The Pritikin diet, rich in high-fibre whole grains, vegetables and fruit, has been previously been related to decreases in blood pressure, oxidative stress and increased levels of nitric oxide.
The latest study, published on-line by the Journal of Applied Physiology (15th December, doi:10.1152), concluded that: "After three weeks, significant reductions in all serum lipids, CRP, sICAM-1, and sP-selectin were noted. Nine of 15 [MetS volunteers] were no longer positive for metabolic syndrome post-intervention."
Comments made by lead researcher Christian Roberts have met with skepticism from experts in the diabetes field.
Roberts said: "The study shows, contrary to common belief, that type-2 diabetes and metabolic syndrome can be reversed solely through lifestyle changes".
He went on: "The effect can be very dramatic given that, of the vast majority of people who go through the programme, at least 50 per cent are no longer clinically defined as diabetic after three weeks, which suggests this disease is reversible," said Roberts.
Roberts also said that although the short-term diet reversed the clinical diagnosis of type-2 diabetes that it did not appear to reverse damage such as arterial plaque development. He suggested that long-term adherence to the diet may reverse atherosclerosis.
Roberts and his team followed 31 obese men, of which 15 had diagnosed MetS. The diet was prepared to contain about 10 per cent of the calories from fat, 15 to 20 per cent from protein, and 70 to 75 from carbohydrates.
The researchers took regular blood samples from the volunteers and measured a range of inflammatory markers, including inflammatory protein C-reactive protein (CRP), chemokine macrophage inflammatory protein-1 alpha (MIP-1alpha), and the cell adhesion molecules (CAM) sP-selectin and soluble intracellular CAM-1.
Roberts' suggestions that diabetes could be reversed at all, let alone in the space of three-weeks, go against medical understanding of the disease. British charity, Diabetes UK, told NutraIngredients.com that there was no cure for diabetes, and that Roberts' claims are based purely on an improvement in blood glucose levels.
The charity did say however that diet and exercise could control blood glucose levels thereby removing the need for insulin injections or tablets for people who suffer from type-2 diabetes.
In a previous study using the Pritikin diet (Circulation, Vol. 106, pp.2530-2532) Roberts wrote: "Increased intake of fibre, antioxidants, and other phytochemicals, as well as the reduced fat and refined sugar consumption, most likely contributed to the reductions in oxidative stress and improvements in blood pressure."
Diabetes currently affects over 200 million people worldwide and, according to WHO estimates, 2.5 to 15 per cent of annual national health budgets are spent on diabetes-related illnesses.