Wednesday, March 23, 2011

Safflower Oil Study

A few people have sent me a new study claiming to demonstrate that half a tablespoon of safflower oil a day improves insulin sensitivity, increases HDL and decreases inflammation in diabetics (1). Let me explain why this study does not show what it claims.

It all comes down to a little thing called a control group, which is the basis for comparison that you use to determine if your intervention had an effect. This study didn't have one for the safflower group. What it had was two intervention groups, one given 6.4g conjugated linoleic acid (CLA; 50% c9t11 and 50% t10c12-CLA) per day, and one given 8g safflower oil. I have to guess that this study was originally designed to test the effects of the CLA, with the safflower oil group as the control group, and that the interpretation of the data changed after the results came in. Otherwise, I don't understand why they would conduct a study like this without a control group.

Anyway, they found that the safflower oil group did better than the CLA group over 16 weeks, showing a higher insulin sensitivity, higher HDL, lower HbA1c (a marker of average blood glucose levels) and lower CRP (a marker of inflammation). But they also found that the safflower group improved slightly compared to baseline, therefore they decided to attribute the difference to a beneficial effect of safflower oil. The problem is that without a control (placebo) group for comparison, there's no way to know if the improvement would have occurred regardless of treatment, due to the season changing, more regular check-ups at the doctor's office due to participating in a study, or countless other unforeseen factors. A control group is essential for the accurate interpretation of results, which is why drug studies always have placebo groups.

What we can say is that the safflower oil group fared better than the CLA group, because there was a difference between the two. However, what I think really happened is that the CLA supplement was harmful and the small dose of safflower oil had no effect. Why? Because the t10c12 isomer of CLA, which was half their pill, has already been shown by previous well-controlled studies to reduce insulin sensitivity, decrease HDL and increase inflammatory markers at a similar dose and for a similar duration (2, 3). The safflower oil group only looked good by comparison. We can add this study to the "research bloopers" file.

It's worth noting that naturally occurring CLA mixtures, similar to those found in pastured dairy and ruminant fat, have not been shown to cause metabolic problems such as those caused by isolated t10c12 CLA.

28 comments:

Helen said...

Interesting! I did see an article about that study, and noticed it seemed to be a "surprising result" of a study initially designed to study CLA, for which, perhaps, safflower oil was intended as a placebo. It seemed fishy.

Ned Kock said...

I haven't seen the study Stephan. Just going by your post I'd say that I would not be too surprised to see short-term beneficial effects from safflower oil consumption. The effects may well be due to the high vitamin E content of this oil.

The problems associated with consumption of any seed oil rich in omega-6 are due to long-term complications. Over years, these oils cause chronically elevated levels of pro-inflammatory hormones, such as tumor necrosis factor; and ultimately to tissue damage in the liver, pancreas, and other organs.

David said...

All CLA is not created equally...

Might-o'chondri-AL said...
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Reijo said...

Nice post. Anyway, isn't it intriguing that safflower oil (omega-6 FAs) did not accelerate inflammation during the study period (baseline vs 16 weeks) but seemed to improve it?

Another study also showed that safflower oil (vs CLA) may not be as poisonous as suggested: http://www.ncbi.nlm.nih.gov/pubmed/19535429

Things get pretty complicated with these fatty acids..

Chris said...

Again goes to show we cannot compare the effect of synthetic nutrients/vitamins to naturally occurring one's. Give me some butter any day over over priced CLA supps.

Donnie said...

Do you still take butter oil or did you replace it permanently with thorne's research, Stephan?

Not incredibly relevant, I know but it just popped into my mind when you mentioned CLA.

Matt Stone said...

"This research was also supported by an unrestricted gift from the Cognis Corp."

I think that line is more revealing. Cognis Corp. makes solvent extracts, like the kind used for making vegetable oils.

Stabby said...

Reijo, in your study it says that safflower "increased lean mass". How in the world would it do that?! That is ridiculous. It looks like there was more at play than just addition of dietary oils. Also it said that there was no difference in total fat or fat quality. So no actual change in the composition of the fats, meaning no change. But increased lean mass? So more exercise. Sigh.

David said...

It's stunning that they didn't get much worse with the safflower oil considering that vegetable oil is the devil's fat - perhaps the seasonal effects somehow countered the massive negative effects of that nasty vegetable oil

Kathryn said...

I ignored the study as i don't trust any of them claiming canola, safflower, or the like to be healthy. But i sure appreciate your science on the matter.

As you've given permission to reprint this, i posted it at a forum (with your info) that is dedicated to natural health.

Here is the link: link

Robert said...

Hi Stephan

As ever many thanks for all your hard work and insights

What was the base intake of Omega 6 linoleic acid prior to the trial?

Did the trial represent a reduction in Omega 6 intake.

What was their calorie intake prior to the trial v their calorie intake during the trial.

Did the study involve a significant change from the normal diet of the subjects - eg including reduction of intake of oxidised fats.

Many questions I suspect.

David said...

For the record, Cognis makes CLA, not safflower oil, so the outcome was against their interests... not that that should stop the vegetable fat bashing

Robert said...

If the reduction in inflammation was due to other factors eg lower Omega 6 in trial diet, calorie reduction, lower oxidised fats etc, and an equivalent fall in inflammation was not seen with CLA; it raises some interesting questions as to the impact of CLA on inflammation.

Might-o'chondri-AL said...
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renes said...

Here is the article mentioning the company sponsored results. The company providing the funding sells oil.

A Dose Of Safflower Oil Each Day Might Help Keep Heart Disease At Bay

""Belury is an investigator with the Ohio Agricultural Research and Development Center. This research was also supported by an unrestricted gift from the Cognis Corp., which also provided the supplements; the National Center for Research Resources; the Clinical Research Center at Ohio State; and the National Institutes of Health.

Co-authors of the study include Michelle Asp, Angela Collene, Leigh Norris, Rachel Cole and Michael Stout of the Department of Human Nutrition and Szu-Yu Tang and Jason Hsu of the Department of Statistics, all at Ohio State.

Source: Ohio State University"


Safflower oil has a high omega-6 fatty acid content.

Food Oils in descending rank by short 3/short 6 ratio

Stabby said...
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Stabby said...
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Stabby said...

this rat study of relevance? Seems to show the opposite of that Japan one. http://www.ncbi.nlm.nih.gov/pubmed/15623825

So perhaps we should be careful not to equivocate between different isomers.

Generally the best results in CLA studies come from using actual tallow or butte

renes said...

Cognis also sells emulsifiers used in products made with vegetable and seed oils.

Their CLA product is sourced from safflower oil.

From the Tonalin website:

"Sourced from natural safflower oil, Tonalin CLA(conjugated linoleic acid) is natural and environmentally sustainable."

They still profit in other areas (e.g. emulsifiers) when this study is used to promote safflower oil on shows like Good Morning America as it was recently.

Natalia said...

But are there any primitive (and healthy) societies that have thrived with safflower oil as a major part of the diet? I say guilty until proven innocent.

Stabby said...

I am thinking more and more that if you take DIABETIC women, who are already in deep, and give them just a bit more omega 6, you don't do much extra damage. Tissue HUFA us already terrible, ROS is already terrible. But Safflower has lots of vitamin e. Bottom line is that we are still completely justified in telling anyone who is fairly healthy and does not want to end up diabetic to keep clear of the high dose omega 6.

Unknown said...

Safflower Oil contains 75% LA and only 0.4 to 0.6 mg/g of CLA. So Safflower Oil is not a significant source of CLA. And LA will convent to CLA in some people and not others, this is due to intesinal microb conversion, that rats posses but apperently several humans do not. The LA content in blood rises in direct proportions from consumption Safflower Oil, and the LA has been shown to have several benefits.

So whether of not you believe Safflower Oil or CLA are safe there appears to be several studies that show they have benefits and some related to fat loss, and LA vs CLA have different affects and you won't get CLA from Safflower oil consumption.

renes said...

@Unknown - I prefer to measure the effects of different amounts of linoleic acid with a blood pressure monitor rather than relying on statements about unnamed studies.

On Youtube, you can find a lecture by Prof. Michal Laniado Schwartzman that presents how cytochrome P450-derived eicosanoids (made from arachidonic acid) play a role in the regulation of hypertension.


There are more than enough omega-6 fatty acids in foods without consuming more in manufactured foods like oil.

Caldwell B. Esselstyn, Jr., M.D. (formerly Cleveland Clinic; retired) has many years of data of the improvements seen in heart disease patients using an oil-free diet.

Hydroxy-trans-2-nonenal (and other toxic compounds) form by heating oils to frying temperatures. When restaurants re-use oil, more HNE accumulates.

Based upon what I have seen, what others I know have seen, and the results seen by patients of Caldwell B. Esselstyn, Jr., M.D., when you eat less linoleic acid, blood pressure goes down if it is high.

Granny said...

Now I'm really confused. Dr. Oz had an article in a magazine recently about this study. Although he is a slender guy, he was going to take the safflower oil himself to see what his results would be. So naturally I thought if it was good enough for Dr. Oz it would be good enough for me as well. However when I went to the local health food store, they were out of safflower oil. It seems to be a popular item right now. Not sure what I should do. Help.

VH Photography said...

@ Granny, you can also buy Safflower Oil in the cooking oil section at your local Walmart, Kroger, etc

tech06778 said...

I just bought a 1.5 pint of safflower oil in the cooking section of Walmart for less than $4. The nutritional section had a 10 day supply (based on taking the capsules per the instructions) for almost $13. My calculations are: One-half teaspoonful (2.5ml) twice daily is equivalent to the same dosage on the supplement. It comes to 5 grams of safflower oil a day. The study was at 6.5 grams. I plan to increase the dose as I want to see how it effects digestion and other things.

Terry Siegel said...

Safflower oil bought from the grocery store is high in oleic acid, and meant for cooking. High linoleic acid safflower oil is unstable, must be refridgerated after opening and can not be used in cooking. This type of high linoleic oil is about 75% linoleic acid and 12% oleic acid, and was the kind used in the study. I bought mine from a health food source, and although "of nutritional quality," was marketed as a skin softener. Cost= $8 for 16 ounces.