DrFeb
Health Guide

Propionibacterium shermanii

Ever wondered how to get the bone-strengthening benefits of calcium without actually eating dairy? Enter *Propionibacterium shermanii*. This is a specific strain of friendly bacteria (a probiotic) that plays a unique role in nutritional science. While it naturally lives in your digestive tract and helps ferment Swiss cheese, its superpower in supplements is creating 'Vitamin K2 MK-7.' This is the form of Vitamin K that keeps calcium in your bones and out of your arteries. Think of it as the 'traffic cop' for minerals in your body.
Evidence BasedDietary Supplement
Propionibacterium shermanii
VERIFIED SOURCE

Bio-Activity Analysis

Vitamin K2 Absorption: Food vs. Fermented Bacteria

SCIENTIFIC DATA VISUALIZATION

Y-Axis
Bioavailability (Retention Time in Blood)
Source Type →

Health Benefits & Sources

Why You Need It

  • Stronger Bones: It activates osteocalcin, the protein that binds calcium to your bone matrix.
  • Heart Health: It prevents arterial calcification (stiffening of the arteries) by directing calcium away from soft tissues.
  • Dental Health: Emerging research suggests it helps remineralize tooth enamel.

Deep Dive

Propionibacterium shermanii is a bacterial powerhouse found in the traditional Japanese dish Natto. While you can take Vitamin K2 supplements directly, taking P. shermanii offers a 'bio-active' version. This bacteria produces Vitamin K2 (specifically the MK-7 form) which stays in your bloodstream much longer than other forms of Vitamin K. This means you get a sustained, steady release of bone-building support throughout the day. It essentially works for you, manufacturing the nutrient your body needs to utilize minerals effectively.

Natural Food Sources

While P. shermanii is a bacteria (not a food itself), it is responsible for fermenting foods rich in Vitamin K2. The best way to get it naturally is by eating fermented dairy or vegetables.

FoodAmount (MK-7)% DV
Natto (Fermented Soy)1000mcg1,000%+
Hard Cheeses (Gouda/Brie)75mcg100%
Egg Yolks (Pasture-Raised)32mcg40%
Chicken Liver13mcg15%

Supplementation

If you do not eat fermented foods or dairy regularly, supplementing with P. shermanii is highly recommended. Look for 'MK-7' on the label. A typical dose ranges from 45mcg to 100mcg daily. It is fat-soluble, so take it with a meal containing healthy fats (avocado, eggs, olive oil) for best absorption.

Top Food Sources

Natto
The richest natural source of MK-7
Gouda/Brie Cheese
Aged cheeses contain live cultures
Sauerkraut
Contains related bacteria
Yogurt
Check for 'live active cultures'

Frequently Asked Questions

Yes! The same species is used. However, in supplements, it is cultivated specifically to produce high levels of Vitamin K2, rather than CO2 gas for cheese holes.
No. Spinach is high in Vitamin K1, which is great for blood clotting but not for bone health. The body converts very little K1 to K2. You need fermented foods or supplements for the MK-7 form.
In supplements, the bacteria is usually in a dormant, dried state. In food like Natto, it is alive. If you cook food containing this bacteria, you will kill it, but the Vitamin K2 it produced remains stable.
Bone remodeling is a slow process. It generally takes 3 to 6 months of consistent supplementation to see an impact on bone density markers.

Safety & Side Effects

Is it safe? Yes. Propionibacterium shermanii is generally recognized as safe (GRAS) by the FDA. It is non-pathogenic and does not cause side effects in healthy individuals.

CRITICAL WARNING: Because Vitamin K2 helps blood clot normally, if you are taking blood thinners (like Warfarin/Coumadin), you must consult your doctor before taking this. It can interfere with the medication's effectiveness.

Scientific References

  • [1]The Emerging Role of Vitamin K2 in Bone and Cardiovascular Health (Journal of Osteoporosis)
  • [2]Vitamin K2 (MK-7) and Bone Density: A Randomized Clinical Trial (Nutrients Journal)
  • [3]Probiotic fermentation and Vitamin K production (Food Microbiology)