Research: Cracking the consumer health puzzle

Health scientist Jonathan Little says that when it comes to nourishing breakfast foods, eggs are hard to beat. Now, he’s hoping to shed new light on other health benefits of eating eggs in a new study at the University of British Columbia (UBC).

“Eggs are one of the most nutritionally complete foods people can eat,” says Little, an associate professor at UBC’s School of Health and Exercise Sciences on the Okanagan campus. “The focus now is on learning about the other positive impacts that egg consumption has on human health.”

His new project is a follow up to a recent one-day continuous glucose monitoring study he led involving 25 diabetic people. Participants ate either low-carbohydrate breakfasts (omelettes with cheese and spinach) or conventional high-carb ones (oatmeal and berries).

The results, which were published in the peer-reviewed American Journal of Clinical Nutrition in April, suggest eggs help to both lower and control glucose levels throughout the day. “That’s important because the clinical treatment goal for diabetes is to lower glucose levels,” Little says. Egg eaters also reported feeling less hungry later in the day and had less cravings for junk food.

Little will delve deeper into subject in the new three-month study, which will involve 80 people with type-2 diabetes who are currently being recruited. Forty will eat omelettes for breakfast and forty will eat nutrition guideline-based foods. All 80 participants will eat the same foods for lunch and supper.

“This time we’ll look not just at glucose spikes but overall glucose control, weight loss and body composition and blood and lipid profile and cholesterol levels,” Little says about the study, which is being co-funded to the tune of $220,000 by Egg Farmers of Canada (EFC) and the Egg Nutrition Center (ENC), the science and nutrition education division of the American Egg Board.

He expects to publish his findings in two years’ time.

Little’s study is the latest step in a global scientific journey aimed at identifying and understanding the many impacts – good and bad – of regularly consuming nutrient-packed eggs. Researchers have looked at their impact on everything from human brain development and function to heart and eye health, weight management and muscle strength at various stages in people’s lives.

The cholesterol question
In recent years, a growing body of scientific evidence points to the overwhelming benefits of eating eggs on human health. That said, the road to discovery remains a long and winding one, especially in regards to the decades-old debate over the impact of cholesterol-laden eggs and cardiovascular disease, with many well-designed, evidence-based studies reaching differing results and conclusions.

The latest piece in the egg/cholesterol puzzle appeared in late January. A study by Ontario researchers at McMaster University and Hamilton Health Sciences concluded that eating an egg daily does not increase the risk of developing cardiovascular disease.

The study results, which were also published in the American Journal of Clinical Nutrition, were based on an analysis of egg consumption by nearly 150,000 healthy people and 32,000 with cardiovascular diseases in some 50 countries.

In December, the American Heart Association issued a similar recommendation in a scientific advisory to physicians following a review of several recent studies on cholesterol. “Given the relatively high content of cholesterol in egg yolks, it remains advisable to limit intake to current levels,” read the AHA missive. “Healthy individuals can (eat) up to a whole egg or equivalent daily.”

That recommendation was in stark contrast to the findings of a recent study by researchers with the Department of Preventive Medicine at Chicago’s Northwestern University.

That study analyzed a variety of data – including cardiovascular events, fatal and nonfatal strokes and heart failure, dietary information, physical activity levels and known risk factors like obesity and smoking – from six long-term study groups in the U.S. with nearly 30,000 people participating.

The findings, which were published in the Journal of the American Medical Association in March, received widespread media coverage. They suggested that people who ingest an additional 300 milligrams of dietary cholesterol per day – the equivalent of an added three or four eggs a week or double current nutritional guidelines – are at higher risk of both heart disease (3.2 per cent increase) and early death (4.4 per cent).

The study also calculated that each additional half egg per day resulted in a higher risk of both cardiovascular disease (1.1 per cent) and early death (1.9 per cent) from any cause.

“The importance of limiting intake of cholesterol-rich foods should not be dismissed,” wrote lead study author Victor Zhong. “These results should be considered in the development of dietary guidelines and updates.”

UBC’s Jonathan Little has been studying the impact of egg consumption on diabetics looking to control their blood glucose levels.

EFC nutrition manager Kim Kesseler says to be skeptical of one-off studies and, instead, consider the growing body of evidence showing the health benefits of egg consumption.

An editorial published alongside the study by Dr. Robert Eckel of the University of Colorado’s school of medicine called the study “far more comprehensive” than past research efforts.

It added that it contained enough data “to make a strong statement that eggs and overall dietary cholesterol intake remain important in affecting the risk of (cardiovascular disease) and more so the risk of all-cause mortality.”

For Kim Kesseler, nutrition manager at EFC, the confusing mishmash of studies and recommendations over eggs and cholesterol both distracts from and overshadows other largely positive scientific truths that are being revealed about egg consumption.

“It’s important not to look at these cholesterol studies as one-offs,” Kesseler says. “Research from the past 10 or 15 years overwhelmingly show that cholesterol from eggs is not a problem and that the many nutritional and health benefits from egg consumption far outweigh any potential risk.”

Emerging areas
Kesseler says many other nutrition research projects – some 15 to 20 of which are supported by EFC and ENC each year in addition to in-house research on topics like animal welfare and egg farming sustainability – are being carried out in several fields.

“Diabetes is a huge and emerging one that we’re watching closely,” Kesseler says. Another is choline, an essential nutrient that is naturally present in eggs, fish, liver, red meat and milk and which is vital for healthy liver function, brain development, muscle movement, the nervous system and metabolism.

“Eggs are a real good source of choline,” Kesseler says. “Two eggs a day supplies 75 per cent of an adult’s daily needs. It’s especially important for pre-natal and early childhood development, as well as for the elderly.”

Emerging research, she adds, also supports the benefits of introducing allergen-carrying eggs into the diets of young children.

She points to an update on infant feeding and food allergies issued by the Canadian Pediatric Society in January, recommending the introduction of allergen foods like eggs at only four months instead of the current 12 months.

For his part, Sanjoy Ghosh, a biologist at UBC’s Okanagan campus who has conducted studies on the health impacts of both eggs and egg whites, thinks the specific amino acids contained in egg whites could prove beneficial to older people.

“Egg consumption has not been tested extensively in geriatric populations due to the fact that cholesterol consumption in most clinical guidelines is still considered detrimental,” says Ghosh, who led a recent study in which 110-week-old mice were fed egg whites for eight weeks.

According to an abstract of the study on the U.S. National Library of Medicine’s website, the results suggest egg whites may help to relieve the oxidative stress that leads to cell and tissue damage and chronic conditions in ageing hearts.

“Given the fact that egg whites do not have cholesterol and can still promote such boosting of antioxidants, egg whites might be a safe, high protein alternative in geriatric populations and confer cardiovascular benefits,” Ghosh says.