Fibre to the rescue!

Three new studies link fibre intake to reduced risk of metabolic syndrome. One in every four Americans is affected by a group of risk factors called metabolic syndrome, which raises their risk for heart disease, stroke, and type 2 diabetes.

The risk factors that contribute to metabolic syndrome are high blood pressure, elevated fasting blood glucose, large waist circumference, low levels of the good HDL cholesterol, and high blood levels of triglycerides.

Fat accumulation

The accumulation of fat just beneath the abdominal muscles, called visceral adipose tissue, or VAT, is increasingly recognised as a risk factor for metabolic syndrome. Even apparently lean people can have a significant accumulation of VAT, which increases their risk for cardiovascular disease and diabetes. And obese individuals who have relatively little VAT may in fact have a low risk for these diseases.

Researchers with the Insulin Resistance and Atherosclerosis (IRAS) Family Study examined the effects of lifestyle factors on abdominal fat in 339 African Americans and 775 Hispanic Americans, ages 18 to 81, over a five-year period. Researchers assessed physical activity and dietary intake, and measured abdominal fat using CT scans.

The results showed that the greater the intake of soluble fibre - found in beans, oats, barley and citrus fruits - and the greater the physical activity, the less abdominal fat people had regardless of their overall body weight. More specifically, for every 10 grams of soluble fibre consumed, the rate of VAT accumulation decreased by 3.7 per cent. Those subjects who engaged in moderate physical activity had a 7.4 per cent decrease in the rate of VAT accumulation.

The researchers concluded that consuming more soluble fibre and engaging in exercise could slow the accumulation of abdominal fat over time.

Fruits, beans and grains

In a second study, Iranian researchers studied the relationship between dietary fibre and risk of metabolic syndrome in 2,457 adults aged 19 to 84. Subjects with the highest fibre intakes, which averaged 50 grams per day, were only half as likely to have metabolic syndrome as those whose average fibre intake was 25 grams per day. However, only fibre from beans, fruit, and grains was protective, not from vegetables or nuts.

Costa Rican researchers looked specifically at the effect of bean intake and the ratio of beans to rice in the diet on risk of metabolic syndrome in 1,879 adults. Previous research has shown that a high intake of white rice is associated with metabolic syndrome and type 2 diabetes. In this study, increased intake of white rice was associated with higher blood pressure, triglycerides, and fasting glucose and lower levels of protective HDL cholesterol. In contrast, increased bean consumption was associated with lower diastolic blood pressure.

As the ratio of rice to beans increased, subjects were more likely to have lower HDL cholesterol and higher blood pressure and triglycerides. Substituting one serving of beans for one serving of white rice was associated with a 35 per cent lower risk of metabolic syndrome.

Charlyn Fargo is a registered dietitian with the Creators Syndicate website at www.creators.com.