We know that HDL is good for you, but we know less about what affects it. In a recent Nutrition and Metabolism study, researchers examined this substance in greater detail than ever before.
First, let’s give a little detail on HDL in order to better understand the study’s purpose and results. We normally think of HDL as the good kind of cholesterol, but HDL isn’t actually cholesterol at all. It’s a different sort of molecule called a lipoprotein (as you can tell by its name, a lipoprotein is fat and protein together), which has several functions. One of those functions is to help transport cholesterol. When HDL is combined with cholesterol, they are called HDL-C. There’s only one kind of cholesterol, but several kinds of lipoproteins.
HDL seems to have strong heart health benefits, but when measured by HDL-C alone, which is the cheapest and most common available test, the proof has been hard to come by. That’s because it’s HDL in general that seems to benefit your health, not necessarily HDL-C, specifically. So, in addition to HDL-C the researchers in this study were interested a few other substances.
- HDL-2: First was HDL-2, a very dense kind of HDL which is not only probably cardioprotective in its own right, but is chock full of apolipoprotein A1 (APOA1). APOA1 levels strongly support the formation of HDL and the transport of fat.
- HDL-3: The researchers also looked at HDL-3, a less dense HDL that is a powerful antioxidant. HDL-3 is also associated with enzymes that protect the heart.
This was a large study, involving 1,566 participants. For these participants, blood was drawn and a dietary questionnaire was created to find out what their HDL levels were and what their diets were like. Specifically, the researchers were interested in the associations between individual nutrients and HDL measures. These tests were much more specific than the type you’d get at a doctor’s office.
Several nutrients correlated with increases in every type of HDL and APOA1. Folate, alcohol, and myristic acid (a kind of saturated fat) were the winners of the study, each having important effects on healthy HDL levels.
The healthiest amount of alcohol seemed to be less than three standard drinks. A beer of five-percent alcohol content, five ounces of wine at twelve-percent, or a shot of forty-percent liquor would count as one drink. Benefits were stunted for people who regularly drink three or more beverages daily, so keep it moderate.
Myristic acid is the type of fat found in coconut oil and a rare few other plant-based oils, as well as butter. As for other fats and proteins, it seems that animal fats balance each other out so long as the total amount is moderate. The researchers warned that although saturated fat is great at raising HDL, it might also raise LDL, which is bad for your health. Again, the common sense advice of not overindulging in animal fats is correct.
The researchers noted the effects of a few other nutrients, as well. Magnesium boosted both kinds of HDL. Dietary fiber increased HDL-3. Vitamin C raised APOA1 levels. Interestingly, carbohydrates had the worst effects on HDL. Higher carb levels had a strong association to every studied HDL factor.
The bottom line is to eat a balanced diet with all of your nutrients in tow. Moderation is important. Don’t go crazy on carbs, and when you do, make them fibrous carbs.
1. Daniel Kim, et. al., “Effects of dietary components on high-density lipoprotein measures in a cohort of 1,566 participants,” Nutrition and Metabolism 2014, 11:44
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