Is Dietary Cholesterol as Bad for You as History Leads Us to Believe?
Egg consumption and risk of coronary heart disease and stroke
Some studies have found an inverse association between egg consumption and stroke risk. For example, an analysis of the Third National Health and Nutrition Examination Survey 1988-1994 (NHANES III) dataset found a significant inverse association between higher egg consumption and stroke mortality among men.34 A cohort study from Japan found that increased consumption of animal products (including eggs) was associated with reduced risk of total and hemorrhagic stroke death.39
We considered several potential reasons for the lack of an overall association between egg consumption and coronary heart disease or stroke. Although dietary cholesterol influences plasma concentrations of serum cholesterol, the effects are relatively small.10 In addition, epidemiologic studies have found weak or little association between dietary cholesterol intake and cardiovascular disease risk.10 Apart from dietary cholesterol, saturated fat and dietary patterns might also influence blood cholesterol levels,44 45 46 suggesting that compliance with general dietary recommendations instead of simply reducing egg consumption could have a greater effect on the risk of cardiovascular disease. Additionally, individual differences in response to dietary cholesterol vary greatly, which could affect the association between egg consumption and risk of coronary heart disease and stroke. Moreover, several studies have shown that egg consumption favors the formation of larger LDL and HDL particles, which might enhance protection against atherosclerosis.47 48
Other than cholesterol, eggs are a good source of other nutrients such as high quality protein and vitamin D. In the Diet, Obesity, and Gene (Diogenes) Project, increased protein consumption together with a modest reduction in glycemic index was beneficial for weight control.49 Substituting protein for carbohydrate also partly resulted in lower blood pressure, improved lipids levels, and concomitantly reduced cardiovascular risk.50 Higher vitamin D intake might have beneficial effects on the reduction of visceral adipose tissue51 and other cardiovascular risk factors52.
Subgroup analyses suggest a positive association between higher egg intake and risk of coronary heart disease in diabetic patients, and an inverse association between higher egg consumption and incidence of hemorrhagic stroke.
Hearth Disease Risk Factors
In 1946, Los Angeles physician, Dr Lester Morrison, began a study that would later reveal the crucial role of diet in heart disease (Morrison, 1960). Morrison reduced the fat intake of 50 heart attack survivors and compared their health to 50 other heart attack survivors whose fat intake was left unchanged (the control group). After eight years, 38 of the control group had died compared to just 22 of the low-fat group. After 12 years, the entire control group had died but 19 of the low-fat diet group were still alive. Around the same time, the residents of Framingham, just outside Boston Massachusetts in the US, took part in a study to investigate the role of diet and lifestyle in heart disease. By observing who suffered from heart disease and who did not, the Framingham Study helped identify several key risk factors (Kannel et al., 1961). A number of these are now firmly associated with heart disease including high cholesterol levels, hypertension, family history of heart disease, diabetes, obesity, smoking and poor diet.
Cholesterol is a fatty substance most of which, contrary to popular belief, is produced by the liver. Only a small amount (15-20 per cent) comes from the diet – and only then if it contains animal foods (however eating ‘bad’ fats and animal protein raises cholesterol levels more than eating cholesterol itself
Sat Fat Drives up Cholesterol
Saturated, hydrogenated (and trans) fats and animal protein are the main culprits in the diet that raise cholesterol levels. It used to be thought that dietary cholesterol itself was the main villain however this is not the case, although those at risk of heart disease should limit their intake or avoid it completely.
The traditional approach to lowering cholesterol levels was to reduce total fat (and cholesterol) intake. However, research shows that replacing saturated fat with unsaturated fat is more effective (Hu et al., 2001). A well-balanced plant-based diet contains less saturated fat and more unsaturated fat than the typical Western diet dominated by meat, poultry, eggs and dairy. However, a vegetarian diet rich in dairy foods is not the answer as high-fat dairy products are a major source of saturated fat and cholesterol.
Dietary Fat and Heart Failure: Moving from Lipotoxicity to Lipoprotection
Studies in rodents show that in the absence of obesity replacing refined carbohydrate with fat can attenuate or prevent ventricular expansion and contractile dysfunction in response to hypertension, infarction or genetic cardiomyopathy
The role of animal-based foods in stroke has raised some controversy with a number of scientists suggesting that animal foods may contain some component that has a protective effect against stroke (Ding and Mozaffarian, 2006). We know that animal products increase the build up of fatty deposits in the coronary arteries so how could they protect arteries in the brain? The theory is yet to be proven but suggests that certain fatty acids (arachadonic acid), mainly obtained from animal sources, may help maintain the integrity of the smaller blood vessel walls in the brain and protect against stroke.
However, the research suggests that the protective effect of animal products may be largely confined to haemorrhagic stroke (Sauvaget et al., 2003), whereas the majority of strokes in the UK are ischaemic (caused by blockages). Furthermore, the supposed protective role may be restricted to those with low cholesterol and high blood pressure. It would be better to change to a healthier diet to lower the blood pressure than to attempt to avoid a stroke by eating more of the types of food that lead to high blood pressure, obesity and heart disease!
Numerous studies do confirm that increasing the amount of fruit and vegetables in the diet can reduce the risk of stroke (Gillman et al., 1995; Johnsen et al., 2003, Pomerleau et al., 2006). One review quantified the effect by examining a group of studies involving a total of 114,279 adults of whom 570 experienced a stroke (Joshipura et al., 1999). Results showed that those consuming the most fruit and vegetables (around 10 servings per day) had a 31 per cent lower risk of stroke. A more recent review of eight studies (including 257,551 people and 4,917 stroke events) concurred fruit and vegetables had a significant protective effect (He et al., 2006).
Nina Teicholz once again misleads your readers about the components of a heart-healthy diet (“The Last Anti-Fat Crusaders,” op-ed, Oct. 29). She claims that a very low-saturated-fat diet “has rarely, if ever, been documented in healthy human populations.” Not so. All of the long-lived peoples of the world eat a basically vegetarian diet, including the Okinawans in Japan, the Seventh Day Adventists here in the U.S. and some Mediterranean populations that eat the heart-healthy Mediterranean diet, which also emphasizes plant foods. There has never been a long-lived human population that primarily ate an animal-based, high-fat diet.
Dr. Dean Ornish proved in a scientifically controlled, double-blind study that a very low-fat diet could actually reverse atherosclerosis, the narrowing of the arteries that causes most heart attacks.
The USDA doesn’t recommend a low-fat diet. It recommends eating less saturated fat
if you have HIGH cholesterol … eating eggs will not increase your cholesterol too much … but you will still die of … http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3648753/