The main collection of nutritional information on foods and their phytosterol content exists in the United States Department of Agriculture's Food Composition Database. Click here to see a search of the database filtered by phytosterol nutrient information. I recommend that you download the CSV file and upload into your favorite spreadsheet program, so that you can read and search all the food items listed at once, instead of clicking through 20 separate pages.
However, the information in the USDA database is incomplete and sometimes does not inspire the most confidence in its accuracy. In the listing for "Sweet potato, cooked, candied, home-prepared," the database claims that there are 0 phytosterols, but in another listing for "Sweet potato, raw, unprepared," the database claims that there are 16 mg of phytosterols per 133 g of the food. Such discrepancy begs the questions:
How was the candied sweet potato prepared that lowered its phytosterol content?
What is the exact effect of cooking on phytosterol content in raw foods?
Was there variability in how the phytosterol content was determined in each food?
Articles on Phytosterol Content in Food
Only through gas chromatography in a lab can the phytosterol content of a food be assessed accurately. The following articles and posts can help the industrious ascertain the phytosterol content of select foods.
There are few books out there reliably covering the extent of phytosterols in food, but Marcel Dekkar's Phytosterols as Functional Food Components and Nutraceuticals (2004) is a good place to start.
The Linus Pauling Institute (Oregon State University) also has a easy webpage on phytosterols with lots of good descriptions and tables.
Low Phytosterol Diet Experiement: "Dose effects of dietary phytosterols on cholesterol metabolism: a controlled feeding study" (January 2010), The American Journal of Clinical Nutrition.
Examples of low and high phytosterol daily diets: "Phytosterol-deficient and high-phytosterol diets developed for controlled feeding studies" (December 2009), Journal of American Dietetic Association.
"Plant sterols in vegetables, fruits, and berries" (2003), The Journal of the Science of Food and Agriculture. Excellent chart of phytosterols content of many foods, good when considering adding foods to an initially very restrictive diet. Key note: bananas appear to be the best fruit in terms of low phytosterol content.
SWEET POTATOES: "Ipomoea batatas (L.) Lam.: A Rich Source of Lipophilic Chemicals" (February 10, 2014); in depth analysis of 13 varieties of sweet potatoes. Sweet potatoes appear to have a moderate level of phytosterols.
REGULAR POTATOES: see Dekkar above, p. 18-19. Russet potatoes appear to have little to no phytosterols.
WHEAT: "Chemical Compositions, Antioxidant and Antiproliferative Properties of Wheat" (2014); brief description and detail of phytosterol content in wheat, p. 18. Also, see Dekkar above. Processed white wheat has little to no phytosterols. Whole wheat has a significant level.
BROWN RICE: "Characterization of High-Value Bioactives in Some Selected Varieties of Pakistani Rice (Oryza sativa L.)" (April 11, 2012), International Journal of Molecular Science; table 2 displays phytosterol content of various brown rices, which appear to have a higher level of phytosterols.
BUCKWHEAT: "Content Phytosterols in Raw and Roasted Buckwheat Groats and By-Products" (2015), Czech Journal of Food Science, pp. 424-430. Appears to contain a higher level of phytosterols.
QUINOA: "Innovations in Health Value and Functional Food Development of Quinoa (Chenopodium quinoa Willd.)" (April 10, 2015), Comprehensive Reviews in Food Science and Safety, p. 435. Appears to contain a higher level of phytosterols.
BEER: "Does Beer Contain Compounds That Might Interfere with Cholesterol Metabolism?" (May 16, 2012), Journal of the Institute of Brewing.
"Sterol Synthesis in Relation to Growth and Fermentation by Brewing Yeasts Inoculated at Different Concentrations" (April 9, 2013), Journal of the Institute and Brewing.
Contains an insignificantly minimal level of phytosterols.
OILS AND FRIED FOODS: "Phytosterols in frying oils: evaluation of their absorption in pre-fried potatoes and determination of their destruction kinetics after repeated deep and pan frying" (2011), Procedia Food Science, pp. 608-615. Appears to contain significant levels of phytosterols.