), but with substantial differences in sources between age groups. Cereal-based dishes; flours, cereals and starches, sweetened beverages, fruit and vegetables juices and drinks all contributed less to dietary GL as age increased, while bread and bread rolls, breakfast cereals, sugar, honey and syrup, cake-type desserts and sweet biscuits contributed more to dietary GL as age increased.
Only the first 24h of recall was used, which was unlikely to capture the usual dietary pattern of an individual, although the use of one 24h recall is commonly used and deemed appropriate for estimating population means. Also, foods were grouped based on the pre-defined minor food classification, which was not developed according to the GI of foods. This meant that similar foods with different GI were not able to be differentiated.
KEY TAKE OUT
Overall, the findings indicated that the average dietary GI of Australian adults was above recommendations to reduce chronic disease risk, with a large proportion of starchy and energy-dense nutrient-poor foods that contributed to a high GL. Dietary interventions should consider reducing dietary GI and/or GL and be age-specific. Interventions aimed at older groups should focus on swapping high GI staple food with low GI versions, while for younger adults discouraging the consumption of high GI processed foods may be more effective.
“Epidemiological research suggests that a dietary GI of 45 or below is associated with reduced risk of chronic diseases such as diabetes. Our results indicate that only 9% of Australian adults are actually meeting this target.”
1. Barclay AW (2008), Glycemic index, glycemic load, and chronic disease risk – a meta-analysis of observational studies. Am J Clin Nutr 87, 627-37.
2. Greenwood DC et. al. (2013), Glycemic index, glycemic load, carbohydrates, and type 2 diabetes: systematic review and dose-response meta-analysis of prospective studies. Diabetes Care 36, 4166-71.
3. Fan J et. al. (2012), Dietary Glycemic Index, glycemic load, and risk of coronary heart disease, stroke and stroke mortality: a systematic review with meta-analysis. PLoS One 7, e52182.
4. Choi et. al. (2012), Glycaemic index and glycaemic load in relation to risk of diabetes-related cacners: a meta-analysis. Br J Nutr 108, 1934-47.
5. Selvin E et. al. (2010), Glycated Hemoglobin, Diabetes, and Cardiovascular Risk in Nondiabetic Adults N Eng J Med 362, 800-11.
6. Louie JCY et. al. (2015), Assigning glycaemic index values to foods in a recent Australian food composition database. Eur J Clin Nutr 70, 280-81.
2. Is it safe to add oats to a gluten-free diet for patients with celiac disease?
A systematic review and meta-analysis of clinical and observational studies.
Pinto-Sanchez MI, Causada-Calo N, Bercik P, Ford AC, Murray JA, Armstrong D, Semrad C, Kupfer SS, Alaedini A, Moayyedi P, Leffler DA, Verdu EF and Green P (2017). Safety of Adding Oats to a Gluten-Free Diet for Patients with Celiac Disease: Systematic Literature Review and Meta-Analysis of Clinical and Observational Studies. Gastroenterology, S0016-5085(17)35474-4.
Celiac disease is an autoimmune disorder triggered by gluten and related prolamins in genetically susceptible individuals.(1) Patients with CD should maintain a gluten-free diet (GFD), excluding wheat, rye and barley. Oats may increase the nutritional value, improve palatability, texture and fibre content of the GFD(2,3), however, their inclusion in the diet is controversial. For this reason, a systematic review and meta-analysis was conducted to evaluate the safety of oats as part of a GFD in patients with CD.
METHODOLOGY / STUDY DESIGN
A search of clinical trials (randomised controlled) and observational studies (cohort or case-control) to evaluate the effects of including oats in GFD of patients with celiac disease was conducted for this systematic review, with only the results of randomised clinical trials pooled for the meta-analysis. The studies reported on celiac disease (CD) patients’ symptoms, and their serological and histological responses to dietary oats.
SUMMARY OF FINDINGS
Oat consumption for 12 months did not affect symptoms (standardised mean difference: reduction in symptom scores in patients who did and did not consume oats, -0.22; 95% CI:-0.56 to 0.13; P=0.22), histologic scores (relative risk for histologic findings in patients who consumed oats, 0.24; 95% CI, 0.01 to 4.8; P=0.35), intraepithelial lymphocyte counts (standardised mean difference: 0.21; 95% CI, reduction of 1.44 to increase in 1.86), or results from serologic tests. Subgroup analyses of adults vs children did not reveal any differences. The authors supported the recommendations by the North American Society for the Study of Celiac Disease to use pure oats in CD patients, but to monitor levels of immune-toxicity markers before and after their introduction into the diet.
The overall quality of evidence was rated very low. There were few studies for many end-points, as well as small sample sizes, lack of control groups and limited geographical distribution. When comparing studies evaluating the safety of oats, there are numerous aspects to consider such as compliance with the GFD, amount and frequency of oats consumption, as well as the cultivars used in the production of pure oats. However, this information was often omitted or unclear.
KEY TAKE OUT / WHAT DOES IT ALL MEAN
In this systematic review, although there was no evidence of deterioration in gastrointestinal symptoms with the addition of non-contaminated oats to a GFD in a majority of CD patients, the overall data quality was very low and not robust enough to make definitive, evidence-based recommendations on the safety of oats for CD patients at this point.
“The general consensus is that pure oats are safe for most patients with CD, however, contamination with other cereal sources needs to be avoided”.
1. Setty et. al. (2008) Celiac Disease: risk assessment, diagnosis, and monitoring. Mol Diag Ther 12(5): 289-98.
2. Comino I et. al. (2015) Role of oats in celiac disease. World J Gastroenterol. 21(41), 11825-31.
3. Peraaho M et al. (2004) Effect of an oats-containing gluten-free diet on symptoms and quality of life in coeliac disease. Scand J Gastroenterol. 39(1), 27-31.
3. Lifestyle recommendations for patients and clinicians for the prevention and management of metabolic syndrome.
An international panel recommendation.
Perez-Martinez P et. al. (2017). Lifestyle recommendations for the prevention and management of metabolic syndrome: an international panel recommendation. Nutrition Reviews, 75(5):307-26.
The prevalence of MetS has increased over time and is now reaching epidemic proportions. MetS is primarily associated with the risk of cardiovascular disease and type 2 diabetes, with a constellation of related factors that may be influenced by over-nutrition and sedentary lifestyle. The available evidence suggests certain nutrients, foods, and dietary patterns have beneficial effects on MetS. The recommendations in this review article were developed to help patients and clinicians understand and implement the most effective approaches for lifestyle management to prevent MetS and improve cardio-metabolic health.
METHODOLOGY / STUDY DESIGN
This position statement was a summary of available scientific evidence and guideline recommendations for the prevention, treatment and management of Metabolic Syndrome (MetS).
SUMMARY OF FINDINGS
Weight-loss through an energy-restricted diet, together with increased energy expenditure through physical activity, contributed to the prevention and treatment of MetS. In addition, quitting smoking and reducing sugar-sweetened beverage, as well as meat consumption, were shown to be mandatory for prevention and treatment. Over-time, research in nutritional epidemiology has moved from the single food approach to a dietary pattern strategy, with the Mediterranean-type diet identified as an effective treatment component. A dietary pattern should be built on an increased intake of unsaturated fat, primarily from olive oil, and emphasise the consumption of legumes, cereals (whole grains), fruits, vegetables, nuts, fish, and low-fat dairy products, as well as moderate consumption of alcohol, including red wine and/or beer. There is some evidence supporting the role of breakfast cereals, particularly those high in fibre, in the management of Type 2 Diabetes, but further research is required.
Due to inconsistencies and gaps in the evidence-base, more research is required to define the most appropriate therapies for MetS.
KEY TAKE OUT / WHAT DOES IT ALL MEAN:
“There is Grade A evidence to support the recommendation of the daily consumption of cereals (whole grains) for cardiometabolic health, and Grade B evidence that eating a variety of cereals (whole grains) is beneficial in the prevention and management of metabolic syndrome”.