Conjugated linoleic acid, CLA, and cancer

Vitamins, minerals, natural compounds and supplements

(Chris Woollams, CANCERactive) Conjugated linoleic acid or CLA could well be one the most important Complementary and Integrative Cancer Treatments available according to the latest research. It has a number of clear health benefits, not least in cancer where it seems to stop inflammation, prevent cancer, limit metastases, stop blood supply formation and tumour development.

CLA is natural fatty acid. Conjugated linoleic acid is actually a collective term for a family of about 30 isomers of linoleic acid (LA, cis-9, cis-12-octadecadienoic acid).

While its fat fighting and insulin lowering abilities are important, the anti-tumour activity of CLA is of special interest. Many studies both in vivo and in vitro have shown that CLA suppresses the development of cancer at various levels and in different areas of the body at relatively low dietary levels (Lee KW1, Lee HJ, Cho HY, Kim YJ. Crit Rev Food Sci Nutr. 2005;45(2):135-44).

CLA has been shown to decrease skin, liver, and colon cancer in a vast number of animal studies. But the results with breast cancer look most impressive. After animals had received chemically induced breast cancer, CLA not only prevented the disease but was shown to be incorporated into the breast tissue itself. When animals already had breast cancer CLA uptake actually resulted in decreases in tumours

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There are increasing numbers of human studies – for example, one from Finland showed that the greater the CLA blood serum levels the less the risk of breast cancer (Aro A, Mannisto S, Salminen I, Ovaskainen ML, Kataja V, Uusitupa M. Nutr Cancer 2000;38:151-157).

In May 2013, Iranian scientists published a study in the journal Integrative Cancer Therapies on the effect of CLA supplementation on inflammation in patients who were receiving chemotherapy treatment for rectal cancer. They showed that CLA increased inflammation-lowering protein levels, stopped angiogenesis (the growth of new blood vessels needed by tumours) and stopped tumour spread. They even stated that, “It seems that CLA may provide new complementary treatment by reducing tumor invasion and resistance to cancer treatment in patients with rectal cancer.”

The French Paradox?

CLA is an important part of the French Paradox and the Rainbow Diet. The French Paradox? The French eat more fat and drink more alcohol than any other nation but have less cancer and less heart disease. The epicenter of the Rainbow diet reflects not just the consumption of lots of colourful vegetables and fruit full of corrective and protective natural compounds (like resveratrol and grape seed extracts in red wine). It isn’t even on the Mediterranean, which Harvard Medical School has numerous studies for. The French conducted their own study of the epicenter and found it was south of Toulouse – the heart of foie gras production and a land of cows grazing in open fields.  And grass fed cattle are one of the best sources of CLA.


Preventing and stopping cancer?

What’s this?? Red meat preventing cancer? Surely not.

Conjugated linoleic acid is formed from a simple structural change in the linoleic acid molecule. And linoleic acid is a common unsaturated fat, the sort that health ‘experts’ have told us not to consume for the last 30 years. But they are wrong. Saturated fat is far from all bad. It’s the ratio of HDL (good cholesterol) to LDL (bad) in the body that is important and avoiding glucose which causes inflammation. If your arteries were not inflamed then the fat would not ‘stick’.
Yes, consuming red meat does cause more inflammation in the body, and vegetarians get less cancer than meat eaters. But then, vegetarians smoke less.

And, as with everything in nature, natural grass fed cows’ meat contains highly anti-inflammatory compounds to balance the inflammatory effects. One of these is CLA. It is found in the meat and milk fat (cheese, butter, and dairy products) of ruminant animals. A ruminant is an animal with a rumen in the gut, and here the grass sits after consumption to be fermented by the important friendly bacteria in the cows’ microbiome. This fermentation produces CLA.

Although CLA resembles linoleic acid in molecular structure, its effects are vastly different. In experiments with mice and rats fed carcinogenic fried and burned meats, the scientists were surprised to find in some cases the animals were protected from developing cancers.

A large number of studies have shown consistently that CLA prevents cells becoming cancer cells. In 1979, a Wisconsin study had to be repeated several times as researchers could not believe the findings. One study showed, where mice were fed different amounts of CLA and then were given a cancer-causing (carcinogenic) chemical that causes breast cancer in most of its victims, 80% of those on a normal diet got breast cancer while only 40% of those consuming CLA were found to have cancer. A 50% reduction!  (Ip C, Chin SF, Scimeca JA, Pariza MW. Cancer Res 1991;51:6118-6124).
Researchers from Roswell noted that it was more powerful against breast cancer than any other fatty acid.

Preventing metastases

In another study from Wistar, this time with mice given prostste cancer, half the mice were given normal linoleic acid, the other half CLA. Incredibly only 10% of CLA-fed mice had cancer metastases compared to 80-100% of the mice fed the normal linoleic acid (Cesano A, Visonneau S, Scimeca JA, Kritchevsky D, Santoli D. Anticancer research 1998;18:1429-1434).

CLA and normal linoleic acid

While CLA seems to stop cancer, research into normal linoleic acid suggests that it can make matters worse (Welsch CW. Cancer Res 1992;52:2040-2048). Linoleic acid is found in corn and other vegetable oils, sesame, and canola oil, and in chicken fat and egg yolks 15%. 

Other health benefits

CLA is a powerful antioxidant. It also appears in research to reduce levels of ‘bad’ cholesterol. It has even been shown to reduce atherosclerosis by as much as 50 per cent (Anand P, Kunnumakkara AB, Sundaram C, Harikumar KB, Tharakan ST, Lai OS, Sung B, Aggarwal BB. Pharm Res 2008;25:2097-2116)

Much of the research on CLA relates to its fat-fighting abilities: for example, it has also been shown to stop the peroxidation of unsaturated fatty acids;
it lowers levels of harmful inflammation-causing omega-6 fatty acids in tissues; it increases plasma levels of good omega-3 fatty acids.

It also improves glucose tolerance and lowers insulin levels in both animals and humans (Brown JM, McIntosh MK. J Nutr 2003;133:3041-3046).  In various research studies, it has been linked to increased lean muscle mass and decreased body fat in animals and humans (Smedman A, Vessby B. Lipids 2001;36:773-781).

Sources

Very small amounts of CLA seem to have huge anti-cancer effects. Just a few weeks consumption changed the course of several research studies. It also seems to have a cumulative effect over time with estimates of 1 gm a day seeming the optimum amount.

Beef and cows’ dairy products are good sources – but only where the animals are free to roam and graze on grass. Cows fed grain are poor sources as are cows given antibiotics and other microbiome destroying chemicals.  Free range chicken, turkey and wild salmon contain good levels too.

Complementary and Integrative Medicine

Scientists are now talking of CLA being an important part of an integrative cancer treatment package. It’s not a cure of course but research would suggest it may have an important support role.

But how many women with breast cancer give up eating red meat and all cows’ dairy? The above research says that not all cows and not all cows’ dairy is created equal. But how can you be sure of what you are eating???

What is fortunately clear from the research studies is that CLA is effective when taken as a supplement. If you are already thinking of supplementing with CLA, why not take a look at what Natural Selection has on its website. Click here to go to the relevant page

Vitamins, minerals, natural compounds and supplements
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