Japanese natto boosts skin elasticity while targeting fine lines and sagging, researchers confirm

05 Oct 2023 ---Scientists have affirmed the skin benefits of regularly consuming a compound in Japanese natto (fermented soybeans), which is commonly consumed for breakfast with rice. The researchers studied the bacillus natto productive protein (BNPP) — a dietary supplement that contains a mixture of proteins produced by the bacterium Bacillus subtilis natto.

Consumed as a functional food ingredient, BNPP contains Bacillopeptidase F, a serine protease enzyme produced by Bacillus subtilis natto that is reported to improve blood flow.

In this new study, in vitro tests were also performed to evaluate BNPP for its inhibitory effects on tyrosinase, elastase and active oxygen (2,2-diphenyl-1-picrylhydrazyl, a free radical also known as DPPH) radical scavenging activities. Tyrosinase is an enzyme that produces melanin, the pigment that gives skin its color, while elastase is an enzyme that breaks down beneficial elastin that keeps skin firm and elastic.

A small-scale, single-armed trial of 15 female participants aged 40 to 65 years was also conducted to assess the effects on human skin of BNPP, administered 250 mg/day orally, for six weeks.

“The beneficial effects of BNPP on the skin were shown by the evaluation of the tyrosinase inhibitory (0.01% and 0.1%), elastase inhibitory (0.00001% to 0.001%), and DPPH radical scavenging (1% and 10%) activities,” detail the study authors.

“In addition, the results suggested that the oral administration of BNPP may significantly enhance skin rosiness and also achieve significant improvement in skin conditions, defined as complexion, skin elasticity and resilience, moist feeling, skin texture, cosmetic adhesion, fine lines, under-eye darkness, eye bags, sagging cheeks and sagging mouth.”

Natto is commonly served in Japan for on a bed of rice and seasoned with soy sauce, mayonnaise and Karashi mustard.Feeding the skin
Japanese traditional foods are known to be healthy overall and have the effects of reducing all-cause mortality, cardiovascular mortality and combined cancer mortality. Natto is a traditional Japanese delicacy — fermented soybeans that have a slimy, sticky and gooey texture — rich in nutrients, including vitamins, proteins, amino acids and dietary fiber.

“Natto has a long history in the traditional diet of Japanese people,” highlight the study authors. “However, some people are unwilling to eat natto because of its distinctive odor.”

“To address this issue, Daiwa Pharmaceutical (Tokyo, Japan) developed BNPP as a functional food ingredient containing Bacillopeptidase F (EC 3.4.21.), one of the proteases produced by natto bacteria, and produces it under the trade name NKCP.”

BNPP is a white or light-yellow powder with a slight fermented odor.

“The natto bacteria are removed from BNPP,” add the researchers. “The distinctive odor and vitamin K produced by natto are also removed from BNPP to negligible levels, creating a product that is easier to ingest than natto.”

Human skin model applied
To investigate the use of BNPP as cosmetics, the study authors conducted a skin irritation study using a cultured human skin model, in addition to their participant tests.

“In this study, we revealed that BNPP has tyrosinase inhibitory, elastase inhibitory and DPPH radical scavenging activities, suggesting that it has the effects of preventing brown spot formation, lightening the skin and improving fine lines/wrinkles and sagging,” confirm the researchers.

However, the researchers flag “several limitations” in their report, such as that the small number of participants could have limited the findings of our study. 

“It should be also noted that the current results of the skin tests are difficult to be extrapolated to other skin complexion types. Further large-scale trials with various skin complexion types are required,” they conclude.

“The results of the skin irritation test and the stability test suggest that BNPP could be used for cosmetic purposes.”

The results also showed that BNPP is non-irritating. “In addition, to confirm the stability of BNPP, the quality of BNPP at the time of manufacture and three years and six months after manufacture was examined,” highlight the authors.

By Benjamin Ferrer