A recent scientific study has analyzedthe relationship between breakfast
 and cardiovascular risk. The results of this work have appeared in the media, with certain conclusions being highlighted. However, things are not as simple as they might appear. We are going to take a detailed look at this to see whether, as it states, breakfast is the most important meal of the day.

TEXT: Óscar Picazo. DIETITIAN-NUTRITIONIST
FUNDACIÓN MAPFRE

ILLUSTRATION: THINKSTOCK

 

No daily intake of food proves as controversial as breakfast. A recent study would appear to have settled once and for all the question of whether or not skipping the first meal of the day is to be recommended.

Specifically, we are referring to “The Importance of Breakfast in Atherosclerosis Disease” published in the journal of the American College of Cardiology. The results are just some of the advances made within the PESA (Progression of Early Subclinical Atherosclerosis) study conducted by Spain’s CNIC (National Cardiovascular Research Center).

This article outlines the association between different breakfast patterns and the condition of the arteries of over 4,000 workers at a major bank. The population was divided into three groups: those taking a high-energy breakfast (which accounts for over 20 percent of daily calories); a low-energy breakfast (intake of 5-20 percent of calories) and those skipping breakfast (less than 5 percent of daily calories). The results indicate that 75 percent of those who skip breakfast had generalized atherosclerosis, compared with 57 percent in the group that has a hearty breakfast. But there is one important caveat: association does not imply causation.

To understand this better, we must analyze the type of study we are talking about here. It is of a cross-sectional nature and takes a “snapshot” of the population analyzed at a given moment in time. The subjects were asked about their nutritional habits and were tested using ultrasound equipment to see whether or not plaques were present in their arteries. This enabled a statistical association to be established between skipping breakfast and the prevalence of atherosclerosis. But this does not mean that the cause is necessarily skipping breakfast.

Skipping breakfast is associated with the most dangerous factors for our health: overweight, smoking, alcohol and hypertension

Although this may seem surprising, we must bear in mind what, in epidemiology, are called “confounding factors”. It is known that skipping breakfast is often a sign of unhealthy habits. In fact, this study revealed that, among the group that skipped breakfast, there was greater prevalence of obesity, hypertension, consumption of alcohol and tobacco, or red meat, all factors associated with cardiovascular disease. Moreover, omitting breakfast may also be associated with a lack of time and stress, or a lack of sleep.

In addition, the causal link between skipping breakfast and being at greater risk of atherosclerosis is not immediate. On the contrary, it might be felt that skipping a meal would reduce the daily caloric intake and, thus, overweight issues. However, other studies have not found differences in body weight between those who eat breakfast and those who do not.

The answer might lie in the circadian rhythms, those hormonal cycles linked to our internal clock which controls day and night. Their discovery by Hall, Rosbash and Young warranted their recently receiving the Nobel Prize in Medicine. The fact is that research seems to indicate that breaking the overnight fast could enhance hormonal control during the rest of the day.

In any case, worrying about whether or not we eat breakfast makes little sense if we smoke, drink alcohol frequently, are physically inactive, stick to a poor diet, or sleep little and poorly. Meanwhile, science will keep making advances, but we should focus on improving our lifestyle habits day by day. And remember: we must not solely heed the headlines, as association does not always imply causation.

 

Spurious correlations

There sometimes appears to be a clear relationship between two facts, which can even be represented graphically and evolve in parallel over time. However, we may be dealing with what is called a “spurious correlation”, in other words a mere coincidence. Tyler Vigen, a Law student at Harvard University, has created a website with a compilation of the weirdest and funniest
statistical coincidences. According to the author, the aim is to highlight the inappropriate use of statistics in the media. Among others, Vigen has found the following associations:

• Per capita consumption of margarine and divorce rate.
• Per capita consumption of mozzarella cheese and civil engineering doctorates.
• Per capita consumption of chicken and U.S. crude oil imports.
• People drowned in pools and Nicolas Cage movies.
• Per capita cheese consumption and people who died tangled in their bedsheets.