Correspondence Address:
Dr. G Vijayaraghavan
Kerala Institute of Medical Sciences, Thiruvananthapuram - 695 029, Kerala
India

Full Text

“Since we cannot possibly eat enough cholesterol to use for our daily needs of the body functions, our body makes its own. When we eat more foods rich in this compound, our bodies make less. If we deprive ourselves of foods high in cholesterol – such as eggs, butter, and liver – our body revs up its cholesterol synthesis. The end result is that, for most of us, eating foods high in cholesterol has very little impact on our blood cholesterol levels. In 70% of the population, foods rich in cholesterol such as eggs cause only a subtle increase in cholesterol levels or none at all. In the other 30%, these foods do cause a rise in blood cholesterol levels. Despite this, research has never established any clear relationship between the consumption of dietary cholesterol and the risk for heart disease… Raising cholesterol levels is not necessarily a bad thing either.”

These are the kind of dangerous information that is going viral in the social media since the last 2 or 3 years. Patients are taking more time for consultation, friends are asking more questions, and even doctors become confused following this barrage of statements in the social media. “Study where there is no link between cholesterol and heart disease,“ “Cholesterol – Read about facts and myths,“ “High cholesterol does not cause heart disease;“ these are some of the internet sites we start browsing. The misinformation leading to disinformation has flooded the internet sites so that the common man is being misled.

From where do you learn modern medicine? I often ask my colleagues and students. Of course neither from “WhatsApp or internet“ nor from lay press such as The Indian Express, The Hindu, or The Times of India. We learn medicine from standard medical textbooks, journals, national and international medical conferences, and continuing medical education programs. We do refer to important internet sites. We always probe for the evidence base and the scientific background of each of the internet sites. We try to follow the guidelines. Guidelines are formulated after detailed deliberations of expert committees of highly reputed international organizations such as the American College of Cardiology, American Heart association, European Society of Cardiology, World Federation of Cardiology, and Cardiological Society of India. Guidelines are discussed and finalized at their annual meetings and published in highly acclaimed and reputed international journals. These are the sources for continuing our medical education and not the social media.

I did browse some of these internet sites and the source of these social media publications. I ended up at very few sources. One of the main source led me to “mercola.com;“ described as the “World's No 1 Health web site.“ Dr. Mercola describes himself as the new apostle of fat advocacy and bases his conclusions on the 2010 dietary advice to the Americas by the US Department of Agriculture, Health and Human Services.[1] I went through the 210 page report and its executive summary. It in no way differs from the old “Adult Treatment Panel iii (ATP iii)“ of the National Cholesterol Education Program (NCEP) of the American Heart Association, which the whole world had been following from 2002. In 2013, the American College of Cardiology and the American Heart Association Task Force on Practice Guidelines published their new guidelines for lipid control as the ATP IV guidelines in the journals Circulation and the Journal of American College of Cardiology.[2] They described 4 treatment groups who required cholesterol-reducing drugs.

ATP IV stated that four treatment groups include:

Individuals with clinical atherosclerotic cardiovascular disease (CVD)Individuals with low-density lipoprotein cholesterol (LDL-C) levels >190 mg/dL, such as those with familial hypercholesterolemiaIndividuals with diabetes aged 40–75 years with LDL-C levels between 70 and 189 mg/dL and without evidence of atherosclerotic CVDIndividuals without evidence of CVD or diabetes but who have LDL-C levels between 70 and 189 mg/dL and a 10-year risk of atherosclerotic CVD >7.5%.

In those with atherosclerotic CVD, high-intensity statin therapy – such as rosuvastatin 20–40 mg or atorvastatin 80 mg – should be used to achieve at least a 50% reduction in LDL-C unless otherwise contraindicated or when statin-associated adverse events are present. In that case, doctors should use a moderate-intensity statin. Similarly, for those with LDL-C levels >190 mg/dL, a high-intensity statin should be used with the goal of achieving at least a 50% reduction in LDL-C levels. For those with diabetes aged 40–75 years, a moderate-intensity statin, defined as a drug that lowers LDL-C 30%–49%, should be used, whereas a high-intensity statin is a reasonable choice if the patient also has a 10-year risk of atherosclerotic CVD exceeding 7.5%. For the individuals aged 40–75 years without CVD or diabetes but who has a 10-year risk of clinical events >7.5% (pooled cohort equation) and an LDL-C level anywhere from 70 to 189 mg/dL, the panel recommends treatment with a moderate- or high-intensity statin.

Persons with documented CVD, Type 1 or Type 2 diabetes mellitus, very high levels of individual risk factors, and chronic kidney disease are automatically at very high or high total CV risk. No risk estimation models are needed for them. They all need active management of all risk factors. Establishing at least 50% reduction of LDL-C is the target of treatment. No target cholesterol levels are to be aimed at. Pooled cohort equation was not tested among all races except the Caucasians. This was the main point of controversy. Many clinicians continued to estimate lipids periodically and checked whether the LDL-C has come down below 100 mg/dL or 70 mg/dL as the case demands.

Dr. Mercola in his internet sites and through social media continued to spread the rumor that 2015 new guidelines might lift the limits on dietary cholesterol. These guidelines were published promptly by the Departments of Agriculture, Health and Human Services. It stated that the diet should contain <10% each from added sugars and saturated fats and also limited the sodium intake to <2.3 g/day. The document mentioned that:

Healthy intake: Healthy eating patterns include fat-free and low-fat (1%) dairy, including milk, yogurt, cheese, or fortified soy beverages (commonly known as “soymilk”). Soy beverages, fortified with calcium, Vitamin A, and Vitamin D, are included as part of the dairy group because they are similar to milk-based foods in nutrient composition and in their use in meals. Other products sold as “milks“ but made from plants (e.g., almond, rice, coconut, and hemp “milks”) may contain calcium and be consumed as a source of calcium, but they are not included as part of the dairy group because their overall nutritional content is not similar to dairy milk and fortified soy beverages (soymilk). The recommendation for the meats, poultry, and eggs subgroup in the Healthy U.S-Style Eating Pattern at the 2000-calorie level is 26 ounce-equivalents per week. This is the same as the amount that was in the primary USDA Food Patterns of the 2010 Dietary Guidelines.

Average intake of meats, poultry, and eggs for teen boys and adult men are above recommendations in the Healthy U.S-style eating pattern. For those who eat animal products, the recommendation for the protein foods subgroup of meats, poultry, and eggs can be met by consuming a variety of lean meats, lean poultry, and eggs. Choices within these eating patterns may include processed meats and processed poultry as long as the resulting eating pattern is within limits for sodium, calories from saturated fats and added sugars, and total calories. Harvard University School of public health added to these by advising:

“While eggs may not be the optimal breakfast choice, they are certainly not the worst, falling somewhere in the middle on the spectrum food choice and heart disease risk. For those looking to eat a healthy diet, keeping intake of eggs moderate to low will be best for most, emphasizing plant-based protein options when possible.”

The intake of saturated fats should be limited to <10% of calories per day by replacing them with unsaturated fats and while keeping total dietary fats within the age-appropriate recommendations. The human body uses some saturated fats for physiological and structural functions, but it makes more than enough to meet those needs. Individuals 2 years and older therefore have no dietary requirement for saturated fats. Strong and consistent evidence shows that replacing saturated fats with unsaturated fats, especially polyunsaturated fats, is associated with reduced blood levels of total cholesterol and of LDL-C levels.

In addition, strong and consistent evidence shows that replacing saturated fats with polyunsaturated fats is associated with a reduced risk of CVD events (heart attacks) and CVD-related deaths. Some evidence has shown that replacing saturated fats with plant sources of monounsaturated fats, such as olive oil and nuts, may be associated with a reduced risk of CVD. However, the evidence base for monounsaturated fats is not as strong as the evidence base for replacement with polyunsaturated fats. Evidence has also shown that replacing saturated fats with carbohydrates reduces blood levels of total and LDL-C but increases blood levels of triglycerides and reduces high-density lipoprotein cholesterol (HDL-cholesterol). Replacing total fat or saturated fats with carbohydrates is not associated with reduced risk of CVD. Additional research is needed to determine whether this relationship is consistent across categories of carbohydrates (e.g., whole versus refined grains; intrinsic versus added sugars), as they may have different associations with various health outcomes. Therefore, saturated fats in the diet should be replaced with polyunsaturated and monounsaturated fats. The fat in some tropical plants, such as coconut oil, palm kernel oil, and palm oil, are not included in the oils category because they do not resemble other oils in their composition. Specifically, they contain a higher percentage of saturated fats than other oils.

Healthy eating patterns limit added sugars to <10% of calories per day. This recommendation is a target to help the public achieve a healthy eating pattern, which means meeting nutrient and food group needs through nutrient-dense food and beverage choices and staying within calorie limits. When added sugars in foods and beverages exceed 10% of calories, a healthy eating pattern may be difficult to achieve. This target also is informed by national data on intakes of calories from added sugars, which accounts on average for almost 270 calories, or more than 13% of calories per day in the U.S. population.

On June 13, 2016, another controversy erupted through the British Medical Journal's (BMJ) “Open Journal.”[3] This article tried to disprove the concepts laid down by the American Heart Association and the American College of Cardiology as well as so many national and international organizations.

It stated that- “cholesterol does not cause heart disease in the elderly and trying to reduce it with drugs such as statins is a waste of time- an international group of experts has claimed”. A review of research involving nearly 70,000 people found that there was no link between what has traditionally been considered “bad“ cholesterol and the premature deaths of over 60-year-old individuals from CVD. In the BMJ open journal, the new study found that 92% of people with a high cholesterol level lived longer. Results showed that the authors identified 19 cohort studies including 30 cohorts with a total of 68,094 elderly people, where all-cause mortality was recorded in 28 cohorts and CV mortality in 9 cohorts. Inverse association between all-cause mortality and LDL-C was seen in 16 cohorts (in 14 with statistical significance) representing 92% of the number of participants, where this association was recorded. In the rest, no association was found. In two cohorts, CV mortality was highest in the lowest LDL-C quartile and with statistical significance; in seven cohorts, no association was found. The authors concluded that “high LDL-C is inversely associated with mortality in most people over 60 years. This finding is inconsistent with the cholesterol hypothesis (i.e., that cholesterol, particularly LDL-C, is inherently atherogenic). Since elderly people with high LDL-C live as long or longer than those with low LDL-C, our analysis provides reason to question the validity of the cholesterol hypothesis. Moreover, the study provides the rationale for a re-evaluation of guidelines recommending pharmacological reduction of LDL-C in the elderly as a component of CVD prevention strategies”.

“Controversial report“ claims that there is no link between “bad cholesterol“ and heart disease – the Daily Mail reports; while The Times states: “Bad cholesterol helps you live longer.“ The headlines were based on a new review which aimed to gather evidence from previous observational studies on whether LDL-C (so-called “bad cholesterol”) was linked with mortality in older adults aged over 60 years. The conventional view is that having high LDL-C levels increases your risk of dying of CVD, such as heart disease. Researchers chose 30 studies in total, to analyze; 28 studies looked at the link with death from any cause; 12 found no link between LDL and mortality, but 16 actually found that lower LDL was linked with higher mortality risk – the opposite to what was expected. Only nine studies looked at CV mortality link specifically – seven found no link and two found the opposite link to what was expected. However, there are many important limitations to this review. This includes the possibility that during their search methods, they may have missed many relevant studies, not looking at levels of other blood fats (e.g., total and HDL cholesterol), and the possibility that other health and lifestyle factors were influencing the link. Most importantly, as the researchers acknowledge, these findings do not take into account the use of statins, which lowers cholesterol. People found to have high LDL-C at the beginning of the study may have subsequently been started on statins, which became popular during the study period and could have prevented deaths. Four of the study authors have previously written book (s) criticizing “the cholesterol hypothesis.“ It should also be noted that nine of the authors are members of THINCS – The International Network of Cholesterol Skeptics. This is described as a group of scientists who “oppose…that animal fat and high cholesterol play a role in the genesis of heart disease.”

Finally, in 2016, American College of Cardiology and American Heart Association as well as the European Society of Cardiology published their guidelines which reiterated the statements in 2015 guidelines for the Americas.[4] There is a carry home message for the medical community as well as the public that “Essentially the lipid guidelines have not radically changed since the ATP III guidelines were published by the NCEP in 2002.“ In 2017, the guidelines of the American College of Cardiology, the American Heart Association, and the European Society of Cardiology remain unchanged. These are the guidelines followed by the entire world for planning prevention of CVD in the community. For our survival, let us stick onto this scientific “evidence-based medicine.”

References