Thursday, February 10, 2011

No, Dr. Katz, Eggs Are Not A Health Food

"Just a second," as Judge Judy says.

This news about eggs has been making headlines:

USDA: Eggs' Cholesterol Lower Than Thought, Vitamin D Higher, Dr. David Katz, The Huffington Post, February 8, 2011

It's based on a re-analysis of the nutrients in a typical factory-farmed egg:

New Study Shows Large Eggs Are 14 Percent Lower In Cholesterol & 64 Percent Higher In Vitamin D, PRNewswire, February 8, 2011

The message coming from the egg industry's American Egg Board is that "Eggs Are Now Naturally Lower in Cholesterol." If you read that fast it looks like it's saying eggs are naturally low in cholesterol. That's intentional. Because eggs are one of the most cholesterol-rich foods we eat, even after the new analysis. And the public has a mindset, which the Egg Board loathes, that cholesterol is bad for you. (Many people do, at least.)

Spence at al.1 say that the cholesterol in one large egg yolk is equivalent to the cholesterol in two-thirds of a pound of beef, plus three slices of cheese, plus four strips of bacon - the contents of a Hardee's Monster Thickburger.

I took a look at the USDA's new analysis and compared it to the old:

Egg, whole, raw, fresh, 50g:

Old (from NutritionData based on USDA) ........ New (USDA):

Calories 71.5 ........ 72

Total Fat 5g ........ 4.75g
Saturated Fat 1.550g ........ 1.563g
Monounsaturated Fat 1.9045g ........ 1.829g
Polyunsaturated Fat 0.7g ........ 1.0g
     Omega-3 37.0mg ........ 51mg
     Omega-6 574mg ........ 792mg
Trans fat 0g ........ 0.02g
Cholesterol 211mg ........ 186mg

Total Carb 0.4g (380mg) ........ 0.4g (360mg)
Dietary Fiber 0g ........ 0g
Sugars 0.4g ........ 0.2g (plus others not noted to come up with 0.4 total?)
     Glucose 105mg ........ 180mg

Protein 6.3g ........ 6.3g

Vitamin D 17.5 IU ........ 41 IU

Someone is getting jiggy with the numbers. You can't keep calories the same and claim a reduction in fat without a corresponding increase in carbs and protein. But they claim the protein remained the same too. Which has to mean that carbohydrate content increased. The USDA's breakdown for the new egg unhelpfully rounds all carbs except for glucose to 0. It doesn't add up.

Upon inspection, glucose content went up in the new egg:
  • 71% increase in glucose, up from 105mg to 180mg per egg.
And along with a reduction in beneficial monounsaturated fat in the new egg, there was:
  • 43% increase in polyunsaturated fat, mostly omega-6 fat which went up by an additional 218 mg.
By the looks of it, the incredible edible egg is turning into the incredible edible soybean, phytoestrogens and all.

After all that, I think the differences aren't that striking, or meaningful. The nutrients in an egg will of course vary ... by egg size, what you feed the chicken, the environment of the chicken (allowed to hunt and peck in pasture vs. housed). And what nutrients we absorb from the egg will vary ... by our constitution, what other foods we eat, how the egg is prepared, etc. The variables are numerous, so it's hard to say that 24 mg this way or 24 IUs that way are meaningful.

By the way, eggs have more vitamin D because the hen is fed more vitamin D. We could take the supplement ourselves, get a lot more than 24 IUs, and skip the fat, cholesterol, environmental toxins, and support of unethical factory farming.

What does mean something are large epidemiological studies that show that eggs are not harmless for people at risk for cardiovascular disease (CVD). The pro-egg messages the Egg Board (and Dr. Katz) is propagating are based on effects in healthy people - people who would need to be followed for longer periods of time before ill effects became apparent.

The very same studies the Egg Board (and Dr. Katz) quoted did find increased CVD risk in people with diabetes:

A Prospective Study Of Egg Consumption And Risk Of Cardiovascular Disease In Men And Women
, Journal of the American Medical Association, 1999
"The apparent increased risk of CHD associated with higher egg consumption among diabetic participants warrants further research."

Regular Egg Consumption Does Not Increase The Risk Of Stroke And Cardiovascular Diseases, Medical Science Monitor, 2007
"The increased risk of coronary artery disease associated with higher egg consumption among diabetics warrants further investigations."

Both of the studies above showed a doubling! of CVD risk in a non-healthy population (diabetes). Yet Dr. Katz referenced the first one saying, "numerous studies ... have suggested that dietary cholesterol in general, and eggs in particular, do not contribute meaningfully to blood cholesterol levels, or cardiac risk."

The first one also showed that regular egg consumption actually increased the risk for diabetes, as do these two:

Food Intake Patterns Associated With Incident Type 2 Diabetes: The Insulin Resistance Atherosclerosis Study, Diabetes Care, 2009
Finding: Consumption of eggs increased risk for type 2 diabetes.

Egg Consumption And Risk Of Type 2 Diabetes In Men And Women, Diabetes Care, 2009
Finding: Consumption of eggs increased risk for type 2 diabetes.

Here's one that found regular egg consumption doubled mortality:

Egg Consumption In Relation To Cardiovascular Disease And Mortality: The Physicians' Health Study, American Journal of Clinical Nutrition, 2008
"Egg consumption was positively related to mortality, more strongly so in diabetic subjects."

I was scanning through the comments under Dr. Katz's pro-egg article and was disappointed to see so many who sided with his argument without digging a little deeper. The methods food industries use to shape public opinion are changing; they're becoming more effective.

1 Dietary Cholesterol And Egg Yolks: Not For Patients At Risk Of Vascular Disease, The Canadian Journal of Cardiology, November 2010


caulfieldkid said...


Are you toying with going to a nearly vegan diet at this point? If so, it seems you are finding reasons that are both ethical and health related in nature.


Bix said...

That seems to be the direction, shaun, yes. For the reasons you stated.

caulfieldkid said...

Well keep us posted. Although I don't eat very much meat/dairy as it is, your posts are thought provoking. I'm pondering the possibility of being more purposeful in a vegan like diet.

manu said...

eggs are one of the things I have most difficulty eliminating from my diet... beef was quite easy and so was pork etc..., but there's nothing better than a big onion salad with beans and eggs. From my personal experience: in periods where I was eating 2-3 eggs a day my blood work didn't show elevated ldl cholestrol levels. Bix, ethical issues aside, if you were given eggs from free range, farm chickens and they weren't going to be slaughtered or consumed and would just be kept as egg laying birds, do you think in the long run these eggs will impact your health negatively?

Matthew said...

Vegan for health reasons? Say it ain't so!

I guess in the past I've said if I moved back to the east coast and I wasn't near polyface farms, I'd probably go vegetarian as well, but that's only due to poor state of our national food supply and the urbanization on the east coast driving out a lot of family farms-- not because being a vegan is healthier. Being a healthy vegan-- not a tofu potato chip popping one requires A LOT of hard work all the time to properly soak, ferment, and sprout everything. On top of that finding clean produce that is covered in pesticide and grown in soil that isn't depleted and needs petrochemical fertilizers just to maintain yields is hard as well.

I prefer Freedom Rangers and their <a href=">pastured eggs</a>, but for convenience I buy stuff at PCC that is certified humanely raised and free range. Also duck eggs with Pure Eire heavy cream make the thickest, silkiest, creamiest, creme brulee you can imagine.

Bix said...

manu ... It depends on how many you eat, and what other foods are in your diet. If I could be sure that the eggs were of the provenance you described, I might eat them occasionally. In my case, I don't have this assurance.

Epidemiological studies show the highest risk for daily consumption.

When I say it matters what other foods are in your diet, two things: 1) A diet high in animal foods has another problem. I'll post it. 2) A diet high in fruits and vegetables is good - it can prevent oxidation of the fat in the rest of the diet, especially if those foods are consumed at the same meal.

virginia said...

"The Emperor and His New Eggs"

If only you could grab the Huffington/AOL audience (with comments off and no ads), Americans might start thinking about what they eat.

I'm attending a vegan wedding reception in April - should be interesting.

mitzi said...

When I hear or see people commenting on the difficulty/impossibility of the vegan or near-vegan diet, I wish I could point them to the devout Hindus with whom I work. They represent millions of Indians. Many of them have never eaten eggs, meat, or fish, yet they are healthy and long-lived. Even the meat eaters generally consider it a feast-day or week-end indulgence. They do consume some dairy products, but from cows that are LOVED (and in a sense worshiped), and fed accordingly. Their robust health (which a lot of North American Paleos would consider impossible) has inspired me toward a near-vegan diet for health reasons. A few eggs once in a while probably won't hurt a person who is healthy (especially if from healthy hens allowed to be hens), but autopsy evidence over the years has shown that even young Americans have atherosclerosis. My grandfather pastured his own farm animals, and ate their meat and his home-grown vegetables, and died of a heart attack at 62. The choice is difficult, and the evidence murky sometimes. Thanks for your postings.

Bix said...

Matthew, that was a pretty good description of our food supply. It's funny, you actually made a good argument for why eating vegan might be healthier. Maybe it's not the optimum diet for humans (I'm not saying I know), but maybe, by process of elimination, it ends up being the least harmful.

Bix said...

virginia, one problem with ads is that it discourages you from speaking poorly about your sponsor. It's not wise to bite the hand that feeds you. I wonder how the Huffington/AOL mating will play out in HuffPost's articles.

Claudia said...

I agree with mitzi. What's so hard about eating plants?

Charles R. said...

If you want to avoid oxidized fat, eat fat that does't get oxidized, i.e., saturated fat.