Influences of dietary linoleic acid on coronary flow, left ventricular work, and prostaglandin synthesis in the isolated rat heart

Because of the frequent occurrence of ischemic heart disease, interest in the consequences of dietary fat intake for the heart has increased strongly. and many studies have shown the importance of dietary fat for the heart. Most studies deal with the role of dietary fat in coronary atherosclerosis and the incidence of ischemic or coronary heart disease due to the obstruction of the coronary arteries by atherosclerotic plaques. Several studies have shown that dietary fat can also affect the myocardial muscle cell directly. The best known and most extensive studies in this field are those of essential fatty acid deficienCy and dietary rapeseed oil containing a high amount of erucic acid. Onty few studies on the effects of other dietary fats on the heart. in which athAosclerosis is not involved. have appeared. However. the interest in direct effects of dietary fat on the heart is growing. The final objective of the present study is to gain information about possible favourable and unfavourable properties of dietary fats used for human consumption. The particular objectives of the study were to investigate influences of fats fed to rats for a short period of time on coronary flow rate and external left ventricular work in their isolated. perfused hearts. As the effects found could be ascribed to dietary linoleic acid. which is the ultimate precursor of the prostaglandins of the 1- and 2-series. it was investigated whether prostaglandin synthesis in the isolated heart waS involved. The build-up of the thesis is as follows. Chapter I gives a review of the effects of dietary fat on the heart (excluding atherosclerosis). as well as a review of the differences found in the heart in the oxidation rates and metabolism of various long-chain fatty acids. Chapter 2 contains methods and procedures and a discussion on the use of the isolated. working rat heart for physiological investigations. A discussion on expressing the heart function parameters used per unit of dry heart mass is given in chapter 3. The investigations into the effects of various dietary fats and of prostaglandins in the isolated heart are presented in chapters 4-6 and in the Addenda. Tbe overall discussion on the influences of the dietary fats used on coronary flow rate and external left ventricular work. and on the role of prostaglandins is given in chapter 7

Health Aspects of Fish and N-3 Pufa from Plant and Marine Origin: Summary of a Workshop

An expert workshop reviewed the health effects of n-3 polyunsaturated fatty acids (PUFA), and came to the following conclusions. Consumption of fish may reduce the risk of coronary heart disease (CHD). People at risk for CHD are therefore advised to eat fish once a week. The n-3 PUFA in fish are probably the active agents. People who do not eat fish should consider obtaining 200 mg of very long chain n-3 PUFA daily from other sources. Marine n-3 PUFA somewhat alleviate the symptoms of rheumatoid arthritis. There is incomplete but growing evidence that consumption of the plant n-3 PUFA, alpha-linolenic acid, reduces the risk of CHD. An intake of 2 g/d or 1% of energy of alpha-linolenic acid appears prudent. The ratio of total n-3 over n-6 PUFA (linoleic acid) is not useful for characterising foods or diets because plant and marine n-3 PUFA show different effects, and because a decrease in n-6 PUFA intake does not produce the same effects as an increase in n-3 PUFA intake. Separate recommendations for alpha-linolenic acid, marine n-3 PUFA and linoleic acid are preferred. Sponsorship: Supported by a grant from Unilever Research

What is the role of a-linolenic acid for mammals?

This review examines the data pertaining to an important and often underrated EFA, &alpha;-linolenic acid (ALA). It examines its sources, metabolism, and biological effects in various population studies, in vitro, animal, and human intervention studies. The main role of ALA was assumed to be as a precursor to the longer-chain n-3 PUFA, EPA and DHA, and particularly for supplying DHA for neural tissue. This paper reveals that the major metabolic route of ALA metabolism is &beta;-oxidation. Furthermore, ALA accumulates in specific sites in the body of mammals (carcass, adipose, and skin), and only a small proportion of the fed ALA is converted to DHA. There is some evidence that ALA may be involved with skin and fur function. There is continuing debate regarding whether ALA has actions of its own in relation to the cardiovascular system and neural function. Cardiovascular disease and cancer are two of the major burdens of disease in the 21st century, and emerging evidence suggests that diets containing ALA are associated with reductions in total deaths and sudden cardiac death. There may be aspects of the action and, more importantly, the metabolism of ALA that need to be elucidated, and these will help us understand the biological effects of this compound better. Additionally, we must not forget that ALA is part of the whole diet and should be seen in this context, not in isolation.<br /