The Metabolic Syndrome and Eating Habits

Summarized by Robert W. Griffith, MD
October 10, 2006

Summary

A study shows that poor dietary habits over a 12-year period increase the likelihood of obesity and the metabolic syndrome in women.

Introduction

It's obvious that the metabolic syndrome (MS) is related somehow to eating - too much, or too much of the wrong food - along with possible genetic factors and lack of exercise. Anything one can do to reduce its frequency is worthwhile, as it has been shown to be closely associated with reduced lifespan, related to subsequent coronary heart disease, stroke, diabetes, and other conditions.

The syndrome affects 29% of American women¹. Scientists from Boston University have examined its development in women enrolled in the Framingham Offspring-Spouse Study over a 12-year period, in relation to their nutritional intake. Their findings are published in the American Journal of Clinical Nutrition, and summarized below.

What was done

Three hundred women between 30 and 69 were selected from those participating in the Framingham Offspring-Spouse Study. They were selected from 967 women examined during the start of the study (1984 to1988), as they had none of the 5 MS risk factors. They were studied over the next 12 years, with extensive physical exam, lab tests, and diagnostic tests every 4 years. Risk factors for the MS were evaluated at these 4-yearly exams done between 1988 and 1992.

At the initial exams nutrient intake was fully characterized, using the Minnesota Nutritional Data System; the nutrient risk score used 19 items to assess nutritional quality, with a lower score representing a more desirable intake. Examples of desirable intake factors were a lower fat intake, a raised fiber intake, or a raised micronutrient intake. Intakes were estimated using a 3-day period (2 weekdays and one weekend day).

To assess the role of nutritional quality, the 300 healthy women were ranked 1 through 300, according to their nutritional risk scores; they were then classified into one of three categories, or tertiles, based on their ranking.

What was found

The age and physical activity profiles of the women without any MS risk factor were similar to those of women in the Framingham study who had one or more MS risk factors. Their average age was 49, and 14% smoked. (In 'controls' from the Framingham Offspring-Spouse Study who had one or more MS factors, but were therefore not included in this study, the average age was 52, and 21% smoked.)

The women with the highest nutritional risk - those in the third tertile - had lower energy intakes, higher percentages of energy from dietary lipids and alcohol, lower total carbohydrate and fiber intakes, lower amounts of all micronutrients (vitamins, minerals), and 3 times the smoking rate of women in the lowest risk tertile.

Development of full-blown MS (i.e. 3 of the 5 risk factors) was 3 times as likely, and abdominal obesity was 2.3 times as likely in the highest tertile of nutritional risk compared with those in the lowest tertile.

More women developed abdominal obesity than any other of the MS risk factors. The links between nutrient quality and occurrence of the MS were found to be independent of the presence of high blood pressure, raised fasting glucose level, a low high-density lipoprotein (HDL) cholesterol level, or raised triglyceride level.

What this study shows

This study provides important evidence that poor dietary habits increase the risk for obesity and the MS in women; there's no reason to believe the results aren't valid for men, too. Of 300 healthy women, those who ate the least-healthy diet over a 12-year period were considerably more likely to develop the syndrome - 2-3 times more likely, in fact. And in the same population, over an 8-year period, the MS accounted for one in five of coronary artery events (e.g. heart attacks), and more than half of newly-diagnosed diabetes cases.

Experts are still arguing about the metabolic syndrome - is it a real or an artificial construct? For the patient, such things don't really matter. The factors that contribute to the diagnosis of the syndrome are all detrimental, in one way or another, and should be addressed by adapting a healthy lifestyle. This study shows that abdominal obesity (i.e. waist size) is the most relevant factor if one's examining diet, and shows the benefits of a healthy diet over the years - low fat (total, saturated, and monounsaturated fats), low alcohol (but not too low), and increased fiber and micronutrients (vitamins and minerals). And, of course, no smoking.

Source

• Nutritional risk and the metabolic syndrome in women: opportunities for preventive intervention from the Framingham Nutrition Study BE. Millen, MJ. Pencina, RW. Kimokoti,  et al., Am J Clin Nutr, 2006, vol. 84, pp. 434--441

Footnotes
1. The metabolic syndrome requires 3 of the following risk factors to be present: (a) Waist size over 40 inches (102 cm) in men, or 35 inches (88 cm) in women. (b) Serum triglyceride level over 150 mg/dL (1.7 mmol/L). (c) Serum HDL ('good') cholesterol below 40 mg/dL (1.0 mmol/L) in men, or 50 mg/dL (1.29 mmol/L) in women. (d) Blood pressure over 130/85 mm Hg (either number), or being on blood pressure medication. (e) Fasting blood sugar over 110 mg/dL (6.1 mmol/L). Take the self-test, at the link below.

Related Links
Do You Have the Metabolic Syndrome?
The Metabolic Syndrome and the Risk of Alzheimer's
Stress at Work and the Metabolic Syndrome

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.