We should look to the Japanese to teach us a few lessons about preventing heart disease. A Japanese male has only 65% of the risk of an American male (despite 40% of Japanese men being smokers), while a Japanese woman has 80% less risk than an American woman. While the U.S. is near the top of the list of nations with highest cardiovascular risk, Japan is the lowest.
What are they doing right?
There is no one explanation, but several. Genetics probably does not play a substantial role, by the way, as demonstrated by observations of Japanese people who emigrate to Western cultures. People of Japanese heritage living in Hawaii, for instance, develop the same cardiovascular risk as non-Japanese living in Hawaii. They also develop obesity and diabetes.
Among the factors that likely contribute to reduced risk in Japanese people:
--A style of eating that does not include a lot of sweet foods. No breakfast cereal or donuts for breakfast, for instance, but miso soup with tofu, fish, green onions, and daikon (as takuan, or pickled radish).
--Seaweed--It's probably a combination of the green phytonutrients and iodine. Typical daily iodine intake is in the neighborhood of 5000 mcg per day from nori, kombu, wakame, and other seaweed forms. (The average American obtains 125 mcg per day of iodine from diet.)
--Seafood--Fish in many forms not seen in the U.S. are popular.
--Green tea--Consumption of green tea has been confidently linked to reduced cardiovascular risk, probably via visceral fat-reducing, anti-oxidative, and anti-inflammatory effects. Although tea in Japan is often the less flavonoid-rich oolong tea, softer benefits from this form are likely.
--Soy--Tofu, miso, and soy sauce are staples. It's not clear to me whether soy is intrinsically beneficial or whether it is beneficial because it serves to replace unhealthy alternatives. (Genetic modification may change this effect.)
--Reduced exposure to cooked animal products (except seafood). This is not a saturated fat issue, but probably an advanced glycation end-product/lipoxidation issue that result from cooking.
--The lack of a "eat more healthy whole grain" mentality, the advice that has plunged the entire U.S. into the depths of a diabetes and obesity crisis (along with high-fructose corn syrup and sugar). Noodles like udon and ramen do have a place in their diet, as do some dessert foods. But the overall wheat exposure is less--no bagels, sandwiches, and breakfast cereals.
--Less overweight and obesity--The above eating style leads to less weight gain.
Japanese foods have a unique taste, consistency, and mouth-feel that go well with saltiness, thus the downside of their diet: salt consumption. On a broad scale, high salt consumption has been associated with hypertension and gastric cancer. But the tradeoff has, on the whole, been a favorable one.
One study trying to find some answers:
Dietary patterns and cardiovascular disease mortality in Japan: a prospective cohort study.
Shimazu T, Kuriyama S, Hozawa A et al.
Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Japan.
We prospectively assessed the association between dietary patterns among the Japanese and CVD mortality. Dietary information was collected from 40 547 Japanese men and women aged 40-79 years without a history of diabetes, stroke, myocardial infarction or cancer at the baseline in 1994.
During 7 years of follow-up, 801 participants died of CVD.
Factor analysis (principal component) based on a validated food frequency questionnaire identified three dietary patterns: (i) a Japanese dietary pattern highly correlated with soybean products, fish, seaweeds, vegetables, fruits and green tea, (ii) an 'animal food' dietary pattern and (iii) a high-dairy, high-fruit-and-vegetable, low-alcohol (DFA) dietary pattern. The Japanese dietary pattern was related to high sodium intake and high prevalence of hypertension. After adjustment for potential confounders, the Japanese dietary pattern score was associated with a lower risk of CVD mortality (hazard ratio of the highest quartile vs the lowest, 0.73; 95% confidence interval: 0.59-0.90; P for trend = 0.003). The 'animal food' dietary pattern was associated with an increased risk of CVD, but the DFA dietary pattern was not.
The Japanese dietary pattern was associated with a decreased risk of CVD mortality, despite its relation to sodium intake and hypertension.