Vitamin K

This helps your body stay healthy.

It helps your blood stop bleeding. This happens when you get a cut.

You can find it in green leaves. Spinach and kale are good foods.

It also comes from eggs and meat.

Some tiny living things in your belly make it too. This is how your body gets what it needs. It is a very important part of life.

Vitamin K is a family of nutrients found in food.

Your body needs it for two main jobs. First, it helps your blood clot. This means it helps stop bleeding when you are hurt. Second, it helps control calcium in your bones.

There are two main kinds of this vitamin. The first is vitamin K1. Plants make this kind. You can find it in green leafy vegetables like spinach. The second is vitamin K2. Animals provide most of this kind. You can find it in foods like eggs and meat. Some bacteria also make K2.

These tiny living things live in your gut.

Sometimes, people do not get enough vitamin K. This is called a deficiency. Without it, blood cannot clot well. This can lead to too much bleeding. Newborn babies may need an injection of vitamin K. This helps them stay safe after they are born. Some medicines also block vitamin K. Doctors use these medicines to stop blood from clotting too much. If someone takes too much, they can use vitamin K as a treatment.

Vitamin K is a family of nutrients that your body needs to stay healthy.

It is made of several parts called vitamers. These vitamers are fat-soluble, which means they dissolve in fat. Your body uses vitamin K for two very important jobs. First, it helps your blood clot so you do not bleed too much when hurt. Second, it helps control how calcium binds to your bones and other tissues.

Without enough of it, your blood cannot clot well, and you might bleed uncontrollably.

To understand how it works, you can look at how it helps proteins.

Some proteins in your body are called Gla proteins. These proteins need to be modified to work correctly. Vitamin K acts as a helper, or cofactor, in this process. In the liver, it helps a special enzyme change these proteins. This change allows the proteins to bind to calcium ions. If these proteins are not changed, it shows that a person might have a vitamin K deficiency.

There are two main natural types of this vitamin. Vitamin K1, also called phylloquinone, is made by plants.

You can find high amounts of K1 in green leafy vegetables like spinach or kale. Vitamin K2, or menaquinone, comes mostly from animal foods. You can find K2 in foods like eggs, poultry, and cheese. Some bacteria also make K2 during a process called anaerobic respiration. For example, a food called nattō is very rich in a K2 type called MK-7.

Different groups of people have different needs for this nutrient. In the United States, the National Academy of Medicine sets guides for how much to eat. For adult men, the suggested amount is 120 micrograms per day. For adult women, the suggested amount is 90 micrograms per day. These amounts are called adequate intakes. For babies under one year old, the amount is much smaller, between 2.0 and 2.5 micrograms per day. There is no set upper limit for how much vitamin K is safe to take.

Vitamin K is also used in medicine to help people in specific ways.

Newborn babies often get an injection of vitamin K1 shortly after birth. This is because babies may not get enough from their mothers. Some medicines, like warfarin, actually work by blocking vitamin K to stop blood from clotting too much. If someone takes too much of that medicine, doctors can use vitamin K as a treatment. Even rat poisons work by blocking this vitamin to stop blood from clotting.

{ "text": "Vitamin K is a family of structurally similar, fat-soluble vitamers. These molecules are essential for several critical biological functions. The name \"K\" comes from the Danish word *koagulation*, which means coagulation. This refers to the process of blood clotting.

Beyond clotting, vitamin K helps control how calcium binds to bones and other tissues. It is found in many foods and is also sold as a dietary supplement. It can even be used as a prescription medication for specific medical needs.\n\nTo understand how it works, we must look at the molecular level. The body uses vitamin K to modify certain proteins called Gla proteins. This process is called carboxylation. An enzyme called gamma-glutamyl carboxylase performs this task. In this reaction, vitamin K acts as a cofactor, which is a helper molecule.

In the liver, the vitamin is used as an intermediate called VKH2. This intermediate helps deprotonate a glutamate residue. Afterward, the vitamin is reprocessed into vitamin K through a vitamin K oxide intermediate. This carboxylation allows the proteins to chelate, or bind, to calcium ions. Without this process, the proteins cannot function correctly.\n\nThe vitamin K family includes different types of vitamers. The two most common natural types are vitamin K1 and vitamin K2.

Vitamin K1 is also known as phylloquinone. It is produced by plants and is directly involved in photosynthesis. Vitamin K2 is known as menaquinone. This type consists of several chemical subtypes. These subtypes differ by the length of their carbon side chains. Two well-studied subtypes are menaquinone-4 (MK-4) and menaquinone-7 (MK-7). While animals can convert K1 into the MK-4 variant, other K2 forms are produced by bacteria.\n\nDifferent sources provide these vitamers in different amounts. Vitamin K1 is found in high concentrations in green leafy vegetables. For example, boiled collard greens provide 530 μg per measure. Spinach and turnip greens are also very rich sources.

Vitamin K2 comes primarily from animal-sourced foods. Poultry and eggs are much better sources than beef, pork, or fish. An interesting exception is nattō. Nattō is made from fermented soybeans. Bacteria produce a very high amount of the MK-7 variant during anaerobic respiration. In nattō, MK-7 makes up about 90% of the vitamin K2 content.\n\nHealth organizations set specific dietary guidelines known as adequate intakes (AIs). In the United States, the National Academy of Medicine provides these values. For adult men, the AI is 120 μg/day. For adult women, the AI is 90 μg/day. Pregnant and lactating women also require 90 μg/day. For infants up to 12 months, the AI is between 2.0 and 2.5 μg/day. Children between ages 1 and 18 have requirements that increase from 30 to 75 μg/day. Interestingly, there is no established upper limit for vitamin K intake. This is because there is not enough human data regarding adverse effects from high doses.\n\nVitamin K deficiency can lead to serious health issues. Because it is vital for blood clotting, a lack of vitamin K can cause uncontrolled bleeding. This is especially a risk for