When there is too much cholesterol in your blood it can cause damage to inner epithelium cells lining of your blood vessels. It can also penetrate the endothelial barrier and cause inflammation of walls of arteries causing arteries.
Reduction of blood cholesterol was the key to success in the treatment of coronary heart disease in Dr.Ornish’s study and Dr. Esselstyn’s study.
There are evidences demonstrating the relationship between cholesterol, particularly LDL cholesterol, and the risk of coronary heart disease (CHD) and CHD mortality. The epidemiological study found that LDL cholesterol range of 50 to 70 mg/dl to be safe and not associated with CHD risk .While, the China Study demonstrated that cholesterol range of 90 to 170 mg/dl, a lower level of cholesterol reduced atherosclerosis risk.
The Multiple Risk Factor Intervention Trial (MRFIT) was published in the Journal of the American Medical Association (JAMA). This trial included 356,222 patients who had history of hospitalization for myocardial infarction. The results showed that the serum cholesterol was associated with Coronary heart disease (CHD) death rate. It was observed that for patients suffering from CHD who had high serum cholesterol, death rate related to CHD were higher (5 folds) compared with patients who were free from CHD even though both groups had the same level of serum cholesterol. The research on very low fat whole food, plant-based diet found that such a diet lead to reduction in cholesterol and could reverse coronary heart disease
Given below are the list of topics covering scientifically validated information related to health impact of cholesterol, oils and fats
Today, the medical community try’s to reduce blood cholesterol not with dietary therapy but with pharmacological therapy (medicines). However, cholesterol-lowering drug cannot replace very low fat, whole food plant-based diet. In patients with hypercholesterolemia who were divided into 2 groups, the group that received treatment only with cholesterol-lowering drug was found to have a higher risk of CHD and CHD death compared with the group that was on cholesterol-lowering drug and also adhered to a very low fat, whole food, plant-based diet even though both groups could reduce cholesterol equally .
In addition there is clear evidence that commonly used cholesterol lowering drugs cause skeletal muscle damage in patients.
The effect of cholesterol-lowering drug therapy on muscle function of older adults found that cholesterol-lowering drug users had higher fracture incidence and falls risk than non-users.. Moreover, long-term use of cholesterol-lowering drug was associated with increased risks ductal and lobular breast cancer among women 55 to 74 years of age.
The coronary heart disease (CHD) events such as heart attack, also known as a "myocardial infarction" (MI) and acute stroke usually occur in early stage of CHD without any symptomatic warnings which can be detected by physical or special examinations. Many heart attacks are caused by "unstable" plaques (a fat-like deposit on the artery walls) which induces endothelial dysfunction leading to occurrence of CHD event. The endothelial function of arteries plays key roles of vasodilatation by nitric oxide production. When nitric oxide production is inhibited, it lead to vasoconstriction, rising of blood pressure, and viscosity of blood causing unstable plaque and leading to heart muscle damage & heart attack.
New technology for detection of atherosclerosis is intravascular ultrasound (IVUS) which is a mini- ultrasound probe into the lumen of the coronary arteries. It has been increasingly used in research to examine risk factors of vasoconstriction, inhibited nitric oxide production by coronary artery and endothelial dysfunction. Risk factors include postprandial, high sodium (salt) intake, and acute stress. In a study about the effect of a single high-fat meal on endothelial function by using IVUS, participants were assigned to eat a single high-fat meal (BigMc from McDonald’s) and their endothelial function monitored. The results showed that after eating a single high-fat meal, serum triglycerides increased for 1 hour but flow-dependent vasoactivity decreased, there was inhibition of nitric oxide production for 4-6 hours postprandial even after serum triglycerides returned to normal  . Similar study in Asian population in Taiwan found the same effect. These finding led to the conclusion that a single high-fat meal transiently impairs endothelial function causing heart attack or acute stroke in early stage of CHD.
Acute effect of the ingestion of large amounts of olive (monounsaturated fatty acid), soybean (polyunsaturated fatty acid), and palm (saturated fatty acid) oils on the endothelial function via oral intake and blood injection found that all kinds of oil either monounsaturated fatty acid, polyunsaturated fatty acid and saturated fatty acid resulted in a similar acute endothelial impairment and acute vasoconstriction .
In a study, 12 healthy subjects and 12 patients with hypercholesterolemia were individually randomized between 2 meal sequences (high-fat meals with 25 g olive oil or 40 g walnut) and were studied on 2 separate days 1 week apart. Their blood taken and their endothelial function monitored by ultrasound after ingestion. The results showed that flow-mediated dilation was better after the walnut meal than after the olive oil. Walnut is whole food so it greatly improved endothelial function than olive oil which is extracted food. Therefore, the conclusion is plant-derived fat which is not an extract such as walnut can protect against endothelial dysfunction while cooking oil such as olive oil impair endothelial function.
Many of you would have experienced that fatty foods induce acid reflux. A research using the ambulatory 24-hours pH monitor to assess esophageal acid exposure in normal subjects and GERD patients following identical meals found that increased upright acid exposure occurred in normal subjects and GERD patients after the high fat meal but progressive increases in acid exposure were found over the 3 postprandial hours in GERD patients in a recumbent position .
We now know that diabetes caused by wrong dietary intake. After food is absorbed, the pancreas responds by producing high amounts of insulin in short-term. In addition to bring glucose into muscle cell, insulin brings fatty acid into fat cells, liver cells, and muscle cells and fat molecule are stored as fat droplets. Long-term fat storage lead to the “insulin resistance”, as the cells are resistant to the insulin pancreas increase the production of insulin, which is typically associated with type 2 diabetes.
The research for the mechanism of insulin resistance found that free fatty acids induced insulin resistance. Skeletal muscle glycogen and glucose concentrations were measured at baseline. After creating condition of normal serum glucose, insulin was administered as a primed-continuous infusion to create conditions of standardized hyperinsulinemia and rates of glucose uptake and glycogen synthesis in muscle were measured. The results showed that insulin stimulated glucose uptake and glycogen synthesis in muscle which is normal function of insulin. In the study periods, subjects were injected by a triglyceride emulsion into their muscle and the condition of normal serum glucose was created. Insulin was administered as a primed-continuous infusion to create conditions of standardized hyperinsulinemia and rates of glucose uptake and glycogen synthesis in muscle were measured again. The results from study found that insulin inhibited the rates of muscle glucose uptake and glycogen synthesis by elevation of intramuscular free fatty acid deposition which might play an important role in the pathogenesis of the “insulin resistance” .
The knowledge of diabetes induced by fatty foods was further enhanced by endocrinologist Dr. Neal D. Barnard. In a randomized clinical trial he studied 99 individuals with type 2 diabetes who had intention to stop hypoglycemic medications. Participants were randomly assigned to a diet following the American Diabetes Association (ADA) guidelines which including meat and animal-derived products or a very low-fat vegan diet and no meat for 6 months Follow-up of the results showed that 43% of the vegan group participants reduced diabetes medications, body weight decreased 6.5 kg, HbA1c (A1C) fell 1.23 points, and LDL cholesterol fell 21.2%. These results indicated that these improvements were greater than ADA recommended diet in which body weight decreased 3.1 kg A1C fell 0.38 points and LDL cholesterol fell 9.3%. This study is a high level of evidence confirming that a very low-fat plant-based diet reverse diabetes, almost half of diabetic patients on this kind of diet stopped all hypoglycemic medications within 6 months
China Study found that high fat consumption and high blood cholesterol were positively associated with various cancers. In another large prospective study almost 1.2 million Korean adults enrolled in the National Health Insurance Corporation to examine the association between total cholesterol and site-speci?c and all-cancer incidence. The researchers found that high total cholesterol was positively associated with the risk of several different cancers .The results from epidemiological studies   showed that obesity was associated with cancer including cancers of the colon, endometrium, breast, kidney, esophagus, pancreas, gallbladder, liver, and leukocytes. The mechanisms by which obesity induces or promotes tumor genesis are complicated and unclear. We know that the satiety hormone named leptin which is produced by adipose cells triggers cancer cells proliferation. Moreover, Insulin-like growth factor 1 (IGF-1), a peptide hormone, increases obesity and it promotes cancer cells proliferation in obese with hyperinsulinemia. The conclusion is that reduction of fat consumption and losing weight are strategies to prevent cancers. In a study obese postmenopausal women who had breast cancer along with high estrogen, obesity, high insulin, and high insulin-like growth factor-I (IGF-I), were put on a low-fat (10% cal), high-fiber (30–40 g per 1,000 kcal/day) diet and daily exercise for 2 weeks. The subjects’ serum and cell apoptosis were measured in vitro. The results show that a very-low-fat, high-fiber diet combined with daily exercise reduces risk factors for breast cancer such as serum insulin and IGF-I. In vitro growth of the breast cancer cell was reduced and apoptosis was increased. These finding showed that a very-low-fat, high-fiber diet combined with daily exercise might reduce cancer risk.
Anyone who don’t live in Europe or the North America need to know about trans-fat because the US Food and Drug Administration (FDA) has announced its final decision to outlaw partially hydrogenated oils, the primary source of artificial trans-fat in processed foods, by 2018. Therefore, the documentation about the harmful effects of trans-fats are gradually diminishing because there are no artificial trans-fat in European and American markets. However, foods produced by trans-fat still remain and are popular since long time, in developing countries. Trans-fat are uncommon in nature but have become common industrially produced food in past 50 year. Medical community believes that saturated fat found in pork or beef is a risk factor of ischemic heart disease and they have also tried to advise people against consuming unsaturated fat found in vegetable oils. Unsaturated fatty acid found in soybean oils that is liquid at room temperature is not suitable for industrial foods production because it is liquid and gets rancid easily. Thus, food manufacturers add hydrogen to vegetable oils (unsaturated fat) to make them more solid called thus forming trans-fat which is solid. Trans-fat usually appear in margarines, non-dairy creamer, cakes, cookies, biscuits, crackers and there are a lot of advertisements inducing people replace saturated fat with these fat.
In vivo studies showed the results that indeed trans-fat is the worst fat affecting health, worse than saturated fat The Harvard Medical School study .,studied dietary intake of 80,082 women who had no known coronary disease, stroke, cancer, hypercholesterolemia, or diabetes. During 14 years of follow-up, the investigator found that there were 939 cases of nonfatal myocardial infarction or death from coronary heart disease (CHD). After analysis of dietary fat intake and risk of CHD, the investigators found that each increase of 5 percent of energy intake from trans unsaturated fat, as compared with equivalent energy intake from carbohydrates, was associated with a 93 percent increase in the risk of CHD while each increase of 5 percent of energy intake from saturated fat, everyone used to fear, was associated with only a 17 percent increase in the risk of CHD.
A prospective population-based study in elderly Dutch to investigate their food consumption patterns and the risk of CHD for 10 years found that trans-fat was only one types of fat associating with the highest risk of CHD .
The medical community had agreed that people should stop eating trans-fat and change to eat other energy sources which should be from the plant. US Food and Drug Administration (FDA) has announced to outlaw artificial trans-fat in processed foods. However, there is still the problem in the developing countries for a long time because processed foods containing trans-fat which are low cost were shifted to countries where there are no regulation prohibiting trans-fat foods. Based on previously published epidemiological evidences medical community believed that high consumption of saturated fatty acids (meat fats and palm oils) causes more diseases than consuming fats with a lower proportion of saturated fatty acids.
In 2014, a systemic review and meta-analysis funded by British Heart foundation . on comprehensive fatty acids consumption 530,525 patients found that in addition to trans-fat, all kinds of fatty acids either saturated fatty acids, unsaturated fatty acids, polyunsaturated fatty acids or monounsaturated fatty acids were associated with the risk of coronary disease and the risk of death from coronary disease. The old belief of the medical communities was fairly shaken from the results of this analysis. Both the old evidences which was the basis of the medical community’s belief and the new evidence from this meta-analysis were just epidemiological evidences. The new evidence from this meta-analysis was more reliable, though it was not a high level of evidence randomized controlled trial. Therefore the guidelines on saturated fat and unsaturated fat consumption are not based on strong evidences .The mainstream medical communities have "believed" in the way that high consumption of saturated fat causes more diseases than consuming unsaturated fat.
High blood cholesterol was definitely associated with the risk of coronary heart disease (CHD) in normal people who had no other specific risk factors. A long-term, ongoing cardiovascular cohort study named the Framingham Heart Study was done on residents of the town of Framingham. After 10 years of follow-up during this study it was unclear which kinds of dietary fat (saturated fat or unsaturated fat) was causing heart disease. It is well agreed that patients with hyperlipidemia (hypercholesterolemia) must try dietary modification to reduce blood lipid. The existing researches indicated that patients can reduced blood cholesterol 150 mg/dl if they adhere to a very low fat, whole food, plant-based diet in natural form no extracts, no refinement or oils and calories from fat less than 10% of total calories