Sunday, January 31, 2010

How A Low Carb Lifestyle Has Similar Effects As Aspirin

A question was asked as seen below about low carbs and aspirin;

Do you advise your patients to take a low dose aspirin each day if they are on a low carb diet?

My Response;

Before I start anyone on aspirin I will perform a carotid doppler to check the carotid arteries (the arteries that supply the brain with blood). If there is even mild thickening I will start them on 81 mg of aspirin a day. If there is no thickening and they are on low carb, I tell them not to take aspirin.

The reason I start aspirin on even mild thickening is that a study was performed about 4 years ago (in the Journal 'Stroke') which showed that even mild thickening of the carotids equated with thickening within the smaller diameter coronary arteries, with a subsequent increased risk of heart attacks seen.

Now here's where it gets very interesting from a biochemical perspective. Aspirin works by irreversibly inhibiting an enzyme known as cyclooxygenase. This enzyme creates prostaglandin and thromboxane, two chemicals which act to make our platelets more stickier, hence facilitating the formation of clots. Stop the production of those chemicals, stop the creation of clots.

It's that simple.

Guess what else inhibits that cyclooxygenase thing. That's right, a low carb diet. This is where it gets a little trickier but here's how it works;

When we eat less carbs, we release less insulin. Insulin exerts it's effects on cells by working through something known as the second messanger sytem. One of these messangers found inside the cell contains a molecule known as arichidonic acid. What i didn't mention above is that cyclooxygenase works on arichidonic acid to create thromboxane and prostaglandin. When we eat less carbs we have less arichidonic acid around for the creation of those 2 molecules that make clots. Thus, low carb diets equate with thinner blood so to speak and this is why people on a low carb diet can get away without taking aspirin.

Hope I didn't confuse you.

I guess the short answer is if we are on a low carb diet, we will biochemically create less clots. I should've just said that, but I like the biochemical explanation as well.

dr jim


  1. If low carb works like aspirin, some people might assume that it will also cause the same side effects as aspirin - ie bleeding in the gut... aspirin prevents arachidonic acid from being formed into prostaglandin... however prostaglandins are also involved in the production of the protective mucus lining of the stomach.. could a low carb diet affect this at all do you think? (I've never known any low carber have such a problem.)

  2. Ahhh, you are correct that some will misconstrue that to mean a low carb diet could have the same side effects as aspirin.

    Clinically, I have never seen any side effect from a low carb diet similar to aspirin. But the similarity really was only in that low carbs will lower the intracellular concentration of arichidonic acid. This is in stark contrast to the inhibition of cyclooxygenase.

    In the low carb scenerio, there is less arichidonic acid around for cyclooxygenase to work on, thus, similar outcome, different pathway. There is no irreversible inhibition of the cyclooxygenase enzyme.

    Thanks for a great question, I had to think about that one. LOL.

  3. Hello Dr. Carlson,

    could you kindly point to some Literature where the insulin / arachidonic acid connection is revealed or explained?

    Thank you very much!