It seems that everyone is watching their cholesterol levels these days. I probably should too, but I’m just not willing to give up some of my favorite high-fat foods. However, after reading a recent paper in the Journal of Agricultural and Food Chemistry (1), I might not have to feel so guilty about eating one of my favorite foods: chocolate. Those of you who enjoy an occasional bite of the rich, creamy goodness that is chocolate will want to continue reading to learn how chocolate might help in the fight against cholesterol. I won’t go so far as to say that chocolate is a health food, but at least I can feel less guilty when I indulge in a few squares.
A lot of research has been done on the topic of cholesterol because high cholesterol levels are often associated with cardiovascular disease, an all-too-common cause of death in many countries. Researchers have known for a few years that daily intake of cocoa can increase levels of HDL (high-density lipoprotein; “good” cholesterol) and decrease levels of LDL (low-density lipoprotein; “bad” cholesterol) in the bloodstream (2,3), and now this new research is shedding light on the mechanism.
Cholesterol and other lipids circulate in the bloodstream in several forms, including HDL and LDL, which contain proteins in addition to lipids. HDL has a higher protein content than LDL and can scavenge cholesterol from tissue and atherosclerotic deposits. The cholesterol is then transported back to the liver, where it is excreted in the bile or reused. The main protein component of HDL is apolipoprotein A1 (ApoA1). LDL has a lower protein content and higher lipid content. The core protein in LDL is apolipoprotein B (ApoB). Whereas HDL is a cholesterol scavenger and recycler, LDL acts as a cholesterol reservoir. When a cell requires cholesterol, it synthesizes and displays LDL receptors to internalize LDL from the bloodstream. When levels in the blood are high, LDL can accumulate in artery walls, where it is oxidized and contributes to atherosclerosis.
In this most recent paper, Yasuda et al. show that polyphenolic compounds in cocoa liquor can affect expression levels of ApoA1 and ApoB. These researchers exposed the hepatic cell line HepG2 and intestinal Caco2 cells to various concentrations of cocoa polyphenols for 24 hours and measured the effect on mRNA and protein levels of ApoA1, ApoB and sterol regulatory element binding proteins (SREBPs), as well as LDL receptor binding activity. They found that cocoa polyphenols increased both ApoA1 mRNA and protein levels and decreased levels of ApoB slightly compared to untreated control cells. Levels of mature SREBP1 and SREBP2 proteins were increased significantly, and LDL receptor activity was slightly elevated. Good news for chocolate lovers.
However, chocolate is not the only source of these beneficial polyphenols. They are also found in red wine, grapes, tea and soy products, and previous research has shown that polyphenols from these other sources have many of the same effects.
While I can feel less guilty about eating a little chocolate once in a while, this is not a license to overindulge. Chocolate might help improve my cholesterol levels, but the sugar and extra calories aren’t doing my adipocytes any good.
- Yasuda, A., Natsume, M., Osakabe, N., Kawahata, K. and Koga, J. (2011). Cacao polyphenols influence the regulation of apolipoprotein in HepG2 and Caco2 Cells J. Agric. Food Chem. 59, 1470–76 : 10.1021/jf103820b
- Baba, S. et al. (2007) Continuous intake of polyphenolic compounds containing cocoa powder reduces LDL oxidative susceptibility and has beneficial effects on plasma HDL-cholesterol concentrations in humans. Am. J. Clin. Nutr. 85, 709–17.
- Baba, S. et al. (2007) Plasma LDL and HDL cholesterol and oxidized LDL concentrations are altered in normo- and hypercholesterolemic humans after intake of different levels of cocoa powder. J. Nutr. 137, 1436–41.
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