The study comes from the University of Toronto and St. Michael’s Hospital in Toronto, Canada. Here researchers discovered that an increased intake of tree nuts and peanuts leads to measurable improvements to blood glucose control. This is despite the higher fat intake with the nuts. Moreover, there is an improvement with lipid risk factors for heart disease in patients with non-insulin dependent diabetes.
The research was led by Dr. David Jenkins and by Dr. Maureen Ternus. For the study 117 men and postmenopausal women with type 2 diabetes were examined. Each was taking oral glucose-lowering agents. The study participants were randomised after some stratification by sex.
Muffins?
Or nuts?
The subjects, placed into three groups, were given one of the following three diets. The first was a so-termed ‘full-dose nut diet’ (40 subjects). In this diet, mixed nuts were included in the diet (75 grams per day or two ounces of nuts a day). With the second group, this was called the ‘full-dose muffin diet’. Here the subjects (39 people) were given a dietary regime that included three whole-wheat muffins each day. The muffins had a similar protein content to the nuts consumed in the first group.
The third group eat a so-called ‘half-dose nut diet’ (38 people). This was a diet with half portions of both the nuts and muffins. Each supplement provided approximately 475 calories per 2,000 calorie diet.
Across the three groups, subjects were measured for glycated haemoglobin (or HbA1c). Glycated haemoglobin is a form of hemoglobin that is measured primarily to identify the three-month average plasma glucose concentration. In diabetes mellitus, higher amounts of glycated hemoglobin, indicating poorer control of blood glucose levels, have been associated with cardiovascular disease, nephropathy, neuropathy, and retinopathy.
The results showed that compared with the full-dose muffin diet, the full-dose nut diet provided a greater total energy intake from monounsaturated fat. Moreover, the full-dose nut diet also reduced HbA1c levels compared with the full-dose muffin diet. This led the researchers to conclude that nut intake, as a replacement for carbohydrate consumption, leads to improved glycaemic control and lower lipid risk factors in individuals already diagnosed with type 2 diabetes.
According to David Jenkins: “The original findings revealed that the full dose nut group had a significant reduction in HbA1c compared to the other two groups.”
He adds: “The current study shows a reduction in HbA1c and the low-density lipoprotein (LDL)-associated cardiovascular disease (CVD) risk factor, apolipoprotein B (Apo-B)…We also found lower levels of small LDL cholesterol— which is an emerging risk factor for CVD.”
And is summarising the outcome, Jenkins adds: “The bottom line is, this study showed a modest but significant improvement in blood glucose control, despite the higher fat intake, and improvement in lipid risk factors for heart disease with increasing nut dose
The study has been published in the journal Diabetologia. The research paper is titled “Nuts as a replacement for carbohydrates in the diabetic diet: a reanalysis of a randomised controlled trial.”
Essential Science
This article is part of Digital Journal’s regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue. Last week we looked at a new type of battery that can re-charge in a matter of seconds and looks set to revolutionize mobile devices.
The week before we looked at ocular lasers, which are based on an ultra-thin membrane laser using organic semiconductors. These have a variety of security applications.
