Two preventable imbalances in lipid nutrition cause cardiovascular and cerebrovascular disease (http://efaeducation.nih.gov/sig/dietdisease.html)-the major disability of people worldwide. Preventing the imbalances in childhood saves future generations from progressively impaired vascular function that eventually needs lifelong treatment with expensive medication. One imbalance is large meals with more energy than is burned. Biomarkers of this are high blood triglycerides, obesity, type 2 diabetes and high blood cholesterol. Another imbalance is eating more n-6 than n-3 fats. These form 20- and 22-carbon highly unsaturated fatty acids (HUFA) that affect formation of eicosanoids. The biomarker of n-6 in HUFA of blood reflects essential fats eaten, predicts likely intensity of n-6 eicosanoid actions and strongly predicts risk of cardiovascular death. A 25-year study showed cholesterol predicted death only to the degree that n-6 exceeded n-3 in HUFA. When tissue n-3 suppressed n-6-mediated inflammation and thrombosis, diet imbalances that elevate mevalonate and isoprenoid metabolites (and blood cholesterol) seemed no longer fatal. Interactive menu planning software, KIM-2, helps find personally palatable foods that balance tissue HUFA at any desired level. It manages details to prevent the two imbalances (see http://efaeducation.nih.gov/sig/kim.html). A good goal is 30% n-6 in tissue HUFA, near that from traditional Japanese foods. Many food combinations can reach this goal. Economical high-throughput assays of HUFA in a finger-tip drop of blood will give fast progress in clinical trials to correct n-3 imbalance. Eventually, we can show that primary prevention saves more and costs less than treatment.
From the results of in vitro and in vivo studies, along with those of animal studies, it is likely that long-chain n-3 polyunsaturated fatty acids (Ln-3 PUFA), which are abundant in fish, have protective effects on colorectal cancer. In contrast, previous epidemiological studies did not provide sufficient evidence for an association between fish intake, Ln-3 PUFA and colorectal cancer. The results from some cohorts or nested case-control study from many countries and with different demographic characteristics do not provide evidence to suggest a significant association between Ln-3 PUFA and colorectal cancer for the moment. To clarify the relation between Ln-3 PUFA and colorectal cancer, further study may be necessary.
One of the major subjects of the Japan Society for Lipid Nutrition is to build up the national guideline of lipid nutrition, which is described in the regulations of the society. It is very important for the society and even for citizens to realize the evidences provided by epidemiology of lipid nutrition. However, there are some inconsistent evidences obtained by some trials of evidence-based nutrition, and the logic in some aspects of epidemiology seems difficult to reconcile some analytical and biological chemists to application of cell lipid metabolic evidences to human collectives. I will propose a chemometric approach for the evidence-based (lipid) nutritional research in combining the data of changes of lipid nutritional state for individuals and epidemiological evidences for the collective.
It has been revealed that the consumption level of meat (especially pork) in Japan is higher in the people from Okinawa than that reported by the Japanese National Nutritional survey. Therefore, we were prompted to conduct a detailed survey of the methods of cooking and eating pork in Okinawa prefecture. The results revealed that pork and pork products are often cooked with food groups such as green vegetables, beans, potatoes, and seaweeds. We considered that the cooking of pork and pork products was a major factor influencing the efficiency of consumption of various nutrients such as vitamins and minerals. In our dietary survey of the main Okinawa island conducted in 1997, the fat-energy ratio in the diet of male subjects 40-59 years was over 32%, which was considered to be due to the use of large amounts of vegetable oil for preparing stir-fried dishes (Champuru) and deep-fried dishes. The EPA(%) of erythrocyte membrane phospholipids was lower in young women about 20 years old of Okinawa as compared with that in their counterparts in the Kanto region, because of the low level of intake of fishes and shellfishes by the Okinawan women. Recently, the life expectancy for men in Okinawa Prefecture fell sharply to 26th among the 47 prefectures of Japan, perhaps attributable to the upward trend of the mortality rate from ischemic heart disease and the cerebrovascular disease. Thus, management of lipid nutrition in the Okinawan people is becoming a more and more important issue that must be addressed.
Fatty acid contents of school lunch meals served in spring-summer season (69 days) in 1995 were analyzed especially on amounts of n-6 and n-3 polyunsaturated ones and their ratio (n-6/n-3 retio). The average n-6/n-3 ratio of meals was 5.5 when calculated on sum total of all the foodstuffs, and was 6.6±2.1 based on separate calculation on each lunch meal, higher than the guided value 4.0. Detailed analysis on kinds and amounts of foodstuffs used for those meals indicated that the n-6/n-3 ratio was elevated by cereals, meats, milks, pluses and nuts. Fishes, shellfishes are expected alternatives for meats to decrease the ratio. Choice of fats and oils and/or seasonings and spices for cooking meals could be important to make n-6/n-3 ratio much closer to the guided value.