Despite its name, morning sickness—nausea and vomiting that is often one of the first symptoms of pregnancy—can happen at any time of the day. Up to 90 percent of pregnant women experience this less-than-pleasant side effect, yet scientists are only beginning to understand why running to the bathroom and saltines are a rite-of-passage for moms-to-be.
Now, new research has shed some light onto morning sickness, and its roots lie in evolution.
Researchers from the University of Liverpool suggest that morning sickness may have developed over time to protect pregnant women from potentially dangerous food or from eating too much unhealthy food.
To test the theory, Dr. Craig Roberts and colleagues looked at the rates of morning sickness in different regions of the world and the typical diet of the population in that region. Ultimately, not only was "high overall food intake correlated with pregnancy sickness, but also the amount of certain types of food predicted the incidence of pregnancy sickness," he said.
In other words, it's not just the amount of food you eat, but the type of food that seems to influence the degree of your morning sickness.
To further look at this phenomenon, Roberts then compared only those women from Europe and North America and pinpointed the types of foods that seem to trigger the symptoms of morning sickness: sugars, alcohol and meat. Additionally, women who ate high amounts of cereal-based products tended to have lower-than-average rates of nausea and vomiting during pregnancy.
The researchers theorize that women's bodies have slowly developed an aversion to sugar, alcohol and meat because all of these foods contain high levels of toxins that could be potentially dangerous to a mother and her child. Cereals, on the other hand, tend to contain a very low level of toxins, so they could possibly be safer for a woman to eat. Remember, however, that these toxins may not pose the same hazard now that they did in the days of ancient man.
"While there may be no particular harm in eating, say, meat, now that we have refrigeration and 'best before' dates," said Roberts,"our bodies may be pre-programmed by evolution to avoid these particular foodstuffs in the first trimester."
If there is a particular food that seems to make your morning sickness that much worse, it may be acceptable to avoid it, but be sure to consult with your doctor before changing your diet. That way, you can be sure that you and your baby are still getting all of the vitamins and nutrients you need.