Researchers have explored many complementary health approaches for preventing or slowing dementia, including Alzheimer’s disease. Currently, there is no strong evidence that any complementary health approach can prevent cognitive impairment. What the Science Says Following are some of the complementary health approaches that have been studied in recent years. Fish Oil/Omega-3s. Among the nutritional and dietary factors studied to prevent cognitive decline in older adults, the most consistent positive research findings are for omega-3 fatty acids, often measured as how much fish people ate. However, taking omega-3 supplements did not have any beneficial effects on the cognitive functioning of older people without dementia. Ginkgo. An NCCIH-funded study of the well-characterized ginkgo supplement EGb-761 found that it didn’t lower the incidence of dementia, including Alzheimer’s disease, in older adults. Further analysis of the same data showed that ginkgo did not slow cognitive decline, lower blood pressure, or reduce the incidence of hypertension. In this clinical …