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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:


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

40 responses to “Morning Sickness Can Be Beneficial

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  1. With both my pregnancies, I water-fasted and went to bed for a week when the embryo was tiny. I threw up bile for the first few days and then my vomit became clear and sweet as water. After that week, I emerged with no morning sickness, cleaned out and ready to have two healthy pregnancies. I have used fasting for any dis-ease. My kids fasted any time they got sick, went to bed and slept. They emerged much sooner than their classmates who seemed to have had the same sickness. My kids had done a thorough housecleaning, leaving them thoroughly well without all the lingering coughs and secondary infections.

  2. I’ve had a vegan pregnancy and my typical food aversions were: beans, whole grains, and greens. I’ve gone through morning sickness four times and have tried it a variety of ways and have determined it has to do with whatever foods you were eating the most before the morning sickness. Tolerable foods tend to be those eaten least often. I tend to live off fruit juices (favorites are mango and pineapple) because the lack of fiber helps me keep it down.

    1. It’ helpful to differentiate between a vegan and WFPB way of eating. The two are VERY different, but a lot of folk use the terms interchangeably. True WFPB means consuming nothing processed – I wonder how many vegans really give that a fair go?

  3. “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”
    This is astounding. I am super curious to know what the experiences of the WFPB mums here are like.
    The hyperlink embedded in the word “are” in the above snippet led me to a website where I had to pay!

    1. I am vegan and had a vegan pregnancy. I had nausea, food aversions,mostly anything that had any flavor or smell to it i could not handle in the 1st trimester. Plain rice cakes, plain pasta and bread were about all i could stomach. Just looking at pictures of food was sickening. My biggest aversion that lasted most of my pregnancy was sweets, but not fruit. After my first trimester I could eat pretty normally though. So I’m not sure how accurate this is. Each person is different though and each pregnancy is different, so maybe as a whole this has some truth to it, but not according to my experience.

      1. It’ helpful to differentiate between a vegan and WFPB way of eating. The two are VERY different, but a lot of folk use the terms interchangeably. True WFPB means consuming nothing processed – I wonder how many vegans really give that a fair go?

  4. In my last pregnancy I had some intense morning sickness. The physician prescribed a whole bunch of different nutritional supplements in the form of pills. I finally discovered that simply drinking all the water I would normally drink to take that many pills cured my morning sickness. I think that taking in more fluids helps the body to process the additional estrogen.

  5. What I find helps those who are terribly sick is vitamin B complex and B12.
    Easily digestible healthy foods then added.
    Doctors in the past gave B 12 shots, and B complex. But then drugs came along, ugh!
    The reaction of most women to morning sickness is to live on soft drinks and crackers. Not helpful at all!
    Personally, I never experienced anything but mild nausea in early morning with 4 healthy children.
    Lots of theories here!

    1. Marilyn,

      You are a wealth of information!

      B12 is a fascinating answer.

      That makes me wonder if Homocysteine is involved.

      I looked it up and elevated Homocysteine is somewhat associated with poor outcomes during pregnancy.

      This one was fascinating!

      They said that studies say that Folate improves nausea, but not vomiting where B12 improves vomiting.

      I wonder what the mechanism is.

  6. Vitamin B12 and Vitamin D are often recommended to reduce morning sickness.
    Dr. Greger, in other places, recommends only two supplements D and B12.
    Wonder why he does not mention the vitamins here?

  7. Well, I guess the above photo could have been of a pregnant female with her head stuck in the toilet bowl.

    With a bit of colorful upchuck on the floor nearby ’cause she didn’t reach the bathroom soon enough.

  8. I was a omnivore for my first pregnancy and mostly wfpb for my second. I had about equal amounts of pregnancy sickness with each. But my second pregnancy produced a healthy 11lb 2oz baby!
    I craved watermelon and… I’m embarrassed to admit… Totinos Party Pizzas with both pregnancies ‍♀️

  9. Thank you Dr. Michael Greger for this groundbreaking information. When I was pregnant, I had morning sickness that to this day, I link with chicken but honestly back then when I was 24 (I’m 42), I had no idea I could suppress this annoying morning sickness and I had not understood that I should avoid meat, fish, animal products. I had not understood the messages my body was sending me. You, Doctors, make us realize the science behind our diseases. Awesome, as usual.

  10. I had been whole foods plant based for ~10 years before becoming pregnant and sadly I had intense nausea and vomiting for weeks on end. There were many days when absolutely nothing sounded good and nothing would stay down (and I literally had to be in bed all day). It was a very challenging time for me and in retrospect I wish I had tried to gain some weight before getting pregnant (losing 10+lbs when you are already quite small isn’t exactly the best way to start out your pregnancy). I am now in my third trimester and still have nausea at times; it appears to be mostly related to hunger/low blood sugar at this point. Obviously this is an anecdotal account ….. I was really hoping being WFPB for so long would spare me from it. That being said, all signs are pointing to a healthy baby :-)

  11. As much as I respect Dr Greger, this just isnt credible. Being sick during pregnancy is vile and unbearable, EVERYTHING makes you sick. Water, any food, tea tastes disgusting, any fruit and veg caused so much gas I was vomiting air. Imagine having vomit pushed into your nostrils its so violent. The thought of eating becomes scary. This lasted 4 months. Every few days I felt hungry and the only thing I could stomach was small amounts of rice krispies and cheese on toast.

  12. I’ve had ten children and this information doesn’t match my experience at all. I was sick with all of them but some were worse than others. I was eating an 80% raw diet when I got pregnant with number 7 and it was the sickest time of all of them. I could hardly keep down a vegetable or fruit for several months. In fact, the only things I could keep down when it was bad with any of my pregnancies was meat, cheese, and starch.

  13. I would love to know if there’s any nutritional research on hyperemesis gravidarum, which I had for all three pregnancies. I was eating WFPB before my first pregnancy and was totally blindsided by the aversion to *any* food, but in particular fresh produce. I literally could not even walk near a produce aisle without vomiting everywhere—I could smell the produce from miles away it seemed. It got bad enough that by the end of the third pregnancy I tied my tubes… But I now had a psychiatric problem where I was terrified of plant foods. I avoided eating altogether and when I did eat, it was a small portion of something high-calorie, because otherwise I probably would have starved to death. Many months of therapy later I am finally getting back to WFPB.

    Thanks for the article. I’ve always hoped that if I raise my kids eating WFPB they’ll be spared the HG when they’re grown, and this is encouraging.

    1. If you scroll down, you will find the theories of what causes it.

      There are some you can’t do anything about, for instance, gender.

      University of Washington found that women who were extremely ill (hospitalized for three days or more) had odds of having a girl that were 80 percent higher than those of women who did not experience severe nausea. A hormone called human chorionic gonadotropin may be to blame: female fetuses produce more of it than males.”

  14. Both of my pregnancies were when I was a meat and junk food eater. No morning sickness, very short labor, and both babies came out very healthy. Same with two of my sisters. Some women have morning sickness some don’t.

  15. I’ve watched my wife go through absolute terrible bouts of morning sickness for both her pregnancies. No way am I buying into meat as a main culprit. There was absolutely no food she could eat that would help, even water made her vomit. I firmly believe it’s mostly related to the hormones and a woman’s sensitivity to them, because there’s otherwise no rhyme or reason to it. It’s more like trying to understand why some people get bad hangovers and others don’t, there just isn’t an answer!

    1. IMHO, it’s helpful if we look at these things at population levels.

      For example, some people are vaccinated but still get the disease that they are vaccinated against. Does that demonstrate that vaccination doesn’t work and there is no answer to the question of how to reduce the risk of acquiring certain infectious diseases? If we were to argue by individual anecdotes, we’d probably have to conclude ‘yes’.

      I’s impossible to remove all risk but avoiding meat might reuce risk for most people. That of course doesn’t exclude morning sickness being spiked by certain plant toxins also.

      ‘Profet (1992) also argued that because not all modern toxins emit the cues that are necessary for triggering the aversions of pregnancy sickness and because the plant foods have become less toxic through selective breeding, the selection pressures maintaining the mechanisms for detecting and avoiding Pleistocene toxins during pregnancy may have been decreasing since the advent of agriculture. In fact, Profet speculated that the variability in pregnancy sickness among women in industrial societies may be due to variations in dietary toxicity or to decreasing selection pressures for detecting and avoiding substances that emit Pleistocene cues of toxicity (Profet, 1992). She proposed a comparison of variability among women in industrial societies and among women in hunter-gatherer societies in order to determine whether pregnancy sickness is more variable among the former.’

  16. I was very sick with both my pregnancies. I was vegetarian with my first child and after being hospitalized and finally being free of nausea, all I wanted to eat was a burger. So I was not averse to meat quite the opposite. My cravings were unbearable and then 2 months later I stopped craving burgers, not averse but just didn’t crave them. With my second child, I was an omnivore and again very sick. I drank water and nibbled crackers, threw up and repeated that over and over. I had no crazy cravings and was averse to fried shrimp which I rarely ever ate anyway. Nothing in the article seems to coincide with my experience. :(

    1. Holly,

      It may still coincide with your experience.

      Omnivore certainly would be higher in saturated fat and vegetarian often means eating cheese, which is also high in saturated fat.

      Food cravings is often associated with nutritional deficiencies. You might have needed B12.

      Also, there are things like: having girls, having thyroid problems, having blood sugar problems, being low in magnesium and vitamin D and not eating enough foods with folate all can cause it.

      And, saturated fats are associated with it, too.

  17. Well, I know personal anecdotes are not science, but this article cries out to us and reminds us of our own personal recollections. “Back in the day” when I was pregnant, I could not STAND the smell of bacon which my husband was eating every single morning. Just the smell of it made me nauseous.

  18. Great blogs and videos as usual Dr. Greger. This is a very interesting & most talked about subject among women who became pregnant. I counseled many pregnant women with morning sickness when I worked at the WIC office.
    What worked for me were vit. B6 and whole grains especially grape nut cereal dry. Unfortunately, ginger did not work for me and till this day I am hesitant to try ginger teas etc.

  19. I suffered from very severe morning sickness for all 3 of my pregnancies. My first one I was hospitalized on IV fluids for a week because I could not even hold down water that was 13 wks into my pregnancy . I was off work for 3 wks following because of uncontrolled vomiting even taking Diclectin(anti nausea pregnancy medication) could not control it.I did not want to take medication but was told by my doctor I was in danger of miscarry due to reoccurring dehydration. I would get motion sickness riding in the car it was terrible. Even in labor I could not escape it vomiting between contractions. The morning after giving birth the nausea finally left ! With each pregnancy it got a little better with my second pregnancy the nausea was better at 7 month mark and the third at 6 month. My experience was it had nothing to do with what I ate but I do understand the theory .

  20. Dr Greger, Can you please comment on the new longevity research focusing on epigenetics and the use on NAD, Resveratrol, and NMN supplementation. Thank you

    1. If you’ve been keeping up with aging and science news, you’ve probably already heard of a critical molecule known as nicotinamide adenine dinucleotide (NAD). You may even already know that NAD is critical to human survival and that it decreases as we get older and undergo metabolic stresses.

      “A new dietary supplement could mimic the effects of calorie reduction and reduce the risk of heart disease and diabetes.

      A dietary supplement that could mimic the effects of strict calorie reduction shows promise for lowering the risk of conditions that shorten life, including heart disease and diabetes.

      In a small study out of University of Colorado in Boulder, scientists determined that a daily dose of a natural dietary supplement, nicotinamide riboside (NR), boosted enzymes that are active in many of the body’s metabolic processes in the same way that cutting calories does. It also had a positive effect on blood pressure.

      While just 30 participants were involved in the research, “This was the first-ever study to give this novel compound to humans over a period of time,” said senior author Doug Seals, a professor and researcher in the university’s Department of Integrative Physiology. “We found that it is well tolerated and appears to activate some of the same key biological pathways that calorie restriction does.”

      Calorie restriction as a path to longevity is not new. Animal studies have shown that managing calorie intake can lead to health benefits. As early as the 1930s, calorie cutting was thought to be beneficial to extending life.

      In fact, a recent study published in March in the journal Cell Metabolism showed new evidence that cutting calories by 15 percent over two years can lead to a drop in metabolic rates and a subsequent drop in oxidative stress within the body, a process linked to age-related conditions like Alzheimer’s, cancer, and diabetes.

      Of course, cutting that number of calories can be difficult, requiring discipline to maintain. In addition, caloric reduction can be impractical or sometimes dangerous for some. A supplement that provides the benefits of cutting calories without the difficulty or risks could be a breakthrough. However, the supplement is a long way from approval. Researchers hope for further funding to study the supplement in a wider clinical trial. ”

      “A new study published in Nature Metabolism finally reveals the answer to how NMN enters the cell in order to become NAD+ and that it does not need to convert into NR to do so.

      In the last few years, there has been considerable interest in restoring levels of the nicotinamide adenine dinucleotide (NAD+) coenzyme to combat age-related diseases. Evidence suggests that NAD+ systemically declines with age in a variety of organisms, including rodents and humans, which contributes to the development of many age-related diseases and metabolic conditions.

      What is NAD+?

      Nicotinamide adenine dinucleotide (NAD) is a coenzyme found in all living cells. It is a dinucleotide, which means that it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine base, and the other contains nicotinamide.

      NAD facilitates redox reactions, carrying electrons from one reaction to another. This means that NAD is found in two forms in the cell; NAD+ is an oxidizing agent that takes electrons from other molecules in order to become its reduced form, NADH. NADH can then become a reducing agent that donates the electrons it carries. The transfer of electrons is one of the main functions of NAD, though it also performs other cellular processes, including acting as a substrate for enzymes that add or remove chemical groups from proteins in post-translational modifications.

      In metabolism, NAD+ helps facilitate cellular functions, DNA repair, growth, and many more things. Quite simply, without NAD+, life would not be possible.

      NAD+ is created from simple building blocks, such as the amino acid tryptophan, and it is created in a more complex way via the intake of food that contains nicotinic acid (niacin) or other NAD+ precursors. These different pathways ultimately feed into a salvage pathway, which recycles them back into the active NAD+ form.”

  21. Elizabeth,

    Great find… not unlike the litany of studies of any medication, be that a supplement or a prescription this article highlights the confounding findings often times present and underlines our lack of full information. The weakness of human studies is exemplified here as the costs, time and multitude of inputs, with daily variations is a challenge.

    The title unlike the article is more balanced than expected. The reality in our industry is that we are still practicing rough forms of medicine. By that I mean that it’s the exception, not the rule, to know the interactions of anyone let alone more than one input into our systems in detail and especially for long term outcomes.

    Examples of confounding issues abound in all areas of medicine. Let’s take for example the now popular microbiome and it’s interactions that directly affect our detox pathways. Given the information in the article how would you or any researcher isolate the “correct” person for this or any other form of supplementation?

    Let’s not forget that even though we are just short of 2020 the computational power needed to even tease out the details of interactions molecularly for an individual are still rudimentary at best. Are we making progress, absolutely and the newest work is shedding light on many areas we never even knew existed in the form of interactions?

    If your inclined to explore this area further you’ll want to look at the international groups that are working in concert to understand our friends, in our gut. See: as one of the many collaborators. Hearing their work and being present for international chats relates how knowing the computational and chemical aspects is confounding even the best minds in medicine/academia. Great work in progress.

    With that said I have seen patients respond to NAD application and although it’s remains a question for whom it should be used, the takeaway is to be aware that perhaps limiting it from those whom we suspect or know have a current cancer might be a wise choice.

    Without getting too deep into the metabolomics of food, It would probably make most people uncomfortable to recognize the limitations of our current knowledge in dietetics. If you expanded that lack of knowledge into the farming and crop sciences and fast forward to you table, we need to recognize our limitations and revel in the fact that we are so much closer to recognizing that a more PBWF diet trumps the current intake by most of us.

    Sorry if this was a bit long winded but….. please recognize science is an ongoing process and we are learning faster and with more accuracy all the time. Stay tuned and keep learning as we all benefit from new information.

    Dr. Alan Kadish moderator for Dr. Greger

    PS If you think the lack of info is exclusive to supplements……think again as this came up on my email while writing this post. And don’t miss the 600 or 40% numbers quoted…..

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