Ellen White counseled against eating mustard primarily because she considered it an "irritating condiment" that is injurious to health. In her writings, she groups mustard with other condiments such as pepper, spices, and pickles, stating that these substances "irritate the stomach and make the blood feverish and impure." She explains that the use of such condiments can inflame the stomach lining, similar to the effects of alcohol, and can lead to a craving for more stimulating foods, ultimately weakening the system and contaminating the blood.
Here is a direct quote from her book Ministry of Healing:
"Condiments are injurious in their nature. Mustard, pepper, spices, pickles, and other things of a like character, irritate the stomach and make the blood feverish and impure. The inflamed condition of the drunkard's stomach is often pictured as illustrating the effect of alcoholic liquors. A similarly inflamed condition is produced by the use of irritating condiments." (Ministry of Healing, p. 325)
In summary, Ellen White advised against eating mustard because she believed it irritates the digestive system, contributes to poor health, and stimulates unhealthy cravings.
References:
- White, E. G. (1905). The Ministry of Healing. Pacific Press Publishing Association, p. 325.