What is Vascular Alzheimer's Disease?

While many people have heard of vascular dementia, not many have heard of vascular Alzheimer’s. Since these two are often mistaken for each other, it can be challenging to find information on vascular Alzheimer’s alone.

So, what is vascular Alzheimer’s? Vascular Alzheimer’s is the fourth subtype of Alzheimer’s disease that is characterized by the presence of cardiovascular risk factors and reduced blood flow to the brain. Vascular Alzheimer’s is often treated by improving cardiovascular health and repairing damage to the cerebrovascular system.

What causes vascular Alzheimer’s?

Systemic cardiovascular health

When we speak about cardiovascular health, we are often speaking about the large and medium arteries of the body. However, if disease is occuring in the vasculature of the body, then it is safe to assume that it is occuring at the level of the brain [1]. Vascular disease typically manifests in the brain as inflammation of the blood vessel lining. This inflammation has a series of negative effects such as activating the immune cells of the brain and reducing overall blood flow [2]. Both of these are known contributors to the progression of Alzheimer’s and can increase the amount of amyloid plaque in the brain as outlined in our article on inflammatory Alzheimer’s. For this reason, there is a large crossover between the presence of cardiovascular disease and vascular Alzheimer’s.

Blood brain barrier integrity

It has been long established that the blood brain barrier (BBB) often breaks down in those with Alzheimer’s disease. The BBB is a special lining of the blood vessels around the brain that gives the brain an extra level of protection from bloodborne pathogens, toxins, and even normal molecules like hemoglobin and iron that can be neurotoxic when directly exposed to the brain. Since the BBB is so selective with what is and is not allowed to pass through, it can be a big deal when the structural integrity begins to degrade. Things that are not supposed to get into the brain begin to leak in, and nutrients that require an intact BBB to enter can no longer get in. This is why nutrients like omega-3 tend to be lower in those with BBB integrity issues. Cardiovascular health appears to play a large role in BBB breakdown with a positive ApoE4 status being highly correlated with vascular Alzheimer’s. 

Signs and Symptoms of Vascular Alzheimer’s

The tests below are the best indicators we currently have to assess the presence of vascular Alzheimer’s. These test for cardiovascular risk factors along with the presence of an impaired blood brain barrier. These tests are not a diagnosis of any disease, but rather an indicator of risk for vascular Alzheimer's. 

Tests and optimal ranges:

• sdLDL: less than 20
• oxLDL: less than 60
• Homocysteine: less than 7
• ApoB: less than 90
• Omega-6/Omega-3 ratio: 0.5-3
• C-reactive protein: less than 0.9
• Blood brain barrier antibodies: Negative

Treatment of Vascular Alzheimer’s

Improve Vascular Health

The vasculature of the brain is the main target for treating vascular Alzheimer’s. To improve vascular health via lifestyle factors, it is necessary to take a two-pronged approach. The first goal is to increase nitric oxide production in the blood vessels of the brain, and the second approach is to lower oxidative stress. Fortunately, there are many things that can be done to accomplish these goals.

Nitric oxide is a chemical that our body produces to relax our blood vessels. As we age, our blood vessels often get stiff and inflamed. By increasing nitric oxide production, we can help our blood vessels to dilate and let in more blood flow. The best way to improve nitric oxide production is through consuming foods with nitrates or nitrites. Beets and dark leafy greens are some of the healthiest sources of nitrates and nitrites. Increasing the consumption of beets and dark leafy greens can be an effective way to improve vascular health for this reason [3].

Oxidative stress occurs when our bodies’ natural antioxidant system becomes overworked and it causes our arteries to become stiff and for arterial plaque to begin to accumulate. This is why it is important to regularly consume foods rich in antioxidants. Consuming antioxidants helps to restore our bodies’ antioxidant reservoirs to prevent oxidative damage. Foods like turmeric and green tea can be especially effective at reducing oxidative stress [3].

Improve Insulin Sensitivity

Unlike most other subtypes of Alzheimer’s, it is not immediately advisable for individuals to embark upon a ketogenic diet. Since most people with vascular dementia tend to have issues with their blood lipid levels, it can be dangerous to consume a high fat diet without proper guidance. For this reason, it is important to work with a professional to restore insulin sensitivity, and then acclimate towards a higher fat diet. More information on how to improve insulin sensitivity can be found in our article on glycotoxic Alzheimer's. 

Improve Blood Lipid Status

As stated before, vascular Alzheimer’s is highly correlated with a dysregulation of blood lipid levels. This means that there is usually more fat and cholesterol in the blood than is ideal. The goal for treating this is to lower these blood levels without starving the brain for the adequate fat and cholesterol that it needs to survive. To achieve this, it is best to be selective with the types of fat you are consuming, and to eat a fiber rich diet. 

Choosing fat sources that are rich in omega-3s and monounsaturated fatty acids tends to be the best choice for most people. Omega-3 rich foods include SMASH fish (salmon, mackerel, anchovies, sardines, herring), walnuts, chia seeds, flax seeds, and fish eggs [4]. Omega-3 is an anti-inflammatory fatty acid that helps to fuel our brain with an important building block called DHA. Monounsaturated fatty acid sources include oils like avocado and olive. Swapping other vegetable oils like soybean or canola for avocado or olive can be a great way to improve blood lipids and systemic inflammation without starving the brain of important fats.

Increasing fiber is crucial for maintaining healthy cholesterol and lipid levels. Fiber acts as a sponge in our intestines to help our body get rid of fats that it does not need anymore [5]. When we do not consume enough fiber, our body has a hard time getting rid of fats from our blood. For this reason, consuming fiber-rich fruits and vegetables can aid our body in reducing our blood lipid levels along with providing a diverse array of nutrients.

Conclusion

Vascular Alzheimer’s can often be difficult to tease apart from other conditions like vascular dementia, metabolic syndrome, dyslipidemia, and atherosclerosis. If you are worried that you might have vascular Alzheimer’s, it is important to work with a doctor and dietitian who are trained in both the Bredesen protocol and can make a functional diagnosis of cognitive disease states. Contact the Amos Institute today to make an appointment with a dietitian trained in the Bredesen Protocol and functional medicine.

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References

1. Altman and Rutledge, 2010, https://doi.org/10.1042/CS20100094
2. Snyder et al., 2014, https://doi.org/10.1016/j.jalz.2014.10.008
3. Rossman et al., 2018, 10.1152/japplphysiol.00521.2018
4. https://health.clevelandclinic.org/the-best-sources-of-omega-3-fatty-acids/

Soliman, 2019, 10.3390/nu11051155