Is there a link between inflammation, intelligence and death?

According to a recent study in Brain, Behavior, and Immunity, there appears to be a connection.  The study was based on data from a two-day nationwide survey conducted on 50,000 Swedish males 18-20 years of age in 1969-70 before they went into military service.  Blood samples were taken at that time to test for a general marker of inflammation known as ESR (erythrocyte sedimentation rate).  Although ESR is a very crude marker of inflammation, it was one of only a few available in the late ‘60s.  Then the blood samples were taken again 35 years later.  In their statistical analyses, the authors took into account a wide number of other variables, which may have influenced the results (socio-economic status, height, weight, blood pressure, smoking, etc.) and concluded that as inflammation (as measured by ESR) increased, there was a decline in IQ.  In addition, a higher level of inflammation at age 18–20 was significantly associated with an increased risk of mortality during a 35-year follow-up (1).  The results of the study show that even at an early age low-grade inflammation can significantly impact intelligence and premature death.

The underlying cause of chronic disease (and therefore early mortality) is increased cellular inflammation.  Likewise a drop in intelligence is usually an indication of an increase in dementia at an earlier age.  Dementia is also driven by cellular inflammation in the brain.   The most sensitive marker of cellular inflammation is the AA/EPA ratio in the blood.  Therefore it is not surprising that five years ago it was demonstrated the higher the AA/EPA ratio in the blood of elderly age-matched individuals, the greater their degree of their cognitive deficits (2).

The anti inflammatory diet was developed to reduce cellular inflammation and has been clinically validated to do exactly that (3,4).  So if you have a wish to live a longer and better life, then life-long control of cellular inflammation through the anti inflammatory diet makes perfect sense.  That’s why the anti inflammatory diet is not a diet but a way of life.

1.    Karlsson H, Ahlborg B, Dalman C, and Hemmingsson T.   “Association between erythrocyte sedimentation rate and IQ in Swedish males aged 18–20.” Brain, Behavior, and Immunity 24: 868–873 (2010)
2.    Conquer JA, Tierney MC, Zecevic J, Bettger WJ, and Fisher RH. “Fatty acid analysis of blood plasma of patients with Alzheimer’s disease, other types of dementia, and cognitive impairment.” Lipids 35:1305-1312 (2005)
3.    Pereira MA, Swain J, Goldfine AB, Rifai N, and Ludwig DS.  “Effects of a low glycemic-load diet on resting energy expenditure and heart disease risk factors during weight loss.” JAMA 292: 2482-2490 (2004)
4.    Johnston CS, Tjonn SL, Swan PD, White A, Hutchins H, and Sears B.  “Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets.” Am J Clin Nutr 83: 1055-1061 (2006)

Nothing contained in this blog is intended to be instructional for medial diagnosis or treatment. If you have a medical concern or issue, please consult your personal physician immediately.

Share and Enjoy:
  • Print
  • Digg
  • StumbleUpon
  • Facebook
  • Yahoo! Buzz
  • Twitter
  • Google Bookmarks

Related Posts:

This entry was posted in Zone Health and tagged , , by Dr. Barry Sears. Bookmark the permalink.

About Dr. Barry Sears

Dr. Barry Sears is a leading authority on the impact of the diet on hormonal response, genetic expression, and inflammation. A former research scientist at the Boston University School of Medicine and the Massachusetts Institute of Technology, Dr. Sears has dedicated his research efforts over the past 30 years to the study of lipids. He has published more than 30 scientific articles and holds 13 U.S. patents in the areas of intravenous drug delivery systems and hormonal regulation for the treatment of cardiovascular disease. He has also written 13 books, including the New York Times #1 best-seller "The Zone". These books have sold more than 5 million copies in the U.S. and have been translated into 22 different languages.

15 thoughts on “Is there a link between inflammation, intelligence and death?

  1. I’m curious about rheumatoid arthritis (which I have). Do you believe that an anti-inflammatory diet alone can reduce or eliminate the flaring of this disease or is it possible there is an underlying virus or environmental situation that also could be at play? Practicing rheumatologists generally don’t give a whiff about diet and would rather just pass out methotrexate or biological drugs such as Enbrel. I don’t doubt an anti-inflammatory lifestyle would help to reduce the inflammation levels, but do you think that can be the whole answer?

    On a side note, eggs were mentioned as inflammatory yet I can go through long periods of non-flaring while eating 3 eggs for breakfast , 5 days a week and not feel ill effects. So when I do flare, I can’t really blame the eggs, can I?


    • An anti-inflammatory diet (especially when coupled with high-dose fish oil) can have dramatic effects on reducing arthritic pain. This is because such a diet can reduce the precursor levels of the fatty acids that are substrates to make the hormones (eicosanoids) that drive the inflammatory process. In pharmacology, this is known as going upstream. Drugs work downstream after the excessive levels of the precursors have been built up in the target tissue. This approach is not as elegant as the diet and leaves a lot of collateral damage. The more you reduce inflammation by the diet, the less drugs you will need to control any residual inflammation. Eggs are not inflammatory per se, but the fatty acids found in the yolk can build up those inflammatory mediators that lead to increased inflammation. With arthritis I would suggest eating a lot of egg whites and dramatically lowering the intake of egg yolks.

  2. I buy into your theory but does it not presume that diet alone is the cause behind the build-up of the inflammatory process? Could it be something else that was causing inflammation? Is it possible that one could eat an anti-inflammation diet and still have severe RA? I ask that because I’ve gone through flare-free periods of up to a year or two and during those times ate well, but not perfectly (and ate a lot of egg yolks). I also have type 2 diabetes although it’s more like type 1 since I think my pancreas is slowly burning out due to the inflammation in my body. It’s part of the reason I eat so many eggs for breakfast – an attempt to avoid grain products.

    Thanks – love your insights – always intrigued by these discussions – just wish all the docs I’ve tried out would be half as interested.


    • Although microbial invasion and injuries can also turn on inflammatory responses, I suspect your diet is still the major contributor. Especially the egg yolks which are rich in arachidonic acid.

      There are two components of any diet. The first is the macronutrient balance and its effects of the macronutrients on hormonal responses. The second is the quality of the food ingredients used to maintain that macronutrient balance. The more you eliminate recent additions to the human food supply, the less inflammatory load you will have on the system. The least inflammatory impact will come from food ingredients in common use more than 10,000 years ago. Ingredients used 2,000 years ago (whole grains, dairy, and legumes) will have more of an inflammatory impact. Those ingredients that are the most recent additions (refined sugar, refined carbohydrates, and vegetables oils) will the most negative inflammatory impact. Try eliminating as many of the food ingredients that you can starting with most recently introduced ones and moving your way back to the ingredients that our genes have been evolving with over the past 200,000 years. This should dramatically reduce the inflammation in your body as long as you continue to maintain the macronutrient balance of the anti inflammatory diet.

  3. A appreciate the comments. I was recently reading a book on the paleolithic diet – suggesting that one toss out all grains, legumes, dairy and go from there. I’m prepared to do about anything – quite a radical change to say the least. I do keep grains to a minimum, but I have liked cheese,eggs,etc. I do take 4 grams of Lovaza a day which gives me 1860mg of EPA and 1500 of DHA, consume some flaxseed meal on occasion, as well as chia seeds. And I do try to eat a lot of salads, blueberries,strawberries, wild salmon, sardines,etc. Not sure where nuts fit on the spectrum – I’ve been eating more than I should of almonds,pistachios,pecans – good fats no doubt, but I’ve discovered they can have a lot of Omega 6′s in them as well, so I guess moderation is the key there.

    I am thinking about trying your SeaHealth Plus product or the polyphenol plus product. I’m guessing from the price that the SeaHealth Plus product is more potent and perhaps a better choice. Couldn’t quite figure out how many ORAC units were in either. The website suggests that one capsule of the Polyphenol Plus products is the equivalent of 10 servings of fruits and veggies, but doesn’t suggest how many servings would pertain to the SeaHealth Plus product. Any suggestions there would be helpful.

    Thanks again for all you do!


    • First I would double the amount of EPA and DHA you are taking. With any fish oil supplementation, you have to increase your intake of polyphenols to prevent potential oxidation of the supplemented omega-3 fatty acids. I usually recommend about 8,000 ORAC units for every 2.5 grams of EPA and DHA that you are taking. Both our polyphenol products have an equal potency at 8,000 ORAC per capsule or one ounce of the liquid.

  4. So, I should take 8000mg of fish oil per day? I thought 4 grams of Lovaza was alot, but I’m game if it will help. In comparing Lovaza to the Zone Omega RX, Lovaza has 1860 mg of EPA and 1500mg of DHA (4,000mg servings).. The Omega RX has 1600 EPA and 800 DHA. I get a 3 month subscription of Lovaza from my eye doc (4G/day) for $50 via insurance. Hard to beat that and I’m on a pretty limited budget as my wife isn’t working at the moment. So, if I take double, then I’ll be getting 3720mg of EPA and 3000mg of DHA. Just so you know, I’m 60, weigh about 150, 5’9″. Total cholesterol around 160. Triglycerides around 56, LDL around 100-110, HDL between 35-40. Just started taking Niacin in the hope that might help boost HDL. Just wanted to make sure doubling my fish oil dosage is ok thing to do.

    Here’s an interesting lab test I had done about a year ago that you might find of interest. I’m sure you’ll understand it better than I. :) It’s the Holman Omega 3 test.


    • I checked your blood test and the AA/EPA ratio is fine, but I would like to have the EPA greater than 4% in the isolated plasma phospholipids. I believe the test you were using my have used the red blood cells as opposed to the isolated plasma phospholipids. Usually the EPA levels are lower with the red blood test. I would still recommend the higher EPA and DHA intake for another 30 days to see if you get better relief. Recent data in 2010 issue of the American Journal of Clinical Nutrition indicated that even though the blood levels of EPA and DHA leveled out at higher doses, the levels in the target tissue (in this case breast tissue) where still rising. I suspect the omega-3 levels in your joints is still not high enough.

      You are lucky to be getting the Lovaza at that price since it is being prescribed off-label by your physician since you don’t have highly elevated triglyceride levels (>500 mg/dl). Most insurance companies would force you to pay full price ($220 for a one month supply of 120 capsules).

  5. Thanks again for your input Dr. Sears. I’ll push the Fish Oil to the higher dosage. Yes, I’m lucky with the Lovaza (eye doc prescribed it for dry eye), but I’ve switched eye docs, so not so sure I’ll be that lucky to get it with new eye doc.

    In order to get my blood sugars back under control (had recently risen to a 6.8% HBA1c), I’ve switched in the last few days to veggies,fruits, and fish/meat/chicken,salads. Pretty much a paleo approach – have already seen the beginning of positive results. I am a bit concerned about my weight on this new diet – I currently weigh only 141 sopping wet. Suggestions for boosting that calorie intake? I can eat lots of nuts, but I worry a bit about the amount of Omega 6 that is contained in them. Salads and veggies don’t comprise a lot of calories – just eat larger quantities?

    Thanks again – this is proving quite helpful.


    • Nuts are low in omega-6 fatty acids. Raw almonds are among the best. What you want to do is to increase lean body mass which means consuming adequate levels of protein on a daily basis and adequate levels of leucine (about 2 g) per meal to activate mTOR necessary to initiate protein synthesis when coupled with resistance training. Don’t be concerned about weight as much as your body fat percentage. This can be easily determined using the Body Fat Calculator in the Tools section.

  6. The reason I bought up the Omega 6 issue in nuts was a recent blog post I read by David Mendosa - Mendosa writes frequently about diabetes. I wonder what you think about his comments on nuts near the end of the article?

    Also, I went back at looked at my Holman Omega 3 test and saw that my AA/EPA was around 2.4 which is pretty darn good, I suspect. What puzzles me is that I was surely eating 12-15 whole eggs/week back then and if they are full of AA, then wouldn’t my levels be higher? Could it be that they’re not because I don’t eat a lot of things with lots of AA? Curious about that. I have switched to egg whites in the meantime.

    Also wondering what you think of dairy products and RA and whether you have some thoughts on that issue? I’ve cut out dairy (outside of the egg whites) and grains and am eating lots of veggies/fish/chicken and some fruits to see if that has an effect. I’ve only been doing this for about 4 days now – blood sugars are decreasing ( a good thing), but RA seems to remain in current flare. How long would you guess it takes to begin to see the effect of eating so much better in regards to my RA?


    • Egg yolks are very rich in AA. Considering that you have diabetes and RA, this indicates you have a high level of inflammation in the joints as well as in adipose tissue, muscle tissue, and liver. You may have to reduce the AA/EPA ratio to 1.5 to reduce your current levels of cellular inflammation. This taking more fish oil Likewise removing as much of the incoming AA from you diet also makes perfect sense. Starting with removing relatively recent food ingredients (grains and dairy) that can cause sub-chronic inflammation already seems to be reducing the inflammatory burden in the adipose tissue as well as in the muscle cells and liver. The reduction of the inflammation in the joints will take longer, but the extra fish oil should speed up the process.

  7. I appreciate all the help you’ve offered Dr. Sears. How you find the time to do your work and still contribute so heavily to these blogs amazes me. I’m certainly thankful for the advice you’ve given me. On a very good note – this morning my blood sugar was 89! It had been staying between 130 and 150 for some time, so this new diet is having some positive outcomes.

    One last question and then I’ll leave you alone – I’m having some serious shoulder pains and I’m not sure if it is just inflammation or if some tendon or ligament has finally given way. My rheumatologist wants me to see an orthopedic guy. In the meantime, do you see any risks of taking 8 Grams of fish oil a day and knocking down 6-800mg of ibuprofen every 4 hours to give some temporary relief? I wasn’t sure if there was some risk of internal bleeding that way or …. I don’t want to be stupid about this.

    The link to Mendosa’s article didn’t come across correctly, so not sure if you saw his comments on nuts – something that still confuses me. So here it is again and hopefully it comes through better this time.

    Thanks again!

    • There should be no problem in taking 8 grams of fish oil since that would only supply 5 grams of EPA and DHA if you are taking a high potency version. Although blood levels stabilize in 30 days, it takes longer for the tissue levels to stabilize. I would take the least anti-inflammatory drug necessary to keep the pain manageable. As the tissue levels of the omega-3 fatty acids increase, you should be able to taper down on the drug.

      Bill Lands is correct that you have to simultaneously reduce omega-6 fatty acid intake to get the real benefits of omega-3 supplementation. That is an increasingly more difficult task with over-abundance of omega-6 fatty acids in our diet. The easiest way is to increase the amount of egg white omelets in your diet. You get an excellent source of high quality protein without any omega-6 fatty acids. It is only when you get to low ratios of AA to EPA that the real anti-inflammatory benefits of omega-3 fatty acids begin to emerge. I discuss this great detail in my book, Toxic Fat.

  8. Is Krill oil as effective as fish oil in reducing inflammation? Do you recommend one supplement over the other?

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>