Over the last several years, it has become accepted that oxidative stress and systemic inflammation are important mediators of atherosclerosis and poor heart health. One of the main contributors to oxidative stress and inflammation is oxidized low-density lipoprotein (oxLDL). Low-density lipoprotein is a complex of lipids and proteins with many of the lipids being rich in polyunsaturated fatty acids. Exposure to oxidative stress causes these fatty acids to become oxidized into a variety of products that are collectively called oxLDL.
The role of oxLDL in atherosclerosis and heart health has been the focus of intense investigation.
- A study in mice reported that blood levels of oxLDL increased before the expansion of atherosclerotic lesions, suggesting that the rise in oxLDL is one of the earliest steps towards atherosclerosis.
- Another study reported that heart muscle cells are severely damaged by oxLDL, while native LDL had no effect on the heart muscle cells.
- A clinical study showed that blood levels of oxLDL were substantially higher in patients with complex atherosclerotic plaques.
- Individuals with the highest levels of oxLDL were 4 times more likely to have a coronary event than individuals with the lowest levels of oxLDL.
Collectively, these studies suggest that oxLDL is a greater predictor of coronary heart disease than LDL cholesterol, total cholesterol, and the ratio of total cholesterol to HDL cholesterol, and therefore clearly indicate the importance of oxLDL for heart health and the importance of preventing LDL oxidation.
Antioxidants are an effective way to fight oxidative stress and dietary consumption of antioxidant foods and supplements can help reduce LDL oxidation. Consuming foods and supplements that lower cholesterol and/or block LDL oxidation can be an effective approach to supporting normal heart health. Some of my favorite foods and supplements for heart health include omega-3 fatty acids, sea buckthorn fruit, red yeast rice, and prickly pear fruit.
Omega-3 Fatty Acids
Omega-3 fatty acids, particularly EPA and DHA, are well known for a number of potential health benefits including heart health. Recently, research studies have suggested that EPA and DHA may protect against the negative impact of oxLDL. One recent study reported that consumption of rapeseed oil, a dietary source of omega-3 fatty acids, by men with the metabolic syndrome resulted in 8% decrease in total cholesterol, an 11% decrease in LDL-cholesterol, and a 16% decrease in oxLDL after six to eight weeks. A separate study in adult women reported that higher blood levels of EPA were linked to lower levels of oxLDL. Additionally, cell cultures studies showed that both EPA and DHA blocked oxLDL’s ability to stimulate proteins involved in the attachment of white blood cells to blood vessel cells, an important step in arterial plaque formation .
Sea buckthorn fruit is a rich source of nutrients (vitamins A, C, E, and some B vitamins) and phytochemicals (lycopene, quercetin, isorhamnetin). These constituents give sea buckthorn excellent antioxidant potential.
In addition to lowering total cholesterol and LDL-cholesterol, initial studies suggest that sea buckthorn can help protect against the effects of oxLDL. In one cell culture study, oxLDL was shown to trigger the formation of superoxide free radicals, block the production of the antioxidant enzyme superoxide dismutase (SOD), and increase a marker of inflammation. Treatment of the cells with flavonoids from sea buckthorn blocked the oxLDL-induced formation of free radicals and helped maintain natural levels of SOD. Furthermore, a study in healthy men showed that consumption of sea buckthorn juice boosted HDL-cholesterol and reduced the susceptibility of LDL-cholesterol to oxidation.
Red Yeast Rice
Red yeast rice is a fermented product where red yeast is grown on the rice. Red yeast rice is rich in compounds called monacolins that block cholesterol production. Because of this ability, red yeast rice has rapidly grown in popularity as a natural way to lower cholesterol. One recent study reported that individuals taking a combination of red yeast rice and phytosterols averaged a 19% decrease in total cholesterol and a 33% decrease in LDL-cholesterol after only 6 weeks. Similarly, daily consumption of 2,400 mg of red yeast rice for 16 weeks reduced LDL-cholesterol by 23% and total cholesterol by nearly 16% in patients with high cholesterol levels. In a comparison of red yeast rice with the cholesterol-lowering drug pravastatin, red yeast rice lowered LDL-cholesterol by 30% while pravastatin lowered LDL-cholesterol by 27%. It is clear from these and many other studies that red yeast rice is highly effective for heart health support.
The fruit of the prickly pear cactus (Opuntia ficus-indicus) is a good source of vitamin C and betalain pigments (indicaxanthin and betanin). These pigments, which give the fruit its color, have been shown to have considerable antioxidant capabilities and are believed to play an important role in prickly pear’s free radical scavenging abilities. In addition to the ability of prickly pear leaves and stems to support healthy cholesterol levels, a recent study showed that prickly pear fruit might reduce the oxidation of LDL-cholesterol. In this study, volunteers consumed 250 grams of fresh prickly pear fruit pulp twice daily for 2 weeks. Consumption of prickly pear fruit resulted in substantial decreases in blood markers of oxidative stress and reduced oxLDL by nearly 50%.
It is clear that oxLDL is an important contributor to the development of atherosclerosis and poor heart health. Combating the formation of oxLDL and promoting healthy levels of total cholesterol, LDL-cholesterol, and HDL-cholesterol are both important avenues to better heart health. Therefore, it is important to make dietary and/or supplement choices that support both pathways to improved heart health. Omega-3 fatty acids, sea buckthorn, prickly pear, and red yeast rice are just a few choices you can make in maintaining good heart health.