Good Cholesterol's Heart Benefits Challenged

CBC  |  Posted:

Having naturally high levels of "good" cholesterol doesn't lower the risk of heart attacks as believed.

LDL cholesterol is referred to as "bad" cholesterol because when there's too much, it promotes the build-up of plaque in artery walls.

HDL cholesterol is known as "good" cholesterol because higher concentrations have been associated with lower risk of heart attacks in observational studies.

The hoped for benefits of increasing high-density lipoprotein or HDL cholesterol for lowering heart attack risk haven't panned out in randomized trials of experimental drugs.

According to conventional wisdom, those who inherit genetic variants for higher HDL levels should have lower cardiovascular risk. When researchers tested 116,000 people, they found 2.6 per cent of them were genetically predisposed to have higher concentrations of HDL.

These people did have higher levels of HDL, but there was no evidence that they actually enjoyed a lower susceptibility to heart attack, also called myocardial infarction.

"Some genetic mechanisms that raise plasma HDL cholesterol do not seem to lower risk of myocardial infarction," Dr. Sekar Kathiresan of Harvard Medical School in Boston and his co-authors concluded in Thursday's issue of the medical journal The Lancet.

"If an intervention such as a drug raises HDL cholesterol, we cannot automatically assume that risk of myocardial infarction will be reduced."

Heart-healthy lifestyle
The findings refute the thinking that low HDL plays a causal role in heart disease, Steve Humphries and his colleagues of University College London in the UK said in a journal commentary.

The observation from the genetic analysis "calls into question whether raising of HDL cholesterol therapeutically would translate into the expected clinical benefit," the commentators said.

Eating foods such as walnuts, almonds and salmon seems to help cholesterol levels.

The vitamin niacin was also proposed as a way of raising HDL but a U.S.-government funded trial into it was stopped early last year when those taking it showed no reduction in heart attacks and strokes.

The British Heart Foundation said the relationship between HDL and heart attack risk is complex and more research is needed to understand how it interacts with other risk factors.

"What we do know is that having too much harmful cholesterol in your blood can increase your risk of getting cardiovascular disease," said Shannon Amoils, the group's research advisor.

"A healthy lifestyle is vital to improve your overall cholesterol levels and protect your heart. Cutting down on fatty and sugary foods, as well as reducing the amount of alcohol you drink, will all have a beneficial effect on your heart health."

Many of the authors have received grants or are employed by pharmaceutical companies selling medications to lower LDL cholesterol levels.

Related on HuffPost:

SEE: 7 Superfoods To Improve Cholesterol
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  • Almonds

    Substances in almond skins help prevent LDL "bad" cholesterol from being oxidized, a process that can otherwise damage the lining of blood vessels and increase cardiovascular risk. Sprinkle almonds on cereals and salads; nibble on a handful for an afternoon snack. <strong>More from <em>Eating Well</em>:</strong> <a href="http://www.eatingwell.com/nutrition_health/heart_healthy_diet_center/the_worst_and_best_things_to_eat_for_your_heart ?utm_source=HuffingtonPost_Brierley_SuperfoodsToLowerCholesterol_021612" target="_blank">The Best and Worst Foods For Your Heart</a> <a href="http://www.eatingwell.com/nutrition_health/nutrition_news_information/what_to_eat_for_a_healthy_heart_mind?utm_source=HuffingtonPost_Brierley_SuperfoodsToLowerCholesterol_021612" target="_blank">What to Eat for a Healthy Heart and a Healthy Mind</a> <a href="http://www.eatingwell.com/recipes_menus/recipe_slideshows/heart_healthy_dinner_recipes_to_help_lower_cholesterol?utm_source=HuffingtonPost_Brierley_SuperfoodsToLowerCholesterol_021612" target="_blank">Heart-Healthy Dinner Recipes</a> <em>Flickr photo by <a href="http://www.flickr.com/photos/greencolander/1791143844/" target="_hplink">Michelle Tribe</a></em>

  • Avocados

    The monounsaturated fats in avocados have been found to lower "bad" LDLs and raise "good" HDLs, especially in people with mildly elevated cholesterol. Slice avocados into sandwiches and salads or mash with garlic, lemon juice and salsa for a terrific guacamole. <em>Flickr photo by <a href="http://www.flickr.com/photos/hulagway/6057216897/" target="_hplink">whologwhy</a></em>

  • Barley

    When volunteers in a USDA study added barley to the standard American Heart Association diet, LDL "bad" cholesterol levels fell more than twice as far. Barley makes a great substitute for rice, adds depth to soups and is terrific combined with dried fruits, nuts and a little oil and vinegar for a hearty salad. <em>Flickr photo by <a href="http://www.flickr.com/photos/andrea_nguyen/6101617696/" target="_hplink">Andrea Nguyen</a> </em>

  • Beans & Lentils

    From a recent study in the <em>Annals of Internal Medicine</em>, LDL "bad" cholesterol levels fell almost twice as far in volunteers on a low-fat diet who added beans and lentils (along with more whole grains and vegetables) to the menu. Experiment with beans in soups, salads and dips. Tuck them into burritos, lasagna and casseroles. <em>Flickr photo by <a href="http://www.flickr.com/photos/mote/144636082/" target="_hplink">Nick Mote</a></em>

  • Blueberries

    Blueberries contain a powerful antioxidant called pterostilbene that may help lower LDL cholesterol. Toss a cup of frozen blueberries together with a half-cup of orange juice and vanilla yogurt into the blender for a healthy breakfast drink. Sprinkle fresh blueberries on cereals and eat them by the handfuls for snacks. <em>Flickr photo by <a href="http://www.flickr.com/photos/plutor/23920826/" target="_hplink">Logan Ingalls</a></em>

  • Oats

    When women in a University of Toronto study added oat bran to an already heart-healthy diet, HDL-cholesterol levels -- the beneficial kind -- climbed more than 11 percent. Consider a daily bowl of oat bran hot cereal or old-fashioned oatmeal for breakfast. Oat bran muffins can also pack a tasty dose into your day. <em>Flickr photo by <a href="http://www.flickr.com/photos/pixelnaiad/260678394/" target="_hplink">pixelnaiad</a></em>

  • Alcohol

    Drinking a glass of wine with dinner -- any alcoholic beverage, in fact -- has been shown to raise good-cholesterol levels and lower the risk of a heart attack. (Excessive drinking, however, raises heart-disease danger.) <strong>More from <em>Eating Well</em>:</strong> <a href="http://www.eatingwell.com/nutrition_health/heart_healthy_diet_center/the_worst_and_best_things_to_eat_for_your_heart ?utm_source=HuffingtonPost_Brierley_SuperfoodsToLowerCholesterol_021612" target="_blank">The Best and Worst Foods For Your Heart</a> <a href="http://www.eatingwell.com/nutrition_health/nutrition_news_information/what_to_eat_for_a_healthy_heart_mind?utm_source=HuffingtonPost_Brierley_SuperfoodsToLowerCholesterol_021612" target="_blank">What to Eat for a Healthy Heart and a Healthy Mind</a> <a href="http://www.eatingwell.com/recipes_menus/recipe_slideshows/heart_healthy_dinner_recipes_to_help_lower_cholesterol?utm_source=HuffingtonPost_Brierley_SuperfoodsToLowerCholesterol_021612" target="_blank">Heart-Healthy Dinner Recipes</a> <em>Flickr photo by <a href="http://www.flickr.com/photos/dasprid/4234602020/" target="_hplink">Ben Scholzen</a></em>

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Filed by Rebecca Zamon  |