Morning Sickness Can Be Beneficial

“Since the beginning of time, pregnant women have been reported to suffer from a syndrome variously known as morning sickness, pregnancy sickness, or nausea and vomiting during pregnancy.” The term “morning sickness” is actually misleading, as women can feel sick all day long. Sometimes, it can get so serious that women have to be hospitalized.

Researchers at Harvard’s Brigham and Women’s Hospital found that saturated fat seemed to be a primary dietary risk factor for severe sickness, with five times the odds for every 15 grams intake of saturated fat, “equivalent to one quarter-pound cheeseburger.” The reason saturated fat intake may be such a strong risk factor could be through its effects on estrogen, as “[s]aturated fat has been shown to increase circulating levels of estrogen.”

Why would we evolve to have such a negative reaction to saturated fat? Why would we evolve to get sick at all? As I discuss in my video Morning Sickness May Protect Mother and Child, “[p]regnancy sickness is a universal phenomenon, affecting 70% to 85% of all pregnant women.” If food aversions are included in the criteria, along with nausea and vomiting, the incidence is more like 100 percent. “Because pregnancy sickness is such a common phenomenon, one must question why is this so? Is there a purpose for such a potentially devastating condition?” In the past, pregnancy sickness was dismissed as just being in women’s heads, but recent “studies have reconsidered pregnancy sickness as an embryo-protective mechanism, an evolutionary adaptation to protect the embryo.”

Protect the baby from what? From meat. “Meat is the principal source of pathogens for humans. Meat is also the most common type of food avoided by pregnant women.” So, the development of an aversion to meat during pregnancy could be protective because “meat may have toxins that are mutagenic, carcinogenic, and teratogenic,” meaning causing birth defects, and tainted meat may also be contaminated by pathogens. “Pregnancy is a time of relative immunosuppression.” Normally, we can fend off most meat pathogens. “However, by biological design from evolutionary pressures, pregnant women are immunosuppressed to not reject the developing embryo”––as half the baby (from the father’s side) is foreign. So, morning sickness may have evolved as a way to get us to stay away from meat during this vulnerable time. This would be consistent with a “profound overrepresentation of meat taboos” in sample societies around the world.

If this theory is true, then we should be able to make five predictions. First, if nausea and vomiting in pregnancy are meant to be protective, women who experience them should have better pregnancy outcomes. Indeed, women who suffer from nausea and vomiting are significantly less likely to miscarry or have a stillbirth.

Second, the foods that trigger nausea and vomiting should contain things that can be particularly harmful to the baby, and, in fact, “[o]f all food types, animal protein (including meat, poultry, eggs, and seafood…) is the most dangerous. Meat is the source of a wide range of pathogens that pose a grave threat to pregnant women and developing organisms” that is, their developing embryos.

Third, nausea and vomiting in pregnancy should also coincide with the time when the embryo is most vulnerable, which is approximately weeks 5 through 15, when all the critical organ structures are being formed. And, indeed, that period is right when nausea and vomiting are in fact peaking.

Fourth, pregnant women should find meat and eggs most aversive during this time of heightened embryo sensitivity, and that, too, is the case. And finally, if this theory is true, one should expect a lower frequency of morning sickness among plant-based populations, and, yes, the few societies in which we don’t see such morning sickness problems are the ones that tend to have only plants as dietary staples, rather than meat.


What can you do if you suffer from morning sickness? See Natural Treatments for Morning Sickness.

What other effects can diet have on a healthy pregnancy? See, for example,

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Sparkling or Still Water for Stomach Upset and Constipation?

“Natural bubbling or sparkling mineral waters have been popular for thousands of years,” but manufactured sparkling water was first “‘invented’ in the mid to late 1700s” when a clergyman suspended water over a vat of fermenting beer. “For centuries, carbonated water has been considered capable of relieving gastrointestinal symptoms, including dyspepsia,” or tummy aches. But we didn’t have good data until a study was published in 2002, which I discuss in my video Club Soda for Stomach Pain and Constipation. Twenty-one people with dyspepsia, which was defined in the study as “pain or discomfort located in the upper abdomen” including bloating, nausea, and constipation were randomized to drink one and a half quarts of either carbonated or tap water every day for two weeks.

Carbonated water improved both dyspepsia and constipation compared to tap water. “Drink more water” is a common recommendation for constipation, but researchers didn’t observe a clear benefit of the added tap water. It seems you need to increase fiber and water rather than just water alone, but sparkling water did appear to help on its own. The study used a sparkling mineral water, though, so we can’t tell whether these effects were due to the bubbles or the minerals.

There’s been a concern that carbonated beverages may increase heartburn and GERD, acid reflux disease, but that was based on studies that compared water to Pepsi cola. Soda may put the pepsi in dyspepsia and contribute to heartburn, but so may tea and coffee in those who suffer from heartburn. That may be partly from the cream and sugar, though, since milk is another common contributor to heartburn. Carbonated water alone, though, shouldn’t be a problem.

Similarly, while flavored sparkling drinks can erode our enamel, it’s not the carbonation, but the added juices and acids. Sparkling water alone appears 100 times less erosive than citrus or soda. So, a sparkling mineral water may successfully help treat a stomach ache and constipation without adverse effects, unless you’re the teenage boy who opened a bottle of sparkling wine with his teeth or the nine-year-old boy who tried to do so on a hot day after he’d shaken it up, actions placing them at risk for a pneumatic rupture of the esophagus.


For more on combating acid reflux, see Diet and GERD Acid Reflux Heartburn and Diet and Hiatal Hernia.

Some of my other videos on beverages include:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

A highly effective, cheap, easy-to-use, safer treatment for heavy periods

Ginger is most famous for its role in preventing and alleviating nausea and vomiting. There are now so many studies that there are reviews of reviews. Just a half teaspoon of powdered ginger “is associated with a 5-fold likelihood of improvement” in morning sickness in early pregnancy. (See my video Natural Treatments for Morning Sickness for more on this.) Ginger has also been shown to help with motion sickness, improve postoperative nausea and vomiting, prevent antiretroviral-induced nausea and vomiting during HIV treatment, and was said to be a “miracle” against chemotherapy-induced vomiting.

In a randomized, double-blind, placebo-controlled clinical trial of ginger for breast cancer chemotherapy, chemo-induced vomiting was relieved in all phases—the acute phase within 24 hours of the chemo, two to three days after, and even before chemo sessions with what’s known as anticipatory vomiting. (After a few chemo treatments, the body knows what’s coming and starts throwing up at just the thought of the next session.) Anticipatory nausea can’t seem to be controlled by drugs, even the fancy new ones that can cost 10,000 times more than ginger, which comes in at about two pennies per dose and may work even better in some ways.

Ginger can also help with pain. One-eighth of a teaspoon of powdered ginger, which costs just one penny, was found to work as well as the migraine headache drug Imitrex, without the side effects. (See my video Ginger for Migraines for more.)

Speaking of pain, my video Ginger for Nausea, Menstrual Cramps, and Irritable Bowel Syndrome discusses that it may also be as effective as ibuprofen for alleviating menstrual cramps. Painful periods are exceedingly common and can sometimes cause severe suffering yet have been “virtually ignored” by pain management researchers and practitioners. Four randomized controlled trials, however, have been published on ginger for menstrual pain, and all four showed significant benefit when ginger was taken during the first few days of periods. Effective doses ranged from about a third of a teaspoon a day to a full teaspoon a day, but because they all seemed to work, one might as well start out with the penny-a-day dose.

As a side benefit, ginger can dramatically reduce heavy flow, which is one of the most common gynecological problems for young women. We know there are pro-inflammatory foods that may contribute to heavy menstrual bleeding, so how about trying an anti-inflammatory food like ginger? Heavy menstrual bleeding is defined as more than a third of a cup (80 milliliters), but all the study subjects started out much higher than that. Just an eighth teaspoon of powdered ginger three times a day starting the day before their period cut their flow in half, and it seemed to work better each month they tried it, providing a highly effective, cheap, easy-to-use, safer treatment for menstrual blood loss and pain.

So, ginger works for migraines and menstrual cramps, but just because it may be effective for many types of pain doesn’t mean it’s necessarily efficacious for all pain. For example, what about intestinal cramps? Is ginger effective for the treatment of irritable bowel syndrome (IBS)? The answer is yes, dropping IBS severity by more than 25 percent. But, so did the placebo. So, the real answer is no—it is not effective for the treatment of IBS, yet “[g]inger is one of the most commonly used herbal medicines for irritable bowel syndrome (IBS).” Silly people, don’t they know it doesn’t work any better than a sugar pill? Or, from another perspective, are they smart for using something that offers relief 53 percent of the time and doesn’t risk the adverse effects of some of the drugs with which doctors may harm one person for every three they help?


If placebos are so safe and effective, should doctors prescribe them? I discuss the pros and cons in The Lie That Heals: Should Doctors Give Placebos?.

What does work for IBS? See my videos:

What else can women do to make their periods more tolerable? See:

For more on ginger, check out:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: