Inclusion Criteria:  Patients may be included in the study if they meet the following criteria:  Males and females over 65 years of age. Diagnosis of Alzheimer's Dementia disorder. Each individual must have a level of understanding sufficient to perform all tests and examinations required. Individuals must be willing to accept all laboratory examinations and MRI examination. Individuals must be willing to provide a small sample of blood for evaluation. Individuals must be willing to participate in a short 30-60 minute clinical interview.  Exclusion Criteria:  Patients may be excluded from the study for any of the following reasons:  Serious unstable illness such that death is anticipated within 1 year or intensive care unit hospitalization for the condition is anticipated within 6 months. Diagnosis of Vascular Dementia disorder. Uncorrected hypothyroidism or hyperthyroidism Participants will be excluded if they had evidence of epilepsy; focal brain lesion; head injury with loss of consciousness or confusion after the injury; DSMIV-TR (text revision) criteria for any major psychiatric disorder including psychosis, major depression, bipolar disorder, or alcohol or substance abuse; or potential bleeding tendency. History of allergy to fish or omega-3 polyunsaturated fatty acids.