HealthInfo Waitaha Canterbury
Food choices & warfarin
Ngā kōwhiringa kai me warfarin
There is no special diet to follow if you're taking warfarin. But there are certain foods and drinks that can affect how your warfarin works.
Keep your intake of vitamin K the same each day
Vitamin K has the opposite effect of warfarin and may cause your blood to clot more quickly.
It's found in some foods and nutrition supplements.
If you're taking warfarin, continue to eat foods that are rich in vitamin K but try to eat the same amount of vitamin K every day. Warfarin works best if you avoid suddenly eating a lot more or a lot less vitamin K-rich foods than usual.
Vitamin K-rich foods include:
- brussels sprouts
- celery
- Chinese cabbage – bok choy, choy sum, tatsoi
- dark green lettuce
- endive
- kale
- mesclun salad leaves
- puha
- silverbeet
- spinach
- watercress.
Aim to have at least five servings of vegetables every day:
- Have a dark green leafy vegetable as one of these.
- One serving of vegetables equals a handful.
- Some herbs, such as parsley and basil are also high in vitamin K. But we usually eat these in small quantities, so this is not enough to affect how your warfarin works.
Keep your intake of canola, olive, and soybean oil low
These oils contain small amounts of vitamin K.
- Use in small amounts in cooking.
- Limit fried foods, mayonnaise, salad dressings and other products that could contain these oils.
Limit your alcohol intake
Having too much alcohol can affect how your warfarin works. If you drink alcohol, limit it to:
- Women: two standard drinks a day with no more than 10 drinks a week.
- Men: three standard drinks a day with no more than 15 drinks a week.
For more advice about alcohol and standard drink equivalents, see Reducing your risks from drinking alcohol.
Limit cranberry juice, grapefruit juice and green tea
Having too much cranberry juice, grapefruit juice or green tea can affect the way warfarin works. Limit yourself to a total of no more than one cup (250 ml) of these drinks per day.
Talk to your pharmacist or general practice team if you take warfarin and want to take cranberry supplements.
Talk to your doctor before starting or stopping any nutrition supplements or herbal medicines
Many nutrition supplements, such as vitamins and minerals and dried or powdered vegetable supplements (such as Super Greens or Super Foods) contain vitamin K. Some do not, but they may still affect the way warfarin works.
Talk to your general practice team:
- before making any major changes to your diet
- if you cannot eat for several days or you have an ongoing stomach upset, diarrhoea or fever.
Important
If you know your recent food or alcohol intake has changed significantly, the safest thing is to have an extra INR blood test to check whether your warfarin has been affected.
Written by HealthInfo clinical advisers. Last reviewed February 2023.
Sources
See also:
Review key: HIBTM-167196
