Sunday, May 24, 2009

High cholesterol in anorexia nervosa

One of the (many) paradoxes of anorexia is that the excessive weight loss that accompanies the disorder often results in high cholesterol levels. This seems to go against what many doctors and researchers say about cholesterol: decreasing food and fat intake as well as increasing exercise should decrease cholesterol levels, not raise them.

It turns out that this high cholesterol (formally known as hypercholesterolemia) also happens to starving people, and is a well-known side effect of malnutrition. The question that remains, then, is why? Why this paradoxical effect?

Let me back up a bit and explain what cholesterol is and what it does. Cholesterol "is a lipidic, waxy alcohol found in the cell membranes and transported in the blood plasma of all animals. It is an essential component of mammalian cell membranes where it is required to establish proper membrane permeability and fluidity." Cholesterol is hydrophobic, meaning it doesn't dissolve in water or blood, so it is transported in the body by lipoproteins. Your total cholesterol count is a combination of triglycerides, low-density lipoproteins (LDLs, aka "bad" cholesterol) and high-density lipoproteins (HDLs, aka "good" cholesterol). Both LDLs and HDLs transport fats along with cholesterol. The lipid hypothesis holds that there is a causal link between high intake of saturated fats, hypercholesterolemia, and heart disease, promulgated by none other than Ancel Keys, he of the Minnesota Starvation Study.

So. What does this all mean?

Besides just having unusually high levels of total cholesterol, patients with anorexia were found to have unusually high levels of an enzyme called cholesterylester transfer protein (CETP), which swaps cholesterol and fat molecules between the different lipoproteins. The researchers speculated that low levels of thyroid hormones and low breakdown of existing cholesterol contributed to high cholesterol levels, and that "CETP activity increases cholesterol turnover as an adaptation to its low intake." The highest levels were seen amongst AN patients who also binged and purged. In severely malnourished AN patients, however, cholesterol levels and CETP activities drop dramatically.

Other studies have suggested that starvation results in the increased synthesis of lipoproteins. It could also be that these lipoproteins are transporting fats in the body, which the body is relying on as fuel due to insufficient food intake. If the body is going to rely on fat as fuel, it needs some way to mobilize those fat molecules and get them to a location where they can be broken down effectively. This could perhaps explain the abnormal rise in cholesterol levels. As body fat is essentially depleted in the severely malnourished AN patients, the body may rely more and more on breaking down organ and muscle tissue, thus decreasing the need for abundant lipoproteins.

Regardless of the reasons for hypercholesterolemia during anorexia, it is NOT an indication that the sufferer needs a low-fat or low-cholesterol diet. With sufficient foot (and fat!) intake, cholesterol levels typically right themselves rather rapidly.

(cross-posted at ED Bites)

10 comments:

IrishUp said...

Great post, Carrie!
"With sufficient foot (and fat!) intake, cholesterol levels typically right themselves rather rapidly."

I think this is a typo, unless you are suggesting that ED sufferers should eat a diet high in Feeties ;->

Carrie Arnold said...

My "Feeties" intake tends to be comprised largely of the kind where I end up sticking my own foot in my mouth.

PTC said...

I was surprised the first time I heard this. I went for a physical last year and my cholesterol was 218! Now, I eat "healthy" (oh wait, apparently I'm anorexic so maybe that's not so "healthy"), but I am not "severely" underweight. The doctor, who doesn't know about my eating "issues" said to me "Your cholesterol is pretty high and it went up, and you've lost weight. Did you fast? Maybe it's just wrong, we'll test it again in 6 months." Well, never did test it again but she didn't seem too concerned when I questioned her about it again. Oh well, it still doesn't make sense that anorexic people would have high cholesterol, but I'm not a doctor.

buy generic viagra said...

I eat very little, you need to check my cholesterol level in my body?.
Personally I always thought it was not necessary, but I do not suffer from such problems

Sara Rides

Anonymous said...

hi

high cholesterol said...

You should prevent high cholesterol when you are young

kurtis said...

I agree. High Cholesterol may cause heart attack or heart diseases. It's important that you follow a strict diet.

Diet for Lowering Cholesterol

Elliott Broidy said...

That's scary.

Samantha Gorton said...

I had this problem, it doesn't make much sense, but it's true. I'm no longer diagnosed with an eating disorder, but I still have the after affects on my body. I'm 21 and my cholesterol is 250. I have to eat much more carefully now. I have to add more fat into my diet so that my body can perform correctly, I was eating too many vegetables. The body needs fat in order to perform correctly and the body has to be able to break that fat down.

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