The Presence of Lunasin, a Soy-Derived Bioactive Peptide in Plasma: A Randomized Clinical Trial

Objectives

Lunasin is a bioactive peptide originally derived from soy protein which is being marketed as a nutraceutical product for its potential beneficial effects. Functionality of lunasin depends on its presence in circulation after digestion and metabolism. We studied safety, tolerability, and presence of lunasin in blood for the first time in humans in a well-controlled randomized clinical trial.

Methods

In a triple-blinded, placebo-controlled crossover study, 31 subjects (female: 19, male: 12, age = 61 ± 9.9 years) were randomized into an 8-week intervention period with capsules containing either 335 mg/d lunasin-enriched soy extract (LES) or corn fiber (placebo). This was followed by a 3-week wash-out period after which participants switched treatment groups for the next 8 weeks. In this crossover randomized study, plasma samples of subjects were collected after ingestion of a daily dose of lunasin-enriched capsules for 8 weeks, which provided 50 mg/d of lunasin. Enzyme-Linked Immunosorbent Assay was used to detect plasma lunasin level after an overnight fast.

In order to assess the dietary intake of lunasin, two 24-hour dietary recalls (one in each intervention period) were obtained from each participant. Dietary intake data were collected and analyzed using Nutrition Data System for Research software version 2015, developed by the Nutrition Coordinating Center (NCC), University of Minnesota, Minneapolis, MN.

Results

During the intervention, no major safety concerns related to lunasin consumption were noticed. Ingestion of 335 mg/d LES for 8 weeks resulted in higher lunasin level in plasma compared to placebo. Fasting plasma lunasin levels ranged 0–10 ng/mL. The mean lunasin concentration in plasma increased by 44% after 8 weeks of daily supplementation with LES.

Conclusions

Lunasin was detectable in plasma after overnight fast in higher levels among LES takers. The difference in lunasin concentration was due to LES capsules and not dietary intake of lunasin-containing foods.

Funding Sources

The study was funded by Soy Labs Inc.

Beyond Meat: A Comparison of the Dietary Intakes of Vegetarian and Non-vegetarian Adolescents

Dietary intake of adult vegetarians from large prospective studies has been well-characterized but is rarely reported in vegetarian adolescents. Our objective was to describe and compare the dietary intake of vegetarian adolescents with their non-vegetarian counterparts in a population known to espouse healthy living. Adolescents (n = 534) aged 12–18 years old from middle and high schools near major Adventist universities in Michigan and Southern California provided dietary, demographic, and anthropometric data. Dietary intake was measured with a validated 151-item self-administered web-based food frequency questionnaire; weight and height were measured during school visits. Vegetarian was defined as the combined intake of meat, meat derivatives, poultry, and fish of <1 serving per week. Descriptive statistics and ANCOVA were used to compare the intake of vegetarians and non-vegetarians. Vegetarians significantly ate more fruits, vegetables, and other plant-based foods, but significantly less foods of animal origin, sugar-sweetened beverages, and coffee/tea compared to non-vegetarians. Vegetarians had significantly higher intakes of carbohydrates and total protein but lower intakes of fats, animal protein, and zinc compared to their counterparts. A majority (75% or more) of both groups met the 2015 Dietary Guidelines' age-and-gender-specific recommendations for most nutrients but only 16–18% of vegetarians/non-vegetarians did not exceed the upper limit for sodium. More vegetarians (49%) than non-vegetarians (25%) had <10% of their caloric intake from SFA. More than 90% of both groups met dairy recommendations, but greater proportions of vegetarians met recommendations for vegetables, fruits, nuts/soy products, and legumes than non-vegetarians. Of the non-vegetarians, only 7% and 44% met the fish and meats/poultry/eggs recommendation, respectively, which none of the vegetarians met. Compared to the general US adolescent population, both diet groups ate more fruits, vegetables, dairy and protein foods, and also consumed more micronutrients but less macronutrients. Overall, vegetarian adolescents have a more favorable dietary intake profile than non-vegetarians, but both vegetarians and non-vegetarians in this study population have a more adequate diet than the general US adolescent population. The influence of the Adventist plant-based diet culture that is translated both at home and at school is evident in our findings.

The Effect of Soybean Lunasin on Cardiometabolic Risk Factors: A Randomized Clinical Trial

Lunasin, a peptide isolated from soybeans, has been shown to exert antioxidant, anticarcinogenic, and hypocholesterolemic effects in animal and in vitro models. In a triple-blind, placebo-controlled crossover study, 31 participants (female: 19, male: 12, mean age 61 ± 9.9 years) were randomized to an 8-week treatment of lunasin-enriched soy extract (335mg/d) or placebo. A 3-week washout period was utilized between treatments. Serum lipids, glucose, and insulin, as well as blood pressure and anthropometrics, were measured at baseline, week 7, and week 8 of each treatment period. There were nonsignificant reductions in cardiometabolic risk factors with treatment: total cholesterol -0.1mmol/L, 95% CI [-0.28, 0.03]; LDL cholesterol -0.07mmol/L, 95% CI [-0.2, 0.06]; triglyceride 0% mmol/L, 95% CI (-10%, 11%]; fasting serum glucose -2% mmol/L, 95% CI [-4%, 1%]; BMI -0.05 kg/m2, 95% CI [-0.17, 0.07] and waist circumference -0.63cm, 95% CI [-1.8, 0.53]. Supplementation with lunasin-enriched soy extract for 8 weeks did not result in significant changes in serum lipids, glucose, insulin resistance, blood pressure, BMI, or waist circumference. Future studies should focus on a higher dosage, larger sample size, and/or longer treatment to determine the independent role of lunasin, if any, in the effect of soy on cardiometabolic risk factors.