We’re often told to “get all of your vitamins and minerals”. But what does that mean, exactly?
Should we take a multivitamin that contains a range of these nutrients? Should we focus on certain vitamins and minerals that we are more likely to be deficient in? Or should we not worry about it and just eat nutritious food?
If you ask me, the last answer is where we should be heading. However, what happens if you have become deficient in a nutrient? Is it OK to keep eating food until it goes back to normal?
Often, when we become low in a particular nutrient, be it a vitamin, mineral, or otherwise, it’s necessary to supplement with that nutrient until it is replete. Then, we can focus on maintaining it through the diet.
Today, I want to discuss an essential nutrient that is often forgotten – Vitamin K. Read on to find out why it’s important, how best to supplement it, and some pitfalls to avoid.
What is Vitamin K For?
Because Vitamin K is a vitamin, we need it, of course. The RDI (recommended daily intake of Vitamin K) for adults is 90-120 micrograms1.
As we’ve seen for other vitamins, the RDI is calculated as the daily intake required to prevent deficiency. It is not intended to indicate an amount needed for optimal health.
Before we get into the reasons why we need Vitamin K, let me first point out that there are two main types of Vitamin K – K1 and K2.
Great! So, what is the difference?
Vitamin K1
Also known as phylloquinone, this form of Vitamin K is mostly found in plant foods and accounts for at least 75% of the total human Vitamin K intake.
The richest dietary sources of K1 include kale, collard greens, spinach, broccoli, and Brussels sprouts. A cup of cooked kale contains more than 1000 mcg of Vitamin K1.
Unfortunately, Vitamin K1 is not well absorbed from dietary sources2. Since all forms of K are fat-soluble, eating K1-rich vegetables with fat, such as butter, can enhance absorption.
Vitamin K2
Vitamin K2 is found in animal products and fermented foods. It is also produced by the bacteria in the gut. Some good sources of K2 are natto, pork, hard and soft cheeses, chicken, and egg yolk.
There are several subtypes of Vitamin K2, called menoquinones, which are numbered according to the length of the side chain the molecule contains. The subtypes range from MK-4 to MK-13.
MK-4 is found in many animal products, like chicken, egg yolks, and butter and is the form of Vitamin K2 that most research has been performed on.
Another subtype that is popular in nutritional supplements is MK-7. It is found in relatively large amounts in the Japanese fermented food, natto.
Because Vitamin K2 is found in many foods that contain fat, its absorption is likely higher than that of K1. The long side chain of K2 makes in circulate in the blood longer, allowing it exert its effects for days, compared to hours for Vitamin K13.
Health Benefits of K1 and K2
According to research, Vitamin K appears to act primarily to influence blood clotting, bone health, and cardiovascular health. Although each of the two forms of Vitamin K have many of the same effects on the body, the relative benefits of each will vary.
1. Blood Clotting
Blood clotting gets a bad name because, if too much of it occurs in the body, it can cause clots that lead to heart attack and stroke.
However, we need the blood to clot when there is an injury to blood vessels. Otherwise, we could bleed to death.
Vitamin K plays an important role here as it’s needed to make 4 out of the 13 clotting factors that the body needs to form a clot. This function is performed by Vitamin K14.
With cardiovascular disease being one of the leading causes of death in North America, many people are on some type of blood-thinning (anti-coagulant) medication. One of the most common types of anti-coagulant medications is Warfarin. This drug acts by interfering with the reactivation of Vitamin K1, resulting in lower levels of clotting factors and, therefore, less clotting.
Eating foods high in Vitamin K1 or taking a K1 supplement will reduce the effectiveness or Warfarin by lowering the time to form a blood clot. Research suggests that Vitamin K2 may have an even greater effect than K1 does on anti-coagulation5.
Anyone on Warfarin medication should keep a steady intake of Vitamin K to prevent the clotting time from fluctuating too much. Low, consistent doses of Vitamin K (especially K2) can often be helpful for those on anti-coagulant therapy, but it should be closely monitored by your prescribing doctor.
2. Bone Health
Most of us think of calcium and Vitamin D when it comes to bone nutrients. But don’t forget about Vitamin K!
In fact, research suggests that Vitamin K2 deficiency increases the risk of osteoporosis6.
However, the research is a little mixed when it comes to overall bone density and Vitamin K supplementation. Some studies show an improvement in bone density with K2 supplementation, but others show no benefit. Vitamin K1 does not appear to improve bone density4.
Bone quality, is another story. Both forms of Vitamin K appear to reduce age-related bone loss7. Although it may not increase bone density, Vitamin K can prevent it from getting worse.
Supplementing with Vitamins K1 and K2 also reduces the risk of hip-, spine-, and other fractures7.
So, the research is pretty strong that getting enough Vitamin K is important for maintaining healthy bones.
3. Cardiovascular Health
One of the proposed mechanisms of cardiovascular disease is the build-up of plaques inside the arteries that impedes blood flow, potentially leading to heart attacks and strokes. A major component of these plaques is calcium.
One of the problems with over-supplementation of calcium is the increased risk of kidney stones and arterial plaque formation8. So, it’s important to get enough calcium – dietary sources are the best – but not too much. Talk to a qualified health practitioner to find out how much calcium is right for you.
The good news is that Vitamin K may help the calcium get to where we need it (in the bones) and out of places where we don’t (the arteries, kidneys, and joints).
A dietary analysis of people over a period of ten years showed an overall risk reduction for coronary artery disease, plaque build-up in the aorta, and all-cause mortality in subjects with higher intake of Vitamin K2 compared to those with the lowest intake9. No relationship was found between these risks and Vitamin K1 intake.
Unlike in the cases of blood clotting and bone health, the primary cardiovascular benefit of Vitamin K appears to be from the menaquinone (K2) form.
4. Other Health Benefits
The research is also promising when it comes to the potential benefit of Vitamin K supplementation for arthritis, kidney stones, diabetes, and brain health4.
Things to Consider with Vitamin K
It’s clear that Vitamin K is essential to human health.
Vitamin K1 exerts its effects primarily in the areas of blood clotting and bone health. While Vitamin K2 also seems to play a role in blood clotting, it really shines when it comes to maintenance of strong bones and keeping the heart and blood vessels healthy.
Along with these benefits, it’s also important to consider some cautions with Vitamin K. Supplementing with too much K could potentially lead to faster blood clotting. This can be especially worrisome for anyone on anti-coagulant therapy.
However, a low, steady dose of Vitamin K, particularly in the form of K2, may be extremely helpful for its cardiovascular benefits. This can sometimes be accomplished by consuming a consistent amount of food rich in Vitamin K2.
In other instances, taking a supplement of Vitamin K2 may be preferable. Typical daily doses of K2 are 50-200 mcg with the MK-7 form the most common.
If you are on blood thinning medication, make sure to check with your prescribing doctor before adding Vitamin K to your supplement regimen or changing its dose.
If used with caution, Vitamin K can help keep your body – the bones, brain, blood vessels, and more – happy and healthy!
- https://www.canada.ca/en/health-canada/services/food-nutrition/healthy-eating/dietary-reference-intakes/tables/reference-values-vitamins-dietary-reference-intakes-tables-2005.html
- https://pubmed.ncbi.nlm.nih.gov/8813897/
- https://pubmed.ncbi.nlm.nih.gov/17158229/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5494092
- https://pubmed.ncbi.nlm.nih.gov/17158229/
- https://pubmed.ncbi.nlm.nih.gov/24089220/
- https://pubmed.ncbi.nlm.nih.gov/16801507/
- https://www.ahajournals.org/doi/full/10.1161/JAHA.116.003815
- https://pubmed.ncbi.nlm.nih.gov/15514282
Book An Appointment With Nardini Naturopathic
Are you concerned that you may not be getting enough Vitamin K?
Or perhaps you’d like a review of your overall diet to see where you could be doing better.
Maybe you have food allergies or intolerances and worry you aren’t getting enough nutrients because of your restricted diet.
I’m Dr. Pat Nardini, a naturopathic doctor who offers nutritional counseling services to help ensure all of those gaps in your diet are filled, and that you’re getting enough of all the important nutrients which your body needs to function at its best.
Contact me today for more information, or book a free 15-minute consultation where I will help you understand how naturopathic medicine can help you.
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