By Peggy Demetriou, ARNP, FNP-BC, Board Certified in Family Practice by the ANCC
Alzheimer’s Disease (AD) is the most common form of dementia, a general term for memory loss and other cognitive abilities serious enough to interfere with daily life. Alzheimer’s disease accounts for 60 to 80 percent of dementia cases. Alzheimer’s is not a normal part of aging. The greatest known risk factor is increasing age, and the majority of people with Alzheimer’s are 65 and older. But Alzheimer’s is not just a disease of old age. Approximately 200,000 Americans under the age of 65 have younger-onset Alzheimer’s disease (also known as early-onset Alzheimer’s).
There are 3 hypotheses as to the cause of Alzheimer’s Disease:
1. The cholinergic hypothesis
a. Proposes that AD is caused by the decreased synthesis of the neurotransmitter acetylcholine. This has not gained much support because medications intended to treat acetylcholine deficiency have not been very effective.
2. 1991 – Amyloid Hypothesis
a. This postulates that amyloid beta (Ab) deposits are the fundamental cause of the disease. The gene for the Ab precursor protein (APP) is on chromosome 21. Together with the fact that people with Down Syndrome (trisomy 21) universally exhibit AD by age 40. Also APoE4, the major genetic risk factor for AD, leads to excess amyloid build-up in the brain before AD symptoms arise. The problem is that an experimental vaccine was tried that cleared amyloid plaques and it had no effect on dementia.
3. 2004 Tau Hypothesis
a. Tau proteins initiate the disease cascade. Tau proteins are microtubule-associated proteins that are abundant in neurons in the central nervous system and are less common elsewhere. Eventually, they form neurofibrillary tangles inside nerve cell bodies and the microtubules disintegrate, collapsing the neuron’s transport system. This may result first in malfunctions in biochemical communication between neurons and later in the death of the cells.
Patients will often ask us if there is a genetic test for AD. Scientists have so far identified one Alzheimer risk gene called apolipoprotein E-e4 (APOE-e4).APOE. This is considered a deterministic gene. So if you test positive for it, it means that you are at higher risk for developing AD but no guarantee that anyone who inherits it will develop the disorder. Because of that, it is not widely used and it also not considered a diagnostic or genetic test with high predictability.
So what can you do to reduce your risk? Prevention is always the best course since it cannot be treated once in the later stages. There have been lifestyles shown to reduce the risk of developing AD. According to the National Institute of Health, The Mediterranean-DASH Intervention for Neurodegenerative Delay, or MIND diet, is a hybrid of two different diets combined, that is gaining attention for its potential positive effects on preventing cognitive decline in older individuals. The DASH (Dietary Approaches to Stop Hypertension) diet, developed to lower high blood pressure, is another popular diet being researched for its effects on the early stages of AD.
Some Foods to Eat on the Mediterranean Diet
Here is a breakdown of specific foods included in the diet:
• Dark green leafy vegetables and other veggies with deeply hued colors (such as beets, bright red peppers, eggplant and sweet potatoes)
• Beans and legumes (plant proteins and healthy carbohydrates)
• Brightly colored fruit (particularly red berries, but also apples, grapes, pears and more)
• Fresh, wild caught fish two to three times per week (such as cod, mackerel, oysters, sardines and wild caught salmon) which is rich in Omega 3 fatty acids
• Heart-healthy olive oil and nuts in place of animal fat (which is saturated fat)
• Limited amount of low-fat dairy for protein (plain yogurt and milk)
• Moderate amounts of lean meat no more than twice per week (like chicken or turkey without the skin)
• Olive oil at every meal (the primary source of oil, used instead of butter for dipping with bread and on vegetables, used in all cooking)
• Plenty of fresh herbs and spices
• Red wine (1-2 glasses per day)
• Whole grains (complex carbohydrates in place of white bread)
• Very limited amounts of red meat
Antioxidants and the Brain
In recent research studies, antioxidants have been found to reverse some of the symptoms of aging, such as cognitive impairment. Here are fruits and vegetables with high antioxidant levels.
• Alfalfa sprouts
• Blackberries, blueberries, raspberries and
• Brussels sprouts
• Eggplant (with the skin on)
• Green and red bell pepper
• Kale and other dark green leafy vegetables
• Red grapes
Other Alzheimer’s Prevention Tools
Studies have shown that several lifestyle changes may also lower the risk of Alzheimer’s. These include:
• Avoiding excessive alcohol intake and quit smoking
• Engaging in social activities on a regular basis
• Getting eight hours of restful sleep every day
• Getting plenty of exercise on a regular basis (including cardio and resistance workouts)
• Implementing regular screening for diabetes, high blood pressure and other types of heart disease
• Managing stress effectively
• Stimulating the brain by reading, writing, or other activities
Alzheimer’s Update 2017, NIH