Walnuts and Health

Nutritious Food for People with Diabetes

Diabetes

A Walnut a Day? A Yale Study published in Diabetes Care1 finds Walnuts Improve Blood Flow in Adults with Type 2 Diabetes

Methods:

  • Randomized, controlled, single-blind, cross-over trial included twenty-four adults (14 women, 10 men) with type 2 diabetes.
  • Participants consumed 2 ounces of walnuts each day along with their normal diets during one 8-week period, and to simply follow their normal diets during another 8-week period.
  • Endothelial function testing and cardiovascular biomarkers were assessed after each 8-week treatment phase.

Results:

  • Endothelial function (a powerful predictor of cardiovascular risk) significantly improved after consumption of the walnut-enriched diet compared to the diet without walnuts.
  • The researchers concluded that a walnut-enriched diet may improve endothelium-dependent vasodilatation in type 2 diabetics, thus reducing overall cardiac risk. It should be noted that not all of the individuals exhibited this improvement.
  • Due to study limitations, future research is required in order to determine the specific role walnuts may have on endothelial function and blood lipids in individuals with type 2 diabetes.

A study published in the European Journal of Clinical Nutrition2 found that walnuts, known for their high content of Polyunsaturated Fat (13g), significantly improve metabolic factors in overweight individuals with type 2 diabetes.

Methods:

  • Fifty adults with non-insulin treated diabetes were randomized into followed either a healthy, low-fat control diet or a similar diet including an ounce of walnuts daily for a year.

Results:

  • The walnut group consumed significantly more Polyunsaturated fats than the control, an outcome attributed to walnut consumption.
  • Both groups demonstrated a consistent weight loss during the first six months, however the control group experienced a consistent weight increase in the second six months, while the walnut group remained stable.
  • The walnut group produced significantly greater reductions in fasting insulin levels, particularly in the first three months.

A study published in the December 2004 issue of Diabetes Care3 reported a positive effect of a moderate-fat diet, inclusive of walnuts, on blood lipid profiles in patients with type 2 diabetes.

Methods:

  • A parallel randomized controlled trial included 58 men and women, ages 35-75, diagnosed with type 2 diabetes at least one year prior.
  • Compared three dietary advice groups each with 30% energy as fat: 1) low fat, 2) modified low fat, and 3) modified low fat, inclusive of 30g walnuts (equivalent to around 8-10 nuts) per day.

Results:

  • The walnut group achieved a 10% reduction in LDL cholesterol and a greater increase in HDL (good) cholesterol levels than the other two treatment groups.

1 Effects of walnut consumption on endothelial function in type 2 diabetic subjects: a randomized controlled crossover trial. Diabetes Care. 2010 Feb;33(2):227-32.
2 Long-term effects of increased dietary polyunsaturated fat from walnuts on metabolic parameters in type II diabetes. Eur J Clin Nutr. 2009 Apr 8.
3 Including Walnuts in a Low-Fat/Modified-Fat Diet Improves HDL Cholesterol-to-Total Cholesterol Ratios in Patients With Type 2 Diabetes. Diabetes Care. 2004 Dec;27(12):2777-83.