Eating breakfast — even among people whose dietary habits are not all that nutritional — is associated with a lower rate of obesity, high blood pressure, type 2 diabetes, and metabolic syndrome (a collection of symptoms associated with a higher risk of heart disease, diabetes and other health problems), according to a new study from the University of Minnesota.
In fact, the incident rate for each of those conditions was around 50 percent lower among the study’s participants who ate breakfast daily than among those who skipped breakfast four or more times per week.
But don’t interpret these results as meaning that anything you gulp down for breakfast — like, say, a bag of doughnuts or bowl (or two) of Cocoa Puffs — is good for you. The study, which was published Monday in the journal Diabetes Care, comes with some important caveats.
First, though, the study’s details.
Data includes Minnesotans
For the study, the U of M researchers analyzed data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, which is an ongoing multi-center research project that has been examining how heart disease risk factors evolve over a lifetime. The CARDIA study began in the mid-1980s with more than 5,115 18- to 30-year-old adults from Minneapolis and three other cities: Birmingham, Chicago and Oakland.
The U of M researchers looked at the data of 3,598 of these participants. None had diabetes at a clinical exam given to them during year seven of the study. Their overall dietary habits were also assessed. Some 43.2 percent said they ate breakfast only infrequently (0-3 days per week); 21.7 percent reported eating breakfast frequently (4-6 days/week); and 35.1 percent said they ate breakfast daily.
The participants underwent additional clinical exams over the next 18 years. By comparing the data from those exams with the breakfast data, the U of M researchers found that people who ate breakfast four or more times a week were significantly less likely than infrequent breakfasters to develop abdominal obesity (a risk factor for heart disease, type 2 diabetes and other diseases), obesity, metabolic syndrome, high blood pressure and type 2 diabetes.
“We hypothesized that this would be explained by their overall dietary pattern,” said Andrew Odegaard, an epidemiologist at the U of M’s School of Public Health and the study’s lead author, in a phone interview Monday. “But we did not see that.”
Instead, Odegaard and his colleagues found that the relationship between the frequency of eating breakfast and metabolic risk did not change with the overall quality of the participants’ diets.
Furthermore, the study’s findings held even after controlling for such factors as exercise, smoking, alcohol consumption, educational level and how often the participants ate at fast-food restaurants.
Now for those caveats. First, this was an observational study, which means it can only show a correlation between two things (in this case, breakfast and a lower risk of certain medical conditions), not a cause-and-effect. Other “hidden” factors, not controlled for in the study, could explain the results.
Also, the study was not designed to determine what specific foods people were having for breakfast, only if they were eating breakfast and what their overall dietary patterns were. It could be that people who eat breakfast tend to make it a healthful meal, even if the rest of their daily fare is nutritionally under par.
The study, therefore, couldn’t determine whether it was the timing of the first meal of the day or its content that resulted in the better health outcomes for the frequent breakfasters.
“I think it’s probably both,” said Odegaard, “but we don’t really know.”
A plausible explanation
Still, the findings are interesting because they build on other, previous studies that have linked breakfast — or, more specifically, breaking overnight fasting soon after awakening — to better health outcomes.
“There is a plausible and realistic mechanisms for why it may be helpful for health,” said Odegaard. Other studies have suggested, he explained, that the act of eating breakfast may have effects on insulin and other metabolic hormones that are independent of the meal’s content.
But, “if you’re going to start eating breakfast and you want it to impact your health, you should probably go for the higher nutritional quality,” Odegaard said.
Plenty of other research has shown that people with healthier overall diets — especially those who eat high amounts of fruits and vegetables and low amounts of unrefined carbohydrates — are less likely to develop metabolic disorders like obesity and type 2 diabetes.
That would mean, of course, not starting your day with sugary breakfast foods.
The U of M study was partially funded with a grant from General Mills. “But they had absolutely no hand in any part of the paper or in the design of it,” Odegaard said. “Like you, they’re reading it for the first time today.”
The study is behind a paywall, but you’ll find its abstract on the Diabetes Care website.