Is Hdl-Cholesterol Really Protective Against Heart Disease?

For years, physicians and even cardiologists have called HDL-cholesterol the “good” cholesterol. In contrast to LDL-cholesterol that has a reputation for clogging arteries, experts believed HDL helped reverse the damage by removing fat deposits from the arterial wall and reducing the build-up of plaque that contributes to heart disease.

One theory as to why heart disease occurs has to do with the interplay between the two forms of “cholesterol,” which are actually different types of lipoprotein carrier molecules that transport cholesterol around the body. LDL carries cholesterol throughout the body and delivers it to cells that need it, but it also has the tendency to build up in the inner walls of arteries and turn to plaque. In contrast, HDL, produced by the liver, sucks up cholesterol and plaque from the walls of arteries and transports it back to the liver where the liver can safely recycle it.

Although it makes sense from a biological standpoint that having a higher HDL-cholesterol level would lower your risk for heart disease, based on how it works, artificially raising HDL doesn’t seem to reduce the risk of heart disease. For example, taking high doses of the B-vitamin niacin raises HDL-cholesterol, but in human studies, didn’t reduce the risk of heart disease more than a statin medication alone.

Interestingly, according to a recent study, at least in women, having a high HDL-cholesterol may actually be harmful. In a study carried out at the University of Pittsburgh, researchers followed more than 200 healthy, middle-aged women for almost a decade. Over the course of the study, they monitored the amount of plaque that built up in the women’s arteries. The results were surprising, to say the least. Long thought to be protective, as the women progressed through menopause, those with higher levels of HDL-cholesterol actually had a greater accumulation of plaque within the walls of their arteries.

As the lead researcher in this study, Samar El Khoudary, an assistant professor of epidemiology, points out:

“It’s not clear why good cholesterol may turn bad. There are many biological changes that happen to women during the menopausal transition”

One theory is HDL-cholesterol may somehow be altered in women after menopause to the point that it functions in a completely different manner, one that actually promotes the development of heart disease rather than prevents it. With so many things happening around the time of menopause, reduction in levels of hormones like estrogen and progesterone and a decline in insulin sensitivity, it’s possible that one of these factors changes the way HDL functions.

Is it time to rethink the role HDL plays in heart disease prevention, especially in women after menopause? Experts are somewhat divided on whether they think artificially raising your HDL through lifestyle or medications has a positive impact on heart disease risk, and more research is needed to say that having a high HDL increases the risk for heart disease after menopause. One thing IS clear though. Heart disease risk goes up after menopause.

HDL-Cholesterol, Heart Disease, and Menopause

Why does the risk for heart disease go up once you transition into menopause? Women who don’t smoke have a relatively low risk of heart disease prior to menopause, but the risk jumps considerably after those first hot flashes start. One reason heart disease is more common after menopause is due to the drop in the hormone estrogen that happens around the time your ovaries stop working. The average age at which menopause starts is around 52, and undergoing menopause at an early age or those who have undergone surgical menopause, before age 46, is linked with a greater risk for heart disease, around twice the risk.

Estrogen helps to open up the walls of blood vessels so blood flows more smoothly. This reduces damage to the inner wall of arteries and lowers blood pressure. High blood pressure also becomes more common after menopause. Many researchers believe there are other yet unidentified reasons heart disease rates climb precipitously after menopause. That’s why this recent study showing a link between HDL and heart disease after menopause is so intriguing.

Lowering Your Risk of Heart Disease after Menopause

Now that you know your risk for heart disease rises sharply after menopause and having a high HDL may not be protective, what can you do to lower your

Exercise! In a sense, exercise mimics some of the effects of estrogen in terms of how it affects your blood vessels. Like estrogen, exercise dilates and expands your arteries thereby protecting them from damaging and helping to keep your blood pressure down. It also improves insulin sensitivity. After menopause, women who don’t exercise tend to suffer from a triad of weight gain, increased visceral belly fat, the worst kind for your health, and insulin resistance. The combination of these factors creates a pro-inflammatory state that can injure the inner walls of blood vessels and make them more susceptible to forming a clot, a problem that can lead to a heart attack or stroke.

As you might expect other lifestyle factors count too, especially diet. Research clearly supports the benefits of a Mediterranean-style diet for preventing heart disease. When you adopt a Mediterranean diet, you can enjoy a luscious variety of whole foods, including fish, whole grains, nuts, olive oil, fruits, and vegetables. The Mediterranean diet de-emphasizes red meat and most processed and packaged foods as well as foods with added sugar. Both fish, rich in long-chain omega-3s, and nuts are linked with a lower risk for heart disease, so enjoy these foods in moderation.

Of course, other lifestyle factors matter too – like not smoking or abusing alcohol. A glass of red wine daily may actually lower your risk for heart disease but it’s best to enjoy alcohol only in moderation. Another way to reduce your risk for heart disease is to keep your weight at a healthy level. When your weight rises into the obese range, your risk for metabolic syndrome and high blood pressure increases. Eat healthy, exercise regularly, and you’ll be taking a big step towards reducing your risk for heart attack and stroke.

 

References:

Medscape Family Medicine. “Raising HDL in Clinical Practice: HDL Metabolism and Reverse Cholesterol Transport”

Health Day. “During Menopause, ‘Good’ Cholesterol May Lose Protective Effect on Heart”

Endocrinology Advisor. “Increased HDL Cholesterol in Menopause May Not Protect Against Heart Disease” October 9, 2015.

El Khoudary SR, Wang L, Brooks M, Thurston RC, Matthew A. Abstract S-18. Increases in High-Density Lipoprotein-Cholesterol Levels are Associated with Greater Intima-Media Thickness Progression over the Menopausal Transition. Presented at: North American Menopause Society (NAMS) 2015 Annual Meeting; Sept. 30-Oct. 3, 2015; Las Vegas, Nevada.

Medscape Family Medicine. “Early Menopause: Precursor to Coronary Heart Disease?” January 12, 2015.

Circulation. 2001; 103: 1821-1822 doi: 10.1161/01.CIR.103.13.1821

 

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Is the Response to Exercise Greater After Menopause?

 

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