What is the difference between linoleic acid and linolenic acid?
Two main fatty acids essential in the diet are linoleic(or omega-6) fatty acid and alpha-linolenic (or omega-3) acid.
Both of them are polyunsaturated fatty acid, which means that they possess two or more double bonds and lack several hydrogen atoms that are found in saturated fatty acids.
What is Linoleic Acid?
By Dr. Tomislav Meštrović, MD, Ph.D.
Fatty acids represent a substantial part of lipids in human body and are important sources of energy. They are either saturated or unsaturated carbosylic acids containing carbon chains between 2 and 36 carbon atoms in length. Although more than 60 fatty acids have been found in blood plasma and tissues, only a fraction of them is relevant from the biological perspective.
The large body of epidemiological evidence about total fat content, fatty acids and human health show that major groups of fatty acids are associated with diverse health effects. When the diet lacks adequate amounts of specific fatty acids, deficiency symptoms will arise as specific clinical entities. Conversely, increased content of saturated fatty acids may result in dyslipidemia.
Characteristics of linoleic acid
Two main fatty acids essential in the diet are linoleic (or omega-6) fatty acid and alpha-linolenic (or omega-3) acid. Both of them are polyunsaturated fatty acid, which means that they possess two or more double bonds and lack several hydrogen atoms that are found in saturated fatty acids.
Linoleic acid keeps the skin impermeable to water, but to exert other effects the compound must undergo specific metabolism. First step is conversion to gama-linolenic acid by delta-6-desaturation. Gama-linolenic acid is subsequently converted to dihomo-gamma-linolenic acid, which is in turn converted to arachidonic acid.
Arachidonic acid can form prostaglandins and thromboxanes – hormone-like lipids that promote blood clotting, induce inflammation and cause smooth muscle contraction. In alternative pathway it can also form leukotrienes, which are one of the most potent inflammatory agents in the human organism.
The necessity of metabolism is reflected by the increasing potency of each substance in the form of an essential fatty acid, as it moves down the chain from linoleic to arachidonic acid; hence to achieve full range of activities, linoleic acid must be metabolized to other substances. Therefore it can be considered as analogous to provitamines.
In infants, delta-6-desaturase is too immature to provide the desired metabolism of linoleic acid, which is a reason why human milk contains gamma-linoleic acid, dihomo-gamma-linoleic acid and arachidonic acid. In contrast, conventional infant formula milks have only linoleic and alpha-linolenic acid, which can lead to a deficiency state in formula-fed infants.
Health benefits of conjugated linoleic acids
Conjugated linoleic acids (CLA) refers to a heterogeneous group of constitutional and geometric isomers of linoleic acid, which are predominantly found in milk, milk products, meat and meat products of ruminants. The effect of CLA on human health became the subject of interest after one study demonstrated inhibitory effects on mouse epidermal neoplasia.
CLA can provoke a wide spectrum of beneficial effects in various cell culture and animal models of disease. However, some studies have reported ambiguous or harmful effects of CLA supplementation and there is less evidence from direct studies on humans, thus careful consideration and further investigation is warranted.
Research has shown that CLA has a significant inhibitory effect on the establishment and progression of atherosclerosis in animal models. Both LDL cholesterol to HDL cholesterol and total cholesterol to HDL cholesterol ratios are reduced when CLA is fed to the test animals.
There is also proof of CLA blocking the growth and spread of malignant tumors, primarily by influencing cell replication and mechanisms of carcinogenesis. The increase in mineralized bone formation was demonstrated in several experiments as well.
On the other hand, it has been shown that CLA can induce insulin resistance and fatty liver. Also, a deeper and more detailed investigation into the complex network of anti-obesity regulatory pathways is necessary to improve our understanding how exactly this compound can affect body weight control.
Recommended CLA daily intake is currently between 0.35 and 1 g per day. More controlled studies of CLA usage in defined populations are needed, as possible health consequences of prolonged treatment periods are unknown at the moment. Mutual comparisons of different and well-defined mixtures of isomers are also essential to secure long-term effects and safety.
Sources
http://www.eolss.net/Sample-Chapters/C03/E6-54-03-05.pdf
umm.edu/.../omega6-fatty-acids
http://ajcn.nutrition.org/content/57/5/732S.long
http://www.nutritionandmetabolism.com/content/6/1/36
Van Nieuwenhove CP, Terán V, González SN. Conjugated Linoleic and Linolenic Acid Production by Bacteria: Development of Functional Foods. In: Rigobelo EC, ed. Probiotics. InTech, 2012; pp. 55-80.
Chow CK. Fatty Acids in Foods and Their Health Implications, 2nd Edition. CRC Press, 1999; pp. 17-46.
Further Reading
All Linoleic Acid Content
Oils Rich in Linoleic Acid
Differences between Safflower Oil and Conjugated Linoleic Acid
Last Updated: Aug 23, 2018
Currently rated 4.0 by 6 people

Written by
Dr. Tomislav Meštrović
Dr. Tomislav Meštrović is a medical doctor (MD) with a Ph.D. in biomedical and health sciences, specialist in the field of clinical microbiology, and an Assistant Professor at Croatia's youngest university - University North. In addition to his interest in clinical, research and lecturing activities, his immense passion for medical writing and scientific communication goes back to his student days. He enjoys contributing back to the community. In his spare time, Tomislav is a movie buff and an avid traveler.
Download PDF Copy
Read in:
English
Citations
Comments
The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News-Medical.Net.

Post a new comment
Login
Post
Trending
Stories
Latest
Interviews
Top Health
Articles

Anti-aging study wins grant from William and Ella Owens Medical Research Foundation

Scientists improve working memory by extending brain signals

Higher coronary artery calcium levels in middle-age linked to increased risk for future heart problems

‘Stomach flu’ vaccine prevents type 1 diabetes in children

Scientists identify early signs of Parkinson’s disease years before symptoms develop
Latest News

MIT engineers design pliable, 3-D-printed mesh materials

New study shows clear link between cannabis use and brain alterations

Targeted therapies benefit many elderly patients with metastatic kidney cancer

Anyone can get hernias, especially after abdominal surgery

Restrictive approach to blood cell transfusions safe for patients undergoing cardiac surgery
Newsletters you may be interested in

Bowel Cancer
(Subscribe or Preview)

Cell Biology
(Subscribe or Preview)

Cholesterol
(Subscribe or Preview)
See all Newsletters »
  
Medical Links
Medical Home
News
Health A-Z
White Papers
Thought Leaders
Insights
MediKnowledge Series
Health & Personal Care
Medical Devices
Drugs
Life Sciences Links
Life Sciences Home
News
Lab Instruments & Equipment
Life Sciences A-Z
White Papers
Thought Leaders
Insights
Webinars
Other Useful Links
About
Meet the Team
Search
Newsletters
Twitter Channels
Sitemap
Advertise
Contact
Update Your Privacy Preferences
Terms & Conditions
Privacy & Cookie Policy

Facebook
Twitter
News-Medical.Net provides this medical information service in accordance with these terms and conditions. Please note that medical information found on this website is designed to support, not to replace the relationship between patient and physician/doctor and the medical advice they may provide.
This site complies with the HONcode standard for trustworthy health information: verify here.

News-Medical.net - An AZoNetwork Site
Owned and operated by AZoNetwork, © 2000-2019
By continuing to browse or by clicking "Accept All Cookies," you agree to the storing of first and third-party cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts.Find out more.
Cookie Settings
Accept All Cookies