Translation guide
Lactose is a sugar found in milk. In Japanese, it is usually referred to by its scientific name or described in context.
Referring to lactose as a substance, especially in scientific, nutritional, or medical contexts.
Standard term for lactose, used in food science, nutrition, and medicine.
People with lactose intolerance cannot drink milk.
Katakana loanword, common in product labels and casual contexts.
This yogurt contains lactose.
Describing the condition of being unable to digest lactose.
In casual conversation, Japanese speakers often use the loanword ラクトース (rakutōsu) or simply describe the condition, e.g., 牛乳でお腹が痛くなる (I get a stomachache from milk). The scientific term 乳糖 is more common in written or formal contexts.
I can't digest lactose, so I drink soy milk.