In early 2014, we hosted a webinar with Sarah L. Booth, PhD, Director of the Vitamin K Laboratory at Tufts University, to provide you with a scientific understanding of how vitamin K is processed in the body and the results of key studies on vitamin K. The information is still useful today, so if you missed the original airing, or need a refresher, here are some of the highlights.

FAQs on vitamin K and D with Dr. Booth

What is the best form of K to consume and how much should I consume?

• At this time, I feel that there is not enough data to promote one form of K over another. Most of the research has been done with K1. I think it is important to have them all.
• Consume K through a varied diet with emphasis toward plant products.  
• The evidence to support a need for additional K supplementation is still very weak. (Per CBaggerly: this is why we are adding a nutrient profile to our questionnaire)

Is it important to consume vitamin K with vitamin D supplement?

• I don't yet see any evidence to support the need for taking supplemental K if you are taking supplemental vitamin D.

What is the right balance between calcium, vitamin D and vitamin K?

• Work with your physician to measure your levels of calcium and D and determine your need for those nutrients.
• Obtain vitamin K from a balanced diet.

Dr. Booth does a thorough job in this webinar explaining that there are different forms of vitamin K (there are 13!), how vitamin K works in the body, and reviewing important results from several studies, mostly with vitamin K1.  She reviews the dietary sources of different forms of vitamin K, explaining that we get K1 from green vegetables and plant oil, and K2 from natto and dairy sources.

The current US dietary recommendation for vitamin K intake is 90 micrograms/day for women and 120 micrograms/day for men. To give you an idea of how much that is - there are approximately 90 micrograms of K1 in ½ cup of broccoli.

If you take oral anticoagulants (Warfarin, Coumadin), it is important to know that vitamin K in any form, and particularly in the form of MK7, will interfere with its action.

There have been some articles about calcification and how it could be caused by excessive vitamin D without sufficient vitamin K. She explains, through studies and diagrams, how that works and alleviates any fear of taking vitamin D.

Much of the webinar is based on summaries of different vitamin K studies - both observational and RCT, both with and without vitamin D and calcium. Her final recommendation is to take vitamin D and calcium and to get K from your diet.

Per CBaggerly: As you can see here, this nutrient has so much attention and as many of you know, has several different viewpoints.  It is our objective to use the very large size of our cohort to help address the questions raised by Dr. Booth.

Watch webinar