In February this year I wrote about the links between refined carbohydrate and heart disease and mentioned some studies which suggested that sugary carbohydrates and those which increased blood sugar levels quickly (carbohydrates with a high glycaemic index, or GI) seemed to be a greater risk for heart disease than fat.
A recent study (1) published in the American Journal of Clinical Nutrition has concluded (1) “that replacing SFAs [saturated fatty acids] with carbohydrates with low-GI values is associated with a lower risk of MI [myocardial infarction, or heart attack], whereas replacing SFAs with carbohydrates with high-GI values is associated with a higher risk of MI”. The authors write in their introduction that studies suggest that replacing saturated fatty acids with carbohydrates has been modestly associated with a higher risk of ischemic heart disease, whereas replacing saturated fats with polyunsaturated fatty acids is associated with a lower risk of ischemic heart disease. However, they point out that it is important to look at the type of carbohydrates consumed since different carbohydrates have very different effects in the body.
High glycaemic index foods (foods that release sugar quickly into the body) include most refined carbohydrates like white bread, long-grain rice, sweets, biscuits, sugary foods and many other processed carbohydrates and processed foods. 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). To identify foods with a high glycaemic index that will contribute to increasing the GL of a meal please view the website The Glycemic Index www.glycemicindex.com, there you will find a database where you can search for specific foods and find out more about GI and health.
Briefly, unbalanced blood sugar levels following a meal (post-prandial dysmetabolism) can cause havoc in the body. A high post-meal blood sugar level can lead to damaging free radicals (reactive oxygen molecules) being released which are a risk for atherosclerosis (damage to blood vessels) and metabolic syndrome (a big risk factor for heart disease). The high blood sugar can lead to internal inflammation, dysfunction in the lining of the blood vessels and may also lead to an increase in triglycerides (blood fats) – all risk factors for heart disease.
The authors of this research paper (1) aimed to investigate the risk of heart attack, (myocardial infarction), associated with a high carbohydrate diet, they also looked at the different glycaemic index of the carbohydrates. The study involved over 53,000 individuals, none of whom had suffered a heart attack at the start of the study. The individuals were followed for an average of 12 years, during this time almost 2000 heart attacks occurred. They found that there was a statistically significant positive association between substitution of saturated fats with carbohydrates with high GI values and risk of heart attack.
Again these results only show and association and not cause and effect but the evidence does add to other studies which indicate that replacing fat intake with sugary, refined carbohydrates probably won’t be good for the heart, or the body in general. Low fat diets really are not all that they were once hyped-up to be. Please read my previous posts here and here for more information and also any of my posts regarding the healthy omega 3 fats and how important they are for health
As I have written previously, personally I feel that the take home message from studies such as these is that a healthy diet, based around natural unprocessed and unrefined foods, is crucially important to prevent disease risk. Any health-full diet will be rich in plant foods such as vegetables, fruits, beans and pulses, nuts and seeds and will include unprocessed meats and fish (especially oily fish), wholegrain unprocessed and unrefined carbohydrates. Particularly I feel that omega 3 fats are important to health. I would also suggest that refined carbohydrates are generally unnecessary and quite possibly damaging to health when eaten regularly and consistently.
(1)Jakobsen UM et al. 2010. Intake of carbohydrates compared with intake of saturated fatty acids and risk of myocardial infarction: importance of the glycemic index. Am J Clin Nutr 91: 1764-1768
Written by Ani Kowal
Related posts:
- Women eating foods with a high glycaemic index could be increasing their risk for heart disease
- More evidence links high sugar diet to increased risk of heart disease
- Certain types of carbohydrates seem to be linked to the risk of developing breast cancer
- Replacing dietary fat with sugar and refined carbohydrates is probably damaging to health
- Eating to prevent heart disease
