Being fat-soluble, the trillions of cells of which are particularly rich in fat.CogniQ Brain function is highly dependent on the efficient functioning of cell membranes, largely formed of fatty tissue, to allow transmission of messages between cells. Free radical damage to cell membranes, worsening rapidly with age, is therefore regarded as one of the principal causes of impaired cognitive function and may even be implicated as a contributory factor in Alzheimer's disease.