V K

ranchgirl

Vitamin K
Menadione; Menaphthone; Menaquinone; Phylloquinone
Vitamin K is a fat-soluble vitamin, so your body stores it in fat tissue and the liver. It is best known for its role in helping blood clot, or coagulate, properly. The "K" comes from its German name, Koagulationsvitamin. Vitamin K also plays an important role in bone health.

It is rare to have a vitamin K deficiency. That’s because in addition to being found in leafy green foods, the bacteria in your intestines can make vitamin K. Sometimes taking antibiotics can kill the bacteria and lead to a mild deficiency, mostly in people with low levels to begin with. Vitamin K deficiency can lead to excessive bleeding, which may begin as oozing from the gums or nose. Other things that may lead to vitamin K deficiency include:

Health problems that can prevent your body from absorbing vitamin K, such as gallbladder or biliary disease, cystic fibrosis, celiac disease, and Crohn's disease
Liver disease
Taking blood thinners, such as warfarin (Coumadin)
Long-term hemodialysis
Serious burns
Other conditions that benefit from vitamin K include:

Excessive Bleeding

Vitamin K is used to reduce the risk of bleeding in liver disease, conditions where your body doesn’t absorb enough vitamin K, or if you take antibiotics for a long time.

In the U.S., Canada, Great Britain, and many other countries, all newborns receive vitamin K injections to prevent the possibility of bleeding, particularly in the brain. Babies are born without any bacteria in their intestines and do not get enough vitamin K from breast milk to tide them over until their bodies are able to make it.

Even though vitamin K deficiency in newborns is very rare, it is dangerous enough that doctors give the injections. Newborns at greatest risk for vitamin K deficiency are premature or those whose mother had to take seizure medications during pregnancy. Mothers on seizure medications are often given oral vitamin K for 2 weeks before delivery.

Osteoporosis

Your body needs vitamin K to use calcium to build bone. People who have higher levels of vitamin K have greater bone density, while low levels of vitamin K have been found in those with osteoporosis. Similarly, some studies suggest that low levels of vitamin K are associated with a higher risk of osteoarthritis.

There is increasing evidence that vitamin K improves bone health and reduces the risk of bone fractures, particularly in postmenopausal women who are at risk for osteoporosis. In addition, studies of male and female athletes have also found that vitamin K helps with bone health. However, some studies have found that vitamin K didn’t help with bone density.

Dietary Sources
Foods that contain a significant amount of vitamin K include beef liver, green tea, turnip greens, broccoli, kale, spinach, cabbage, asparagus, and dark green lettuce. Chlorophyll is the substance in plants that gives them their green color and provides vitamin K.

Freezing foods may destroy vitamin K, but heating does not affect it.

Available Forms
There are 3 forms of vitamin K:

Vitamin K1 or phylloquinone, the natural version of K1 and phytonadione, the synthetic type of K1
Vitamin K2 or menaquinone
Vitamin K3 or menaphthone or menadione
Vitamin K1 is the only form available in the U.S. as a supplement. It is available as part of multivitamin complexes or alone, in 5 mg tablets.

Water-soluble chlorophyll is the most common form of vitamin K found over the counter. It is available in tablet, capsule, and liquid forms.

How to Take It
As with all supplements, check with a health care provider before taking vitamin K or giving it to a child.

People whose bodies can’t absorb enough vitamin K, because of gallbladder or biliary disease, cystic fibrosis, celiac disease, or Crohn's disease, will probably get more benefit from a multivitamin containing vitamin K than an individual vitamin K supplement. In certain circumstances, your doctor may give you a vitamin K shot.

The daily Adequate Intake for vitamin K is:

Pediatric

Infants birth - 6 months: 2 mcg
Infants 7 - 12 months: 2.5 mcg
Children 1 - 3 years: 30 mcg
Children 4 - 8 years: 55 mcg
Children 9 - 13 years: 60 mcg
Adolescents 14 - 18 years: 75 mcg
A single injection of vitamin K is also given at birth.

Adult

Men 19 years and older: 120 mcg
Women 19 years and older: 90 mcg
Pregnant and breastfeeding women 14 - 18 years: 75 mcg
Pregnant and breastfeeding women 19 years and older: 90 mcg
Precautions
Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider.

At recommended doses, vitamin K has few side effects.

Vitamin K crosses the placenta and is also found in breast milk. Pregnant women and women who are breastfeeding should talk to their doctor before taking vitamin K supplements.

People with a rare metabolic condition called Glucose-6-phosphate dehydrogenase (G6PD) deficiency should avoid vitamin K.

People who take warfarin (Coumadin) should not take vitamin K (see “Possible Interactions”).

People who are receiving dialysis for kidney diseases can have harmful effects from too much vitamin K.

Possible Interactions
If you are currently being treated with any of the following medications, you should not take vitamin K without first talking to your health care provider.

Antibiotics -- Antibiotics, especially those known as cephalosporins, reduce the absorption of vitamin K in the body. Using them for more than 10 days may lower levels of vitamin K because these drugs kill not only harmful bacteria but also the bacteria that make vitamin K. People who already have low levels of vitamin K, such as those who are malnourished, elderly, or taking warfarin (Coumadin) are at greater risk. Cephalosporins include:

Cefamandole (Mandol)
Cefoperazone (Cefobid)
Cefmetazole (Zefazone)
Cefotetan (Cefotan)
Phenytoin (Dilantin) -- Phenytoin interferes with the body's ability to use vitamin K. Taking anticonvulsants (such as phenytoin) during pregnancy or while breastfeeding may lower vitamin K in newborns.

Warfarin (Coumadin) -- Vitamin K blocks the effects of the blood-thinning medication warfarin, so that it doesn’t work. You should not take vitamin K, or eat foods containing high amounts of vitamin K, while you are taking warfarin. Speak with your physician for specific dietary guidelines.

Orlistat (Xenical, Alli) and Olestra -- Orlistat, a medication used for weight loss, and olestra, a substance added to some foods, lowers the amount of fat you body can absorb. Because vitamin K is a fat-soluble vitamin, these medications may also lower levels of vitamin K. The Food and Drug Administration now requires that vitamin K and other fat-soluble vitamins (A, D, and E) be added to food products containing olestra. Doctors who prescribe orlistat usually recommend taking a multivitamin with these vitamins. If you should not be taking vitamin K, then you should avoid foods that contain olestra.

Cholesterol-lowering medications -- Bile acid sequestrants, used to reduce cholesterol, reduce how much fat your body absorbs and may also reduce absorption of fat-soluble vitamins. If you take one of these drugs, your doctor may recommend a vitamin K supplement:

Cholestyramine (Questran)
Colestipol (Colestid)
Colsevelam (Welchol)

ranchgirl

维生素 K
甲萘醌；甲萘醌；甲萘醌；叶绿醌
维生素 K 是一种脂溶性维生素，因此您的身体会将其储存在脂肪组织和肝脏中。它最出名的作用是帮助血液正常凝结或凝固。“K”来自其德语名称 Koagulationsvitamin。维生素 K 在骨骼健康中也发挥着重要作用。

很少出现维生素 K 缺乏症。这是因为除了存在于绿叶食物中外，肠道中的细菌也可以制造维生素 K。有时服用抗生素会杀死细菌并导致轻度缺乏，主要是在维生素 K 水平较低的人群中。维生素 K 缺乏会导致过度出血，可能始于牙龈或鼻子渗血。其他可能导致维生素 K 缺乏症的因素包括：

可能阻碍身体吸收维生素 K 的健康问题，例如胆囊或胆道疾病、囊性纤维化、乳糜泻和克罗恩病

肝病

服用血液稀释剂，例如华法林 (Coumadin)

长期血液透析

严重烧伤

其他可从维生素 K 中获益的疾病包括：

出血过多

维生素 K 用于降低肝病、身体无法吸收足够维生素 K 的疾病或长期服用抗生素导致的出血风险。

在美国、加拿大、英国和许多其他国家，所有新生儿都会接受维生素 K 注射，以防止出血，尤其是脑出血。婴儿出生时肠道内没有任何细菌，无法从母乳中获得足够的维生素 K 来度过难关，直到身体能够适应为止。

尽管新生儿缺乏维生素 K 的情况非常罕见，但医生还是会进行注射，这非常危险。早产儿或母亲在怀孕期间必须服用抗癫痫药物的新生儿最容易缺乏维生素 K。服用抗癫痫药物的母亲通常在分娩前 2 周口服维生素 K。

骨质疏松症

您的身体需要维生素 K 来利用钙来构建骨骼。维生素 K 含量较高的人骨密度较高，而患有骨质疏松症的人维生素 K 含量较低。同样，一些研究表明，维生素 K 含量低与骨关节炎风险较高有关。

越来越多的证据表明，维生素 K 可以改善骨骼健康并降低骨折风险，尤其是对于有骨质疏松风险的绝经后女性。此外，对男性和女性运动员的研究也发现维生素 K 有助于骨骼健康。然而，一些研究发现维生素 K 对骨密度没有帮助。

膳食来源
含有大量维生素 K 的食物包括牛肝、绿茶、芜菁叶、西兰花、甘蓝、菠菜、卷心菜、芦笋和深绿色生菜。叶绿素是植物中的一种物质，它使植物呈绿色并提供维生素 K。

冷冻食品可能会破坏维生素 K，但加热不会影响它。

可用形式
维生素 K 有 3 种形式：

维生素 K1 或叶绿醌，K1 的天然形式和植物甲萘醌，K1 的合成形式
维生素 K2 或甲萘醌
维生素 K3 或甲萘醌或甲萘醌
维生素 K1 是美国唯一可作为补充剂的形式。它可以作为多种维生素复合物的一部分或单独使用，以 5 毫克片剂的形式提供。

水溶性叶绿素是最常见的非处方维生素 K 形式。它有片剂、胶囊和液体形式。

如何服用
与所有补充剂一样，在服用维生素 K 或给孩子服用之前，请咨询医疗保健提供者。

因胆囊或胆道疾病、囊性纤维化、乳糜泻或克罗恩病而无法吸收足够维生素 K 的人，服用含有维生素 K 的复合维生素可能比服用单一维生素 K 补充剂更有益。在某些情况下，您的医生可能会给您注射维生素 K。

维生素 K 的每日适当摄入量为：

儿科

出生 - 6 个月的婴儿：2 微克
7 - 12 个月的婴儿：2.5 微克
1 - 3 岁儿童：30 微克
4 - 8 岁儿童：55 微克
9 - 13 岁儿童：60 微克
14 - 18 岁青少年：75 微克
出生时也会注射一次维生素 K。

成人

19 岁及以上的男性：120 微克
19 岁及以上的女性：90 微克
14 - 18 岁的孕妇和哺乳期女性：75 微克
19 岁及以上的孕妇和哺乳期女性：90 微克
注意事项
由于可能产生副作用和与药物相互作用，您应仅在知识渊博的医疗保健提供者的监督下服用膳食补充剂。

在推荐剂量下，维生素 K 几乎没有副作用。

维生素 K 可穿过胎盘，也存在于母乳中。孕妇和哺乳期妇女在服用维生素 K 补充剂之前应咨询医生。

患有罕见代谢疾病（葡萄糖-6-磷酸脱氢酶 (G6PD) 缺乏症）的人应避免服用