Pho and Warfarin

Publication Date: 
Sat, 08/01/2015
By: Alere Staff

Surrounded by steam and sizzle, a street vendor in Vietnam will happily provide you a bowl of hot soup for a small price. The steaming soup of rice noodles in broth, traditionally called “pho”, is a breakfast or lunch that can warm your stomach. However, you no longer have to go to the street vendors of Vietnam to snag this tasty dish. Pho, along with other Vietnamese dishes, is becoming more popular worldwide.

Pho soup, however, is still perhaps the most well-known dish making its way across the ocean. Properly pronounced “fuh”, the soup consists of flat rice noodles in a light, meat-based broth, seasoned with a variety of flavors that include basil, lime, chili, cilantro, cinnamon and ginger.1,2 While the dish is eaten for breakfast or as an early lunch, this is not a rule and it can be enjoyed at any time of day.

The Secret of Pho

The origin of the dish is unknown. References have been found of the soup being sold by street vendors before 1909 as well as stories of pho creation being strongly influenced by the French colonization of Vietnam. While the origin of pho’s original recipe and name is not agreed on, consensus is that pho started in Hanoi in the beginning of the century.1

The secret of pho is in the broth. Traditionally, the broth is made from beef bones, tendons, tripe, fat and sometimes ox tail, simmering for almost three to four hours with onions and spices like ginger, star anise, cinnamon bark, cloves and fennel.1 When the broth is ready and hot, the flat rice noodles are added as well as different varieties of meat like thinly sliced steak that goes in raw, brisket, beef meatballs and flank steak. Served up in a hot bowl, patrons are given a side dish full of condiments including bean sprouts, soy beans, basil leaves, hot peppers, green onions, fish sauce and lime wedges. From there, it’s based on the person’s preferences what they would like to include.

As pho has become popular, the way it is made has changed. Not only has broth become available ready-made, but some restaurants have made it more “tourist-friendly”, using beef, pork and chicken bones to make their broth instead of something more traditional. Of course, if you are feeling brave you are welcome to order the ultimate pho dish called “Specialty Pho” or “Pho dac biet”. This soup will contain every type of meat available in the restaurant at the time, including chicken hearts, liver, beef tripe and tendons.2

Pho and Warfarin

Patients on warfarin are always aware of the different foods that might affect their INR levels. A bowl of pho alone is low in vitamin K. Whether it is made with chicken or beef broth, both are considered low in vitamin K with 5 ounces of chicken broth containing about 0.2 micrograms of vitamin K. Both beef broth and the rice noodles in the soup have almost no vitamin K at all, being labeled as having 0.0 micrograms per serving.3 Even various forms of meat and spices included in the soup are low in vitamin K.3

Where patients need to watch is with the additions, spices and condiments that come with pho. While many spices and chilis are considered low in Vitamin K (one half cup of green chilis has about 6.4 micrograms), sprouts and greens are not. One cup of soybean sprouts can contain about 33 micrograms of Vitamin K while one cup of mung beans, once cooked, can contain about 28.1 micrograms. Pho often contains green onions. One cup of chopped green onions, also called scallions, contains about 207 micrograms of Vitamin K.3

As always with any diet, consistency is the key to making sure you maintain a stable INR level. By being aware of what you put into your pho, you will be able to enjoy this popular soup without worrying whether or not it will wreck your INR. Be sure to speak with your doctor about any concerns you may have about Vitamin K, your diet and your INR.

Interested in learning about more foods? Check out these related articles next:


  1. Pham, J. Pho 101 – A Beginner’s Guide to Vietnam’s Most Famous Dish. BootsnAll. February 7, 2014. Retrieved from website:
  2. Rodgers, G. Pho: An Introduction to Vietnam’s Delicious Noodle Soup. About Travel. 2015. Retrieved from website:
  3. USDA. National Nutrient Database for Standard Reference Release 27. USDA Agricultural Research Service. Retrieved July 17, 2015 from website: