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Carbohydrate nutrition variables and risk of disability in instrumental activities of daily living.
Gopinath, B, Flood, VM, Burlutksy, G, Liew, G, Mitchell, P
European journal of nutrition. 2019;58(8):3221-3228
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Plain language summary
In older adults, maintaining independence is determined by the ability to carry out activities of daily living (ADL), such as bathing and walking. Certain features of carbohydrate-rich foods known as the glycaemic index (GI), and glycaemic load (GL) have been implicated in the development of obesity, diabetes, and cardiovascular disease. Other aspects of carbohydrate quality such as fibre intake have been shown to influence the risk of chronic diseases that are more common with ageing. This prospective study aimed to examine the association between the GI and GL of foods consumed, intakes of carbohydrates and fibre, and the ability to perform ADL in older adults. A total of 844 participants from the Blue Mountains Eye Study in Australia, aged 60 years or older were examined from 2002-2004 to 2007-2009. Dietary information was collected using a food-frequency questionnaire, and functional status was assessed using an activities of daily living scale. Participants who reported moderate consumption of dietary fibre (19.1g to 29.6g fibre per day) had a lower risk of experiencing instrumental ADL (IADL) disability compared with those in the lowest group of fibre consumption (19g fibre or less per day); that is, they were more likely to be able to use the telephone, get to places out of walking distance, do housework, take their own medications, and handle money at the 5-year follow-up. There was no added benefit for fibre intake above 19.6g per day. Other baseline carbohydrate nutrition variables, including GI, GL, and total carbohydrate intake, were not associated with ADL disability over the 5 years. The researchers concluded that these findings could inform the development of targeted intervention strategies to encourage a greater intake of fibre-rich foods in older adults, potentially preserving or delaying further deterioration in physical functioning.
Abstract
PURPOSE We aimed to examine the prospective association between dietary glycemic index (GI) and glycemic load (GL) of foods consumed, intakes of carbohydrates and fiber, and the ability to perform activities of daily living (ADL) in older adults. METHODS A total of 844 participants from the Blue Mountains Eye Study aged 60 years or older were examined from 2002-2004 to 2007-2009. Dietary information was collected using a validated, semi-quantitative food-frequency questionnaire. The Older Americans Resources and Services activities of daily living scale were administered to assess the functional status of participants. Multivariable logistic regression analysis was performed. RESULTS After multivariable adjustment, participants who were in the second and third quartiles of energy-adjusted total fiber intake compared to those in the first quartile of intake (reference group) at baseline had reduced risk of incident impaired instrumental activities of daily living (IADL) 5 years later: OR, 0.39 (95% CI 0.22-0.70) and OR 0.54 (95% CI 0.30-0.95), respectively. Analyses that involved dichotomized total fiber intake showed that participants in the upper three quartiles of total fiber intake (> 19 g/day), compared to those in the lowest quartile of intake (≤ 19 g/day) or reference group, had reduced IADL disability risk 5 years later: OR 0.49 (95% CI 0.31-0.79). Non-significant associations were observed with total carbohydrates, GI, and GL and with risk of impaired total and basic ADL at 5-year follow-up. CONCLUSIONS Habitual fiber consumption might be beneficial in leading to improved health status subserving performance of instrumental daily activities, needed to function in the community.
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Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: Assessment of Causal Relations.
Livesey, G, Taylor, R, Livesey, HF, Buyken, AE, Jenkins, DJA, Augustin, LSA, Sievenpiper, JL, Barclay, AW, Liu, S, Wolever, TMS, et al
Nutrients. 2019;11(6)
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Plain language summary
It is generally accepted that certain diet and lifestyle choices contribute to a person’s risk of developing type 2 diabetes (T2D). In this meta-analysis, researchers set out to review previous studies and assess whether there is any evidence that the amount and type of carbohydrate (measured by Glycaemic Index (GI) and Glycaemic Load (GL)) in a person’s diet has a direct influence on their risk of developing T2D. The authors concluded with a high level of confidence that eating high GI and GL foods can lead to a higher risk of developing T2D. They suggest that nutrition advice that favours low GI and GL foods could produce significant cost savings for public healthcare.
Abstract
While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill's criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost-benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.
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Dietary carbohydrates: role of quality and quantity in chronic disease.
Ludwig, DS, Hu, FB, Tappy, L, Brand-Miller, J
BMJ (Clinical research ed.). 2018;361:k2340
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Plain language summary
Human populations have thrived on diets with widely varying carbohydrate content. Dietary carbohydrates comprise compounds that can be digested or metabolically transformed directly into glucose, or that undergo oxidation into pyruvate, including some sugar alcohols. This study is a review that examines the links between different types of carbohydrates and health, with special focus on obesity, diabetes, cardiovascular disease, cancer and early death. Evidence suggests that the type of carbohydrates may have a greater effect on health outcomes than total amount for the general population. A strong case can be made for consumption of high glycaemic load grains, potato products, and added sugars namely sugary drinks, being causally related to obesity, diabetes, cardiovascular disease, and some cancers. Whereas non-starchy vegetables, whole fruits, legumes, and whole kernel grains appear to protective. Authors conclude that the recent influx of rapidly digestible, high glycaemic index carbohydrates in developed nations has contributed to the epidemics of obesity and cardiometabolic disease.