Tag Archives: triglycerides

Low LDL cholesterol associated with worse cognitive performance

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Summary: cholesterol plays critical roles in cell membranes and steroid hormone production. This study associates low LDL cholesterol with worse cognitive performance. As expected, the effect is amplified by inflammation. Care should be taken to apply a balanced approach to cholesterol lowering therapies.

A truly fascinating study was just published in the journal Neurobiology of Aging investigating lipoproteins and loss of cognitive function. The authors state:

“The aim of this study was to examine the associations between high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, triglycerides, and cognition and focus on the modifying effect of inflammation.”

They collected biological and cognitive data on 1003 persons ≥ 65 years of age over 6 years of follow-up, measuring cognition with the Mini-Mental State Examination (general cognition), Auditory Verbal Learning Test (memory), and Coding Task (information processing speed). High HDL was associiated with better memory performance, but their data seem to suggest the importance of sufficient LDL cholesterol in brain neuronal membranes:

“We found an independent association between high HDL cholesterol and better memory performance. In addition, low LDL cholesterol was predictive of worse general cognitive performance and faster decline on information processing speed.”

Not at all surprisingly they found that inflammation compounds the adverse effects of low LDL:

“Furthermore, a significant modifying effect of inflammation (C-reactive protein, α-antichymotrypsin) was found. A negative additive effect of low LDL cholesterol and high inflammation was found on general cognition and memory performance.”

And since high triglycerides are commonly provoked by the high insulin levels due to insulin resistance which also have deleterious effects on the brain…

“Also, high triglycerides were associated with lower memory performance in those with high inflammation.”

The authors conclude by suggesting that HDL, LDL and inflammatory indicators can be used as predictors of poor cognitive function:

“Thus, a combination of these factors may be used as markers of prolonged lower cognitive functioning.”

This compels us to use caution and see the ‘big picture’ when designing strategies to manage lipids—care should be taken to not suppress LDL cholesterol to too low a level.

Cholesterol levels vary with the menstrual cycle

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A study recently published in The Journal of Clinical Endocrinology & Metabolism proves that we must take the menstrual cycle into consideration when testing cholesterol in cycling women.

“The objective of the study was to evaluate the association between endogenous [internally produced] estrogen and serum lipoproteins across the menstrual cycle.”

The authors found that total and LDL cholesterol were lower during the luteal phase (second half, when progesterone is higher) than the follicular phase:

“More women were classified above the desirable range (LDL ≥130 mg/dl or total cholesterol ≥200 mg/dl) when measured during the follicular phase [first half].”

HDL was higher when estradiol had peaked, corresponding also to lower LDL and triglycerides.

“Because lipoprotein cholesterol levels vary across the menstrual cycle, cyclic variations in lipoprotein levels may need to be considered in the design and interpretation of studies in reproductive-age women and in the clinical management of women’s cholesterol.“

Patients with prostate cancer present lower cholesterol and higher triglycerides

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The Aging MaleThis interesting paper published recently in the medical journal The Aging Male reports a study in which the investigators evaluated “lipoprotein profile and sex hormones in patients with prostate cancer (PCa) and benign prostatic hyperplasia (BPH) and their possible associations with some inflammatory markers linked to PCa.” Not surprisingly, estrogen and androgens were higher and adiponectin (see forthcoming posts) was lower. The authors conclude: “Our most novel findings are that the patients with PCa presented lower total Chol and HDL-chol and higher TG/HDL-chol than BPH and Controls.” Once again, cholesterol was lower and triglycerides higher in the prostate cancer group. What drives up triglycerides more than anything else? Insulin resistance. One more interesting finding: “No differences were found in androgens between BPH and PCa.” This suggests that androgens (including testosterone) add bulk but the other factors are more significant for conversion to malignancy.

Moderate-intensity exercise more effective than vigorous intensity for cardiovascular risk

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A surprising paper of great practical significance was just published in the journal Obesity that documents a significantly greater improvement in cardiovascular risk-related variables (triglycerides, insulin, metabolic syndrome score) with moderate-intensity exercise than with vigorous exercise. The authors offer this life-style pearl: “That all three of these strong, independent, cardiovascular risk factors were significantly affected by moderate-intensity exercise suggests that regular walking exercise might be as effective, if not more so, than more vigorous exercise in favorably modifying cardiovascular risk.” Further research will have to validate my expectation that the adrenocortical stress response plays a role here. Don’t forget the importance of interval training (see earlier posts), but at least get out for a walk.

Fat accumulation around organs linked to decreased heart function

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There are a few newsworthy findings reported in this study, recently published in the journal Obesity, that used MRI and MRS (proton MR spectroscopy) to measure the accumulation of fat around the heart and in the liver.

  1. Fat accumulation around organs is linked to decreased heart function
  2. Body mass index (BMI) is not a reliable predictor of fat accumulation
  3. Fat in the liver was associated with insulin resistance and triglycerides.

I have seen numerous individuals who do not appear overweight and whose BMI was normal, but bioelectric impedance analysis (an objective measurement of body fat percentage) revealed that they were ‘metabolically obese’—there was excess fat around their organs. Insulin resistance was a factor in each case.