Eligibility Criteria:

• 55 years or older
• Probable AD by National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association - NINCDS/ADRDA criteria
• MMSE between 15-26
• Caregiver/study partner that can accompany participant to all study visits
• Stable use of cholinesterase inhibitors and memantine permitted - doses must be stable for 4 months prior to study enrollment
• Stable doses of over-the-counter antioxidants (e.g. vitamin E, ginkgo biloba) are permitted - dose must be stable for 4 months prior to study enrollment
• Stable dose of lipid lowering medication - dose must be stable for 4 months prior to study enrollment
• Geriatric Depression Scale (GDS) - Score of < 5
• General health status that will not interfere with the participant's ability to complete the study.
• Screening laboratory values within normal limits or, if abnormal, deemed clinically insignificant by the investigator
• Sufficient English language skills to complete all testing

Exclusion Criteria:

• Non-AD dementia
• Residence in nursing home facility at screening visit (residence in community assisted living and long-term care facilities in which the participant still performs majority of basic activities of daily living will not be an exclusion)
• History of clinically significant stroke (stroke with neurologic deficits > 6 months after diagnosis)
• Health conditions such as cancer diagnosed < 5 years prior to enrollment (prostate cancer gleason grade < 3 and non metastatic skin cancers are acceptable), liver disease, history of ventricular fibrillation or ventricular tachycardia, major psychiatric disorder, central nervous system diseases (e.g. brain tumor, seizure disorder)
• Insulin dependent diabetes or uncontrolled diabetes (diabetes controlled on medications other than insulin are acceptable)
• Hyperlipidemic (triglycerides >500 mg/dl, LDL > 160 mg/dl, total cholesterol >240 mg/dl). LDL levels between 160 mg/dl and 165 mg/dl will be reviewed by the PI and included if judged to be safe.
• Fish intake of one 6 ounce serving > once a week less than 4 months prior to enrollment
• Omega-3 fatty acid supplement intake (e.g. fish oil capsules, cod liver oil, or flaxseed oil) less than 4 months prior to enrollment
• Lipoic Acid supplementation less than 1 month prior to enrollment
• Taking systemic corticosteroids, neuroleptics, antiparkinsonian agents, and narcotic analgesics. Certain low dose antipsychotic use will be reviewed by the principle investigator on a case-by-case basis and may be allowed if determined that dose is not strong enough to affect performance on cognitive evaluations. Low dose sinemet and dopamine agonist taken once a day for restless leg syndrome is not an exclusion.
• Contraindications to MRI.
• Enrollment in another study