For a very long time, doctors have mistakenly told patients that higher HDL cholesterol levels are a marker for better health, and that the ratio of HDL to LDL was an important metric to monitor. Many doctors have furthermore insisted that lower HDL levels are markers of poor health. None of this is true. Lower LDL AND HDL cholesterol levels should be the goal, and higher HDL levels are not only not protective, but are a risk factor for coronary artery disease and other health issues.
Some Basics
A primary role of HDL cholesterol is reverse transport, the mechanism by which the body takes excess cholesterol from the peripheral tissues and bloodstream and delivers it to the liver for removal by the gall bladder. Generally, HDL levels can be expected to rise in response to higher plasma LDL levels. With few exceptions, higher plasma LDL levels result from consuming a diet high in saturated fat and cholesterol, both of which are concentrated in animal foods. The more LDL and saturated fat consumed, the more cholesterol produced by the liver. Another way of looking at this is that there would be no need for higher HDL levels if a person were not consuming so much food containing LDL cholesterol and saturated fat.
Quality is Better Than Quantity
The measurement of plasma cholesterol that is most related to the prevention of atherosclerosis and coronary events is HDL efflux capacity – the ability of HDL to remove bad, or LDL cholesterol from macrophages.[1] Macrophages are immune cells that become pro-inflammatory foam cells when they engulf LDL cholesterol. This explains why some people with high plasma HDL cholesterol develop coronary artery disease, while others with lower plasma HDL do not.
To illustrate this point, HDL efflux capacity was measured in almost 1000 subjects;
442 of them had been diagnosed with coronary artery disease, 351 had not been diagnosed coronary artery disease, and 203 healthy volunteers.
The researchers reported that:
· Subjects with high HDL efflux capacity had lower levels of atherosclerosis and obstructive coronary artery disease, while those with low HDL efflux capacity had higher levels of atherosclerosis and obstructive coronary artery disease.· Statins were not effective for raising HDL efflux capacity.· There was no relationship between blood levels of HDL and efflux capacity.· Habits influenced efflux capacity: smokers had low HDL efflux capacity even if they had higher plasma HDL levels, for example.· There was a significant relationship between HDL efflux capacity and carotid artery thickening (a marker for atherosclerosis), and this relationship persisted regardless of plasma levels. In other words, higher plasma cholesterol was not protective, while lower plasma levels with higher efflux capacity was.· The proportion of patients with coronary artery disease decreased consistently with increases in HDL efflux capacity.[2]
The bottom line:
Measuring plasma levels of HDL to determine health status is futile. Additionally, attempts to increase HDL levels using drugs and supplements has been shown to increase the risk of cardiovascular events and death.[3] [4]
Furthermore, higher HDL levels are indicators for risk of macular degeneration,[5] fractures,[6] and dementia. Data from a longitudinal study that included 18,668 healthy participants showed that those with HDL levels of 80 mg/dLor higher had a 27% higher risk of dementia than subjects with HDL levels of lower of 60 mg/dL.[7] The diet that protects the cardiovascular system also protects the brain.
Conclusions:
A plant-centered diet that is low in saturated fat and cholesterol is the best diet for humans. The incidence of coronary artery disease is very low in cultures that consistently consume a plant-based diet. These include the Tarahumara Indians[8], The Papua New Guinea highlanders[9], and rural Chinese.[10] In some rural areas of China, hundreds of thousands of people go for years without a single myocardial infarction.
[1] Khera AV, Cuchel M, de la Llera-Moya M et al. “Cholesterol efflux capacity, high-density lipoprotein function, and atherosclerosis.” NEJM 2011 Jan;364(2):127-135
[2] IBID
[3] Keene D, Price C, Shun-Shin MJ, Francis DP. "Effect on cardiovascular risk of high-density lipoprotein targeted treatments niacin, fibrates, and CETP inhibitors: meta-analysis of randomized, controlled trials including 117 411 patients." BMJ 2014; 349:g4379
[4] Michael O'Riordon "No Clinical Benefit to Raising HDL With Existing Therapies, Meta-Analysis Shows" July 23, 2014 www.heartwire.com
[5] Colijm JAM, den Hollander AI, Demirkan A et al. “Increased High-Density Lipoprotein Levels Associated with Age-Related Macular Degeneration: Evidence from the EYE_RISK and European Eye Epidemiology Consortia.” Ophthalmology 2019 Mar;126(3):393-406
[6] Hussain SM, Ebeling PR, Barker A, Neilin LJ, Tonkin AM, McNeil JJ. “Association of Plasma High-Density Lipoprotein Cholesterol Level With Risk of Fractures in Healthy Older Adults.” JAMA Cardiol 2023 Mar;8(3):268-272
[7] Hussain SM, Robb C, Tonkin AM et al. “Association of plasma high-density lipoprotein cholesterol level with risk of incident dementia: a cohort study of healthy older adults.” Lancet Regional Health 2023 Nov: https://doi.org/10.1016/j.lanwpc.2023.100963
[8] Connor WE, Cerqueira MT, Connor RW, et al. “The plasma lipids, lipoproteins, and diet of the Tarahumara Indians of Mexico.” Am J Clin Nutr 1978 Jul;31(7):1131-42
[9] Sinnett PF, Whyte HM. “Epidemiological studies in a total highland population, Tukisenta, New Guinea. Cardiovascular disease and relevant clinical, electrocardiographic, radiological and biochemical findings.” J Chron Diseases 1973 May; 26(5):265-290
[10] Campbell TC, Parpia B, Chen J. “Diet, lifestyle, and the etiology of coronary artery disease: The Cornell China Study.” Am J Card 1998 Nov;82(10B):18T-21T.
Dr. Pam Popper, President, Wellness Forum Health
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