How Dietary Fiber Combats the Metabolic Syndrome?

Though the prevalence of obesity continues to rise in developed nations, there are simple lifestyle and dietary adjustments that can help us win the battle of the bulge. Obesity itself carries a number of health risks including type 2 diabetes, cardiovascular disease as well as certain types of cancer.

Lately, there’s been a lot of buzz amongst researchers about the metabolic syndrome. It’s basically a way of referring to multiple medical disorders which work together to dramatically increase your risk of developing the aforementioned medical conditions–not to mention an increased risk of stroke and fatty liver.

The metabolic syndrome essentially results from a combination of abdominal obesity and insulin resistance. It’s associated with high blood pressure, cholesterol, and blood sugar levels.

Think of it as a perfect storm converging for very bad arterial health. As an analogy, imagine that you don’t want your new car to rust. But for some inexplicable reason, you decide to take some sandpaper to scrape off the paint. To make matters worse, you wash your car daily with seawater. In between washing with seawater, you alternately spray your car with hydrogen peroxide or bleach.

Who would do that to a car they owned? No, it doesn’t make very much sense to intentionally take steps to cause your car to rust. Nor does it make sense to make dietary and lifestyle choices that ruins our health.

In a previous post that I wrote, I described the differences between soluble and insoluble fiber. A new research study published in the British Journal of Nutrition (Pal et al, 2010), explored different dietary interventions on weight loss and metabolic syndrome risk factors.

Dietary fiber intake is inversely associated with BMI, waist circumference, and body weight. Dietary fiber has potential benefits and risk reduction for metabolic syndrome risk. This includes health benefits such as promoting weight loss, improving insulin resistance and blood sugar, as well as improving your cholesterol levels. Yet, most Americans consume roughly only half of the recommended daily intake of fiber (25-30g/day).

Specifically for this study, they compared three interventions including a healthy diet, a healthy diet with psyllium supplementation, and a combination of both. In total, 37 men and 35 women between the ages of 18 to 65 were recruited for the study. The study participants had BMI’s ranging from 25 to 40.

The Fiber supplement used in this study contained psyllium (Metamucil) which included consuming 12g/day. Psyllium is a type of soluble fiber. The dietary intervention involved complying with the Dietary Guidelines for Australian Adults (consuming 30g/day of fiber). The duration of the interventions were 12 weeks in total.

Results:

• Weight, BMI, and body fat % were reduced significantly in the fiber, and in the healthy diet plus psyllium groups.
• Weight and BMI were only reduced in the healthy diet alone compared to placebo group at week 12.
• Triglycerides and insulin levels were significantly reduced in both the healthy diet +/- psyllium groups.
• The healthy diet +/- psyllium groups both demonstrated significant reductions in total and LDL cholesterol

Conclusions:

From the study authors:

“The present study demonstrated that simply adding psyllium fibre supplementation to a normal diet was sufficient to obtain beneficial effects in risk factors. However, a high-fibre diet consisting of a psyllium supplement plus fibre from a healthy diet provided the greatest improvements in metabolic syndrome risk factors.”

The study authors continued:

“Therefore, recommendations for .30 g/d of fibre for overweight or obese individuals, derived from dietary sources in conjunction with psyllium fibre supplementation, may be appropriate to improve metabolic syndrome risk factors in this group.”

Bottom line: For those with BMI’s greater than 25, it’s important to consume 30g per day of fiber from dietary sources. This study suggests that in addition, daily consumption of 12 g/day of psyllium will have additional health benefits.

References:

1. Pal S, Khossousi A, Binns C, Dhaliwal S, Ellis V. The effect of a fibre supplement compared to a healthy diet on body composition, lipids, glucose, insulin and other metabolic syndrome risk factors in overweight and obese individuals. Br J Nutr. 2010 Aug 23:1-10.