Go ahead and eat that egg

I enjoy eating eggs and when I was growing up in the 1960s and 70s, this was an encouraged practice. Eggs are high in a variety of nutrients such as proteins, vitamins, and minerals while being low in calories. They are also high in cholesterol (one egg has 62% of the recommended daily allowance of cholesterol), and around that time the connection between blood cholesterol and heart disease was being made. As a result, the view arose that consuming cholesterol could lead to a rise in blood cholesterol especially LDL ("bad" cholesterol) levels which is a major risk factor for atherosclerosis and cardiovascular disease. In the 1980s, people were discouraged from eating eggs for this reason.

Fortunately for those who like eggs, times are changing again. This week The Dietary Guidelines Advisory Committee which meets every 5 years published their new guidelines on recommended food consumption practices which are summarized as follows (link):

“The U.S. population should be encouraged and guided to consume dietary patterns that are rich in vegetables, fruit, whole grains, seafood, legumes, and nuts; moderate in low- and non-fat dairy products and alcohol (among adults); lower in red and processed meat; and low in sugar-sweetened foods and beverages and refined grains. These dietary patterns can be achieved in many ways and should be tailored to the individual’s biological and medical needs as well as socio-cultural preferences.”

There are five take-home messages from the revised guidelines which are highlighted here.

1. Loosening of dietary cholesterol restrictions. More recent studies have shown that eating cholesterol-rich food does not increase blood LDL levels as much as previously thought. For example, a typical healthy person can eat one egg a day without raising the risk of heart disease. It has been found that most cholesterol (60-70%) is synthesized by the body, and the rest is taken from the diet. Thus, only about ~10% of the ingested cholesterol will become cholesterol in the blood (link); the rest is digested, stored, or excreted.

2. Reducing sugar in diet. This is a major point of emphasis of modern medicine; many people consume too much sugar. Sugar contains lots of calories without possessing any nutritional value. Too many calories will inevitably result in obesity. The recommendation from the panel is that "Americans should limit added sugars to no more than 10 percent of daily calories. This is in line with the World Health Organization's guideline, though WHO suggests a goal of limiting sugars to 5 percent of daily calories." For the typical American, added sugar represents roughly 17.5% of daily calories.

3. Moving toward a more plant-based diet. Examples include fruits, vegetables, nuts, whole grains, and legumes (beans, peas, lentils). This plant matter contains valuable nutrients without unwanted sugar (calories), salt, or saturated fat.

4. Moving away from red meat and animal fat (saturated fat). Less animal, more plant. Among the meats, fish and lean white meat are preferred to fatty, red, or processed meat which tend to have higher levels of saturated fat. Remember unsaturated fat, found in fish, nuts, olive oild, and vegetable oils is more healthy than saturated fat which is better than trans fat (e.g. fried foods and baked goodies made with shortening).

5. Adopting a healthy dietary pattern. The classic example of a healthy dietary pattern is the Mediterranean diet. As previously described, the Mediterranean diet emphasizes abundant plant foods, fresh fruit for dessert, olive oil as the principal source of fat, dairy products, low to moderate consumption of meat in general. As a result, the diet is low in saturated fat and low in refined carbohydrates. Note the key is a pattern of food consumption rather than avoiding specific items, which often then are replaced with something that may be equally or more harmful.

A final important statement by the dietary guidelines committee was to emphasize not only the human health aspects of a plant-based diet, but also the beneficial environmental impact: "The committee concludes that a plant-focused diet not only promotes health, but is also more environmentally sustainable." Indeed, we need to be concerned about our ability to produce enough healthy food in a way that is sustainable.

There has been an interesting evolution in the guidelines from the Advisory Committee. In 1980, the emphasis was on limiting cholesterol and fat with the thinking being that consuming them would raise levels of cholesterol and lipoproteins in the blood that contributed to atherosclerosis. However, foods high in cholesterol and fat were replaced with refined carbohydrates (e.g. sugar) found in junk food, bread, rice, and sugary drinks. The resulting explosion in calorie consumption led to an obesity epidemic; obesity and its complications (e.g. Type 2 diabetes) are significant risk factors for cardiovascular disease. This realization along with more recent studies that show that dietary cholesterol has a small effect on blood cholesterol of healthy people (see above) has resulted in the change in guidelines.

So go ahead and eat that egg (Figure 1). Dietary cholesterol (in moderate amounts) is not dangerous for healthy people. The more general message is that you want to foster a dietary plan that involves more plant-derived foodstuffs and less animal meat.

Figure 1. An egg a day is fine for most healthy people.