ERA JUMP: Omega-3 fatty acids and plaque

The results of the uniquely-constructed ERA JUMP Study were just released, a fascinating study of the relationship of omega-3 fatty acids to coronary and carotid plaque.

The study adds insight into why the Japanese experience only one third of the heart attacks of Americans, and why Japan occupies the bottom of the list for least heart attacks among all developed countries.

The Electron-Beam Tomography, Risk Factor Assessment Among Japanese and U.S. Men in the Post-World War II Birth Cohort Study (ERA JUMP), a collaborative U.S.-Japanese effort, compared three groups of men:

-- 281 Japanese men living in Japan
-- 306 non-Japanese men living in the U.S. (Pittsburgh, Pennsylvania)
-- 303 Japanese Americans (having both parents Japanese without “ethnic admixture”) living in Hawaii.

The last group represents a group that is genetically similar to the group in Japan, but exposed to an American diet and lifestyle.

Three main measures were compared:

-- Blood levels of omega-3 fatty acids, EPA and DHA)
-- Carotid intimal-medial thickness (CIMT, the thickness of the carotid artery lining that can serve as an index of body-wide atherosclerosis)
-- Coronary calcium (heart scan) scores.

Interestingly, at the start of the study, the Japanese men possessed an overall cardiovascular risk profile worse than the Americans: Though more slender (BMI 23.6), Japanese men were more likely to be smokers, alcohol drinkers, had more high blood pressure, and were less likely to take cholesterol medications. The Americans, conversely, although heavier (BMI 27.9), were less likely to be smokers and drinkers, and had a four-fold greater use of cholesterol medications.

The Japanese Americans were the most likely to be hypertensive, diabetic, with a similar proportion of overweight as the non-Japanese Americans.

Despite the overall greater heart disease risk for profile for Japanese men, compared to non-Japanese Americans they had 10% less CIMT. In addition, only 9.3% of Japanese men had abnormal coronary calcium scores vs. 26.1% of non-Japanese Americans. Japanese-Americans were the worst, however, with nearly 10% more CIMT than non-Japanese Americans and 31.4% with abnormal calcium scores.

The most intriguing finding of all was the fact that, of all the various groups and degrees of atherosclerosis, whether gauged via CIMT or coronary calcium scores, the blood level of omega-3 fatty acids was inversely related, i.e., the greater the omega-3 blood level, the less plaque by either measure was detected.

Japanese men had the highest omega-3 blood levels: twice that of the non-Japanese Americans. The Japanese-Americans had levels only slightly greater than non-Japanese Americans.

While other studies, like the GISSI Prevenzione study, have persuasively demonstrated that omega-3 fatty acids substantially reduce heart attack, a weak link in the omega-3 argument has been a study that links greater omega-3 intake with less atherosclerosis. The unique construction of the ERA JUMP Study, employing two groups with sharply different omega-3 intakes, very powerfully argues for the plaque-inhibiting effects of this fraction of fats.

How much omega-3 fatty acids do Japanese people eat? Estimates vary, depending on part of the country, coastal vs. inland, age, etc., but Japanese tend to ingest anywhere from 5 to 15-times more omega-3 fatty acids than Americans. The actual intake of omega-3 fatty acids (EPA +DHA) in Japanese ranges from 850 to 3100 mg per day.

Comments (5) -

  • Jenny

    8/1/2008 12:41:00 AM |

    Thanks for pointing this out.

    But I cannot help but wonder about what these Japanese men got if they did NOT get heart disease.

    It was my impression that the rate of stomach cancer was higher in Japan than anywhere else in the world.

    I also know that the Honolulu study found a much higher rate of dementia in men who ate traditional diets high in tofu.

    Finally, and most concerning, I personally know two people who ate "healthy" diets high in fish only to came down with mercury poisoning bad enough that they had to undergo chelation therapy. (These were people whose mainstream doctors sent them for the therapy, not adherents of alternative medicine.)

    Having observed what happens to people who do not get heart disease but do live long enough to develop both cancer and dementia, and having concluded that heart disease is much to be preferred, I'm not entirely sure that we should rush to eat the Japanese diet.

    We are all going to die of something. I would much prefer a swift heart attack to a decade of cancer and dementia.

  • TedHutchinson

    8/1/2008 8:45:00 AM |

    Dr Cannell says at "activated vitamin D lessens heavy metal induced oxidative injuries in rat brain. The primary route for brain toxicity of most heavy metals is through depletion of glutathione. Besides its function as a master antioxidant, glutathione acts as a chelating (binding) agent to remove heavy metals, like mercury."

    It may be that, as well as keeping your vitamin D3 status optimal, using molecullarly distilled fish oil or krill avoids the pollution problems?

  • Peter

    8/1/2008 2:52:00 PM |

    I wonder how eating fish compares to drinking fish oil.

  • carolina1954

    8/2/2008 4:57:00 AM |

    I must demur from some of Jenny's comments.

    First,  I do not believe that the overall effect of the Japanese diet is to trade heart disease for cancer, as she seems to imply.   E.g., the Japanese, despite smoking multiples more than Americans, have a rate of lung cancer less than half ours.

    Second, although it is true that eating a lot of certain species of fish, such as shark, swordfish, and large tuna, creates a risk of mercury poisoning, other species, such as salmon, have very low levels of mercury and may be eaten virtually ad libitum.

    Third, dying from heart attack, or its evil twin stroke, is not necessarily "swift".  If a heart attack interrupts blood flow for a few minutes, it causes massive brain damage but not necessarily death.  It can also cause terminal congestive heart failure, which is also not my idea of going "gentle into that good night."

  • Rich Lee

    8/14/2008 6:39:00 PM |

    Which fish oil brand is recommended?