Saturday, March 30, 2013

Indulging in Eggs

Indulging in Eggs

It’s Easter and it's Passover. Eggs are everywhere. But should you be eating eggs?

I still see patients and doctors afraid to eat eggs. They worry that their blood cholesterol levels will go up. They may skip the egg yolk and only eat egg whites since egg whites contain virtually no cholesterol.

A typical chicken egg provides 70 calories and 6 grams of protein and virtually no carbohydrates. That egg contains about 5 grams of fat of which only 1.5 grams is saturated. Saturated fat is the type that tends to raise blood levels of the bad cholesterol.  LDL cholesterol is the “bad” cholesterol and is abbreviated LDL-C.

Eggs are an excellent source of protein. They contain all the essential amino acids, those amino acids that our body cannot make.
And about half of the protein in chicken eggs is in the yolk.
The yolk also contains many other nutrients.
In fact, all the vitamins in eggs are in the yolk.

So why be afraid to eat eggs including the yolk?
Well, eggs contain about 200 to 300 milligrams of cholesterol for each egg. And the concern is that eating all that cholesterol from eggs may increase the blood levels of that LDL cholesterol (LDL-C), the “bad” cholesterol.  

Now we all know that it’s not good to have a high level of LDL-C in the blood. 
In general, the higher the LDL-C, the greater the risk of coronary artery disease.
Drugs, known as statins, lower that LDL-C and reduce the risk of coronary artery disease. 

So how many eggs can you eat in a week or in a day without increasing your blood cholesterol much? That answer is not known.

Genetic factors are most important in determining our blood levels of cholesterol. Our genetic makeup determines how much cholesterol our liver makes. When it comes to the diet, it is clear that what is most important is the saturated fat in the diet not the amount of cholesterol in our diet.

A recent meta-analysis showed no compelling connection between egg consumption and heart disease or stroke. Another recent expert analysis questioned the previous concerns raised about dietary cholesterol, eggs and heart disease.

And it has been 8 years  since the American Heart Association published anything significant on diet and cholesterol. At that time they stated:

“The principal dietary strategy for lowering LDL-C is to replace cholesterol raising fatty acids (i.e. saturated and trans fatty acids) with dietary carbohydrate and/or unsaturated fatty acids”.

“On average, an increase of 100 mg/day of dietary cholesterol results in a 2 to 3 mg/dL increase in total serum cholesterol, of which about 70% is in the LDL fraction.

The authors state further that  “there is considerable inter-individual variation in response to these dietary interventions”.  
That is definitely true. In fact, the majority of people do not have a significant increase in the LDL-C with increases in dietary cholesterol.  

Some data show an increase in the HDL-C, the good cholesterol with egg consumption; one such study was published back in 1994.

Based upon feeding studies, the authors state that a  “3% to 5% reduction in LDL-C can be seen when dietary cholesterol is reduced to less than 200 milligrams per day."  That’s what I would call a trivial benefit in LDL-C for a drastic reduction in dietary cholesterol. 

And those cited studies were not studies done simply with eggs. It is possible that egg consumption does not lead to the same changes in blood lipids as do other sources of cholesterol in the diet. 

Heath Canada nutritional recommendations do not suggest an upper limit on dietary cholesterol.

And there are reports of people who eat lots of eggs each day and still have excellent levels of cholesterol in the blood. That fact points out the importance of genetics and other factors in the diet.

Updated American Heart Association guidelines on treating high blood cholesterol, the so-called Fourth Report of the Adult Treatment Panel, should be out this year.
It will be interesting to see how diet is addressed.

I am not convinced there should be any limit on egg consumption. 
I suggest you have your lipids monitored regularly by your doctor whether you are an egg eater or not.
You can make specific dietary changes and then get your levels rechecked to see how those changes impacted your LDL-C,  other lipid measurements and your weight.
And you should stay active, try to maintain a healthy weight, and otherwise eat a balanced diet.

Happy Easter. Happy Passover.

1 comment:

  1. I agree, Dr. Weiss. Eggs are a highly nutritious food and I also believe that we make it out to be a bad food because of its high cholesterol content. But, as you point out, it's fat content is low in saturated fat, and thus will have a minimal increase in the LDL-C. I also view shrimp in this same manner. I believe shrimp also gets a bad rap because of its high cholesterol content, but it is also low in saturated fat. Just another reason to emphasize the importance of an individualized well-balanced diet with appropriate physical activity that promotes a healthy weight. There are no BAD foods.....only BAD diets! Thanks for sharing!