The FastDay Forum

Am following the 5-2 diet and have to take daily warfarin Does anyone have any information about the impact of this diet on INR readings? So far 3 weeks in and feeling well and positive about continuing IFD for as long as possible.

Hi Carol! Welcome to the boards.

I'm not sure if your question will be seen by the right people here, so I'm going to move your post down to the Nerdy Stuff area. There are some very smart people who hang out there and may have some input for you.

Like you I take daily Warfarin too......would also like to know the effect of the diet on my INR reading......first day of fasting today.....was planning to speak to the nurse at my surgery next time I have a blood test.

I'm afraid I don't know. But there are a couple of doctors who come on here, hopefully they will know...

I think fasting whilst taking warfarin should be approached with caution. I think there are a number of things to consider before embarking on a fasting regime
1. How stable is your INR and warfarin dosage? Some people have very stable INR and their warfarin dose changes very rarely other people however struggle to be stabilised and have frequent changes in warfarin doses. If your INR is unstable particularly if it fluctuates widely then your risk of blood clots and/or bleeding is higher and you should be very careful fasting which might cause additional swings in INR.
2. Why are you taking the warfarin? In some conditions it is very important to maintain anti coagulation within tight limits such as people who have metal heart valve replacements where a loss of anti coagulation even for a short period of time can be catastrophic. Again in these cases fasting on warfarin should be approached very carefully.
3. Your diet. warfarin works by inhibiting a number of blood clotting protein which are dependant on vitamin K for their action. Vit K will counteract the action of warfarin and is given in emergencies to reverse the effect of warfarin if a patient on warfarin starts to bleed uncontrollably (during surgery, after injury or spontaneously if the INR has become uncontrolled). Vit k is found in some foods so if your diet is high in foods containing vitamin k you will need more warfarin for the same effect compared to someone with a diet low in vitamin k. By fasting the vitamin k usually found in the diet is lost and so with the same dose of warfarin the anticoagulant effect will be greater and the INR will rise. However the 5:2 is not a complete fast so some vit k will be taken in within the food allowed on fast days. Vit k is largely found in leafy green vegetables and a few other foodstuffs (this is a good summary of the amount of vit k in foods http://www.med.umich.edu/cvc/services/s ... indiet.pdf. So before you fast it is worth making some judgement of the amount of vit k you have in your normal daily diet and try to get a similar amount on your fast days perhaps by altering the types of food you eat on a fast day (eg increasing the amount of green leafy veg if you usually eat foods with moderate/high vit k content in your normal diet)

I would recommend that anyone on warfarin who starts any dietary modification has more frequent INR checks initially to see what effect the changes have on their anticoagulation. The ideal is a frequent check with a calibrated home monitor but not many patients currently have their own INR monitors so these checks will have to be with the GP or anticoagulant service.
I hope this is of help, remember also that if you loose a significant amount of weight then the warfarin dose often needs changing anyway as there is less of you to anticoagulate!

Niki

Thank you all for responses, helpful in deciding next steps. Niki have taken on board your comments; my INR stable; have a window of optimum INR scores rather than a specific score; current warfarin dosage reflects the amount of foods with high Vit K eaten consistently - will ensure this goes for fasting days - will ask for INR check asap rather than wait another month. Finally thanks for the link now have a handy Vit K reference chart.
carol974

Hi Carol1974
I take warfarin for a mechanical heart valve and am on my 8th fast today.
I take on board what Niki says but I haven't had any real difference in my INR levels. Have just had second test since starting 5:2. I wouldn't say my levels are that stable, I tend to be tested every 2 weeks cos as soon as it seems settled and they put me on a monthly or 6 weeks test, bizarrely it drops or goes up for no apparent reason. I'm no expert but if you do something all the time, ie fast for 1 or 2 days a week, wouldn't your body adapt to that?

Yes Teedoff it's all about consistency, eating the same foods, drinking the same amount of alcohol taking the same amount of medication to keep the INR and so warfarin dose stable. So if you make a change in your diet then your body will adapt to the new regime and once stabilised out your INR will settle to the new normal. So it's when you make the change the risk of uncontrolled anti coagulation occurs hence tying to change the amount of vit k in the diet slowly and having your INR checked more frequently when you start on the 5:2.

Thanx for that Niki

Having had two DVT's (one behind each knee) I am now on warfarin permanently. Before going on to 5:2 I was stable at 8mg per day. On 5:2(/4:3) its gone up to 9mg per day.

Main problem for me is because when the INR is not stable you get called in more often stopping over christmas mean I am still going in every 2 weeks whilst they get the dosage right again. (reading after christmas too high so they put me on a lower dose just as I was restarting 4:3 so next one was then too low, etc.)

Must be said that I am not too worried about my INR going up or down too much (only went as low as 1.6 and as high as 3.0, target is 2 to 2.5) as it is very much a precautionary thing against getting another DVT and I am currently more active than I was at the time I got the other 2.

I am on warfarin for life following 2 deep vein thrombosis and a pulmonary embolism. Levels were consistently stable, but after one week of 5:2 regime, levels plummeted to 1.5. However, as my own GP is 110% in favour of this method of eating, he will monitor my warfarin levels and adapt dosage when necessary to suit the 5:2 regime as the benefits have been quite amazing. I gained weight following years and years of breast cancer drug therapy and high dose chemo. Not only is my weight very steadily decreasing but a long-term knee problem has almost disappeared. I also sleep better and buzz around all day with seemingly endless energy. At 61 years of age I feel like the proverbial spring chicken! Only one slight fly in the ointment - the day after fasting, I quite often feel a bit light-headed. I stay well hydrated during fasting so not sure why this is. Anyone else find this a problem?

Hi YumYum2 and welcome to the forum!

The day after fasting has often been reported to result in some odd feelings. I think it is to do with the fact that you have used up your glycogen reserves overnight and so may have lowish blood sugar. As your body gets used to fasting and learns to burn more fat, this should resolve I think. Do you feel better after having had breakfast?

Welcome to the forum YumYum2! Fantastic that you are seeing such positive effects from this WoE and that your GP is on board as well!