Fish and/or exercise to help Alzheimer’s disease?

Alzheimer’s disease background:

Alzheimer’s disease is the leading neurodegenerative dementia disorder. In most cases Alzheimer’s does not appear until after the age of 60, but there is an early onset form. It is estimated that 5.1 million Americans have Alzheimer’s. With about 36 million American’s in the 60+ age group the numbers suggest that 1 in 7 people above the age of 60 develop Alzheimer’s disease, but the official numbers from a 2010 report states 1 in 8 (13%) over 65 years old have Alzheimer’s. It is estimated over the next 20 years we will see a 50% increase in the number of people with this disease.

There have been 858 clinical trials testing out more than 400 pharmaceutical treatments (wiki). While there is a great deal of research currently going on the effectiveness of the treatment options are limited. According to the National Institute of Aging these are the current options:

Four medications are approved by the U.S. Food and Drug Administration to treat Alzheimer’s. Donepezil (Aricept®), rivastigmine (Exelon®), and galantamine (Razadyne®) are used to treat mild to moderate Alzheimer’s (donepezil can be used for severe Alzheimer’s as well). Memantine (Namenda®) is used to treat moderate to severe Alzheimer’s. These drugs work by regulating neurotransmitters (the chemicals that transmit messages between neurons). They may help maintain thinking, memory, and speaking skills, and help with certain behavioral problems. However, these drugs don’t change the underlying disease process and may help only for a few months to a few years.

While this is not encouraging there is continued hope as researchers try to find new and better options.

Omega-3 for Alzheimer’s disease?

Omega-3 has been studied previously in Alzheimer’s disease and a recent clinical trial with DHA, one component of omega-3, failed to provide improvements for patients. But work continues to explore omega-3 as a potential treatment for Alzheimer’s.

Differential genetics influence the propensity for Alzheimer’s and may underlie response to various treatments.

One risk factor for developing Alzheimer’s disease is the particular version of the APOE gene you inherit. More specifically, if you have the APOE ε4 (APOE4) allele you have a higher risk of developing the disease. Most people have the APOE3 allele, which lowers the risk of the disease. But having APOE4 doesn’t mean you will develop the disease and on the other hand those with APOE3 can still be stricken with Alzheimer’s.

Omega-3 for Alzheimer’s with the APOE4 version

A report of an unreleased study indicates that in a mouse model a diet high omega-3 and low in cholesterol significantly reduced the symptoms in mice carrying the APOE4 gene.

Exercise and Alzheimer’s disease

Previous work in animal models indicate that exercise can protect against Alzhiemer’s, and the general consensus in humans is that exercise can help ward off Alzheimer’s disease but proper randomized clinical trials to examine if exercise can be effective in people already diagnosed with the disease are ongoing.

Exercise for Alzheimer’s with the APOE4 version

Exercise as we discussed above can possibly help with Alzheimer’s disease but what about in a model examining APOE4.

The same upublished report informs us that an enriched environment that including a running wheel helped the mice that carried the ‘good’ versions of APOE. However, in the mice with the unfavorable APOE4 exercise had a negative effect in terms of Alzheimer’s progression. In the good APOE version mice exercise/enriched environment increased neuronal connections, but in the APOE4 the same treatment caused the death of neurons.

The senior author on the paper states in this way:

Extrapolating this to the human population, individuals with the bad APOE4 gene are more susceptible to stress caused by an environment that stimulates their brain,” says Prof. Michaelson.

Complexity of treating Alzheimer’s disease (and other medical conditions)

Normally, I don’t write about unpublished results but I found these results interesting because over the last year I have seen several similar results. A particular intervention or treatment might help one population, but actually end up being detrimental for another.

I am a big proponent of the power of exercise and an enriched environment to help protect your brain health, but here is a possible example where things aren’t always so simple.

Take home message:

For Alzheimer’s disease it is possible that a good diet can overcome bad genetics

Omega-3 (fish) may help those Alzheimer’s patients with the APOE4 allele (but a recent clinical trial using DHA did not find any positive effects – but they did not separate the patients based on this gene). Also remember the positive results of omega-3 was found in a genetic mouse model of the disease and needs to be tested clinically.

Exercise which is good for your overall and brain health might not be a good option for those already with Alzheimer’s disease and the APOE4 allele. What would be interesting is to study if exercise done in APOE4 mice (and/or humans) before the onset of Alzheimer’s helps prevent the start of the disease.

Life and biology is complex, though this statement does not help people with Alzheimer’s disease,or their loved ones.