Research Review: DHA & Alzheimer’s Disease
SYNOPSIS:
Alzheimer’s Disease sucks.
Over a course of 14 years DHA levels were measured in a group of individuals.
Individuals who had the highest percentage of DHA in their red blood cells had roughly half the risk of the developing Alzheimer’s Disease compared to those with the lowest amount of DHA in red blood cells.
Individuals who have the APOE-e4 gene, which increases the risk of developing Alzheimer’s disease, have more of a protective effect from DHA red blood cell levels compared to those who don’t have the APOE-e4 gene, meaning that carriers of this gene may benefit more from higher DHA levels than non-carriers.
An increase in the proportion of DHA in red blood cells was related to a lower risk of Alzheimer’s disease and all cause dementia.
Extra factoids:
Omega-3 fatty acids include both DHA and EPA, both which are beneficial for health.
Omega-3 Index, which measures how much of your red blood cells are made up of Omega-3, has an inverse correlation with with risk for stroke, heart disease, and hear attack. An Omega-3 Index of > or = 8% was associated with the greatest protection for heart health, whereas an index of < or = 4% was associated with the least.
Individuals in the Alzheimer’s study who had an averaged DHA level in the red blood cells of 6% or more had a 49% reduction in risk from incident Alzheimer’s.
Omega-3 Index Test can be bought online.
Eating fish rich in DHA and EPA and/or supplementing with Fish Oil/Krill Oil/Algae Oil can increase the level of DHA and EPA in red blood cells on a dose dependent level.
Now onto the details!
Today we’re examining an article published in the research journal Nutrients. This study looked to see if Docosahexaenoic acid (DHA) might help, or play a role in preventing Alzheimer’s disease.
The title of the article is, “Red Blood Cell DHA Is Inversely Associated with Risk of Incident Alzheimer’s Disease and All-Cause Dementia: Framingham Offspring Study.”
Before we get started let’s go ahead and go over some terms and things to know.
First Alzheimers disease.
Currently in America more than 6 million Americans of all ages have Alzheimers disease. Over 6.5 million people over the age of 65 are living with Alzheimers and 73 percent of those individuals are 75 or older.
Alzheimer’s disease typically starts with memory problems followed by a decline in thinking, such as finding the right words, vision/spatial issues, and impaired reasoning or judgement. However, initial symptoms seem to vary from person to person.
One thing we 100% know about Alzheimers is we don’t know everything about Alzheimers Disease.
Here are some things we do know. Alzheimers is a neurodegenerative disease, meaning that it’s a disease that causes a slow degeneration of the brain. The decrease in brain function that comes with Alzheimer’s disease is associated with the accumulation of Beta-Amyloid (AB) and tau proteins in the brain. Both AB and Tau Proteins
In the research article “Alzheimer’s Disease: An Update and Insights Into Pathophysiology” researchers state, "the major theories related to the mechanisms involved in the pathogenesis of AD(Alzheimer’s disease) are the neuronal extracellular deposition of Aβ peptides (senile/amyloid plaques), and neuronal intracellular accumulation of hyperphosphorylated tau protein to form neurofibrillary tangles (NFTs).”
Essentially, it is believed that the overabundance of beta-amyloid plaques outside the brain cells(neurons) and an overabundance of tau proteins in the cell leads to dysfunction of the cells ability to work properly which then eventually results in the death of the cells.
Neurons need to be able to communicate with each other to properly function and continue to live. These brain cells/neurons communicate by releasing neurotransmitters and receiving neurotransmitters from other brain cells. Think of the neurotransmitters as pieces of a puzzle that only fit in certain areas. When the neurotransmitter/puzzle piece then fits in the right area of the brain cell the first one is communicating with it then performs a specific function.
When there is a build-up of the beta-amyloid plaques and tau proteins this stops/slows the sending and receiving of neurotransmitters and after a time results in the death of the cells.
While the minutia of why beta-amyloid plaques and tau proteins build up and negatively affect the communication of the cells isn’t completely understood we do have some ideas about why this happens and many of the drugs that are approved to treat Alzheimers disease specifically target these neurotransmitters and their function.
Now onto the study!
We know that diet influences our overall health. When we don’t eat enough food our body breaks down fat, protein, and glycogen in order to maintain our body and allow us to continue to function. If we don’t get enough vitamins or minerals it results in certain processes that create energy for our body not to work and we start to see a breakdown in areas based off of the lack of the specific vitamins or minerals. On the other side of the coin when we eat too much food or too much highly processed foods it often results in an increase in systemic inflammation in the body and brain, increased stress on the body and eventually leads to the breakdown of systems in our body that work to keep us functioning and alive.
When it comes to Alzheimers and really overall function of the brain and nervous system there is one nutrient that continues to be shown to be beneficial for overall health of the brain and nervous system. That nutrient is docosahexanoic acid, aka DHA. DHA is an omega-3 fatty acid that is naturally found in fatty fish like tuna, salmon, trout, and in seaweed and some other foods. DHA is also a crucial building block when it comes to making the tissues that form the brain. Specifically the areas of the brain that play a role in planning, problem solving, and focused attention. ,. Specific areas that are negatively affected in Alzheimer’s disease. DHA also helps the brain cells communicate, mature, acquire the proper nutrition to maintain their health and function, and helps reduce inflammation in the brain.
So DHA does a lot and because DHA does a lot it’s possible that individuals who have higher levels of DHA in their blood have lower prevalence of Alzheimer’s Disease. A group of researchers set out to find if this was true.
Here’s what they did.
They looked at the level of DHA in red blood cells in a group of people over 65 years of age, then they looked at the incidence of Alzheimer’s Disease and dementia in this population as well as if there was any effect of DHA levels on Alzheimer’s Disease or Dementia in individuals who carry the gene APOE-e4, a gene that may increase the risk for Alzheimer’s and Dementia.
A few questions to answer first.
We talked about DHA, but let’s cover a little about red blood cells and why they looked at red blood cell’s DHA levels.
Red blood cells are the functional part of our blood that is responsible for gases and nutrients throughout our body. They are specialized cells that live only around 120 days and primarily deliver oxygen from the lungs to our tissues and return carbon dioxide from our tissues back to our lungs so we can breathe it out.
Since red blood cells have a decently long life-span they are a great way to look at long term DHA levels in the body.
Now let’s get started.
First the population they looked at in this study is one of the coolest little research enclaves out there in my opinion because it involves the Framingham Health Study. The Framingham Study was established in 1948 to follow a group of individuals over the course of their lifetime to look at what contributes to cardiovascular disease. In 1971 they started looking at the health of the offspring from individuals in the Framingham study and the information collected from this study was from those individuals in the offspring branch. While this group of individuals in total numbers 5124 participants only 1490 were used in this study because the individuals had to meet certain qualifications.
What did they do with this group of individuals?
They drew their blood and analyzed it to look at how much of their red blood cells were made up of DHA.
What were they looking for?
The researchers were looking to see if any of the individuals developed Alzheimer’s Disease during the course of the study (a period of 0-14 years) and they were looking at all cause dementia, which to fit that criteria individuals required an issue with memory and at least one other domain of cognitive function, along with impaired functional ability. They were able to track all of this because they had the individuals come in for neuro-cognitive testing throughout the time frame of the study.
After this they had all the information they needed and they analyzed the data. They looked at multiple things specifically:
Baseline Difference between individuals who had the gene APOE-e4 and those that didn’t, remember the APOE-e4, is the gene that is associated with a higher risk of developing Alzheimer’s disease.
Associations of DHA levels in red blood cells and the risk of incident Alzheimer’s Disease.
Associations of DHA levels in red blood cells and all-cause dementia.
Estimated effects of change of Red Blood Cell DHA content on all-cause dementia and Alzheimer’s Disease free years as well as the effects age and APOE-e4 carrier-ship had on these changes.
And
Whether there was an interaction between Red Blood Cell DHA and APOE-e4 carrier-ship and if this was associated with Alzheimer’s Disease and all-cause dementia.
Overall, they looked at a lot. Here’s what they found.
When looking at individuals who had the lowest amount of DHA in their red blood cells compared to those who had the most. The ones who had the high amount of DHA had a reduction in Alzheimer risk by 49% and a 44% risk reduction in all cause dementia.
When looking at individuals who had high red blood cell DHA levels in the beginning of the study compared to the end of the study they found that when comparing individuals who had lower levels at the beginning of the study to individuals that had higher levels at the end of the study. The individuals with low levels had a decrease in years free from Alzheimer’s Disease and years for from all-cause dementia. They also found that individuals who carry the APOE-e4 gene versus not were associated with a decrease in years free from Alzheimer’s Disease and all-cause dementia.
When looking at individuals who had the APOE-e4 gene they found that those who had an increased DHA level in their red blood cells had a lower risk regarding all-cause dementia but the same effect was not found in those who weren’t carriers of the gene.
So those are the specifics of what they found, but what did the researchers conclude about these?
That an increase in the proportion of DHA in red blood cells was related to a lower risk of Alzheimer’s disease and all cause dementia.
Individuals who had the highest percentage of DHA in their red blood cells had roughly half the risk of the developing Alzheimer’s Disease compared to those with the lowest amount of DHA in red blood cells.
Individuals who have the APOE-e4 gene, which increases the risk of developing Alzheimer’s disease, have more of a protective effect from DHA red blood cell level compared to those who don’t have the APOE-e4 gene, meaning that carriers of this gene may benefit more from higher DHA levels than non-carriers.
Why is this important?
This study continues to support the link between our diet and brain health. Since the most effective way to increase DHA in our red blood cells is through ingesting more DHA.
This study adds to the research that shows an increase in DHA might slow the progression of Alzheimer’s Disease.
Overall, the researchers concluded, “Our results, which concur with a growing experimental research foundation, suggest that an increased DHA intake may be a safe and cost-effective strategy in preventing AD in specific populations.”
So increasing the amount of DHA we ingest may decrease the risk of developing Alzheimer’s Disease by up to 49%.
How do we go about doing that?
Well maybe the simplest way to increase your level of DHA is to consume more fish. A can of light tuna (100g) contains approximately 270mg of both DHA and EPA. While the same amount, 100g, of wild caught Atlantic Salmon contains 1840mg of DHA and EPA. In America we don’t consume as much fish as many other countries with lower dementia and Alzheimer’s rates so increasing the amount of fish you eat per week can be a good option to increase your DHA levels if you are wanting to increase your levels but don’t want the hassle of ordering supplements and taking them every day.
The other option is supplementation. In a perfect world we wouldn’t need to take supplements because we would be able to get all of our needed nutrients from the food we eat. However, for many of us that isn’t the case. In those times where we can’t get a nutrient or the quantity of a nutrient that is needed to gain a specific benefit supplementing your diet with a supplement becomes a pretty great option.
Currently there are no specific protocols or recommendations on how much DHA you should get daily for brain health benefits. However, DHA is an omega-3 fatty acid along with EPA and consuming omega-3 fatty acids has been recommended by the American Heart Association for cardiovascular disease. So what do they say about what our intake should be?
The American Heart Association states:
“Although the ideal amount to take is not firmly established, evidence from prospective secondary prevention studies suggests that intakes of EPA+DHA ranging from 0.5 to 1.8 grams per day (either as fatty fish or supplements) significantly reduce the number of deaths from heart disease and all causes. These data support the 2000 AHA Dietary Guidelines recommendation to include at least two servings of fish (particularly fatty fish) per week. For ALA, a total intake of 1.5 to 3 grams per day seems beneficial, although definitive data from prospective, randomized clinical trials are still needed.
In randomized clinical trials (RCTs) that enrolled patients with coronary heart disease, omega-3 fatty acid supplements significantly reduced CV events (death, nonfatal heart attacks, nonfatal strokes). Omega-3 supplements can also slow the progression of atherosclerosis in these patients.”
So the recommended intake of EPA + DHA from the American Heart Association for cardiovascular benefits is .5-1.8 grams per day. However, that’s a really big range. Luckily, another set of researchers set out to find how much EPA + DHA needs to be ingested to change the actual percentage of DHA and EPA in the red blood cells. The minimum amount of your red blood cells that can be made up of EPA and DHA is 2% and where major health benefits are seen is when 8% or more of your red blood cells are made of EPA and DHA.
Here’s what they did in the study.
They took a large group of people then divided them into 5 different groups and measured how their EPA and DHA changed in their red blood cells. The five groups took different amounts of total EPA and DHA over a course of 5 months.
Ingested EPA + DHA at the following levels.
Group A: 0mg
Group B: 300mg
Group C: 600mg
Group D: 900mg
Group E: 1800mg
If you look at the picture on the right it shows the initial percentage of red blood cells made up of DHA and EPA, also know as the Omega-3 Index. As you can see the individuals ranged from having a low percentage to a high percentage of RBCs made up of EPA + DHA.
The average of the majority of individuals in the study had an Omega-3 Index at 4% at the beginning of the study, visualized by the hashed line in the picture on the right.
Here is how each groups Omega-3 Index changed over the course of 5 months.
Group A: 0mg : No Change
Group B: 300mg : (+) 1.8%
Group C: 600mg : (+) 2.5%
Group D: 900mg : (+) 3.2%
Group E: 1800mg : (+) 5.1%
Overall, only the individuals who took 600mg a day or more reached the Omega 3 Index of 8% where most health benefits are seen.
Lastly, many of the fish oil supplements that you can buy in stores are old, rancid, and of low quality. One of the leading brands, the brand they used in the above study, is Nordic Naturals it has a pretty good price point and they offer liquids as well as pill form.
I hope you enjoyed this blog and as always if you have any questions about health or want me to dive into another topic feel free to reach out to me by email at drcoffman@optimizecolumbus.com