In a recent article published within the journal Nutrients, researchers evaluate the impact of 12 weeks of standard lentil consumption on metabolic health. 

Study: Twelve Weeks of Day by day Lentil Consumption Improves Fasting Cholesterol and Postprandial Glucose and Inflammatory Responses—A Randomized Clinical Trial. Image Credit: Gulcin Ragiboglu / Shutterstock.com

The health advantages of lentils

America Department of Agriculture (USDA) recommends that adults eat about 300 grams of cooked pulses weekly. Lentils, a form of pulse, are known for his or her high dietary fiber and protein content, in addition to the presence of certain bioactive compounds like polyphenols.

So far, few studies have investigated the long-term impact of lentil consumption on the USDA-recommended dose. Furthermore, pulse intervention studies have rarely evaluated the gastrointestinal (GI) symptoms which will arise in response to pulse consumption.

In regards to the study

The current randomized clinical trial assessed dynamic lipidemic, glycemic, and inflammation responses during a 12-week dietary intervention of seven midday meals totaling 980 or zero grams of cooked green lentils every week on the health of 18-70-year-olds at a greater risk of developing chronic metabolic disorders.

Included men and women had a waist circumference of 40 or 35 inches or more, respectively, as that is an accepted proxy for central adiposity. Moreover, all study participants had non-fasting serum triglyceride (TG) levels exceeding 1.69 mmol/L or 150 mg/dL. 

Surveys were administered once every week to evaluate how lentil consumption impacted GI symptoms and satiety throughout the 12-week intervention. At baseline, anthropometric measurements and every participant’s written consent were obtained.

Habitual dietary patterns and specific food regimen components were also reported to detect differences between meal groups. At visit two, postprandial serum TG levels were measured to be sure that the study participants continually met the inclusion criteria.

Through the 12-week dietary intervention period, study participants were asked to finish a high-fat meal challenge, wherein they consumed a 50-gram oral fat load. Blood samples were collected after fasting and hourly for five hours postprandially for blood marker assessment. 

General linear models were used to evaluate physical and biological changes across each groups from pre- to post-intervention. Linear mixed-effects models were used to find out the impact of timing and meals on satiety measures and GI symptom severity.

Study findings

A complete of 38 chubby and obese adults with a mean age of 47.2 years and body mass index (BMI) of 34.4 kg/m² accomplished the 12-week intervention. From pre- to post-intervention, anthropometric metrics didn’t change in either meal group.

Throughout the study period, total fiber consumption averaged 17.3 g and 22.9 g within the lentil and control groups, respectively. While sodium intake increased amongst lentil consumers, dairy and refined grain consumption decreased amongst controls.

For lentil recipients, every day average legume consumption significantly increased from baseline at 0.1 to 0.6 cups, which increased their Healthy Eating Index (HEI) scores in 4 domains. Those that consumed lentils also had higher total, insoluble, and soluble fiber intake.

The mean response rates to the satiety and GI surveys were 89.6 and 90.8% for the control group, respectively, and 89% and 89.4% for the lentil group, respectively. While satiety measures didn’t vary by meal groups, GI symptom severity responses for each groups were rated as none or mild amongst 87.7%, with only 10% and a pair of.3% rating them as moderate or severe, respectively, throughout the 12-week intervention.

Twelve weeks of every day lentil consumption decreased fasting measures of lipid metabolism, including total and low-density lipoprotein (LDL) levels of cholesterol. As well as, long-term lentil consumption improved postprandial glucose and inflammation responses to a high-fat meal challenge. 

A possible explanation for this remark is that fiber binds bile acids, thereby stopping their return to the liver and stimulating the production of hepatic bile acids. The body replenishes hepatic levels of cholesterol through cholesterol uptake from the blood, which decreases serum levels of cholesterol.

One other mechanism by which lentils likely helped reduce serum cholesterol is thru saponins, that are bioactive compounds that regulate lipid metabolism and stop cholesterol absorption. Habitual lentil consumption could also lower total saturated fat intake, a food regimen component that increases levels of cholesterol. 

Conclusions

The study findings indicate that 12 weeks of lentil consumption in individuals at the next risk of developing metabolic disease could reduce fasting levels of cholesterol, in addition to improve postprandial glucose and systemic inflammatory responses.  

Lentil consumption exceeding the USDA beneficial dose didn’t cause GI distress. Importantly, these metabolic improvements were independent of changes in anthropometric measures, thus suggesting a direct impact of lentil consumption on metabolism.

Thus, increased lentil consumption might be a secure and effective dietary technique to improve metabolic health in high-risk populations. Future studies are needed to analyze the impact of prolonged consumption of other pulses on metabolic health.