High dietary glycemic load (GL) and carbohydrate intake from high-GI foods – but not from low-GI foods - were found to increase the overall risk of coronary heart disease (CHD) in women, the researchers concluded. Yet there was no associated risk for men.
The prospective study is published in the Archives of Internal Medicine and could add weight to the low-glycemic food trend.
The authors include Vittorio Krogh of the Nutritional Epidemiology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, in Milan.
They commented: “The role of carbohydrates as a risk factor for CHD in women was found to depend on carbohydrate type, with an increased association for carbohydrate intake from high-GI foods but no association for carbohydrate intake from low-GI foods.
“Thus, a high consumption of carbohydrates from high-GI foods, rather than the overall quantity of carbohydrates consumed, appears to influence the risk of developing CHD.”
Food companies trying to tap into the health and wellness market have been formulating with ingredients said to be effective at lowering the GI of food - such as resistant starch.
However, last month the European Food Safety Authority updated dietary reference values (DRVs) for carbohydrates, among other nutrients and said it could not find sufficient evidence to support the role of the GI and GL in maintaining weight and preventing diet-related diseases.
Using dietary questionnaires, the Italian researchers studied more than 40,000 men, (aged 35-64) and women (aged 35-74) in Italy, looking at the effect of a high glycemic diet on CHD risk.
During a median of 7.9 years of follow-up, there were 463 CHD cases (158 women and 305 men).
Women in the highest carbohydrate intake quartile had a significantly greater risk of CHD than those in the lowest quartile, with no association found in men. Increasing carbohydrate intake from high-GI foods was also significantly associated with greater risk of CHD in women.
The main sources of carbohydrates from high-GI foods were bread (60.8 percent), sugar or honey and jam (9.1 percent), pizza (5.4 percent), and rice (3.2 percent). The low-GI foods sources were pasta (33.3 percent), fruit (23.5 percent), and cakes (18.6 cent).
GI measures how quickly certain foods release carbohydrates into the body, which then raise consumers' blood glucose levels. High GI foods cause blood sugar levels to rise more rapidly.
Dietary GL captures the quality and quantity of carbohydrates consumed.
The study suggests that “the effect on CHD is conferred not by a diet high in carbohydrates but by a diet rich in rapidly absorbed carbohydrates”.
It was also suggested the results could be due to sex-related differences in lipoprotein and glucose metabolism, although further studies were necessary.
Source: Archives of Internal Medicine
Volume 170 (No. 7), Apr 12, 2010
“Dietary Glycemic Load and Index and Risk of Coronary Heart Disease in a Large Italian Cohort”
Authors: Sabina Sieri, PhD; Vittorio Krogh, MD, MS; Franco Berrino, MD et al.