Diet and the Metabolic Syndrome

Summarized by Robert W. Griffith, MD
November 10, 2004

Introduction

The metabolic syndrome (sometimes called the insulin resistance syndrome or 'syndrome X') is becoming well known. Unfortunately, it's also becoming more common. It comprises elevated blood sugar, high blood pressure, high cholesterol levels, and increased girth. And it's associated with increased mortality from coronary heart disease and diabetes. (If you want to see if you may have the metabolic syndrome, go to the first link below.)

Weight control, diet, and physical activity are clearly related to the different components of the syndrome. Now a study has been reported which examines the effect of diet on the frequency of the syndrome itself. The publication in the American Journal of Clinical Nutrition is summarized here.

What was done

In 1995-6 a group of young people in Bogalusa, Louisiana, had their dietary intake measured by analysing questionnaires. They were examined for possible risk factors for the metabolic syndrome, according to the National Cholesterol Education Program definitions. The risk factors are:

• Abdominal obesity - waist circumference greater than 102 cm (40 inches) in men, or 88 cm (35 inches) in women
• Blood triglyceride level 150 mg/dL or above (1.7 mmol/L or above)
• HDL-cholesterol 40 mg/dL (1.04 mmol/L) or below in men, or 50 mg/dL (1.29 mmol/L) or below in women.
• High blood pressure - 130/85 mm Hg or higher, or taking blood pressure medication
• High fasting glucose level - 110 mg/dL (6.1 mmol/L) or above

The subjects were then classified into one of three groups - those with 0, 1-2, or 3- or-more risk factors. Those with 3-or-more risk factors were diagnosed as having the metabolic syndrome.

Analyses were done to see the differences in diet in the subjects in each class of risk factors.

What was found

There were 1420 people enrolled - 65% were white, 35% African American. Their ages ranged from 19 to 38. The percentage of people in each class is given in the table:

	Men		Women
Number of Risk Factors	343 Whites	107 African American	541 Whites	190 African American
None	40%	53%	38%	34%
1-2	44%	36%	51%	56%
3-or-more	16%	11%	11%	10%

Before the analyses, appropriate adjustments were made to allow for age, total calorie intake, body mass index (BMI), and physical activity.

The average intakes of fruit, fruit juice, and vegetables were significantly higher in those people who had no risk factors for the metabolic syndrome than in those who had 1 or 2 risk factors; and those with 1 or 2 risk factors ate more of these items than those with 3 or more risk factors.

Perhaps even more importantly, the average intake of sweetened beverages was lower in those people with no risk factors, than in the other two classes in Whites, but not in African Americans. On the other hand, the intake of diet beverages was higher in those with no risk factors.

What these findings mean

The results here suggest strongly that low fruit and vegetable consumption and high sweetened beverage consumption are linked with the likelihood of development of the metabolic syndrome, and all that it entails. This is supported by the fact that increased consumption of diet beverages was found in the 'no risk factor' group.

This study is another strong indicator that too many of our young people are on the wrong path, from a dietary point of view. Not enough fruit and veggies, too many Pepsi- or Coca-Colas, and the risk of getting the metabolic syndrome increases. The recommendations are clear. And if you must drink sodas, make sure they're sugar-free!

Source

• Comparison of dietary intakes associated with metabolic syndrome risk factors in young adults: the Bogalusa Heart Study. S. Yoo, T. Nicklas, T. Baranowski,  et al., Am J Clin Nutr, 2004, vol. 80, pp. 841--848

Related Links
Tool: Do You Have the Metabolic Syndrome (Syndrome X)?
Fast Food
Survey Reveals Gaps in US Eating Habits
Fruits and Vegetables: The Benefits Come From the Sum of Their Parts

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