Health food...or bad yolk?

“Love to eat eggs? U.S. panel now says they’re not a health risk,” reported Reuters in February.

“Cholesterol in the diet: The long slide from public menace to no ‘appreciable’ effect,” ran the headline in the Washington Post.

Both articles were referring to a report from a panel of scientists that the government will rely on this year as it revises its Dietary Guidelines for Americans. Did the report get it right? And should you avoid eggs—the food that supplies our biggest dose of cholesterol?

Cholesterol Confusion

“Cholesterol: And Now the Bad News,” announced the March 1984 TIME magazine cover.

“Cholesterol is proved deadly, and our diet may never be the same,” the magazine reported.

Oops. Not for the first (or last) time, the media mixed up the dangers of cholesterol in blood and cholesterol in foods.

The article was about a major study showing that reducing high blood cholesterol lowers the risk of heart disease. It wasn’t about eggs. But since eggs contain more cholesterol than most other foods, eggs got more than their share of the blame, even though foods rich in saturated fat (like red meat, cheese, and butter) are bigger culprits.

“The saturated fat in foods has a greater effect on the average person’s LDL, or bad, cholesterol levels than the cholesterol in foods,” says Frank Sacks, professor of cardiovascular disease prevention at the Harvard School of Public Health.

And the confusion hasn’t disappeared. This past February, when the Dietary Guidelines Advisory Committee issued its report, the New York Daily News mangled the distinction between foods that are high in cholesterol and foods that are high in saturated fat.

“It’s ok to dig in to red meat,” explained the newspaper. “Embracing red meat and eggs marks a shift from previous versions of the report, which used to cap cholesterol consumption at 300 milligrams a day—the amount in a stick of butter, a 10-ounce steak or two eggs.”

In fact, the report urged Americans to eat less red meat. And it urged us to limit saturated fat. But the panel did scrap the previous 300-milligram daily cap on cholesterol in food.

Why?

The Evidence

“After reviewing scores of studies that showed no correlation between dietary cholesterol and serum cholesterol, or ‘bad’ cholesterol present in the blood, the committee determined that cholesterol was not ‘a nutrient of concern for overconsumption,’” reported Reuters.

Really? If the panel reviewed scores of studies, it didn’t say so.

The panel’s only explanation was brief: “Available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol, consistent with the conclusions of the AHA/ACC report.”1

Only one problem: that’s not consistent with the 2013 report from the American Heart Association and American College of Cardiology. That report concluded that there was “insufficient evidence” to know if eating less cholesterol would lower LDL cholesterol in blood.2

“No evidence doesn’t mean the evidence is no,” says Robert Eckel, a professor of medicine at the University of Colorado Denver who chaired the AHA/ACC panel.

“A three-to-four-egg omelet isn’t something I’d ever recommend to a patient at risk for cardiovascular disease,” adds Eckel, who says that he still uses only egg whites for his omelets.

For decades, experts have relied largely on studies in which people were fed or sent home with either eggs or cholesterol-free egg substitutes.

“When we looked at 17 of those high-quality studies, we showed that eating one egg a day raises LDL cholesterol by 4 points,” says Martijn Katan, an expert on diet and cardiovascular disease and an emeritus professor at VU University Amsterdam in the Netherlands.3 An earlier meta-analysis got virtually identical results.4

(To put that in perspective, you’d get the same rise in LDL from eating a daily tablespoon of butter—with 7 grams of saturated fat.)

But the AHA/ACC decided that those studies hadn’t tested realistic doses of cholesterol on enough people.

Tracking Egg Eaters

What about studies that ask people what they eat and count heart attacks years later?

When Harvard researchers tracked roughly 38,000 men for eight years and 80,000 women for 14 years, those who ate the most eggs had no higher risk of heart disease or stroke than those who ate the fewest.5

But “the most” wasn’t much. “In these studies, intakes only ranged from around zero to one egg per day,” says Sacks.

Yet people rely on those studies to declare that the sky’s the limit for eggs. “Stop Trashing Eggs: Large Study Finds No Harm,” announced Forbes magazine in 2013.

“The question remains whether more than one egg a day would be harmful,” says Sacks.

And some studies find a risk even for one-a-day egg eaters. For example:

■ Heart disease if you have diabetes. Women with type 2 diabetes who ate at least one egg a day had a 44 percent higher risk of heart disease than those who ate less than one egg per week. Worse yet, men with diabetes who ate at least one egg a day had double the risk—a 100 percent higher risk—of heart disease.5,6 “We don’t know exactly why,” says Luc Djoussé, associate professor of medicine at Harvard Medical School. “People with diabetes have a higher risk of heart disease.” Maybe they’re more sensitive to cholesterol.

Type 2 diabetes is no small matter. One out of three people with the disease don’t know they have it. And experts predict a diabetes tsunami now that one out of three Americans have prediabetes. (See July/August 2014, cover story.)

■ Diabetes. Djoussé and his colleagues tracked roughly 20,700 men in the Physicians’ Health Study for 20 years and roughly 36,300 women in the Women’s Health Study for 12 years.7

“We found that men who ate five or more eggs a week had about a 50 percent higher risk of diabetes compared to those who didn’t eat eggs,” he notes. “And women who ate seven or more eggs per week had a 77 percent increased risk.”

How might eggs cause diabetes?

“There’s some data suggesting that eating egg yolks could lead to insulin resistance,” says Djoussé.

“But the jury’s still out. We’re not quite sure whether it’s the cholesterol in eggs or not.” Something else about egg eaters might raise their risk of diabetes (though researchers account for every difference they can detect).

■ Prostate cancer. When researchers followed roughly 1,300 men with prostate cancer for two years, cancers were twice as likely to progress—that is, spread to bone, require more treatment, or lead to death—in those who typically ate about six eggs a week than in those who ate less than one egg every two weeks.8

“The results were interesting, but we weren’t sure if they were due to chance,” notes lead author Erin Van Blarigan (formerly Richman) of the University of California, San Francisco.

So Van Blarigan looked at roughly 27,600 healthy men in the Health Professionals Follow-Up Study. Those who reported eating at least 2½ eggs per week had an 81percent higher risk of dying from prostate cancer over 14 years than those who said they consumed less than half an egg per week.9

“There’s too little data to make recommendations,” cautions Van Blarigan. “But if my dad were at high risk for prostate cancer, I’d think it would be prudent for him to limit his intake of whole eggs.”

How Many Eggs?

so, how many eggs (or, more precisely, egg yolks) can you safely eat? For decades, most health authorities recommended a limit of 300 milligrams of cholesterol per day. (One large egg has around 200 mg. A modest 3oz. Serving of fish, poultry, or meat has 50 to 100 mg.) For years, the American Heart Association translated that advice into no more than three or four eggs per week.

And today? “I would say limit eggs to four to five per week,” advises Djoussé. “The fact that eggs contain protein and minerals doesn’t mean we can eat uncontrolled amounts. Common sense still matters.”

Others agree. “It’s reasonable to eat eggs several times a week, but eating one or two eggs every morning may raise your risk of type 2 diabetes or your risk of heart disease if you already have diabetes,” says Sacks.

“And eggs and toast aren’t the best breakfast,” he adds. “You’re better off eating something like unsweetened yogurt with fresh fruit and nuts.”

Lost in the cholesterol hubbub was the key advice from the Dietary Guidelines panel, which was to eat a “healthy dietary pattern” like those used in the DASH study (which gave people foods with only 150 mg of cholesterol per day). That pattern is:

■ higher in vegetables, fruits, whole grains, low- or non-fat dairy, seafood, legumes, and nuts

■ moderate in alcohol (for adults)

■ lower in red and processed meats

■ low in sugar-sweetened foods and drinks and refined grains

Ain’t much room for eggs in there.

1 health.gov/dietaryguidelines/2015-scientific-report.

2 J. Am. Coll. Cardiol. 63: 2960, 2014.

3 Am. J. Clin. Nutr. 73: 885, 2001.

4 BMJ 314: 112, 1997.

5 JAMA 281: 1387, 1999.

6 Am. J. Clin. Nutr. 79: 999, 2004.

7 Diabetes Care 32: 295, 2009.

8 Am. J. Clin. Nutr. 91: 712, 2010.

9 Cancer Prev. Res. 4: 2110, 2011.