The ≤10:1 carbohydrate to fiber ratio to identify healthful grain foods: panorama of consumption, association with cardiometabolic risk factors and impact on nutrient intake

Author(s)

Mariane de Mello Fontanelli

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Saúde Pública (FSP/CIR)
• Defense date: 2020-02-14

Examining board members

Regina Mara Fisberg; Rita de Cássia de Aquino; Jose Eduardo Corrente; Flávia Mori Sarti

• Advisor: Regina Mara Fisberg; Cristiane Hermes Sales

Abstract

Introduction: There is a pressing need for methods to assess the healthfulness of grain foods to promote consumer awareness, evidence-informed industry reformulations, and policy efforts such as guidelines, labeling, and health claims. In this sense, the presence per 10 g of carbohydrate of at least 1 g of fiber (≤10:1-ratio) has been proposed as a pragmatic metric to identify healthier grain products. Objective: To investigate the application of the ≤10:1-ratio to identify healthful grain foods, and its association with cardiometabolic risk factors, to evaluate trends and determinants of this intake, as well as to estimate the potential nutritional impact of strategies to increase the consumption of these foods in São Paulo population. Methods: Data came from the population-based study Health Survey of São Paulo (2003, 2008 and 2015). This is a cross-sectional, population-based study including a probabilistic sample of urban residents in São Paulo. Participants aged 12+ years answered a structured questionnaire, at least one 24-h dietary recall, had blood sample, anthropometric and blood pressure measurements collected. The nutritional value of grain foods meeting the ≤10:1-ratio was compared to grain foods not meeting this criterion using univariate linear regressions with robust variance. The association between the intake of grain foods meeting the ≤10:1-ratio and cardiometabolic risk factors was assessed by multivariable linear regression models (First manuscript). The consumption of grain foods meeting the ≤10:1-ratio from 2003 to 2015 was investigated using linear regression models. Determinants of these intakes and prediction of the prevalence of intake for the next years were estimated using multivariable logistic regression models (Second manuscript). We estimated the potential nutritional impact of replacing white rice and white bread with healthful equivalent options in mean change of healthful grain foods, energy and nutrients intake (Third manuscript). Results: Foods meeting the ≤10:1-ratio had lower available carbohydrate (-3.0 g/serving), total sugar (-7.4 g/serving), added sugar (-7.2 g/serving) and saturated fatty acids (-0.7 g/serving), as well as more dietary fiber (+3.5 g/serving), protein (+2.1 g/serving), potassium (+100.1 mg/serving), iron (+0.9 mg/serving), selenium (+4.2 ?g/serving), magnesium (+38.7 mg/serving) and zinc (+1.1 mg/serving). Each increase in 1% of energy (E) of these foods was associated with lower levels of blood triacylglycerol (-10.7%), the triacylglycerol/HDL-c ratio (-14.9%), fasting insulin (-13.6%), and HOMA-IR (-14.0%). From 2003 to 2015, a growing trend in the intake of grain foods meeting the ≤10:1-ratio (from 0.9 %E to 1.5%E) was observed. Also, the proportion of the population consuming at least one-grain food meeting the ≤10:1-ratio increased from 8,7% in 2003 to 15,8% in 2015, and 19,9% of the population would be consuming some kind of healthful gain food by 2030. Older individuals (+78%), females (+28%), those with higher education (+137%), and higher family income (+135%) were more likely to consume grain foods meeting the ratio, whereas participants who self-reported black, brown or indigenous ethnicity were less likely to consume these foods (-30%). The substitution of white rice and white bread for brown rice and whole wheat bread, respectively, would result in increased intake of zinc (9.1%), calcium (9.3%), vitamin E (18.8%), dietary fiber (27.0%) and magnesium (52,9%), while decreased intake of total carbohydrate (-6.1%), available carbohydrate (-8.5%), vitamin B6 (-12,5%), vitamin B2 (-17,4%), and vitamin B1 (-20,7%) would be seen. Pre- and post-modeled healthful grain foods intake were 4,0% and 69,4% of total grain intake, respectively, an increase of 220 g/d. Conclusion: The ≤10:1-ratio identified grain foods with higher nutritional quality, and higher intakes of these foods were associated with cardiometabolic risk factors related to atherogenic dyslipidemia and insulin resistance. There was a growing trend to consume grain foods meeting the ≤10:1-ratio from 2003 to 2015, but this consumption continues to be far from recommended levels. Overall, younger individuals, males, those with lower education levels, lower family income, and who self-reported black, brown or indigenous ethnicity were less likely to consume grain foods meeting the ≤10:1-ratio from 2003 to 2015. Shifting consumption from usually eaten grain foods to healthful equivalent options may lead to favorable changes in nutrient content of the diet, in addition to a remarkable increase in healthful grain foods intake. (AU)

• FAPESP's process: 16/18742-1 - Carbohydrate Quality Index: overview of the last decade, relation with micronutrient status and insulin resistance
• Grantee: Mariane de Mello Fontanelli
• Support Opportunities: Scholarships in Brazil - Doctorate