Diet, fats and cholesterol

Part 4: Heart disease and high blood glucose

Here is a curious fact which you can check with any veterinary surgeon: There are three basic types of animal when it comes to diet: Herbivores which eat only plants, omnivores which eat both meat and plants, and carnivores, which eat only meat. While all three types can suffer a heart attack, the only animals where atherosclerosis builds up are those which eat plants, whether they eat plants exclusively or together with meat. And this includes Man. This suggests that, contrary to popular wisdom, it is not something in meat that is the contributory factor, but something in plants.

In 2005, the medical Journal, Archives of Internal Medicine, published a study with showed clearly that when blood glucose levels were raised for significant lengths of time, the risk of a heart attack was greatly increased.[1] This is because high levels of glucose in the blood over a long period of time 'glycosylate' haemoglobin. This glycosylation was found to increase the risk of a heart attack in both diabetics and non-diabetics. Long-term blood glucose levels are measured by the amount they glycosylate haemoglobin. The measurement is known as 'HbA1c' or 'haemoglobin A1c'.

What this study showed was that, in diabetic adults,

• each 1% increase in HbA1c increased the risk of a heart attack by 14%.
• And in non-diabetics with a level of over 4.6%, each 1% increase in HbA1c increased the risk of a heart attack by a huge 136%.

The study concluded that:

'In general, study has demonstrated that multiple risk factors for coronary heart disease are worsened for diabetics who consume the low-fat, high-carbohydrate diet so often recommended to reduce these risks.'

While presenting results of the Glucose Abnormalities in Patients with Myocardial Infarction (GAMI) study at the European Society of Cardiology Congress 2004, Dr Lars of the Ryd?n Karolinska University Hospital, Solna, Sweden, said that abnormal glucose metabolism is common in acute heart attack patients.

'We know', he said, 'that blood glucose increased to a level below the diagnostic target for diabetes increases the risk for mortality and cardiovascular disease.' He told delegates that patients' prognosis if they had normal glucose regulation was 'quite nice'; none in the normal group died. But amongst patients without any previously known diabetes newly detected a few days after a heart attack who had abnormal glucose tolerance 'there is a substantial increase in end points.'

Forget cholesterol; in this study abnormal glucose metabolism was the strongest predictor of a future heart attack. And that points to 'healthy eating' as a causal factor.

Long-term high glucose levels are, of course, only caused by eating a 'healthy', carbohydrate-rich diet.

References

1. Selvin E, et al. Glycemic control and coronary heart disease risk in persons with and without diabetes: the atherosclerosis risk in communities study. Arch Intern Med. 2005; 165: 1910-6.

2. Norhammar A, et al. Glucose metabolism in patients with acute myocardial infarction and no previous diagnosis of diabetes mellitus: a prospective study. Lancet 2002; 359: 2140-4.

for more on cholesterol and heart disease, see Cholesterol-and-Health.org.uk