Reducing Dementia with Diet

Fork U with Dr. Terry Simpson

Three Great Diets

The Mediterranean diet, the DASH diet (Dietary Approaches to Stop Hypertension), and the MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay) are all great eating patterns. Each diet focuses on different aspects of health.

Mediterranean Diet

The Mediterranean diet comes from the traditional dietary patterns of countries bordering the Mediterranean Sea, such as Greece, Italy, and Spain. High in the consumption of fruits, vegetables, whole grains, nuts, seeds, legumes, olive oil, fish, and moderate amounts of poultry, dairy, and red wine. Shown to decrease the risk of heart disease and cancer and to improve longevity.

DASH Diet

Discussed in last week's podcast (ref). DASH (Dietary approach to stop hypertension) was developed to prevent and manage hypertension (high blood pressure). Focuses on increasing intake of fruits, vegetables, whole grains, lean proteins, and low-fat dairy products while limiting sodium, saturated fats, and cholesterol.

MIND Diet

Developed by researchers at Rush University Medical Center as a hybrid of the Mediterranean and DASH diets, with a focus on brain health and reducing the risk of neurodegenerative diseases like Alzheimer's disease. It also emphasizes the consumption of fruits, vegetables, whole grains, nuts, olive oil, fish, poultry, and beans while limiting the intake of red meat, butter/margarine, cheese, pastries/sweets, and fried/fast foods.

Three Diets are Branches of the Same Tree

The Mediterranean, DASH, and MIND diets share some common elements. All focus on whole foods and plant-based sources of nutrients. The Mediterranean diet emphasizes health and longevity. While the DASH diet targets hypertension and cardiovascular health. Finally, the MIND diet specifically supports brain health to reduce the risk of neurodegenerative diseases.

1. Rush Memory and Aging Project:

A study conducted by researchers at Rush University Medical Center followed over 900 older adults for an average of 4.5 years. Findings showed that individuals who closely adhered to the MIND diet had a substantially lower risk of developing Alzheimer's disease, with a reduction in risk ranging from 21% to 53%, depending on the level of adherence. (ref )

2. Columbia University Medical Center Study:

Researchers at Columbia University Medical Center examined the dietary habits of over 1,000 participants. Individuals who closely followed the MIND diet had a 53% lower risk of developing Alzheimer's disease than those with low adherence to the diet.

3. Alzheimer's Disease Neuroimaging Initiative (ADNI):

The ADNI study found that adherence to the MIND diet was associated with better cognitive performance and a reduced rate of cognitive decline over time.

4. Systematic Reviews and Meta-Analyses:

Several systematic reviews and meta-analyses have summarized the findings of multiple studies investigating the association between the MIND diet and dementia risk. Overall, these reviews reveal that adherence to the MIND diet is associated with a significant reduction in Alzheimer's disease and dementia.

5. Mechanisms of Action:

Components of the MIND diet, such as leafy greens, berries, nuts, whole grains, fish, olive oil, and poultry, have been linked to improved cognitive function and a lower risk of dementia.

More research is needed to elucidate the mechanisms underlying the protective effects of the MIND diet. Current evidence suggests that adherence to this dietary pattern can be a valuable strategy for reducing the risk of cognitive decline and Alzheimer's disease in older adults.

Diagnosis of Alzheimer's Disease.

On TikTok, a non-physician said the only way to diagnose dementia was an autopsy. This is false. Alzheimer's disease is diagnosed based on established criteria. These are outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Also can be found in the National Institute on Aging-Alzheimer's Association (NIA-AA) criteria.

• The healthcare provider will conduct a complete history and physical examination
• Neuropsychological assessment may evaluate cognitive function, memory, attention, language, and executive function.
• Blood tests can rule out underlying medical conditions, such as vitamin deficiencies (e.g., vitamin B12 deficiency), thyroid disorders, infections, metabolic imbalances, or kidney or liver dysfunction.
• MRI or CT scans will be ordered to assess structural abnormalities in the brain or detect signs of conditions like stroke, brain tumors, or hydrocephalus. Genetic testing for mutations associated with familial Alzheimer's disease, cerebrospinal fluid analysis to assess for biomarkers associated with Alzheimer's disease (e.g., amyloid beta and tau proteins)

Genetics of Dementia

Several genetic factors are correlated, but not causative of, an increased risk of dementia, including Alzheimer's disease. Lifestyle changes can mitigate these. Hence, the MIND diet is important to those who have a genetic predisposition to dementia.

1. APOE ε4 Allele

The apolipoprotein E (APOE) gene ε4 allele is the strongest known genetic risk factor for late-onset Alzheimer's disease. Individuals who inherit one copy of the APOE ε4 allele from one parent have an increased risk of developing Alzheimer's disease. while those who inherit two copies (one from each parent) have an even higher risk. Chris Hemsworth, who plays Thor in Marvel movies, has two copies of these genes.

2. Presenilin Genes (PSEN1 and PSEN2)

Mutations in the presenilin 1 (PSEN1) and presenilin 2 (PSEN2) genes are associated with early Alzheimer's disease before 65. These mutations can cause abnormal processing of amyloid precursor protein, which leads to the accumulation of amyloid beta plaques in the brain.

3. Amyloid Precursor Protein (APP) Gene

Mutations in the amyloid precursor protein (APP) gene are also associated with rare cases of early-onset Alzheimer's disease. APP mutations can lead to the production of abnormal forms of amyloid beta protein, which contributes to the development of Alzheimer's pathology.

4. TREM2 Gene

• Variants in the triggering receptor expressed on myeloid cells 2 (TREM2) gene have been identified as risk factors for late-onset Alzheimer's disease and other neurodegenerative diseases.

• TREM2 is involved in the regulation of the immune response and microglial function in the brain, and variants in this gene may affect the brain's ability to clear amyloid beta and other toxic proteins.

5. Other Genes

• Several other genes have been implicated in the risk of developing dementia, including genes involved in inflammation, cholesterol metabolism, synaptic function, and neuronal signaling pathways.

While genetic factors can increase the risk of dementia, they do not guarantee that an individual will develop the condition. Environmental factors and lifestyle factors (such as diet, physical activity, and cognitive engagement) play significant roles in determining an individual's risk of dementia. Additionally, not all cases of dementia are attributable to genetic factors.