ALZHEIMER'S PREVENTION 101

Honeybrains Blog

What Is Alzheimer's Disease and Dementia?

A simple guide to understanding Alzheimer's disease, dementia, risk factors, testing, and ways to support long-term brain health.

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What is Alzheimer's disease?

Alzheimer's disease, or AD, is an incurable, slowly progressing, fatal brain disease. It is the most common cause of dementia.

Dementia is a medical diagnosis that means trouble with memory or thinking has become serious enough that a person depends on others to help manage daily life. When dementia is caused by an abnormal buildup of brain proteins called amyloid and tau, the diagnosis is Alzheimer's disease.

Who can get Alzheimer's disease?

Anyone can get Alzheimer's disease, even without a family history.

Risk depends on factors you can control and factors you cannot. Age and genetics are the main risk factors outside your control. The older you are, and the more copies you have of the APOE4 gene, the higher your risk of developing amyloid buildup in the brain. Even without a family history, someone can still carry the APOE4 gene.

But age and genes are only part of the picture. Overall brain health also matters. Body health, nutrition, and lifestyle are some of the most important factors you can influence over time.

What causes Alzheimer's disease?

No one fully knows what causes Alzheimer's disease, but it appears to involve a breakdown in the brain's internal connectivity.

Human abilities like wisdom, language, and empathy depend on special brain regions that act as hubs between other areas. These hub regions need high amounts of energy to maintain strong internal connections. Without enough energy supply, they may experience metabolic stress, inflammation, and eventually cellular loss. That means anything that affects energy supply to the brain, or weakens brain connections, may influence Alzheimer's risk.

When does Alzheimer's disease begin?

Alzheimer's disease can begin decades before symptoms appear.

Doctors now understand that the earliest stage, marked by amyloid buildup in the brain, may begin 10 to 20 years before symptoms show up. This stage is known as preclinical Alzheimer's disease. It is symptom-free, but amyloid levels are already abnormally high.

Preclinical AD can begin as early as age 40, though it may begin later. Around 10 years after this stage starts, mild cognitive impairment due to Alzheimer's may begin as tau protein also starts to build up. Once amyloid, tau, and brain cell loss are present and symptoms begin to create dependence on others, the condition is known as dementia due to Alzheimer's disease.

In the past, Alzheimer's was often diagnosed only at the dementia stage. Today, this new understanding has changed how the disease is viewed and has opened the door for earlier intervention and prevention efforts.

Are there genes that increase Alzheimer's risk?

Two genes, APOE4 and MTHFR, may increase the risk of Alzheimer's disease.

People with certain variants of APOE4 and MTHFR tend to have higher rates of heart disease, stroke, and B12 deficiency. These are all factors that may raise Alzheimer's risk over time. Because of that, some people choose to learn whether they carry these genes through commercial testing companies such as 23andMe or AncestryDNA.

Genetic counseling is important before and after testing. It is also important to remember that someone can still develop Alzheimer's disease without APOE4 or MTHFR.

Are there tests for controllable Alzheimer's risk?

Routine blood tests through your primary care doctor may help assess controllable risk factors tied to preclinical Alzheimer's disease.

If you are concerned about preclinical AD, you can ask your doctor to check six important brain-related biomarkers. These numbers look at how well the body systems that support your brain are working. They focus on factors you may be able to improve through nutrition, lifestyle, or medical care.

• Vitamin B12 above 400 ng/dL
• Vitamin D above 30 ng/mL
• Systolic blood pressure below 120 mmHg
• Homocysteine below 10 umol/L
• Fasting blood sugar below 90 mg/L
• Hemoglobin A1C below 5.6%

People looking for a broader risk picture can also join online registries that offer memory tests and validated questionnaires. Examples include Alzheimer's Universe, the UCSF Brain Health Registry, and the Alzheimer's Prevention Registry.

Are there tests for preclinical Alzheimer's disease?

Two tests can check for preclinical Alzheimer's disease by measuring amyloid levels: a PET scan and a spinal tap.

These tests can show whether amyloid levels are higher than normal. They are not usually covered by insurance, must be done with a doctor, and are not recommended for everyone. They may be more useful for people at the highest risk levels.

Some people choose to pay out of pocket, while others join Alzheimer's prevention studies that include this testing and may offer treatments aimed at slowing amyloid buildup if it is found to be too high.

What can I do today to strengthen my brain for life?

Everyone can take steps to strengthen their brain by getting enough essential nutrients through daily food choices.

A diet built around fruits, vegetables, whole grains, legumes, foods high in Omega 3s, herbs, spices, fermented foods, and natural sweeteners can provide the color pigments, healthy fats, fibers, vitamins, and minerals that support the body systems protecting the brain.

Since many Americans get less than half of the recommended daily intake of essential brain nutrients, eating this way can help the body naturally move closer to healthy brain biomarker targets.

Beyond nutrition, regular physical activity, enough rest, strong social connection, and lifelong learning are all natural ways to strengthen both body and brain over time.