The Glycaemic Index (or GI) is something I have written about a number of times. There appears to be a link between eating refined carbohydrates, imbalances in blood sugar (blood glucose) levels and heart disease. Eating a diet loaded with foods with a high glycaemic index or high glycaemic load has been increasingly linked with a raised risk for heart disease and other health problems.
High glycaemic index foods are foods that release sugar quickly into the body. They include most refined carbohydrates like white bread, long-grain rice, sweets, biscuits, sugary foods, ice-cream and many other processed carbohydrates and processed foods. Glycaemic index (GI) and glycaemic load (GL) are terms used to characterise foods and diets based on their effects on blood glucose levels. Foods that release sugar quickly into the bloodstream have what is known as a high Glycaemic Index (GI), meals that favour a spike in blood sugar levels are said to have a high Glycaemic Load (GL). White bread, potatoes, processed/refined carbohydrates have a high glycaemic index i.e. they tend to cause a rapid surge in blood sugar. Vegetables, whole-grain high-fibre carbohydrates, create a more gradual change in blood sugar levels and are considered to have a low glycemic index. For the classification of more food examples please visit the website ‘The Glycemic Index’, there you will find a database where you can search for specific foods and find out more about GI and health.
A recent study (1) has found that a “high dietary GL and carbohydrate intake from high-GI foods increase the overall risk of CHD [coronary heart disease] in women but not men”. The study investigated the association of GI and GL with coronary heart disease in over 47,000 Italian individuals (men and women). The individuals involved completed a dietary questionnaire and were followed for almost 8 years. Over 450 cases of coronary heart disease were identified in this time. When the data was analysed by the authors it was found that women who had the highest carbohydrate intakes had a significantly greater risk of coronary heart disease than those women with the lowest intakes. No association was found in men. It was also found that increasing carbohydrate intake from high GI foods was also significantly associated with a greater risk of coronary heart disease in women, whereas increasing the intake of low GI carbohydrates was not. Women with the highest GL also had a significantly greater risk of coronary heart disease than women with the lowest GL diets. The authors of the study say “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 also say that “further prospective studies are required to verify a lack of association of a high dietary glycemic load with cardiovascular disease in men,”
I have written about blood sugar and the link to heart disease this year and last year. Unbalanced blood sugar levels following a meal can lead to high levels of free radicals being released in the body – these can cause damage to blood vessels. High blood sugar levels can also lead to high triglyceride levels (blood fats) a risk for metabolic syndrome which is in itself a huge risk for heart disease. Inflammation can also result from high blood sugar levels. More research is needed in the area of GI and GL diets and risk for disease.
A healthy balanced diet will include low GI carbohydrates such as beans, lentils, nuts, vegetables and wholegrains. These kinds of foods stop post meal spikes in blood glucose and blood fats (triglycerides). As mentioned in the posts linked above omega 3 fatty acids from oily fish such as salmon, trout, sardines and mackerel may also play a role in reducing triglyceride levels and heart disease. Eating at least two portions per week is advisable.
(1)Sieri S et al. 2010. Coronary Heart Disease in a Large Italian Cohort: The EPICOR Study. Arch Intern Med. 170 (7): 640-647
Written by Ani Kowal