The purpose of this study was to see if taking lipoic acid plus omega-3 fatty acids (omega-3s) can slow the Alzheimer's disease (AD) process. To see if the treatment can slow the AD process, the investigators looked at changes in memory and changes in a person's daily activities over 18 months.

Current pharmacological agents for AD have had no impact on disease prevalence and have had limited effects on improving the clinical course of AD. The exponential rise in the prevalence, incidence, and cost of care for AD make finding therapeutic agents that can either prevent AD or delay disease progression an urgent health care need. Since inflammation, lipid dysregulation, and insulin resistance have each been associated with AD pathology, the combination of lipoic acid plus fish oil has the potential to maximize therapeutic benefit by acting on all three mechanisms associated with disease pathology.

Inclusion Criteria:

1. 55 years or older
2. Probable AD by National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association - NINCDS/ADRDA criteria
3. MMSE between 15-26
4. Caregiver/study partner that can accompany participant to all study visits
5. Stable use of cholinesterase inhibitors and memantine permitted - doses must be stable for 4 months prior to study enrollment
6. 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
7. Stable dose of lipid lowering medication - dose must be stable for 4 months prior to study enrollment
8. Geriatric Depression Scale (GDS) - Score of < 5
9. General health status that will not interfere with the participant's ability to complete the study.
10. Screening laboratory values within normal limits or, if abnormal, deemed clinically insignificant by the investigator
11. Sufficient English language skills to complete all testing

Exclusion Criteria:

1. Non-AD dementia
2. 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)
3. History of clinically significant stroke (stroke with neurologic deficits > 6 months after diagnosis)
4. 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)
5. Insulin dependent diabetes or uncontrolled diabetes (diabetes controlled on medications other than insulin are acceptable)
6. 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. Patients who have a history or hyperlipidemia, but are not taking lipid-lowering medications due to potential memory impairment side effects will be reviewed on a case-by-case basis by the PI and enrolled in the study if deemed safe by PI and the patient's primary care provider.
7. Fish intake of one 6 ounce serving > once a week less than 4 months prior to enrollment
8. Omega-3 fatty acid supplement intake (e.g. fish oil capsules, cod liver oil, or flaxseed oil) less than 4 months prior to enrollment
9. Lipoic Acid supplementation less than 1 month prior to enrollment
10. 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.
11. Contraindications to MRI (for subjects enrolled at Bend, Medford, and Klamath sites that decide not to undergo MRI, this will not be an exclusion).
12. Enrollment in another study

Adverse events (AEs) were monitored once a month as a part of the clinic visits and monthly by phone. Reported AEs include events that occurred on or after Day 0 and on or before month 18.