Thursday, June 2, 2011

Diet Effects on Blood Coagulation

In Nutrition and Evolution, Michael Crawford and David Marsh make the following statement (page 238):

“The library shelves groan with data showing that feeding saturated fats increases blood cholesterol, damages the arteries, stimulates the blood clotting mechanism, and, indeed, affects blood pressure and the immune system.  By contrast, the essential polyunsaturated fatty acids are needed for reproduction, brain growth, vascular system development, cholesterol excretion, control of blood lipids, blood pressure, and other important regulatory functions.”

So I decided to check PubMed for the data on fats and blood coagulation.   I found a number of very interesting articles. 

In 1954, Cullen and Swank (1, full text), seeking to understand their finding that a low-fat diet can improve multiple sclerosis in humans (2, 3, 4 abstracts, see also Swank's Multiple Sclerosis Diet Book), reported that feeding hamsters with cream produced marked aggregation of red blood cells:

“In many vessels the flow of blood became extremely slow, and frequently the flow stopped completely in some vessels.  These changes became first evident and remained most pronounced in the venules.”

Cullen and Swank provided these photos of the process:
Click for larger version

Row A shows normal circulation in hamsters on a low fat diet.  Rows B and C show clumping of red blood cells in a hamster after a high fat feeding.  The photos are enlargements of frames from a colored motion picture taken during the experiments.  In the discussion, the authors state:

“The underlying mechanism of the circulatory changes produced by a high fat intake is not clear. Previous darkfield microscopic observations and the cinephotomicrographs taken in the present study leave no doubt that an adhesive envelope develops around the red blood cells.  In all likelihood this is the principal cause of the aggregation of the red blood cells and of the slowed circulation.”

After discussing the possible mechanism for formation of this adhesive envelope, Swank and Cullen make other comments including this:

“A high fat diet has long been thought to increase the coagulability of the blood.  Moolton and colleagues have shown that a diet rich in animal fat causes a distinct rise in the adhesiveness of the platelets and in some cases in the count as well.  He has isolated a lipid substance, present in all fatty tissue, which when injected increases the platelet cound and adhesiveness and the coagulability of the blood.  The efficacy of a high fat diet in relieving bleeding disorders has been reported, and a diet poor in fat has been utilized to combat the thrombotic tendency in surgical patients and in patients following coronary thrombosis.  Of interest also is the reported decrease in vascular thrombosis in Norway during the recent war when the fat intake was reduced by about 50 per cent.”

You might object that this study involved hamsters, not humans or an animal adapted to meat-eating.  Swank actually performed a similar study using humans and dogs, with a similar result (5, abstract), about which the authors comment:

“In an attempt to determine the mechanism by which the fat intake influences multiple sclerosis, studies have been made of the effects of large fat meals on the blood of dogs and humans.  Six to nine hours after large fat meals the red blood cells observed in vitro in darkfield illumination have a tendency to aggregate, become adhesive to one another and be distorted. These changes in the suspension stability of the blood occur about an hour after the peak of the alimentary lipemia and finally disappear 9 to 12 hours after the fat meal when the lipemia clears.”

This would suggest that someone eating one high fat meal daily would have this stagnation of blood circulation for half of that day, and two to three high fat meals could result in virtually round-the clock sluggish circulation.  As Swank and Cullen note, this could have adverse effects on the nervous system because of its dependence on nutrients and oxygen.  

In Nutrition and Evolution, Crawford and Marsh make a similar point, noting that the nervous and vascular systems coevolved, such that the more developed the nervous system in any species, the more developed the nervous system.  For example, the human vascular system must serve the nervous system innervating the five digits of each hand, whereas in the hooved animals, both vascular and nervous systems are less complex in the extremities.  Anything that adversely affects the vascular system will perforce adversely affect the nervous system.  The Swank research suggests that dietary impairment of circulation causing neural ischemia or malnourishment may cause neural damage leading to M.S. and other neural diseases.

In 1976, O’Brien et al reported in the Lancet (6, abstract):

“Large amounts of saturated fats (S.F.) or unsaturated fats (U.S.F.) were given to healthy volunteers at a single meal. The heparin thrombin clotting-time, which may measure platelet factor 4 released from platelets into the plasma, was shortened after S.F. and prolonged after U.S.F. The antithrombin clotting activity decreased after S.F. and increased after U.S.F. The platelet-count decreased and the platelet volume increased after both S.F. and U.S.F.”

Hence, in this study, blood was more prone to clot with high intake of saturated fats, and less prone to clot with unsaturated fats.  Other studies (9, full text) indicate that the effect of unsaturated fats depends on dose and background diet, with low doses (low fat diets) reducing coagulability, and high doses increasing coagulability if consumed against a background diet high in saturated fats.

Silveria et al fed 33 heart disease (myocardial infarction) patients and 10 controls a fat load consisting of soybean oil in a dose of 50 g/m2 body surface area.(7, full text)  This oil contained about 14% saturated fats, 23% monounsaturated fats, and 62% polyunsaturated fats.  The subjects all had increases in serum triglycerides from the dietary fat load.  The fat load increased coagulant activity, and Silveria et al concluded:

“Alimentary lipemia is a procoagulant state that is likely to promote formation of occlusive thrombi on fissured atherosclerotic plaques that evolve through other mechanisms. A hypercoagulable state may also predispose to increased fibrin deposition on injured intimal surfaces, fibrin incorporation, and subsequent evolution and growth of atherosclerotic plaques. Since most of our lives are spent in the postprandial state, disturbances of lipoprotein metabolism leading to postprandial triglyceridemia may thus have both atherogenic and thrombotic consequences.”
Elmas et al (8, abstract) investigated “Activation of coagulation during alimentary lipemia under real-life conditions.”  They fed 33 healthy physicians and 27 heart disease patients a large meal containing liversausage, bacon, lard, goose, and chocolate as main fat sources; rye bread, potatoes, and sugar were the main carbohydrate sources.  The whole meal provided 57 percent of calories from fat, 28 percent from carbohydrate, and 13 percent from protein. They found a roughly threefold increase in fibrinopeptide A levels in both healthy subjects and patients.  Fibrinopeptide is released as a part of the blood clotting process.

Elmas et al concluded:

“Fat-rich meals may cause procoagulant episodes, which may promote vascular complications such as myocardial infarction, transient ischemia attacks in susceptible persons.”

Some may respond that this meal was high in carbohydrate, wondering if that rather than the fat caused the hypercoagulability.  This is not likely because studies have clearly shown that low fat high carbohydrate diets reduce coagulability of the blood in humans. (9, full text) 

Blood circulation to all tissues keeps those tissues alive.  Anything that impairs circulation impairs delivery of oxygen and nutrients to tissues, and removal of wastes from those tissues.  I'll let you imagine what happens to cells that experience nearly continuous deprivation of nutrients combined with build up of waste products due to impaired circulation.  


P. Winter said...

Hi Don,
I wonder if you have read this :-

Paul Winter

Theo said...


Are there any long term studies showing this? I know that in a lot of short term feeding studies a drastic effect can be observed that would not appear in a longer study because the participants would have had time to adapt to their new diet. For example, short term high dosage fish oil supplementation shows positive effects, but those effects tend to level off after the need for omega 3 becomes filled.

Bolt Bud Robin said...

So what's the take away message?

Theo said...


I think the takeaway message here is think for yourself, don't simply accept dogma, and be open-minded to new ideas.

Don said...


Some of the studies have lasted more that 4 weeks. With these studies already published, no ethics committee would approve a longer term study of this in humans, because the short-term studies predict occlusive diseases that could cause sudden death (heart attack, stroke) in people on high fat diets.

The long term study is actually ongoing in the population that has high rates of degenerative cardiovascular and neurological diseases, e.g. the U.S. These studies have been done to try to understand why people in westernized nations have high rates of myocardial infarction, occlusive stroke, Multiple sclerosis, Alzheimer's, etc., in which blood doesn't circulate well and tissues appear to be dying off (degenerating) prematurely. Oxygen and nutrient deprivation tends to do that to animal cells.

BTW, these studies suggest that high fat diets might cause heart disease etc not because they raise "cholesterol" but because they cause blood stagnation; which is why conventional medicine prescribes aspirin to prevent heart and brain attacks. That's nice...don't correct the blood quality, just put another poison (aspirin) in it to make it thin out.

So, all those people on aspirin...those are the long term subjects with the sticky blood, and these studies show that a high fat diet causes blood stagnation.


Have you seen this:

or this:

In vitro live blood analysis is, as far as I can tell, useless for the types of diagnosis and detection of pathology claimed by the WAP study. The Swank study did in vivo cinematography of blood flow. When you take blood out of the body and put it on slides, any number of mistakes can contaminate the results.

Just one look at Mary Enig or Sally Fallon will tell you the results of following their recommendations (assuming that they follow their own recommendations). See them in the FATHEAD movie. You don't need to look at blood to see long term blood stagnation. Just look for dark complexion, visible blue venules, spider veins, bluish tint to skin, distended veins on underside of tongue, dry skin especially at scalp and extremities....all show sluggish blood flow, accumulation of blood in veins, poor nourishment of the surface tissues.

a said...

Did you notice these effects (Enig and Fallon) as well?

Cliff said...

Do they have studies testing for blood coagulation with a high carbohydrate/semi low fat diet? something like 65%c/25%f/10%p

Eric said...

OK Don, we need some of your newer guidelines here... Stop teasing me :)

The Tiny Homestead said...

When I stopped using veg oils (replaced with coconut, lard and butter) and reduced my carbs I noticed that I get cold hands and feet LESS often than before. I took this to mean that I had an improvement in my circulation. I also lost the undereye circles, my complexion is improved. My skin feels more balanced in that it doesn't feel like it needs moisturizer or soap and I finally stopped breaking out (but will again if I have any veg oil). As they say, if this is wrong, I don't want to be right.

Theo said...


If saturated fat has such an incredible ability to promote heart disease through the mechanism that you suggested, then why are the epidemiological studies so inconclusive?

And what is your explanation for the French Paradox?

dianaedd said...

Actually, I am a retired physician who is very interested in the subject of proper diet. I think you brought up some interesting observations about the effects of fat on coagulation. However, I question the following statement, particularly in regard to MS: "The Swank research suggests that dietary impairment of circulation causing neural ischemia or malnourishment may cause neural damage leading to M.S. and other neural diseases." MS is a disease of the central nervous system, that is, the brain and spinal cord. The peripheral nerves are not damaged. Why would such a mechanism of fat affecting coagulation only cause central, and not peripheral injury?

Anonymous said...

> So what's the take away message?

That fat is evil, of course.

Don woke up one day a couple months ago and suddenly realized that fat is bad. All his years of prior posts saying the opposite suddenly became inaccurate, despite him being 100% convinced they were correct when he posted them.

This time he has it right, though. Now we can really trust him. Seriously.


Jay said...

Oh come on.
People tend to have an inherited tendency to get spider veins and varicose veins because they have weaker valves in the veins or possibly a weaker form of collagen and thus weaker vessel walls. They are more common in females because increases in hormones during pregnancy and menopausal fluctuations also contribute. Spider veins are also caused by sun damage, rosacea and injury.
I've had spider veins (legs) all my adult life - regardless of my diet whether as it used to be for 15 or so years and when I was a lot younger - 'low-fat, healthy whole-grain' or as it is now (higher fat/paleo) - and I definitely got a new batch after each pregnancy. I have spider veins on my face due to sun damage (lived in Australia) and because I used to have rosacea (which actually went away with higher fat/paleo/no gluten).
I think in my case that it is down to wonky collagen - I have soft bendy nails - not something I can do anything about.
Mary Enig is 80 (she might have been thus 77 or so when 'Fat Head' was made) and to me she looks as if she might be/have been hyperthyroid, so her appearance is hardly relevant.
If the blood was that stagnant and it was that bad, people would be getting peripheral neuropathy and bits would be turning black and dropping off - like they do in diabetes.

Miki said...

"Nothing in biology make sense except in the light of evolution" - Primal Wisdom from Prof. Theodosius Dobzhansky
(look him up at wikipedia). Archeological sites all over the world are full of animal bones and almost nothing but animal bones. only few have some fish or seafood remains. I doubt that our ancestors bothered to separate the saturated fat prior to consuming the fat that they had so cherished.

sandra said...

Hi Don,

I changed from VLC (which I started eating by accident really) to LC after reading in one of your comments awhile ago that you get leg cramps when you go below 50 g of carbs...

I have been plagued with leg cramps since my first pregnancy. I had them under control, but they returned with a vengeance when I was VLC- adding some carbs has not resolved them... could it be not a lack of carbs, but the presence of too much fat causing this problem? I may have other signs of poor circulation as well...

On the other hand, I am taking tomoxifen and my Dr. said that this could be causing the cramps. I certainly was not eating so much saturated fat when I first starting getting leg cramps.

In any case, I've decided to try high carb/lower fat again as an experiment in case the fat is the cause...

Problem is so far I am wanting to eat every 2 hours... but perhaps that is not a problem??

I still worry about blood sugar/insulin - I get that spikes are OK...but when I switched to low carb my FASTING BG went down about 10 points. Is that irrelevant if starting point was not in the diabetic range?

I got breast cancer at 38 w/no family history (at least none that was considered relevant) and tested BRCA neg. I was blaming carbs after reading Taubes- he details a mechanism on this link but unfortunately I do not have my copy of GCBC as I lent it out and cannot remember of the top of my head. Perhaps you are aware of his theory though...

Also, can you speak to the fact that humans can better absorb animal sources of fat soluble vitamins A and K (or is that false?)? I have seen this used as evidence that humans did evolve eating plenty of animal fat and that we should eat animal fat to get these nutrients.

Helen said...

Jay - Thank you. I've had visible blue veins in my chest and even prominent veins in my hands since I was a kid. I've had spider veins in my legs since I was 26. I'm guessing this is genetic, but since I'm adopted, I don't know.

Now, at 45, some of my veins are getting ropier. They got more prominent with my twin pregnancy, and now that I've lost a lot of weight (now on a lower-fat diet, actually), they stick out even more. Feeling self-conscious, I actually Googled "women ropey veins" last week and got back pictures of Madonna and Angelina Jolie. Common denominator is their highly muscled arms.

I'm not saying my blood's not stagnating, but I don't have any evidence that it is. My blood pressure and heart rate are on the low end of normal.

Dark circles under the eyes are often an allergy thing. My children, husband, and I all have them, whatever we eat.

Stan (Heretic) said...


Most of what you wrote is probably not true.

You have to be careful about the early studies on high fat feeding done on rodents. Those often meant a very large percentage of hydrogenated fat as well as very high percentage of sugar (like 40:40 etc). Such fats are pro-inflammatory by themselves, especially with added sugars (especially fructose!)

Even more recent studies (such as linked here)that do not feed the animals Crisco, tend to also call the high sugar feeds misleadingly - the "High Fat" even if the fat contents were much lower than the carbs. A half-and-half (carbs plus fat) diet is metabolically very different from either the low fat or the true high fat diet!

You can find more about that in Kwasniewski's books. This is as far as I know the only available published data on this subject to date (not peer-reviewed!).

Re: Blood coagulation.

Blood coagulation and clotting become lower the moment you go on a high animal fat low carb diet!

For example my own case, in 1999 I begun showing bruising on my hands after pressing against something even lightly. That fortunately lasted only for a few weeks. This is commonly reported by HF dieters and sometimes is warned against by diet promoters (Kwasniewski for example - you should read his book "Homo Optimus" and "Optimal Diet" - this would pre-empt a lot of misunderstanding!).

The low blood clotting due to a high fat low carb diet, may persist (in a less drastic form) for a few month from the start of a HF diet thus some sources also warn people to reduce or to avoid all blood-thinning-meds (and blood-thinning supplements) on such diets, and to abstain for a while from certain high risk sports such as boxing or bungee-jumping that may carry a hemorrhaging stroke risk.

Stan (Heretic)

Stan (Heretic) said...

An interesting aspect of the studies you quoted, animal or human - is that none used a pure high animal fat diet! They all consisted basically of adding fat, (often artificial) to an already high carb food or feed. The lowest carb diet you got in one paper was 28% carbs. Without knowing their total calories, I would guess that it was ~800kcal or 200g, which is 4 times the recommended carb limit under a true high fat diet or even under Atkins' diet!

The reason a combined medium carb plus medium fat diet is so different is because it maximizes the insulin requirement and thus one's own insulin secretion! Insulin itself increases blood clotting risk! For example, an impaired capilliary circulation is the common symptom in diabetics, using intravenous insulin.

Insulin requirement (and secretion) is the lowest on the true high fat very low carb (less than 50g/day or 0.8g/1kg body/day) - it is about 6-10iu/day. It is sufficiently low that even type 1 diabetics may sometimes abstain from insulin injections if their residual secretion is sufficient.

Insulin requirement is also relatively low on a very low fat diet - amounting to approx 1 iu per every 10g of carbohydrate.

Re: "Fat-rich meals may cause procoagulant episodes, which may promote vascular complications such as myocardial infarction, transient ischemia attacks in susceptible persons."

Sure. I once witnesses a man in his 50-ties dropping off a chair in a restaurant during our company's Christmas party. Heart attack. His plate had a copious amount of potatoes and beefsteaks piled up. Must have been the fatty sauce...

If your theories and those of your quoted papers were true, would you then not expect me to have died on multiple attacks from clogging my arteries eating 200g blobs of fat a day (continuously for 12 years) rather than having this conversation? I hope you don't mind talking to a ghost. 8-:)

Stan (Heretic)

Alan said...

>> Others have claimed that humans can tolerate no more than 35% of calories as protein for extended periods of time due to limits on the liver's ability to synthesize urea from waste nitrogen, and I have taken this as a demonstrated fact.

Well then, you're not very thorough in your research. Humans are NOT dependent upon the urea cycle. Reference: Figure 73-5, on page 1626 of the 8th edition of Feldman: SLEISENGER & FORDTRAN'S GASTROINTESTINAL AND LIVER DISEASE, 2006 Elsevier

You were shown an epidemic of obesity. You want to cry about an epidemic of hyperammonemia. Where ==is== that epidemic?!?

Dr. Curmudgeon Gee said...

Hi, Tiny Homestead:

add (n=2) experience of mine (re. cold feet & hands less cold, skin less dry after having more SFA)


Peter said...

Hi Don,

I'm curious how you would fit your world view in with these two studies, especially the first as it used saturated fat (the second used peanut oil):

"In patients with coronary disease, exercise testing after a high carbohydrate meal results in a lower ischemic threshold and greater ischemia magnitude. Conversely, compared to fasting, a high fat meal does not induce additional detrimental effects"

"In conclusion, patients with chronic stable angina have impaired effort tolerance and a lower angina threshold after high calorie containing liquid meals. Meals rich in carbohydrate have greater effects than meals where the majority of calories are derived from fat"

BTW the "adverse" effect of fat in the latter study was ns, while carbohydrate gave p<0.01...

Two studies, 15 years apart, replication... Hard for me to dismiss.

Are the studies fakes? Twice? How would you accommodate them, assuming they are true?


Don said...


I just remembered to add that the reason that these researchers decided to look at fat-content of the diet as the variable is that the diseases in question occur rarely or not at all in populations eating low fat diets, and very frequently in populations eating high fat diets.

Some of the studies showed that putting people on a low fat diet actually made their blood clotting activity less than baseline (on their habitual diet).

Walter said...

Hi, Tiny Homestead & Dr. Curmudgeon Gee.

I always used to be the coldest person in the room. I was the first to want the heat put on and the last to want the air conditioning put on.

Now after going zero carb (although I do have some VLC and LC days) people ask me in the winter what are you doing outside without a coat on?


Stan (Heretic) said...

I also used to be cold-intolerant before, until adopting a high fat LC diet. Recently, lunch-break swimming in a river in October (age 55, living in Ontario, Canada).


Stan (Heretic) said...

To Peter's list of counter-papers I should add this:


Fatty splurge may reduce heart risk

( I don't have the original paper only the report, probably not yet published. If you find it please post it here )


Chase Saunders said...