Doctors and scientists alike have long denigrated the egg for it’s high cholesterol content. It has been established for some time that high blood levels of the blood vessel clogging fat, called cholesterol, is an independent risk factor for heart disease. It would seem to make logical sense then that eating foods high in the cholesterol (like eggs), would raise our blood levels of cholesterol and increase our heart disease risk. The association, however, is not as simple as it seems, and new research is pointing towards only a very weak association between egg intake and high LDL (or bad) cholesterol and some strong associations between certain nutrients in eggs and a reduced risk of heart disease.
The Cholesterol Debate
An October 2009 report, which appeared in the International Journal of Clinical Practice Supplement, looked at studies examining the interplay between blood cholesterol, high cholesterol foods and heart disease to date and concluded that the relationship between dietary cholesterol and heart disease risk was likely largely over-exaggerated.
A large Japanese study, conducted on 90735 subjects, which appeared in the British Medical Journal in November 2006, showed that although blood cholesterol was associated with an increased risk of coronary heart disease, daily egg consumption, was not. Another study in the Journal of Nutrition in February 2008, showed that in obese men on a low carbohydrate diet, that egg consumption of 3 eggs per day had no effect on LDL cholesterol but did increase HDL (or good) cholesterol levels after 12 weeks.
Eggs were first given some reprise a decade ago after results from a large study published in The Journal of the American Medical Association in April 1999. The study looked at results from two large cohorts: The Health Professionals Follow-up Study (1986-1994) and the Nurses' Health Study (1980-1994). Analyses showed no significant association between egg consumption at an average of one egg per day and risk of cardiovascular disease in men and women. This same insignificance was not seen for diabetics and those with Familial Hypercholesterolemia though, who showed a slight positive relationship between egg consumption and high LDL cholesterol. No major cohorts examining egg consumptionand heart disease risk in diabetics and and those with Familial Hypercholesterolemia have been done since, which marks this a grey area in the egg debate.
Registered dietician and consultant dietician to the Egg Industry of South Africa, Madeleine De Villiers, explains that its saturated and trans fatty acids have a far greater impact on blood LDL cholesterol then foods that are just high in cholesterol. Eggs, although high in cholesterol, are also low in saturated fats, which is part of the reason as to why an egg a day does not seem to raise LDL cholesterol, explains De Villiers.
According to the Heart and Stroke Foundation South Africa (HSFSA) recommendations, the daily recommended cholesterol intake is 300 milligrams for people with normal LDL cholesterol levels and 200 milligrams or less for those with heart disease or very high LDL cholesterol levels. Just one egg contains just over 200 milligrams of cholesterol. To follow these guidelines, it means that you would need to take into account your cholesterol intake from other animal sources (e.g. meat, chicken, fish or dairy products). If you eat a whole egg, you would need to avoid or limit other sources of dietary cholesterol on that day. Provided a low saturated fat diet is followed and the recommended intakes are no more than four eggs per week if you have high blood cholesterol levels and no more than two eggs per week for those with heart disease, eggs should not pose a major threat. The British Heart Foundation, however, no longer set limits on the number of eggs that should be eaten, provided they are consumed as part of a healthy diet low in saturated and trans fats. This does not mean a green light for eggs, and consumption of more than one egg yolk per day (or more than 7 eggs a week) may be associated with other health risks, like an increased risk of heart failure, according to results from the Physician’s Health Study published in Circulation in 2008. In addition, people diabetes and those with Familial Hypercholesterolemia (an inherited form of high cholesterol that carries a very high heart disease risk) should possibly still restrict their egg intake.
Egg Nutrition
Eggs are powerhouses of nutrition, with the majority of the nutrients (including cholesterol) concentrated in the yolk. Egg yolks contain most of the vitamins the human body requires, with the exception of vitamin C. Eggs contain a good concentration of B complex vitamins as well as fat soluble vitamins A and D and small amounts of vitamin E. Eggs are also a good source of iodine, which regulates thyroid function, and phosphorous, which is involved in bone health. Eggs are also rich in the minerals zinc and iron.
Besides containing about 200mg of cholesterol, one egg yolk, approximately seventeen percent of an egg’s fatty acids are polyunsaturated, forty-four percent mono-unsaturated and thirty-two saturated, which means that two-thirds of the egg’s fats are unsaturated. This means that two thirds of the fat in eggs is of the healthy, unsaturated kind. When hens are fed a special diet rich in omega-3 fatty acids, eggs will also have the added benefit of being rich in these anti-inflammatory fats. Omega-3 eggs will be labeled as such.
The egg yolk also contains a fat-like substance known as lecithin. Lecithin, a phospholipid, is a constituent of all cell membranes, plays a role to repair tissue cells and is also an important component of HDL, the "good" lipoprotein that helps to transport fats to the liver for excretion, lowering the risk of CHD. De Villiers believes that lecithin is another plus factor for eggs, but holds that health claims made for lecithin, especially lecithin supplements, are unproved, at least in humans.
According to the Heart and Stroke Foundation South Africa (HSFSA) recommendations, the daily recommended cholesterol intake is 300 milligrams for people with normal LDL cholesterol levels and 200 milligrams or less for those with heart disease or very high LDL cholesterol levels. Just one egg contains just over 200 milligrams of cholesterol. To follow these guidelines, it means that you would need to take into account your cholesterol intake from other animal sources (e.g. meat, chicken, fish or dairy products). If you eat a whole egg, you would need to avoid or limit other sources of dietary cholesterol on that day. Provided a low saturated fat diet is followed and the recommended intakes are no more than four eggs per week if you have high blood cholesterol levels and no more than two eggs per week for those with heart disease, eggs should not pose a major threat. The British Heart Foundation, however, no longer set limits on the number of eggs that should be eaten, provided they are consumed as part of a healthy diet low in saturated and trans fats. This does not mean a green light for eggs, and consumption of more than one egg yolk per day (or more than 7 eggs a week) may be associated with other health risks, like an increased risk of heart failure, according to results from the Physician’s Health Study published in Circulation in 2008. In addition, people diabetes and those with Familial Hypercholesterolemia (an inherited form of high cholesterol that carries a very high heart disease risk) should still restrict their egg intake.
Egg white, or albumin, is pure protein and contains no traces of any cholesterol raising fats. Albumin is a complete protein (it contains all 8 essential amino acids) providing 5.5 grams of protein (11.1% of the daily value for protein) in one egg.
Healthy Heart Eating Guidelines
It’s all very well following the guidelines on egg consumption, but if you are serious about heart health, a more holistic approach to cholesterol management should be followed. The HSFSA recommends the following:
Eat small, regular meals and snacks
Limit the amount of saturated or animal fats that you eat and replace then with small amounts of unsaturated vegetable fats
Cut down on your red meat intake, or choose lean cuts. Take the skin of chicken and choose more fish and vegetable proteins, like legumes and soya.
Instead of frying meats, rather grill, bake, boil or steam.
Cut down on high cholesterol foods, like egg yolks, organ meats and some seafood (prawns and calamari for example).
Cut down on hydrogenated and trans fats (like those found in many margarines, vegetable shortenings, fast foods and high calorie commercially baked goods).
Increase you intake of high fiber foods, especially soluble fiber (found in oats, oat bran, legumes, rice bran, barley, citrus fruits, strawberries and apples).
Eat at least five servings of fruit and vegetables per day and choose from a variety of deeply hued plant foods
Reduce your intake of salt and salty foods
Read labels and choose foods with the Heart Mark