Eating foods that quickly raise blood sugar could boost the risk of heart disease in women, according to new research done in Italy and published in the Archives of Internal Medicine.
Women who had the highest consumption of high glycemic index foods more than doubled their risk of heart disease, compared to women with the lowest consumption of high glycemic index foods in the study.
Read the announcement of the study from Archives:
Women Who Eat Foods With High Glycemic Index May Be at Greater Risk for Heart Disease
CHICAGO—Consuming carbohydrates with high glycemic index—an indicator of how quickly a food affects blood glucose levels—appears to be associated with the risk of coronary heart disease in women but not men, according to a report in the April 12, 2010 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
High-carbohydrate diets increase the levels of blood glucose and of harmful blood fats known as triglycerides while reducing levels of protective HDL or "good" cholesterol, thereby increasing heart disease risk, according to background information in the article.
However, not all carbohydrates have the same effect on blood glucose levels. The glycemic index is a measure of how much a food raises blood glucose levels compared with the same amount of glucose or white bread. A related measure, the glycemic load, is calculated based on the glycemic index of a given food and also on the total amount of carbohydrates it contains.
Sabina Sieri, Ph.D., of Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy, and colleagues studied 47,749 Italian adults—15,171 men and 32,578 women—who completed dietary questionnaires. Based on their responses, the researchers calculated their overall carbohydrate intakes as well as the average glycemic index of the foods they consumed and the glycemic loads of their diets. During a median (midpoint) of 7.9 years of follow-up, 463 participants (158 women and 305 men) developed coronary heart disease.
The one-fourth of women who consumed the most carbohydrates overall had approximately twice the risk of heart disease as the one-fourth who consumed the least. When these carbohydrates were separated into high- and low-glycemic index categories, increased intake from high-glycemic index foods was significantly associated with greater risk of coronary heart disease, whereas low-glycemic index carbohydrates were not.
"Thus, a high consumption of carbohydrates from high-glycemic index foods, rather than the overall quantity of carbohydrates consumed, appears to influence the risk of developing coronary heart disease," the authors write.
The one-fourth of women whose diet had the highest glycemic load had 2.24 times the risk of heart disease compared with the one-fourth of women with the lowest glycemic load.
Overall carbohydrate intake, glycemic index and glycemic load were not associated with heart disease risk in men. This could be because the adverse changes associated with carbohydrate intake, including triglyceride levels, are stronger risk factors for heart disease in women than in men, the authors note.
"We tentatively suggest that the adverse effects of a high glycemic diet in women are mediated by sex-related differences in lipoprotein and glucose metabolism, but further prospective studies are required to verify a lack of association of a high dietary glycemic load with cardiovascular disease in men," they conclude.
Editor’s Note: The EPICOR study is supported by the Compagnia di San Paolo. The Italian EPIC collaboration is supported by the Associazione Italiana per la Ricerca sul Cancro.
Arch Intern Med. 2010; 170(7):640-647.
Dietary Glycemic Load and Index and Risk of Coronary Heart Disease in a Large Italian Cohort
The EPICOR Study
Sabina Sieri, PhD; Vittorio Krogh, MD, MS; Franco Berrino, MD; Alberto Evangelista, BSc; Claudia Agnoli, PhD; Furio Brighenti, PhD; Nicoletta Pellegrini, PhD; Domenico Palli, MD; Giovanna Masala, MD; Carlotta Sacerdote, MD; Fabrizio Veglia, MD; Rosario Tumino, MD; Graziella Frasca, PhD; Sara Grioni, BSc; Valeria Pala, PhD; Amalia Mattiello, MD; Paolo Chiodini, PhD; Salvatore Panico, MD
Background: Dietary glycemic load (GL) and glycemic index (GI) in relation to cardiovascular disease have been investigated in a few prospective studies with inconsistent results, particularly in men. The present EPICOR study investigated the association of GI and GL with coronary heart disease (CHD) in a large and heterogeneous cohort of Italian men and women originally recruited to the European Prospective Investigation into Cancer and Nutrition study.
Methods: We studied 47 749 volunteers (15 171 men and 32 578 women) who completed a dietary questionnaire. Multivariate Cox proportional hazards modeling estimated adjusted relative risks (RRs) of CHD and 95% confidence intervals (CIs).
Results: During a median of 7.9 years of follow-up, 463 CHD cases (158 women and 305 men) were identified. Women in the highest carbohydrate intake quartile had a significantly greater risk of CHD than did those in the lowest quartile (RR, 2.00; 95% CI, 1.16-3.43), with no association found in men (P = .04 for interaction). Increasing carbohydrate intake from high-GI foods was also significantly associated with greater risk of CHD in women (RR, 1.68; 95% CI, 1.02-2.75), whereas increasing the intake of low-GI carbohydrates was not. Women in the highest GL quartile had a significantly greater risk of CHD than did those in the lowest quartile (RR, 2.24; 95% CI, 1.26-3.98), with no significant association in men (P = .03 for interaction).
Conclusion: In this Italian cohort, high dietary GL and carbohydrate intake from high-GI foods increase the overall risk of CHD in women but not men.
Author Affiliations: Nutritional Epidemiology Unit (Drs Sieri, Krogh, Agnoli, and Pala; Mr Evangelista; and Ms Grioni) and Etiological and Preventive Epidemiology Unit (Dr Berrino), Fondazione IRCCS (Istituto di Ricovero e Cura a Carattere Scientifico) Istituto Nazionale Tumori, and Centro Cardiologico Monzino, IRCCS (Dr Veglia), Milan, Italy; Department of Public Health, University of Parma, Parma, Italy (Drs Brighenti and Pellegrini); Molecular and Nutritional Epidemiology Unit, Cancer Research and Prevention Institute, Florence, Italy (Drs Palli and Masala); Institute for Scientific Interchange Foundation and Department of Genetics, Biology, and Biochemistry, University of Turin, Turin, Italy (Drs Sacerdote and Veglia); Cancer Registry (Drs Tumino and Frasca) and Histopathology Unit (Dr Tumino), Department of Oncology, Civile M. P. Arezzo Hospital, Ragusa, Italy; and Department of Clinical and Experimental Medicine, University of Naples Federico II (Drs Mattiello and Panico), and Department of Public Health and Preventive Medicine, University II of Naples (Dr Chiodini), Naples, Italy.