Healthy ageing: Going green while taking Warfarin

Q Following on from the question about medications in HFG May 2019, can you tell me which green vegetables I can eat when taking Warfarin medication?

A There is a misbelief that people who have been prescribed Warfarin need to exclude all green vegetables from their normal meals, but this is not true. This unnecessarily limits people’s vegetable intake and reduces their mealtime pleasure.

You can safely eat all green vegetables, provided you have them on a regular basis.

Warfarin acts as a blood thinner and is prescribed to prevent blood clots which can cause a stroke or heart attack.

When people are prescribed Warfarin, they are advised to take care in eating foods rich in vitamin K. Since vitamin K is a natural blood-clotting agent, if eaten in large amounts, it will reduce the effectiveness of Warfarin medication in preventing blood clots.

Foods rich in vitamin K that are regularly consumed in New Zealand include a range of green vegetables such as broccoli, Brussels sprouts, cabbage, kale, lettuce, silver beet, spinach and watercress.

Other foods, such as beef, liver, soy beans, wheat bran, kiwifruit, avocado, blueberries and green tea, also contain vitamin K. Vitamin K-rich foods can be eaten safely when you are taking Warfarin medication.

The key is to eat one to two servings every day as part of a balanced diet, rather than eating lots one day and none the next. One serving of green vegetables is half a cup of cooked green vegetables or a handful of green salad.

Some vitamin and herbal supplements will also interfere with the actions of Warfarin, so before using any of these products discuss them with your doctor.

In the meantime, keep eating and enjoying your greens!