Findings of the recent study associating low-carbohydrate diets with reduced longevity (Replacing carbs with wrong food could shorten life; Sept 25), should not be generalised to people with diabetes.
Several of the cohorts in the meta-analysis excluded individuals with diabetes.
Poor blood-sugar control increases the risk of developing cardiovascular and kidney disease, which are the main causes of death and illnesses in diabetes. In fact, high-carbohydrate intakes have been associated with an increased risk of death in individuals with diabetes.
There is now good evidence from longer-term, well-controlled, randomised trials of people with Type 2 diabetes that low-carbohydrate diets confer additional benefits for achieving glycaemic control and more stable blood-glucose profiles with lower diabetes medications over conventional low-fat diets, with no adverse renal effects. And when these low-carbohydrate diets are low in saturated fats/high in unsaturated fats, greater improvements in lipid profile are observed.
Low-carbohydrate diets also produce more favourable effects in patients with high triglyceride levels, low high-density lipoprotein levels, abdominal obesity and insulin resistance - risk factors associated with diabetes.
Notably, the study also found that high-carbohydrate diets (greater than 70 per cent) were associated with shorter lifespans when compared with moderate-carbohydrate diets (45 per cent to 55 per cent). This finding was mainly derived from Asian and multinational cohorts and is, thus, of greater relevance to Singapore.
While the study did not distinguish between the type of carbohydrates consumed (whole grains versus refined grains/sugars), the authors acknowledged the ubiquity of high-carbohydrate intakes, especially refined carbohydrates - for example, white rice - in Asia. This chronically high glycaemic load could cause metabolic dysfunction.
A reduction in carbohydrate intake, especially refined carbohydrates, would therefore be prudent, particularly when insulin deficiency appears to characterise the variant of diabetes in Asians.
In Singapore's war on diabetes, the potential advantage of low-carbohydrate diets is an important public health message that must not be obscured by the findings of the observational study.
Nutrition therapy plays an integral role in overall diabetes management and, while there is no one-size-fits-all dietary approach, current evidence highlights the clinical utility of low-carbohydrate diets in diabetes prevention and management.
Jeannie Tay (Dr)