Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) sitosterolemia ?
    ### Response:
    Sitosterolemia is a condition in which fatty substances (lipids) from vegetable oils, nuts, and other plant-based foods accumulate in the blood and tissues. These lipids are called plant sterols (or phytosterols). Sitosterol is one of several plant sterols that accumulate in this disorder, with a blood level 30 to 100 times greater than normal.
    