Eating Fish May Prevent Dementia, Alzheimer’s Disease

Elderly people who consume fish or seafood at least once a week may have a significantly lower risk of developing age-related (senile) dementia or Alzheimer’s disease (AD), according to a study in British Medical Journal (2002;325:932–3). This is the latest study to demonstrate the health benefits of regular fish consumption.

More than one million new cases of age-related dementia and Alzheimer’s disease are diagnosed in the Unites States each year. While senile dementia often affects those over 70 years old, AD may affect people as early as 50 years old. Dementia is a progressive decline in brain function that is often characterized by memory loss, confusion, depression, anxiety, or changes in behavior. Alzheimer’s disease is similar to senile dementia, but memory loss is the predominant symptom and often occurs more rapidly than in senile dementia.

Although the cause of dementia and AD are unknown, some evidence suggests AD may be caused by an accumulation of aluminum in the brain. There is no conventional treatment to reverse dementia or AD, although medications such as tacrine (Cognex®), donepezil (Aricept®), rivastigmine (Exelon®), and aspirin may relieve some memory impairment. Because of the lack of effective treatments, attention has been focused on potential ways of preventing these disorders.

In this study, 1,674 people aged 68 years or older were questioned about their fish, seafood, and meat consumption. Frequency of consumption was recorded as daily, at least once a week, less than once a week, or never. Participants were then periodically evaluated for up to seven years to determine if any changes in mental status had occurred.

People who consumed fish or seafood at least once a week reduced their risk of developing dementia and Alzheimer’s disease by 34% and 31%, respectively, compared with those who never ate fish. No association was found between meat consumption and risk of dementia or Alzheimer’s disease. The types of fish and seafood consumed were not specifically mentioned, so it is unknown whether certain fish may be more beneficial than others.

Diets high in fish and seafood have been associated with decreased risk of heart disease, stroke, attention-deficit disorder, and other conditions. Despite these apparent benefits, concerns have been raised about the safety of some fish, especially in regards to accumulation of mercury and other toxic substances in the fish. A recent report showed that tuna (especially canned tuna), shark, marlin, swordfish, and mahi-mahi have higher amounts of mercury than other types of fish. However, it is unknown if consuming these fish in large quantities will have any long-term adverse side effects. Some physicians recommend consuming cod, halibut, salmon, and flounder, which tend to accumulate less mercury.

Nutritional supplements that may help slow the progression of dementia or AD include acetyl-L-carnitine, vitamin E, thiamine (vitamin B1), melatonin, Ginkgo biloba, and Huperzine A. For specific amounts to take, consult a physician knowledgeable in nutritional medicine.

Darin Ingels, ND, MT (ASCP), received his bachelor’s degree from Purdue University and his Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. Dr. Ingels is the author of The Natural Pharmacist: Lowering Cholesterol (Prima, 1999) and Natural Treatments for High Cholesterol (Prima, 2000). He currently is in private practice at New England Family Health Associates located in Southport, CT, where he specializes in environmental medicine and allergies. Dr. Ingels is a regular contributor to Healthnotes and Healthnotes Newswire.

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