D2 dopamine receptor Taq1A polymorphism, body weight, and dietary intake in type 2 diabetes.

Abstract

OBJECTIVE:

Certain D2 dopamine receptor Taq 1A genotypes (A1A1, A1A2) have been associated with obesity and substance abuse. We hypothesized that their presence would be associated with reduced efficacy of dietary interventions in individuals with type 2 diabetes.

METHODS:

In the course of a randomized clinical trial in an outpatient research center in which 93 adults with type 2 diabetes were assigned to a low-fat vegan diet or a diet following 2003 American Diabetes Association guidelines for 74 wk, Taq 1A genotype was determined. Nutrient intake, body weight, and hemoglobin A1c (A1c) were measured over 74 wk.

RESULTS:

The A1 allele was highly prevalent, occurring in 47% of white participants (n = 49), which was significantly higher than the 29% prevalence previously reported in non-diabetic whites (P = 0.01). The A1 allele was found in 55% of black participants (n = 44). Black participants with A1(+) genotypes had significantly greater mean body weight (11.2 kg heavier, P = 0.05) and greater intake of fat (P = 0.002), saturated fat (P = 0.01), and cholesterol (P = 0.02) compared with A2A2 (A1(-)) individuals; dietary changes during the study did not favor one genotype group. Among whites, baseline anthropometric and nutrient differences between gene groups were small. However, among whites in the vegan group, A1(+) individuals reduced fat intake (P = 0.04) and A1c (P = 0.01) significantly less than did A1(-) individuals.

CONCLUSION:

The A1 allele appears to be highly prevalent among individuals with type 2 diabetes. Potential influences on diet, weight, and glycemic control merit further exploration.

• Authors: Neal D Barnard, Ernest P Noble, Terry Ritchie, Joshua Cohen, David J A Jenkins, Gabrielle Turner-McGrievy, Lise Gloede, Amber A Green, Hope Ferdowsian
• Journal: Nutrition (Burbank, Los Angeles County, Calif.) (Nutrition) Vol. 25 Issue 1 Pg. 58-65 (Jan 2009) ISSN: 0899-9007 [Print] United States
• PMID: 18834717 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Glycated Hemoglobin A
• Receptors, Dopamine D2

Topics

• Black or African American (genetics)
• Body Weight (physiology)
• Diabetes Mellitus, Type 2 (diet therapy, epidemiology, ethnology, genetics)
• Diet, Diabetic
• Diet, Reducing
• Diet, Vegetarian
• Energy Intake (physiology)
• Female
• Gene Frequency
• Genotype
• Glycated Hemoglobin (analysis)
• Humans
• Male
• Middle Aged
• Obesity (diet therapy, epidemiology, ethnology, genetics)
• Polymorphism, Genetic
• Receptors, Dopamine D2 (genetics)
• Treatment Outcome
• White People (genetics)