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CHOLESTEROL - WHAT TO EAT, WHAT TO AVOID

Cholesterol is arguably one of the most misunderstood substances.

For decades, people avoided healthy yet cholesterol-rich foods such as eggs, fearing that these foods would increase their risk of heart disease.


However, recent research shows that, for most people, eating healthy high cholesterol foods is not harmful to health. What’s more, some cholesterol-rich foods are loaded with important nutrients that are lacking in many people’s diets.

Emerging research into underappreciated aspects of cholesterol biochemistry has revealed that levels of cholesterol account for only a portion of the cardiovascular risk profile, while the properties of the molecules responsible for transporting cholesterol through the blood, called lipoproteins, offer important insights into the development of atherosclerosis.


How Does Cholesterol Contribute to Heart Disease?

Cholesterol is a steroid molecule that is a large component of cellular membranes and a precursor to steroid hormones and vitamin D, among other functions. Cholesterol is transported throughout the body as lipid-protein complexes called lipoproteins. Low-density lipoproteins (LDLs) and high-density lipoproteins (HDLs) are generally measured when testing blood cholesterol levels.


LDL (commonly referred to as “the bad cholesterol”) can transport cholesterol to arterial walls, contributing to the development of atherosclerosis (hardening and narrowing of arteries) and cardiovascular disease. Less commonly known is that size, density, and metabolic processes (eg, oxidation and glycation) that alter lipoproteins play a large role in how damaging LDL can be to the endothelial cells that line arteries. HDL (often referred to as “the good cholesterol”) transports cholesterol away from tissues to the liver for reprocessing or disposal.


What Dietary and Lifestyle Changes Can Help Manage Cholesterol?

  • Dietary modifications to reduce intake of saturated and trans fats, sodium, added sugar, and cholesterol, while increasing fruits and vegetables, whole grains, nuts and legumes, fish and poultry, and oils low in saturated fat (like olive oil).

  • Caloric restriction may help some individuals.

  • Regular exercise—at least 150 minutes of moderate-intensity activity or 75 minutes of high-intensity activity each week

What Natural Interventions Can Help Manage Cholesterol?

  • Artichoke may help the body get rid of excess cholesterol. Several clinical trials have shown artichoke reduces LDL cholesterol.

  • Garlic has shown benefits on blood lipid profiles confirmed in multiple reviews and over 30 clinical trials. Garlic can lower total cholesterol and LDL, as well as triglycerides. Garlic also has favorable effects on blood pressure for added cardiovascular benefits.

  • Plant sterols are steroid molecules found in plants that may compete with cholesterol for absorption in the intestines, reducing LDL levels. Numerous clinical studies have repeatedly shown plant sterols to be effective for reducing LDL.

  • The cholesterol-lowering effects of soluble fibers, like beta-glucan, pectin, and those from oats and barley, have been substantiated in hundreds of clinical trials. Intake of soluble fiber is linked with lower incidence of cardiovascular disease as well.

  • Coenzyme Q10 (CoQ10) is well known for its impact on cardiovascular health. Statins, first-line drugs for treatment of high cholesterol, suppress CoQ10 levels. It is advisable for those taking statins to also supplement with CoQ10. Additionally, CoQ10 may reduce total cholesterol and increase HDL.

  • Pomegranate contains high amounts of polyphenols, especially punicalagins. Several placebo-controlled clinical trials have shown pomegranate can lower total cholesterol and LDL levels in people with high cholesterol and may also improve other parameters indicative of atherosclerosis.

Size Matters

Cholesterol and related blood lipids are far more complex than the traditional cholesterol blood test would lead us to believe. Most people are familiar with the traditional lipid risk factors: LDL, high-density lipoprotein (HDL), total cholesterol, and triglyceride levels. What few people outside the cardiovascular research community appreciate is that a more detailed look, that includes non-traditional blood lipids, can offer important insights into an individual’s cardiovascular risk.


The protein apolipoprotein B (ApoB), a structural component of all non-HDL cholesterol particles including LDL- and very low-density lipoprotein (VLDL)-cholesterol, has emerged as perhaps the most valuable marker of cardiovascular risk. ApoB is an even stronger predictor of risk than LDL alone.


A 2018 expert panel on cholesterol management, representing numerous cardiology and physician societies, including the American College of Cardiology and American Heart Association, referred to ApoB as “a stronger indicator of atherogenicity than LDL-cholesterol alone,” and recommended measurement of ApoB for cardiovascular risk assessment, especially in those with elevated triglycerides. A prospective cohort analysis published in JAMA Cardiology in 2021, which included a large population study (UK Biobank) and two large international clinical trials, found ApoB was the best predictor of heart attack risk when compared with triglycerides, LDL-cholesterol, or non-HDL cholesterol. They further suggested ApoB may be the main driver of atherosclerosis.


Also, the size and density of cholesterol-transporting proteins, called lipoproteins, are important factors that influence cardiovascular risk. Large, buoyant LDL particles are less atherogenic than smaller, more dense LDL particles. Similarly, large, buoyant HDL particles offer greater vascular protection than smaller, denser HDL. Furthermore, metabolic processes, such as oxidation and glycation, modify the functionality of lipoproteins, transforming them from cholesterol transport vehicles into highly reactive compounds capable of damaging the delicate endothelial cells that line our arterial walls. This endothelial damage both initiates and promotes atherogenesis. Some natural interventions and lifestyle changes can target the formation of these modified lipoproteins and help avert vascular damage and dysfunction.


A comprehensive strategy for decreasing vascular risk should incorporate dietary and lifestyle changes.


High Blood Sugar Increases the Atherogenicity of LDL

Elevated levels of blood sugar create ideal conditions for glycation reactions to occur. Glycation is a process by which a protein or lipid is joined together non-enzymatically with a sugar. The resultant product is highly reactive and capable of damaging tissues it comes in contact with.


Glycation of LDL particles is a well-documented phenomenon that greatly increases the atherogenicity of LDL. Glycated LDL has been shown to be significantly more susceptible to oxidation than native LDL, and to substantially impair endothelial function. Also, glycated LDL stimulates oxidative stress and inflammation in vascular smooth muscle cells, which exacerbates plaque buildup within blood vessel walls. Glycated, oxidized LDL causes degradation of endothelial nitric oxide synthase (eNOS), an enzyme involved in maintaining proper vasodilatation and blood flow. Moreover, once LDL has become glycated it is no longer recognized by the LDL receptor on cell surfaces, meaning it will remain in circulation and is more likely to contribute to the atherosclerotic process.


Individuals with diabetes are known to be at substantially greater risk for developing atherosclerosis than people with normal blood sugar.


Dietary and Lifestyle Changes

Dietary modifications aim to reduce the intake and uptake of unhealthy fats such as saturated and trans fats and cholesterol from the diet. The inclusion of specific dietary compounds with cholesterol-lowering or cardioprotective properties may also reduce cardiovascular disease risk by several different mechanisms.


Diet is the most important aspect of a cholesterol management program. The American Heart Association and other experts recommend a diet that emphasizes:

  • Fruits and vegetables

  • Whole grains

  • Nuts and legumes

  • Fish and skinless poultry

  • Non-tropical vegetable oils, such as olive, sunflower, safflower, canola, and other oils low in saturated fat. Note that the American Heart Association does not recommend deep frying foods regardless of the type of oil used. They also do not recommend coconut oil, which is high in saturated fat.

  • Avoiding hydrogenated oils to reduce dietary trans fat

  • Reducing added sugar and sodium

  • Limiting daily alcohol consumption to no more than one drink for women and two drinks for men

In controlled clinical trials that replaced dietary saturated fat with polyunsaturated vegetable oils such as those listed above, cardiovascular disease was reduced by about 30%, which is roughly the degree of protection conferred by statin drugs. Substituting saturated fat for polyunsaturated vegetable oil lowers LDL cholesterol, which may in part explain the benefits observed. On the other hand, oils high in saturated fat, like coconut oil (which is approximately 90% saturated fat), can increase LDL cholesterol. In a systematic review and meta-analysis of 16 clinical trials published in the journal "Circulation," coconut oil consumption was shown to increase LDL cholesterol levels by 10.47 mg/dL compared with non-tropical vegetable oils. The authors concluded that this increase in LDL may lead to an increased risk of major vascular events, and "coconut oil should not be viewed as healthy oil for cardiovascular disease risk reduction and limiting coconut oil consumption because of its high saturated fat content is warranted."


Observational trials have also found that higher intake of monounsaturated and polyunsaturated fats is associated with lower rates of death from cardiovascular disease or any cause. It should be noted that replacing saturated fat with refined carbohydrates and sugars has not been shown to reduce cardiovascular disease.


Specific dietary approaches that are generally heart healthy are the Dietary Approaches to Stop Hypertension (DASH) diet and Mediterranean diet.


Caloric Restriction

Caloric restriction is the reduction of dietary calories (by up to 40%) while still maintaining good nutrition. Restricting energy intake slows down the body’s growth processes, causing it instead to focus on protective repair mechanisms; the overall effect is an improvement in several measures of health. Observational studies have tracked the effects of caloric restriction on lean, healthy individuals, and demonstrated that moderate restriction (22‒30% decreases in caloric intake from normal levels) improves heart function and reduces markers of inflammation (C-reactive protein, tumor necrosis factor [TNF]), risk factors for cardiovascular disease (LDL cholesterol, triglycerides, blood pressure), and diabetes risk factors (fasting blood glucose, insulin levels).


Preliminary results of the Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy (CALERIE) study, a long-term multicenter trial on the effects of calorie-restricted diets in healthy overweight volunteers, showed moderate calorie restriction can reduce several cardiovascular risk factors (LDL cholesterol, triglycerides, blood pressure, and C-reactive protein).


Exercise

Exercise is a fundamental component of any lipid management strategy. The American Heart Association and American College of Sports Medicine recommend adults engage in at least 150 minutes of moderate-intensity activity or 75 minutes of high-intensity activity each week for the prevention of cardiovascular disease. Exercise helps raise HDL levels and boost the efficiency of reverse cholesterol transport, the process by which cholesterol is carried from the blood vessels back to the liver for excretion. Exercise reduces LDL significantly when combined with a heart-healthy diet.


A meta-analysis of 37 studies found that exercise usually resulted in moderate-to-strong improvements in levels of total cholesterol, LDLs, triglycerides, and HDLs. This same analysis also found that exercise consistently improved glucose and insulin levels, which are often elevated in people with an unhealthy lipid profile. Both aerobic and anaerobic exercise have beneficial effects on blood lipids, so an exercise regimen that combines strength training (e.g., weightlifting) and endurance training (e.g., running) is suggested.


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