Four fat soluble vitamins: vitamin A, vitamin D, vitamin E, and vitamin K need lipids in order to be absorbed fully. It does not require a huge amount of fat: a small amount of fat approximately 3-5 g is enough per meal. Fat is also where these vitamins are stored long term. That means the body can run on such storage for a while before one experiences signs and symptoms of deficiencies.
Vitamin K itself is the most special one of its class because it is the only vitamin being produced everyday by gastrointestinal bacteria. While the bacteria provide some, the amount is not adequate to meet human’s need. Therefore, vitamin K is still needed through foods. There are 3 forms of vitamin K:
- Vitamin K1 is found in plant foods.
- Vitamin K2 is produced via fermentation by yeast. Examples: miso, tempeh, mushrooms, bean curd, bean pastes, soy sauce, fish sauce etc.
- Vitamin K3 is produced by gastrointestinal bacteria.
1/ Functions of vitamin K:
a. The most important role: coagulation of blood. This function is very crucial because it affects how fast blood is coagulate. Thus, one’s life can be threatened if excessive blood loss or blood clot occurs. This role is crucial enough that doctors need to delivery a shot of vitamin K at birth to ensure since the GI tract is not mature.
b. Vitamin K helps prevent osteoporosis. As stated earlier, there are 3 forms of vitamin K. The K3 mostly participates in coagulation. The K1 and K2 forms are the ones playing a role in bone protection. Vitamin K1 and K2 must be ingested. They help prevent osteoporosis because they help vitamin D work smoothly. It can be explained clearly below:
- First, bones have two kinds of cells that directly participate in bone remodeling process: osteoclast cells and osteocalcin cells. The cells that break down damaged or old bone cells-osteoclasts-if left uncheck, can destroy healthy bone cells. This is how vitamin K comes in and saves the day: vitamin K1 or K2 keeps osteoclasts in check.
- Second, the osteocalcin cells or the ones producing new bone cells, is destroyed by carboxylation process. Vitamin K again controls this carboxylation. Thus, vitamin D earns the reputation but vitamin K is the one in the back stage doing the preps.
2/ Recommended Daily Intake (RDI) for vitamin K
It was established that the unit of vitamin K to be communicated among healthcare professionals was micro gram (mcg).
- 0-6 months old: 2 mcg/day
- 6-12 months old: 2.5 mcg/day
- 1-3 years: 30 mcg/day
- 4-8 years: 55 mcg/day
- 9-13 years: 60 mcg/day
- 14-18 years: 75 mcg/day
- Female 19 years and above: 90 mcg/day
- Male from 19 years and above: 120 mcg/day
3/ Vitamin K deficiency: Who’s at risk?
Infants are usually not at great risk of vitamin K deficiency mostly due to vitamin K contained formula and/or breast milk. However, by the milestone of one year old, most are weaned to solid food.
- Thus, young children who are picky eaters or without proper feeding are at great risk of vitamin K deficiency.
- Males are also at risk of vitamin K deficiency mostly because the tendency of voiding plant foods.
- Teenagers with poor eating habits or eating out of the home are also at great risk of vitamin K deficiency.
- People with liver diseases are at risk of not just vitamin K deficiency, but many more.
- People with poor digestive system of course risk vitamin K deficiency, since vitamin K required proper fat absorption in order to be absorbed.
- People taking anticoagulant, such as Warfarin, are also at risk of vitamin K deficiency.
When I was in junior year taking Nutrition Medical Therapy class, we spent 2 class periods on food drug interaction during which, professor shared a case in which a patient almost lost her life in ER because the medical team could not figure out how to stop the blood loss. Shortly later her family came in with her bags of OTC supplements she was taking. Sure enough many of those contained vitamin K!
4/ Who should be careful with vitamin K consumption?
Certain individuals with medical conditions, such as stroke, brain aneurysm, thrombosis etc. These patients are usually prescribed to blood thinners (e.g. Warfarin)
Following is the list of oils with low vitamin K: Ranking from lowest content to highest content:
Peanut oil <Corn Oil<Almond oil<Walnut oil<Sesame oil<Sunflower oil< Olive oil
—->Olive oil is the oil with pretty high vitamin K content!
Following is the list of very high vitamin K contained oil (You should avoid this list if you take blood thinners)—Ranking from lowest to highest
Canola oil<vegetable oil<Soybean oil<
—->Soybean oil is a big NO.
6/ Complications due to vitamin K deficiency
Since vitamin K is fat soluble which means the body can stock it up for rainy days, it’s rare to have vitamin K deficiency. Besides, vitamin K3 is manufactured in one’s gut everyday by friendly bacteria. However, vitamin K deficiency, particularly in the forms of vitamin K1 and vitamin K2 can occur when one finally runs out his storage without replenishing it throughout years. Thus, the complications include:
- Osteoporosis (love your plant foods because that’s where vitamin K1 and K2 supporting bone health are found.)
- Blood clot disorder
- Heart diseases (due to blood clot disorder)
7/ Vitamin K: how to get the most out of your foods
- Vitamin K in plants foods are quite stable even under high heat cooking.
- Vitamin K is not lost into liquid as part of preparing and cooking process because it is fat soluble and not water soluble.
- However, oils rich in vitamin K can be compromised if they are exposed to light for months.
8/ Food list
Vitamin K can be easily obtained if you can eat some of the following throughout the day. The trick of vitamin K absorption is to consume it along with fat. It is not necessary to eat foods with fat all at one setting but it is recommended to provide fat within 1 hour afterwards at the latest before your GI tract completes the processing.
While it is important to consume foods rich in vitamin K, it is also important among certain population to look out for foods low in vitamin K. Thus, this list will contain some common foods with low vitamin K content. While these foods may be low in vitamin K, they are absolutely good sources for other key nutrients such as vitamin C, antioxidants, and fiber.
For those who are raw eaters, it is very easy to provide fat along with your meals: 1/4 avocado, 5mL of oil used in dressing, or guacamole on the side are a few examples for those who believe in Raw Diet.
- Cabbage, cooked, 150 g: provides 79% vitamin K for an adult
- Turnip greens, cooked, 150 g: 600%
- Swiss Chard, cooked, 150 g: 774%
- Spinach, cooked, 150 g: 1000%
- Bok choy, cooked, 200 g: 75%
- Broccoli, cooked, 150 g: 245%
- Soybeans, cooked, 170g : 35%
- Cauliflower, cooked, 150 g: 25%
- Green beans, cooked, 150 g: 26%
- Green peas (English Peas), cooked, 100 g: 28%
- Cilantro, 8 g (1 hand full), 28%
- Celery, 100 g, raw: 33%
- Cucumber, 100 g, raw: 15%
- Carrots, 100 g, cooked: 16%
- Avocado, 150 g, raw: 35%
- Kiwi, 1 average, 31%
- Grapes, raw, 150 g: 24%
- Blueberries,raw, 150 g: 32%
- Cranberries, raw, 100 g: 6%
- Raspberries, 100 g, 8%
- Pear, edible portion, 180g: 9%
- Tomatoes, 150 g, raw: 14%