Vegan Diet Outshines ADA Diet

Since we had the honor of an e-visit from the distinguished Dr. Neal Barnard, and in light of our previous post describing the suspension of the intensive blood glucose treatment arm (medication-based) of the large ACCORD trial, I present the findings of one of Dr. Barnard's more recent studies - one that finds benefit without the use of drugs.

Barnard, et al's study which appeared in the August 2006 issue of Diabetes Care,¹ found that people with diabetes who followed a low-fat, vegan diet saw improvements in HbA1c, body weight, BMI, waist circumference, total cholesterol, and LDL cholesterol that were significantly greater than improvements in a group following an ADA diet (which adhered to American Diabetes Association guidelines).

Participants (n=99) were followed for 22 weeks, at the end of which:

"Among participants whose diabetes medications remained unchanged throughout, A1C fell 1.23 points in the vegan group and 0.38 points in the ADA group (P = 0.01)."

"Body weight decreased 6.5 kg (14.3 lbs) in the vegan group and 3.1 kg (6.8 lbs) in the ADA group (P < 0.001)."

"Among those who did not change lipid-lowering medications, LDL cholesterol fell 21.2% in the vegan group and 10.7% in the ADA group (P = 0.02)."

A vegan diet includes grains, legumes, vegetables, and fruits, and excludes animal products. The vegan diet in this study also excluded added fats.



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¹ A Low-Fat Vegan Diet Improves Glycemic Control and Cardiovascular Risk Factors in a Randomized Clinical Trial in Individuals With Type 2 Diabetes

Photo of vegan pyramid: Nutrispeak.com, the home page of Vesanto Melina, MS RD.

Hemoglobin A1C Predicts Diabetes

Boy, does it predict diabetes.

A study appearing in the August issue of the American Journal of Medicine found that women, aged 45 or older, whose HbA1c was >7.0%, and who did not have diabetes, had an 81 times greater risk of being diagnosed with type 2 diabetes in the following 10 years, than women whose HbA1c was 5.0% or less.¹

Participants were 26,563 women who took part in the Women's Health Study (WHS). They were followed for median of 10.1 years.

Findings

The risk for diabetes increased as HbA1c levels increased:

For women whose HbA1c was:

• <5.0%, there was no greater risk.
  
• 5.0% to 5.4%, the risk was 2.9 times greater.
  
• 5.5% to 5.9%, the risk was 12.1 times greater.
  
• 6.0% to 6.4%, the risk was 29.3 times greater.
  
• 6.5% to 6.9%, the risk was 28.2 times greater.
  
• >7.0%, the risk was 81.2 times greater.

These researchers also investigated whether HbA1c levels in non-diabetic women could predict cardiovascular disease (CVD) in the following 10 years. They found that HbA1c did not predict CVD.

________¹ Hemoglobin A1c Predicts Diabetes but Not Cardiovascular Disease in Nondiabetic Women

A Change May Be In the Works for HbA1c

You've just had an A1C (hemoglobin A1C) test. The result was 7.5%. What does that mean? How does that relate to the average blood glucose readings you take at home? If preliminary results from the ADAGE trial hold, that A1C lab result may be reported as average glucose, in the familiar mg/dl reading, beginning next year.

The ADAGE study is a clinical trial being conducted at a number of centers across North America, Europe, and Africa. Its goal is to confirm the relationship between HbA1C levels and average blood glucose. Preliminary findings, reported at the 2007 ADA Scientific Sessions, are showing that relationship is closely correlated, for both type 1 and type 2 diabetes. This could lead to results of an A1C test being reported as A1C-Derived Average Glucose (ADA-G).

What Is HbA1C?

Hemoglobin A1C is that portion or percent of total hemoglobin that has glucose attached to it. In people without diabetes, about 4% to 6% of their hemoglobin is glycosylated. Red blood cells that contain the hemoglobin circulate in the bloodstream for 3 or 4 months before being broken down and replaced. During that time the RBC can bond, irreversibly, to glucose in the bloodstream. Thus, A1C readings higher than about 6% indicate higher than normal amounts of glucose roaming the bloodstream in the past 120 days.

Using the Conversion Table from the ADA's 2005 Position Statement on Standards of Medical Care in Diabetes, the 7.5% A1C reading at the beginning of this post would equate to an average blood glucose of about 188 mg/dl:


If this change happens, instead of receiving a 7.5% HbA1C, you might receive a result such as 188 mg/dl ADA-G. Improved calibration of lab machines that measure glycosylated hemoglobin are also in the offing. These changes may make lab results easier to interpret leading to improved blood glucose management.
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