Vitamin K

Most of us are familiar with the blood clotting aspect of this vitamin earning its reputation as the “band-aid” vitamin, however when we look at the different types K1 (phylloquinone), K2 (menaquinone) and K3 (menadione) we need a little more investigation to understand the wide scope of benefits this vitamin bestows. Before we take them one at a time its important to note that K1 and K2 are fat soluble and can be absorbed in the intestinal tract in the presence of certain intestinal flora.  K3 is a synthesized vitamin originally produced for those that lack the bile necessary for the absorption of fat soluble vitamins.

We now understand enough about K1 and K2 to think about them separately, each having their own vital role in our health.  And, this may be wisdom, as they have different dietary sources.

The main function of Vitamin K is to activate the calcium-binding properties of proteins.  K1 is mostly involved in blood clotting, while K2 helps regulate where calcium ends up in the body.  That’s right K2 (in concert with D) makes sure that it’s not the soft arterial walls that receive the calcium building patch but rather where its needed on the bones and teeth, et cetera.  I see it as a sort of “which way do I go” vitamin. This could be the reason we are discovering K2’s importance in heart disease prevention. (The relationship between vitamin K and peripheral arterial disease.  Prostate health is another interesting focus for K2.  Studies are showing the bodies reliance on K2 but not K1 for battling advanced prostate cancer. (Dietary intake of vitamin K and risk of prostate cancer in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg).  We’re just getting started on our understanding of K2’s potential health benefits for bone, cardiovascular, skin, brain and prostate.

Of course, all this is to say, “Get your vitamins!”  Vitamin K1 is mostly found in plant foods like leafy green vegetables. It makes up about 75–90% of all vitamin K consumed by humans.  However, as always, digestion and uptake are the end all and be all for nutrition. One study shows that less than 10% of the K1 makes it to usefulness in the body. (Effect of food composition on vitamin K absorption in human volunteers.  That makes it even more essential to   source the high end, rich sources of K like kale. Very convenient that kale starts with K don’t you think? Also remember that phyllo in phylloquinone means leafy.

We know less about the up-take of K2 but it is theorized that because these are fat soluble vitamins that K2 which is found in fatty foods like hard cheeses, butter and egg yolks from grass fed animals may have a better chance of absorption.  Somewhere in my mind’s nutrition archive that translates to . . . “Yes, a nice slather of good quality butter on my kale is the right move.”

Better still are the higher concentrates of K2 found in fermented foods.  Not something prevalent in the American diet. But we can learn, can’t we?  Here is where I’m going to recommend one of my favorite cookbooks which I believe is a fun and easy introduction to the world of fermentation for health.  Wild Fermentation: The Flavor, Nutrition, and Craft of Live-Culture Foods  by Sandor Ellix Katz.  In the meantime, taking a trustworthy supplement eases my mind when I find its been three weeks since I’ve had a good sausage smothered in my homemade kraut.

A quick word for K3 or menadione which is the synthetic form.  I certainly understand the dynamic of how this synthetic supplement came about as vitamin K deficiency is a serious matter.  If you do not have the necessary bile for K absorption the water soluble alternative must seem like a rescue, but for someone who does not have this issue why would you consider the more inferior, man made substitute which has a toxicity level whereas K2 supplementation is natural and non toxic even at 500 times the RDA.  I don’t take very many supplements because a dietary source is usually a superior idea with a natural balance of minerals and vitamins suited for health, however, when I know it is probable I’ll have trouble obtaining enough (like vitamin D in the dead of winter for northern folk) that’s when I cross the line. 

Written by a nutrition investigator just like you, Linda Saffer.  May 2018.

What else besides calorie counting?

When my brother got his act together and lost a lot of weight he summed it all up by saying don’t eat more than you burn. Very good advice and I loved the simplicity because our complex society can create dizzy spells when it comes to our health. And, as much as I don’t want to muddy that clear water, I have noticed a few questions that seemed to be settled on the bottom. Its possible that calorie restriction alone just doesn’t cut it for some people.  Quoted from Cynthia Sass’s Health article here are some other things to look at if you’re one of those stuck on a scale number that is not satisfactory for your health.

Research shows that a number of lifestyle and environmental factors play roles in influencing metabolism and weight control. 

Artificial additives

  • Just released animal research from Georgia State University found evidence that artificial preservatives used in many processed foods may be associated with metabolic problems, such as glucose intolerance and obesity. In rodents genetically prone to inflammatory gut diseases, the chemicals led to an increase in the severity and frequency of metabolic problems. Scientists believe the effects are due to changes in gut bacteria. When chemicals break down the mucus that lines and protects the gut, unhealthy bacteria come into contact with gut cells, which triggers inflammation, and as a result, changes in metabolism.
  • Combat it: This is preliminary research, but even more of a reason to read food labels and eat clean. When buying anything that comes in a box, bag, or jar, read the ingredient list first. My philosophy is that it should read like a recipe you could whip up in your own kitchen.

Shift work

  • Researchers from the University of Colorado at Boulder found that people who work the night shift burn fewer calories during a 24-hour period than those who work a normal schedule. The difference can lead to weight gain, even without an increase in calories. In other words, when you throw off your body’s circadian rhythm, your normal diet can suddenly become excessive due to a metabolic slowdown. This parallels research which found a relationship between body clock regulation, gut bacteria, and metabolism. When mice received gut bacteria from jet-lagged humans, they gained significant amounts of weight and had abnormally high blood sugar levels.
  • Combat it: If you work when most people are sleeping, or you travel through different time zones, seek out nutrient-rich foods that help boost satiety, increase metabolic rate, and regulate hunger, including fresh veggies and fruit, beans and lentils, nuts, ginger, hot peppers, and good old H2O.

Weight criticism

  • University College London researchers found that over a four-year period, people who experienced weight discrimination or fat shaming€ gained weight, while those who did not shed pounds. Another study from Renison University College at the University of Waterloo found that over five months, women with loved ones who were critical of their weight put on even more pounds.
  • Combat it: You may not be able to control the type or amount of support you receive from others, but there are effective techniques for improving your personal mindset. For example, practicing mindfulness meditation has been shown to help reduce stress, lower hunger hormones, and prevent weight gain. In a study published in the Journal of Obesity, this practice led to a greater loss of belly fat, without following a calorie-counting diet.

Environmental chemicals

  • It may seem odd for a nutrition professor to study flame retardants. But one such professional at the University of New Hampshire found that these substances which are found in everything from furniture to carpet padding and electronics trigger metabolic and liver problems that can lead to insulin resistance, a major cause of obesity. Compared to a control group, rats exposed to these chemicals experienced dramatic physiological changes. In just one month, levels of a key enzyme responsible for sugar and fat metabolism dropped by nearly 50% in the livers of rats exposed to flame retardants. According to the researcher, the average person has about 300 chemicals in his or her body that are man made, and we’re only beginning to understand the possible effects.
  • Combat it: You can’t eliminate your exposure to synthetic substances, but you can limit it. You can now find natural products in nearly every shopping category, including cosmetics, cleaning supplies, toys, and household goods.


  • It’s no surprise that we take after our parents when it comes to body type, but new research shows that the type of bacteria that live in our digestive systems are also influenced by genetics. That’s an important finding, because more and more research indicates that gut bacteria are strongly connected to weight control. Scientists at King’s College London found that identical twins had a similar abundance of specific types of gut bacteria, compared to non-identical twins. This indicates that genes strongly influence bacteria, since identical twins share 100% of their genes, while non-identical twins share about 50% of their genes. They also found that the presence of a specific type of bacteria was most influenced by genetics, and that type strongly correlated with leanness. In fact, transplanting this bacteria to the digestive systems of mice caused the animals to gain less weight than those that did not receive the bacteria.
  • Combat it: You can’t change your genetics, but there’s a great deal of research now about how you can transform your good gut bacteria. The top strategy: avoid artificial and processed foods, and load up on a variety of whole, plant-based foods, including vegetables and fruits, whole grains, beans and lentils, and fermented foods like kimchi and sauerkraut.

Cynthia Sass is a nutritionist and registered dietitian with master’s degrees in both nutrition science and public health. Frequently seen on national TV, she’s Health’s contributing nutrition editor, and privately counsels clients in New York, Los Angeles, and long distance. Cynthia is currently the sports nutrition consultant to the New York Rangers NHL team and the New York Yankees MLB team, and is board certified as a specialist in sports dietetics. Her latest New York Times best seller is S.A.S.S! Yourself Slim: Conquer Cravings, Drop Pounds and Lose Inches.