**Acknowledgements**

*Visions of Cardiomyocyte - Fundamental Concepts of Heart Life and Disease*

on risk in both countries [50].

fatty acid) intake [51].

discouraged.

nal microbes.

**6. Conclusion**

mediators such as quinolinic acid [51].

healthy old men in Japan and the US.

fatty acids by gut microbes.

It may be surprising that TFA is not necessarily adverse for health. Some are beneficial for health. In a recent study from Germany, total trans-fatty acids in erythrocyte membranes were shown to be inversely associated with mortality, but this was mainly driven by the naturally occurring 16:1 trans (trans-palmitoleic acid) [49]. As to relationship between IP-TFA or SFA intakes and CHD mortality, excessive intakes of both had a greater impact on risk for CHD in the US compared with Japan, whereas insufficient intakes of omega-6 PUFAs had about the same impact

Our results also indicate that plasma levels of SFAs are higher in American than in Japanese. Saturated fatty acids are considered to be one of the dietary risk factors of CVD, primarily because these fats raise LDL-cholesterol levels. Many health and government organizations have recommended the reduction of intakes of SFA s to lower the incidence of CVD. Although this difference in SFA plasma levels may also be one of the reasons that Americans have a higher mortality rate for CVD than Japanese, plasma saturated (and monounsaturated) fatty acids are claimed to be relatively poor markers of dietary SFA (saturated

Plasma fatty acid profiles in older men from Japan and US differed in many ways that are consistent with the lower rate of CHD in the former country. Efforts to lower TFA levels and increase EPA + DHA levels may help lower risk for CHD in the US, and current trends in Japan toward a more western diet [52] should be

As to relationship between TFA or SFA intakes and CHD mortality, excessive intakes of both had a greater impact on risk for CHD in the US compared with Japan, whereas insufficient intakes of omega-6 PUFAs had about the same impact on risk in both countries [50]. As stated above, naturally occurring trans fats are consumed in smaller amounts (about 0.5% of total energy intake) in meats and dairy products from cows, sheep, and other ruminants; these trans fats are produced by the action of bacteria in the ruminant stomach [22]. Since trans-fatty acids are not used in foods in Japan, all the trans-fatty acids must come from meat or dairy products. We found that there was no relationship between various foods intake and plasma levels of trans-fatty acids in Japanese old men. Only intakes of preference drinks such as tea and coffee had significant relationship with plasma levels of palmitoelaidic acid and linoelaidic acid. These results seem to indicate that plasma levels of trans-fatty acids are not derived from foods but derived by intesti-

Human gut microbes are important in neural, endocrine, and immune communication with the host [53]. Communication is considered to be bidirectional. Mediators of microbiota-gut-brain communication affected by microbial

metabolism include short-chain fatty acids, neurotransmitters such as serotonin, γ-aminobutyric acid (GABA), hormones such as cortisol, and immune system

In conclusion, some of trans-fatty acids may be produced by hydrogenation of

We here report our results of comparison of plasma levels of fatty acids between

The higher levels of DHA and EPA, along with the lower levels of the IP-TFAs, are consistent with the markedly lower risk for coronary heart disease in Japan vs.

**110**

the US.

Experiments were designed and performed by all of the authors. AT and WSH wrote the manuscript. Statistical analyses were done by FS. All authors read the manuscript and approved the final version. All the authors take responsibility for the final content.
