In addition to overall pattern, fried foods, diet sodas, and meat are independently associated with metabolic syndrome
by Craig Weatherby
“Metabolic syndrome” is the label researchers apply to a cluster of physical signs linked to increased risk of diabetes and heart disease.
One in three adult Americans has the signs of metabolic syndrome (MetS)—compared with one in seven Europeans—and obesity is the main risk factor.
In addition to sedentary lifestyles, it seems likely that the high-calorie, low-nutrient, low-fiber nature of the standard American diet—which promotes obesity—also causes the MetS cluster of risk factors.
Yet surprisingly, the role of diet in promoting metabolic syndrome (MetS) has not been studied very much.
Prior studies support preventive effect of "prudent" diets
Early in this century, twin studies from England and Ireland linked so-called “prudent” diets —that is, Mediterranean-style diets rich in fruits, vegetables, whole grains, and fish—with reduced risk of MetS and one of its several signs, insulin resistance (Williams DE et al. 2000; Villegas R et al. 2004).
And a team of scientists from Harvard and Iran came to similar conclusions two years ago: “Higher intakes of fruit and vegetables are associated with a lower risk of the metabolic syndrome; the lower risk may be the result of lower CRP concentrations.” [CRP is a marker for inflammation and a risk factor for heart disease] (Esmaillzadeh A et al. 2006).
Their findings were ratified by a recent analysis of data from the Greek ATTICA study, whose results linked higher fish intake to lower inflammation. (Inflammation is one of the signs of MetS and it's a risk factor for heart disease and diabetes; see “Fish Inhibits Heart-Attacking Inflammation.”
Last year, the Greek researchers analyzed data from the ATTICA study and came to this conclusion: “A dietary pattern that includes cereals, fish, legumes, vegetables, and fruits was independently associated with reduced levels of clinical and biological markers linked to the metabolic syndrome, whereas meat and alcohol intake showed the opposite results” (Panagiotakos DB et al. 2007).
And studies we covered suggest that fish, berries, and a shift in dietary fat might help deter MetS (see “Omega-3s May Fight Metabolic Syndrome,” “Tart Cherries Seen Suppressing Metabolic Syndrome,” and “Omega-6/Omega-3 Imbalance Pushes Heart/Diabetes Perils”).
New US study finds that American diet promotes MetS
A desire for data from the American context led researchers from the University of Minnesota and the University of North Carolina to analyze data from the Atherosclerosis Risk in Communities (ARIC) study, which involved 9,514 volunteers between 45 and 64 years old (Lutsey PL et al. 2008).
The participants completed a 66-part diet questionnaire, and were classified as eating a high-calorie “Western” (standard American) or prudent dietary pattern rich in whole plant foods and fish.
The researchers followed the subjects over nine years, during which 3,782 volunteers developed the MetS symptom cluster.
The results indicate that eating the Western dietary pattern increases the risk of MetS.
When the researchers adjusted the results to account for the participants' intake of meat, dairy, fruits and vegetables, refined grains, and whole grains, they linked greater consumption of fried foods, diet sodas, and meat to increased risk of developing MetS.
In line with some obesity studies, higher consumption of dairy products seemed to reduce risk.
Surprisingly, and contrary to the findings of all of the few prior studies, diets higher in fruits and vegetables, nuts, and whole grains showed no protective benefit. This result is anomalous enough to cause us to wonder how much of these foods the researchers considered "high consumption" (it wouldn't take much in the American context), and whether they accounted for confounding factors such as sedentary lifestyles and simultaneous consumption of lots of junky food.
The findings with regard to fatty, sweet foods come as no surprise, since the standard American diet is high in fried foods, diet sodas, and meats, and is associated with risk of obesity and the diseases associated with MetS (diabetes and heart disease).
- Esmaillzadeh A, Kimiagar M, Mehrabi Y, Azadbakht L, Hu FB, Willett WC. Fruit and vegetable intakes, C-reactive protein, and the metabolic syndrome. Am J Clin Nutr. 2006 Dec;84(6):1489-97.
- Lutsey PL, Steffen LM, Stevens J. Dietary Intake and the Development of the Metabolic Syndrome. The Atherosclerosis Risk in Communities Study. Circulation. 2008 Jan 22; [Epub ahead of print]
- Panagiotakos DB, Pitsavos C, Skoumas Y, Stefanadis C. The association between food patterns and the metabolic syndrome using principal components analysis: The ATTICA Study. J Am Diet Assoc. 2007 Jun;107(6):979-87; quiz 997.
- Williams DE, Prevost AT, Whichelow MJ, Cox BD, Day NE, Wareham NJ. A cross-sectional study of dietary patterns with glucose intolerance and other features of the metabolic syndrome. Br J Nutr. 2000 Mar;83(3):257-66.
- Villegas R, Salim A, Flynn A, Perry IJ. Prudent diet and the risk of insulin resistance. Nutr Metab Cardiovasc Dis. 2004 Dec;14(6):334-43.