9.1.1) Alzheimer’s
Your normal genetic risk of developing Alzheimer’s disease
Alzheimer’s is the most common form of dementia, causing problems with memory, thinking and behaviour. It becomes worse over time and eventually interferes with simple, everyday tasks. Symptoms usually start with memory loss followed by issues with word-finding, vision/spacial issues and impaired reasoning or judgement. While Alzheimer’s mostly affects people over the age of 60, about 5% occurs in younger people, age 40 – 50, and is known as early onset Alzheimer’s.
The APOE gene is the most widely studied in relation to Alzheimer’s. It’s believed that APOE may influence the accumulation of a protein named amyloid beta, which can along with other factors, ultimately lead to Alzheimer’s. There are three common variants of the APOE gene: E2, E3, E4. APOE E3 is the most common variant, APOE E4 is associated with increased risk of Alzheimer’s, and E2 is the least common variant of the gene and may have protective effects against Alzheimer’s in some populations.
Scientists continue to try and understand the complex disease, both its onset and progression. Increasingly, research is finding links between diet and Alzheimer’s.
It is common to have variations in this panel. Review the gene results to identify your specific risk.
Prevalence: About 5.4 million Americans have the disease and at least 46 million people around the world are living with a form of dementia. This number is expected to grow rapidly in the coming years as the baby boomer generation reaches the age of 65 and beyond.
Symptoms: One of the first and most common signs is memory loss of recently obtained information. Other early signs involve difficulty following a plan, difficulty with numbers, confusion over a time or place and the inability to retrace steps.
Diagnosis: Alzheimer’s is diagnosed through a thorough medical examination which includes your medical history, mental status testing, a physical and neurological exam plus additional tests may be ordered to rule out other causes.
Table 9-1 APOE status based on the possible rs429358 and rs7412 alleles.
Table 9-2 Risk of developing Alzheimer’s disease by 85 years of age.
Foods and activities that have been recommended for a brain health diet include:
- Fatty fishes such as albacore tuna, salmon and trout.
- Blueberries, dark green leafy veggies (such as spinach and kale), sweet potatoes. Other vegetables, nuts, berries, beans, whole grains and olive oil have also been cited.
- Eliminate sugar, processed meats and excess omega-6 fats.
- Consider supplementing with omega 3 oil, coconut oil or MCT oil.
- One study cited higher levels of daily protein reduced levels of amyloid beta in the brain, which is a precursor to Alzheimer’s disease.
- Get 30 minutes of exercise per day.
- Engage your brain in activities such as dance, reading, learning a language, playing an instrument, crosswords, sudoku, detail crafts (knitting, sewing, woodworking), cooking classes.
- Be social.
An example of a gene that has been associated with risk of developing Alzheimer’s disease is:
APOE: Plays many important roles in the body, including transporting cholesterol and cholesterol-like molecules, including beta-amyloid, in and out of cells.
Avoiding Alzheimer’s
Individuals who carry two copies of the APOE E4 genetic variation have been shown to carry a 51-52% chance of developing Alzheimer’s disease by 85 years of age if they are male and a 60-68% chance if they are female.
Alzheimer’s disease is strongly influenced by diet. Knowing if someone has these genes can allow them to make diet and lifestyle changes that dramatically reduce the risk of developing the disease. Know your risk, change your life!
Carrasquillo, M., Belbin, O., Hunter, T., Ma, L., Bisceglio, G., Zou, F., . . . Younkin, S. (2010). Replication of CLU, CR1, and PICALM Associations with Alzheimer Disease. Archives of Neurology, 67(8), 961-964.
Guerreiro, Gustafson, & Hardy. (2012). The genetic architecture of Alzheimer’s disease: Beyond APP, PSENs and APOE. Neurobiology of Aging, 33(3), 437-456.
Wiener, H. W., Perry, R. T., Chen, Z., Harrell, L. E., & Go, R. C. P. “A polymorphism in SOD2 is associated with development of Alzheimer’s disease.” Genes, Brain and Behavior 6.8 (2007): 770-776.