Initial Posting: 1/25/2014    Last Update: 4/9/2019
Answer: Lunasin is a protein peptide first identified in soybean and later confirmed to be present in wheat, rye, barley, triticale and oats. Lunasin is sold as a branded ingredient (LunaRich and Lunasin XP, both by Soy Labs LLC) in capsules and soy protein drinks and is promoted for lowering cholesterol. (Other proposed benefits include reducing inflammation and cancer prevention).
There mixed evidence for whether soy can lower cholesterol. Although the FDA currently allows companies to make the claim that "25 grams of soy protein daily, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease," the agency has proposed revoking this health claim due to inconsistent findings (a final decision has not yet been made).
The makers of LunaRich XP state that one 125 mg capsule contains the same amount of lunasin as 25 grams of soy protein. They also claim that lunasin is "the active component in soy protein responsible for reducing LDL cholesterol." This is based on in-vitro and animal research conducted by Soy Labs which found that lunasin reduced the expression of the gene that produces a key enzyme (HMG-CoA reductase) needed for the liver's production of cholesterol. (Prescription statin drugs act to block this same enzyme after it has been produced by the gene, rather than slowing down the gene's production.) Lunasin was also found to increase the number of receptors available in liver cells to remove LDL cholesterol from the bloodstream (Galvez, Circulation 2012).
However, a study among 31 adults with borderline-high LDL cholesterol, triglycerides, fasting blood sugar and/or blood pressure found that taking two capsules of lunasin-enriched soy extract (Soy Labs, LLC) with lunch and dinner for two months did not decrease total or LDL cholesterol, triglyceride levels, fasting blood sugar, blood pressure, or waist circumference, compared to placebo. Each capsule contained 84 mg of lunasin-enriched soy extract as well as 40 mg of soy protein isolate and 186 mg of soy fiber. One case each of bloating, abdominal pain, and difficulty swallowing was reported among those taking lunasin (Tabrizi, J Diet Suppl 2019).
Laboratory and animal studies suggest that lunasin may have anti-inflammatory effects and inhibit the expression of genes involved in tumor growth, while increasing the expression of genes involved in DNA repair and tumor suppression; however, there are no studies in people on the effects of lunasin supplementation on inflammatory diseases or cancer (Hsieh, J Sci Food Agric 2018).
In people taking very large doses of lunasin (12 capsules per day or more), severe constipation requiring hospitalization, becoming full quickly when eating, and weight loss have been reported (Bedlack, International Symposium on ALS/MND 2017).
People with an allergy to soy should not take this supplement. Be aware that soy drink powders and mixes made with lunasin (Reliv NOW with Soy, ProVantage Sports Performance Powder, Carefast Soy Protein Drink Mix with Lunasin XP) may also contain soy isoflavones, which are not recommended for pregnant and nursing women, and women with estrogen-receptor positive breast cancer.
The bottom line:
Although lunasin may reduce the expression of the gene that produces a key enzyme needed for cholesterol production in the body, lunasin has not been demonstrated to lower cholesterol in people, nor improve blood sugar levels, blood pressure, or waist circumference. Large amounts of lunasin may cause gastrointestinal side effects. Women who are pregnant, nursing, or who have been diagnosed with estrogen-receptor positive breast cancer may want to avoid lunasin.