Warfarin dietary taboos

The core dietary principle of taking warfarin is never to completely abstain from certain types of food; Maintain a long-term stable daily diet, avoid consuming large quantities of foods with high vitamin K content in a short period of time, and avoid foods that are known to directly interfere with the metabolism of warfarin. , there is no need to completely isolate yourself from green leafy vegetables and fruits just because you take this medicine.

A while ago, I met a 62-year-old Aunt Zhang in the outpatient clinic. She has been taking warfarin for half a year with atrial fibrillation. The international normalized ratio (INR) is the core indicator for judging whether the efficacy of warfarin reaches the standard. Such patients usually need to maintain it at 2.0-3.0. (between) has been stable at 2.2-2.6, but suddenly dropped to 1.1 during the reexamination. After asking for a long time, I said that I heard from the community health group that spinach supplements iron. If I cook spinach and egg soup for three consecutive days and eat half a catty in one meal, there will be a problem.

To put it bluntly, the principle of action of warfarin is to "check and balance" with vitamin K - it anticoagulates by inhibiting the synthesis of coagulation factors involved in vitamin K. The amount of vitamin K you take in every day is stable, and the dosage adjusted by the doctor can be accurately matched, and the drug effect will naturally not fluctuate. Here I would like to mention a change in the academic community: clinical guidelines in the early years did recommend that patients strictly limit the intake of vitamin K, and many older doctors now advise not to touch green leafy vegetables. However, evidence-based evidence in the past decade or so has shown that a complete ban on vitamin K will make the INR fluctuate even more, and vitamin K deficiency will also increase the risk of osteoporosis and vascular calcification. Now the mainstream anticoagulation guidelines at home and abroad have changed to "stable intake, no deliberate fasting is required."

Of course, this does not mean that you can open up to show off high-vitamin K foods. The vitamin K content of spinach, kale, broccoli, asparagus, avocado, and pork liver is not low. You can eat it as often as you like. For example, if you usually eat broccoli 1-2 times a week, don’t suddenly eat a big plate every day for a week, and don’t eat small rapeseed every day. Suddenly you don’t touch a bite. Sudden high and low intakes are much more dangerous than eating high-vitamin K foods steadily. I have seen too many patients take the "warfarin fasting list" searched online and dare not touch even a piece of lettuce. Eating every day is like a prison sentence. It is really unnecessary.

In addition to dietary fluctuations related to vitamin K, there are several types of foods that are really recommended to be avoided as much as possible. Their impact is much greater than eating two more bites of spinach. For example, it is best not to touch grapefruit, as well as derivative products such as grapefruit juice and grapefruit-flavored pre-mixed wine. The furanocoumarins in it will directly inhibit the CYP3A4 enzyme in the liver that metabolizes warfarin, which is equivalent to directly blocking more than half of the metabolic channels of warfarin. If the dosage remains unchanged, the efficacy of the drug will directly increase, and it is easy to cause bleeding gums, nose bleeding, and even gastrointestinal bleeding. I once met a 28-year-old young man who had a mechanical valve replacement. He had been stable on warfarin. He bought a box of grapefruit juice to drink as water in the summer. After drinking it for two days, his gums bleeded uncontrollably. When he came to check, his INR soared to 4.3. He quickly stopped the juice and took vitamin K supplements before he recovered. There is also a large amount of alcohol, regardless of white wine, beer or red wine. Drinking too much will damage the liver. The liver itself is the place where coagulation factors are synthesized. Drinking too much will also disrupt the INR level. Try not to drink it if you can, and don’t drink more than one or two low-alcohol drinks.

People have asked a lot about traditional Chinese medicines and tonics, but there is currently no completely unified conclusion: Western medicine generally recommends avoiding blood-activating herbs such as angelica root, salvia miltiorrhiza, and safflower, which can easily enhance the anticoagulant effect of warfarin, while ginseng and American ginseng can weaken the efficacy of the medicine.； However, some Chinese medicine practitioners believe that warfarin can be used as long as the syndrome differentiation is accurate and the dosage of warfarin is adjusted simultaneously. The current consensus between both parties is: if you want to take Chinese medicine or supplements, you must make it clear to your anticoagulant doctor and Chinese medicine doctor at the same time that you are taking warfarin, and never secretly add it yourself.

To be honest, I usually don’t recommend patients to use a food composition table to calculate the vitamin K content every day. It’s too fiddly and ordinary people can’t remember it. You only need to have a rough idea of ​​whether you have eaten anything that you don’t usually eat recently - for example, you have eaten a lot of local wild vegetables while traveling, or you have suddenly followed the trend and bought kale powder every day. Just mention it to the doctor the next time you check your INR, and you don’t have to be scared after eating two bites of spinach.

Of course, everyone’s metabolism is quite different. I’ve also seen people who are naturally particularly sensitive to warfarin. Their INR dropped by 0.5 after eating three more green vegetables. There are also people whose INR didn’t budge after eating broccoli. There’s really no need to copy other people’s experiences. Pay more attention to your own body’s reactions and review them regularly. It’s more reliable than any online fasting list.