The human body needs a wide spectrum of vitamins and minerals to function correctly. One of these micronutrients is vitamin K, in addition to vitamin C, B complex, and others.
Many people take vitamin K supplements, but it’s also possible to get enough from diet alone.
The main focus of this post is vitamin K, its functions, benefits, and how much you need. Read on to learn more.
What is vitamin K?
Phytonadione (vitamin K) is a fat-soluble vitamin naturally present in some foods and also taken as a dietary supplement. The most significant forms of this micronutrient include vitamin K1 (phylloquinone) and vitamin K2 (menaquinone).
Like other micronutrients, vitamin K has several important functions. This vitamin helps make various proteins such as prothrombin necessary for blood clotting and the building of bones.
In addition to the production of vitamin K-dependent protein, vitamin K helps regulate calcium levels in the body. Yet another function of vitamin K is that it participates in energy production in the mitochondria of the cells.
When discussing the functions of this vitamin, it’s also important to mention vitamin K prophylaxis, one of the first health care interventions doctors typically recommend for newborns to prevent morbidity and mortality in neonates.
Why do people take vitamin K?
People usually take vitamin K supplements to prevent vitamin deficiency, especially if they don’t consume sufficient amounts of this micronutrient through diet.
Low vitamin K levels can cause various symptoms and complications, including uncontrollable bleeding. Additionally, some people take vitamin K to counteract an overdose of Coumadin, a blood thinner.
Generally speaking, vitamin K deficiency isn’t common. But you could be at risk of developing this nutrient deficiency if you drink alcohol heavily, take medications that interfere with absorption of vitamin K, have a disease that affects absorption in the digestive tract.
Examples of these diseases are active celiac disease and Crohn’s disease. Severely malnourished people are also at a higher risk of developing vitamin K deficiency.
Many people take vitamin K supplements to manage morning sickness and cancer symptoms, and remove spider veins. However, these effects require a lot of research.
5 benefits of vitamin K
Just like other vitamins and minerals, vitamin K has a lot of health benefits. That’s exactly why we need to make sure to consume it enough. Below, we focus on some of the most important benefits of vitamin K.
1. Blood clotting
When the term blood clotting comes to mind, most people immediately think of those dangerous clots that may lead to a stroke. That said, blood clotting factor is necessary for your health.
It is vitamin K that prevents excessive bleeding even with the tiniest cuts and injuries. As mentioned above, vitamin K is essential for the production of proteins for blood clotting i.e., blood coagulation.
2. Better heart health
Our heart health depends greatly on the quality of our diet. For that reason, your diet should include plenty of vitamin K as well. Not only can vitamin K prevent cardiovascular damage, but it also improves heart health.
One review explained that vitamin K2 activates a protein that prevents the formation of calcium deposits in blood vessels walls. In other words, vitamin K2 can prevent arterial calcification and vascular calcification, which would narrow down blood vessels and impair circulation.
Remember, heart health depends on proper blood flow. That’s why a diet high in vitamin K can lower the risk of coronary heart disease. The benefits of vitamin K on vascular health explain why many people use this supplement to remove spider veins as well.
Some people may not be able to take vitamin K supplements due to potential atrial fibrillation risk. However, this is not the case for everyone.
That’s why you need to consult your doctor if you are taking blood thinners or medications for your heart function. Further research on this subject is necessary because some studies didn’t find a link between the two.
3. Bone strength
Many bone health supplements contain vitamin K on the ingredient list along with vitamin D. This isn’t an accident.
Vitamin K, especially K2, supports healthy bone mineral density and bone metabolism. You see, vitamin K activity involves carboxylation, a protein that binds calcium to your bones, called osteocalcin.
One study evaluated the effects of vitamin K supplementation in postmenopausal women with a history of vertebral or hip compression fractures. Results showed daily supplementation with vitamin K decreased the concentration of uncarboxylated osteocalcin. The amount of this protein was similar to that in premenopausal women.
These findings confirm the benefits of vitamin K for bone health and the prevention of bone loss. Remember, postmenopausal women are at a higher risk of osteoporosis and hip fracture.
4. Cancer protection
Even though this area requires a lot more research, current evidence shows that vitamin K could exhibit protective effects against cancer.
Results of one review showed vitamin K2 may restrain tumor cell growth in animal subjects. This vitamin could also inhibit the growth of several cancer cell lines. Various proteins are involved in the ability of vitamin K to act on cancer cells.
One study suggested that K2 could significantly decrease the activity of HIF-1A (hypoxia-inducible factor 1-alpha) in hepatocellular cancer cells. Basically, HIF-1A is an important target in cancer treatment research.
5. Management of anxiety and depression
Anxiety and depression affect millions of people around the globe. While their symptoms are severe, both conditions are manageable. Simple lifestyle adjustments could reduce anxiety and depression.
In one study, supplementation with vitamin K reduced symptoms of these mental health problems but also normalized blood glucose levels. High levels of blood sugar can increase the risk of various health problems, including anxiety.
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What is the recommended daily intake?
The average diet delivers sufficient amounts of vitamin K. The exact amount of daily vitamin K intake depends on age and gender. Recommended dietary intake values of vitamin K are demonstrated below.
| Age | Recommended daily intake of vitamin K in micrograms (mcg) |
| Birth to 6 months | 2.0 |
| 7-12 months | 2.5 |
| 1-3 years | 30 |
| 4-8 years | 55 |
| 9-13 years | 60 |
| 14-18 years | 75 |
| Males 19+ years | 120 |
| Females 19+ years | 90 |
| Pregnant/breastfeeding adolescents | 75 |
| Pregnant/breastfeeding adults | 90 |
Signs of vitamin K deficiency
Excessive bleeding is the primary symptom of vitamin K deficiency. The bleeding may occur in areas other than wounds or cuts. This symptom is more noticeable if a person:
- Gets small blood clots under nails
- Bruises easily
- Produces dark tar-like stool that contains blood
- Bleeds in mucus membranes lining areas inside the body
Additionally, vitamin K deficiency can contribute to:
- Poor bone development
- Increased risk of cardiovascular disease
- Osteoporosis
Foods that contain vitamin K
Luckily, many foods contain vitamin K and they’re easily accessible. Some of the best sources of this micronutrient include:
- Broccoli, spinach, lettuce, kale, and other green leafy vegetables
- Soybeans
- Eggs
- Meat
- Cheese
- Fruits such as prunes, kiwi, avocado, blackberries, blueberries, dried figs
- Vegetable oils
Since vitamin K is a fat-soluble vitamin it’s useful to eat the abovementioned foods with some fat to improve absorption. Make sure to choose healthy fats, though. You can also take it with Omega-3 fatty acid.
What are the side effects or risks of taking vitamin K?
Some people take vitamin K supplements in order to balance the levels of this micronutrient. Also, a doctor may prescribe vitamin K injections to people who need them to manage their health condition. Generally speaking, vitamin K is considered safe, but some side effects may occur.
When it comes to oral administration of vitamin K, adverse reactions are unlikely but when do appear, they may include:
- Irritability
- Reduced appetite
- Difficulty breathing
- Muscle stiffness
- General body swelling
- Reduced movement or activity
- Paleness
- Enlarged liver
Serious side effects are rare but may include difficulty swallowing, shortness of breath, lightheadedness or fainting, tightness in the chest, increased sweating, and dizziness.
Adverse reactions of vitamin K injections include pain, swelling, and soreness at the injection site. Other side effects include taste changes, dizziness, temporary flushing, sweating, shortness of breath, and bluish lips, skin, and nails. Injections are only administered with the doctor’s permission.
While supplements are safe, you should consult your healthcare provider before you buy them. This is especially the case if you have a health condition or you’re taking medications such as anticonvulsants, blood thinners such as warfarin, cholesterol-lowering medications, antibiotics, and weight loss drugs.
Conclusion
Vitamin K is crucial for blood coagulation and other functions in the body. Two main forms of this micronutrient are vitamins K1 and K2.
Deficiency in vitamin K is rare primarily because we can obtain sufficient amounts through diet. Excessive and severe bleeding is a major symptom of vitamin K deficiency.
Supplementation is a viable option for people with absorption problems and those who can’t get enough vitamin K through the food they eat. If you’re taking anticoagulation medicines or have some other health problem, make sure to consult your doctor before you start with vitamin K supplementation.
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