With the age of internet and social media, information is easy to find. However, how do you separate the myths from the truth – not always easy. Here is a series of four myths associated with diet and what affects fertility.
What you can and should eat during the preparation phase and throughout pregnancy and while breastfeeding can be summed up in two words: REAL food.
While this series of blogs focuses on women, much of the same advice applies to men and sperm quality as well. What supports your fertility is also good for your partner! (But if you need more specifics, refer to chapter one of my book, How to Have a Healthy Baby).
The notion that a plant-based diet is best for our health, and that consuming meat is detrimental, has persisted for many decades. And it’s no different in the fertility space, where advice to lower meat consumption and follow a mostly plant-based diet is commonly recommended.
I am continually shocked at the anti-meat bias in study design or methods and also the way in which some researchers discuss and present their findings. This can be seen in the title of the study, as well as the abstract, results, discussion, and conclusion. Researchers can also manipulate the data analysis or presentation in a way to downplay any beneficial findings on meat or animal protein. And yes, some studies can have conflicts of interest based on the funding source or the dietary preferences of the authors.
Let me give you a few examples. In one study, dietary sources of protein were analyzed relative to their effect on ovulatory function. The title of the study suggested that plant proteins were superior, but at closer analysis of their findings, the only plant protein category that was actually supportive of ovulatory function was legumes. The “meat alternatives” category — aka fake meat — was actually associated with worse ovulatory function (it scored worse than any of the animal protein categories, by the way). And yet, their study title and abstract did not differentiate between the type of plant protein, nor did it acknowledge that many animal protein sources were also beneficial (or net neutral) in their effect on ovulatory function. Even processed meat scored better for ovulatory function compared to all plant protein categories, with the exception of legumes.
In another study, researchers looked at associations between various protein sources and treatment outcomes from assisted reproductive technology, such as IVF. The study concluded that fish consumption was related to a higher probability of live birth following fertility treatment. Interestingly, red meat was also shown to improve the rates of live birth (to the same degree as fish intake), but this finding was not highlighted in the study abstract or conclusion; it was only briefly mentioned in the results section in the full text of the paper. Since most clinicians don’t have the time to read full research papers, they’re often just relying on the highlights in the abstract of a paper (or even the title of the paper). And sadly, this rarely tells the full story.
In other studies, I’ll see positive findings about meat left out of the discussion. In a large epidemiological study that specifically looked at ovulatory function in women relative to their diet, women who ate the most animal protein (a difference of about 60-70 grams of animal protein daily) actually had the lowest rates of ovulatory infertility. However, despite this relevant and noteworthy finding, it was only briefly mentioned in the results section of the study. What is especially fascinating about this is that the women who consumed the most meat were more likely to have other dietary and lifestyle factors that are typically detrimental to fertility, including higher alcohol consumption, cigarette use, and being inactive. The researchers never stopped to ask whether they had miscategorized meat as being “unhealthy” or whether the higher meat consumption may have had a protective effect.
Another issue is when some study designs try to rank a “healthy” or “unhealthy” dietary pattern, by awarding points towards factors like vegetable consumption and low sugar intake, and deducting points towards factors like smoking and alcohol consumption. But you know what else is typically included in the list of “unhealthy” habits? Meat intake. For studies that use this design, any beneficial (or neutral) effects of meat consumption on fertility are diluted because the findings are presented as an aggregate of all of these factors. While I generally like seeing researchers consider dietary patterns (versus only considering a single dietary factor), this type of study design doesn’t give us enough information to draw any strong conclusions on individual dietary factors. I actually found it a bit ironic that in one study (that is widely cited in the fertility space), the lowest rates of ovulatory infertility were found in women who consumed the most animal protein, but of course, they minimize this finding in their paper.
There are countless other examples of studies in which the titles or summaries misrepresent the actual data, but I’ll stop here.
We also must zoom out when considering nutrition research and consider the bigger picture. What are the micronutrients — vitamins, minerals, etc. — that support egg quality, ovulatory function, and pregnancy outcomes? And where do we find these in whole foods? These simple questions are ones that are often glossed over in the silos of academia. We’ll have paper after paper come out on the benefits of amino acids, like L-carnitine, for various markers of fertility, yet no one stops to ask where we get that nutrient from food. I’ll tell you: red meat.
And another aspect of which foods are beneficial or not that is often overlooked is where does the food come from? When it comes to meat, we need to ask where and how were the animals raised? What were they fed?
The notion that a plant-based diet is best for our health, and that consuming meat is detrimental, has persisted for many decades. And it’s no different in the fertility space, where advice to lower meat consumption and follow a mostly plant-based diet is commonly recommended. Proponents of this approach are quick to point out supporting research, but have you ever taken a closer look at these studies?
I have. I am continually shocked at the anti-meat bias in study design or methods and also the way in which some researchers discuss and present their findings. This can be seen in the title of the study, as well as the abstract, results, discussion, and conclusion. Researchers can also manipulate the data analysis or presentation in a way to downplay any beneficial findings on meat or animal protein. And yes, some studies can have conflicts of interest based on the funding source or the dietary preferences of the authors.
Let me give you a few examples. In one study, dietary sources of protein were analyzed relative to their effect on ovulatory function. The title of the study suggested that plant proteins were superior, but at closer analysis of their findings, the only plant protein category that was actually supportive of ovulatory function was legumes. The “meat alternatives” category — aka fake meat — was actually associated with worse ovulatory function (it scored worse than any of the animal protein categories, by the way). And yet, their study title and abstract did not differentiate between the type of plant protein, nor did it acknowledge that many animal protein sources were also beneficial (or net neutral) in their effect on ovulatory function. Even processed meat scored better for ovulatory function compared to all plant protein categories, with the exception of legumes.
In another study, researchers looked at associations between various protein sources and treatment outcomes from assisted reproductive technology, such as IVF. The study concluded that fish consumption was related to a higher probability of live birth following fertility treatment. Interestingly, red meat was also shown to improve the rates of live birth (to the same degree as fish intake), but this finding was not highlighted in the study abstract or conclusion; it was only briefly mentioned in the results section in the full text of the paper. Since most clinicians don’t have the time to read full research papers, they’re often just relying on the highlights in the abstract of a paper (or even the title of the paper). And sadly, this rarely tells the full story.
In other studies, I’ll see positive findings about meat left out of the discussion. In a large epidemiological study that specifically looked at ovulatory function in women relative to their diet, women who ate the most animal protein (a difference of about 3.5 oz of animal protein daily) actually had the lowest rates of ovulatory infertility. However, despite this relevant and noteworthy finding, it was only briefly mentioned in the results section of the study. What is especially fascinating about this is that the women who consumed the most meat were more likely to have other dietary and lifestyle factors that are typically detrimental to fertility, including higher alcohol consumption, cigarette use, and being inactive. The researchers never stopped to ask whether they had miscategorized meat as being “unhealthy” or whether the higher meat consumption may have had a protective effect.
Another issue is when some study designs try to rank a “healthy” or “unhealthy” dietary pattern, by awarding points towards factors like vegetable consumption and low sugar intake, and deducting points towards factors like smoking and alcohol consumption. But you know what else is typically included in the list of “unhealthy” habits? Meat intake. For studies that use this design, any beneficial (or neutral) effects of meat consumption on fertility are diluted because the findings are presented as an aggregate of all of these factors. While I generally like seeing researchers consider dietary patterns (versus only considering a single dietary factor), this type of study design doesn’t give us enough information to draw any strong conclusions on individual dietary factors. I actually found it a bit ironic that in one study (that is widely cited in the fertility space), the lowest rates of ovulatory infertility were found in women who consumed the most animal protein, but of course, they minimize this finding in their paper.
There are countless other examples of studies in which the titles or summaries misrepresent the actual data, but I’ll stop here. For more detailed examples, read the section in Chapter 5 in Real Food for Fertility entitled “But I was told that meat is bad for fertility. Is that true?”.
We also must zoom out when considering nutrition research and consider the bigger picture. What are the micronutrients — vitamins, minerals, etc. — that support eqq quality, ovulatory function, and pregnancy outcomes? And where do we find these in whole foods? These simple questions are ones that are often glossed over in the silos of academia. We’ll have paper after paper come out on the benefits of amino acids, like L-carnitine, for various markers of fertility, yet no one stops to ask where we get that nutrient from food. I’ll tell you: red meat.
The very important aspect of where does our food originate is often overlooked. We need to ask questions like Where were the animals raised? What were they fed on? Animals that were raised on organic pastures that feed on grasses, herbs and weeds will produce healthier meat those raised in feed-lots, feed on genetically modified grains like soy, corn and cottonseed, and highly treated with antibiotics (to prevent cross infection due to animal density).
The more natural or real your food, the better it will be for you, for your fertility outcomes and for your baby.
The above information is courtesy of Lily Nichols, author of the book Real Food for Pregnancy.
