Vitamin K2 Supplements
Overview of Vitamin K2
Vitamin K2, also known as menaquinone, is one of the two main forms of vitamin K. It is found in fermented foods and animal products. There are several types of K2 depending on the length of the molecule, with MK-4 and MK-7 being the most common.
While both vitamin K1 and K2 are important, research shows that K2 offers unique benefits for bones and arteries that K1 does not. This is because K2 has a longer half-life in the body and accumulates in tissues that require vitamin K like bones and blood vessels.
Recommended Intakes for Vitamin K2 in Australia
The recommended intake levels for vitamin K2 in Australia are as follows:
Infants
Age | AI |
---|---|
0-6 months | 2.0 μg/day |
7-12 months | 2.5 μg/day |
Children & Adolescents
Age | AI |
---|---|
1-3 years | 25 μg/day |
4-8 years | 35 μg/day |
Boys 9-13 years | 45 μg/day |
Boys 14-18 years | 55 μg/day |
Girls 9-13 years | 45 μg/day |
Girls 14-18 years | 55 μg/day |
Adults
Age | AI (Men) | AI (Women) |
---|---|---|
19-30 years | 70 μg/day | 60 μg/day |
31-50 years | 70 μg/day | 60 μg/day |
51-70 years | 70 μg/day | 60 μg/day |
Over 70 years | 70 μg/day | 60 μg/day |
Pregnancy & Lactation
Age | AI |
---|---|
14-18 years | 60 μg/day |
19-30 years | 60 μg/day |
31-50 years | 60 μg/day |
The Adequate Intake (AI) levels are based on median intakes in the population. There is insufficient evidence to set an Estimated Average Requirement (EAR) or Recommended Daily Intake (RDI) for vitamin K2 specifically.
Reference: Nutrient Reference Values for Australia and New Zealand
Benefits of Vitamin K2
A growing body of research shows that vitamin K2 offers unique health benefits, particularly for bone and heart health:
- Stronger bones - Vitamin K2 activates osteocalcin, a protein involved in bone mineralization and formation. Studies show K2 supplements can improve bone mineral density and reduce fracture risk.
- Heart health - Vitamin K2 prevents calcium deposits in blood vessels by activating matrix GLA protein. Multiple studies show K2 supplements can improve arterial flexibility and reduce stiffness.
- Cognitive health - Vitamin K2 may play a role in preventing cognitive decline by protecting against free radical damage. However limited research is available currently.
- Cancer prevention - Some studies indicate vitamin K2 can inhibit growth and spread of cancer cells. But more research is needed.
Role of Vitamin K2
Vitamin K2 works by carboxylating certain proteins, chemically altering them so they can bind calcium. This helps explain its benefits:
- Osteocalcin - Vitamin K2 carboxylates osteocalcin, a protein involved in bone mineralization. This promotes calcium binding in bones.
- Matrix GLA protein - Carboxylation of MGP prevents calcium deposits in blood vessels by inhibiting calcification.
- Growth arrest protein - GAS6 is carboxylated by K2 to regulate cell growth, apoptosis and inflammation. This may inhibit cancer progression.
Vitamin K2 Deficiency
Subclinical K2 deficiency is believed to be quite common in certain populations:
- Newborns - Vitamin K does not cross the placenta well and levels are low at birth. Injection prevents bleeding.
- Malabsorption disorders - Conditions like celiac and Crohn's disease interfere with K2 absorption.
- Antibiotic use - Alters gut microbiota that produce K2.
- Kidney disease - Impairs vitamin K absorption and metabolism.
- Elderly - Reduced intake and absorption of K2 foods.
Mild deficiency can lead to easy bruising, heavy menstrual bleeding, and decreased bone density. Severe deficiency results in bleeding disorders. Those at high risk may need supplements.
Choosing a Vitamin K2 Supplement
Vitamin K2 supplements can provide clinically effective doses for bone and heart health. Here are some factors to consider when selecting a K2 supplement:
- Form of K2 - MK-7 is preferred for longer lasting effects vs. MK-4. Should be clearly labelled.
- Source - Natto-derived MK-7 is preferred for natural formulation. Check label.
- Dosage - Aim for 45-180 mcg daily. Higher end of range may be better for bone support.
- Bioavailability - Look for formulations with added fat or phospholipids.
- Third party tested - Verify purity and potency through lab certificates.
- Combinations - Some combine with vitamin D3 for synergistic bone benefits.
- Price - Higher quality supplements tend to cost more. Compare cost per dose.
Frequently Asked Questions
Q: What are the benefits of taking a vitamin K2 supplement?
A: K2 supplements can improve bone health, prevent arterial calcification, and promote heart health based on clinical studies.
Q: How much K2 should I take daily?
A: Studies showing benefits have used 45-180 mcg per day. Follow dosage on supplement label.
Q: When should I take vitamin K2?
A: MK-4 is best taken in divided doses while MK-7 can be taken once daily. Take with fat-containing food to enhance absorption.
Q: Are there risks from too much K2?
A: Vitamin K2 is considered non-toxic even at high doses. Those on blood thinners should consult their doctor before supplementing though.
Q: Can K2 reverse osteoporosis?
A: K2 may help slow or halt bone loss progression by improving bone density and aiding calcium deposition.
Q: Does K2 really prevent heart disease?
A: Clinical studies show K2 supplements inhibit arterial calcification and stiffness, reducing cardiovascular risk markers.
Q: Should I take K2 with vitamin D3?
A: Yes, vitamin D improves K2 absorption. Many supplements provide both nutrients for optimal bone health.
Q: Is K2 safe during pregnancy?
A: Yes, vitamin K2 is considered safe and important for fetal development. Supplements may help if intake is low.