The Nutrient Gaps Behind Female Infertility (Episode 628)

Full Transcript: Episode 628

Lisa Hendrickson-Jack:

This is the Fertility Friday Podcast, episode number 628.

In today’s episode, we are going to be diving into key nutrients that are associated with fertility and infertility. We’re going to be looking at a recent study of nearly 4,000 women between the ages of 18 and 44, and these results were divided between women who were identified as fertile, meaning that they had a pregnancy within a 12 month period, versus the women who were reported to be infertile — and as they defined infertility in the study, difficulty conceiving for at least one year.

This study reveals some really interesting results about which key nutrients were associated with fertility. Correlation doesn’t equal causation, but the results, I would say, aren’t necessarily surprising. They’re very interesting, relevant, and especially if you are a practitioner working with women in the area of fertility or infertility, you will find these results to be very useful. Without further ado, let’s go ahead and jump into today’s episode.

The title of the research paper we will be diving into today is quite long. The title is: Nutrient gaps are prevalent among women experiencing infertility: a cross-sectional analysis of the National Health and Nutrition Examination Survey.

You can always head over to fertilityfriday.com — this is episode 628 — to get the show notes for the episode and the links to the paper and all that good stuff.

As I mentioned, this study looked at just under 4,000 women aged 18 to 44. Out of those women, just a little over 400 of them self-reported infertility — that would be difficulty conceiving for at least one year. The researchers analyzed 21 nutrients, including a number of vitamins and minerals, to see if there was a difference between the women who reported that they had conceived — the women in the category of fertile — versus the women who reported difficulty conceiving.

They also took a look at intake from foods alone versus foods plus dietary supplements and found some interesting findings just based on those differences as well.

One of the most interesting findings, as far as I’m concerned, was that women who self-reported infertility had measurably lower intakes of several key nutrients. In particular, women who reported infertility had significantly lower intakes of vitamin A, vitamin E, vitamin K, and lutein and zeaxanthin — from both food as well as food plus supplements. Women who reported infertility also were found to have lower selenium and vitamin C intake from foods, as well as calcium.

This was a pretty significant finding because for many of these nutrients, over half of the infertile women were falling below the basic requirement. Vitamin A stood out pretty significantly — 56% of the women in the infertile category fell below the estimated average requirement for vitamin A retinol, and 87% fell below the estimated average requirement for vitamin E. The women in the fertile category did also fall into this deficiency category, but these numbers were quite pronounced in the infertile group.

What’s even more relevant, especially for women who are trying to conceive and for practitioners working with fertility clients, is that these nutritional gaps were dramatically more pronounced in women who were between the ages of 35 and 44. If you work with a fertility population, if you work in the area of conception and supporting women who are trying to conceive, a significant percentage of your clients will fall into that age category.

When they separated women aged 18 to 34 from women aged 35 to 44, those nutrient gaps were significantly more pronounced — particularly for vitamin A, B6, vitamin C, vitamin D, vitamin E, vitamin K, as well as magnesium and potassium.

The implication here is something that already makes a lot of sense. If you’re in this field, you already know that women in that age category would want to be more mindful and more intentional about nutrient intake in general. But this paper further supports that women in this age category are more likely to be deficient, especially if they have been trying to conceive for a year or more.

A couple of other points that I think are really interesting with this study. Although the primary findings are that women in the infertility category are more likely to be deficient in these key areas and certainly had a higher degree of deficiency compared to women in the fertile category, overall, when you look at the data, both categories had pretty significant gaps in nutrients.

For example, choline was particularly low across both groups. Just under 95% of infertile women and 93% of fertile women failed to meet the choline adequate intake from foods. Yes, the women in the infertile category were slightly higher, but 93% of the women in the fertile category also failed to meet adequate choline intake from their food. Based on what the researchers had to say, this amounts to fewer than 1 in 16 women who are trying to conceive that are meeting the basic choline requirement.

In addition to the study highlighting key nutrients that women who are struggling to conceive certainly need to focus on, there’s still an underlying message that this does apply to all women who are trying to conceive.

Another interesting finding — as I mentioned at the top, the researchers were looking at dietary intake from food as well as food and supplements. About half — just under half — of the women in the study were already taking dietary supplements. But even the women who were supplementing, the supplements did not eliminate the nutrient deficiency. The supplements did have an impact, they did reduce the inadequacy overall, but they didn’t eliminate it.

This is an important reminder that supplements alone aren’t just going to fill the issue. For the vitamin A issue, the inadequacy dropped, but only marginally. While the overall number was 56% of women found to have inadequate intake of vitamin A, the women who were taking supplements saw that go down to 55% — a very marginal increase. The supplements weren’t really making that big of a difference.

I would say that’s because the vast majority of supplements available aren’t necessarily going to provide a significant amount of vitamin A. The most meaningful source — especially when we’re looking at vitamin A and choline — is actually going to be from eating liver. Similarly, vitamin K and K2 are also best obtained from food. It’s worth considering that in a perfect world, when we’re looking to maximize our nutrient intake, taking a prenatal, even if it’s an excellent prenatal, is certainly not going to be more effective than combining a mindful diet that incorporates key nutrients and key foods with supplements.

The researchers stated: “Nutrient gaps were reduced with dietary supplementation, but persisted, highlighting the need for public health action to improve dietary intake. Currently, dietary guidance focuses on averting nutrient deficiencies rather than supporting optimal health. The nutritional needs of women during the preconception period are thus not currently part of public health guidelines.”

This is really key to think about. What the researchers are saying is that public health guidelines are typically for pregnant women and for the general population. Not only are the guidelines not necessarily distinct for women versus men, but they’re certainly not for women who are trying to conceive. We don’t really have a standard dietary guideline for what would be optimal for women who are trying to conceive.

This is what Lily and I are addressing with our book, Real Food for Fertility. We’re really looking at what the research is saying — what would be optimal so that when you’re looking to conceive, you can actually prepare your body for that, instead of simply taking a prenatal and then waiting until you get pregnant and trying to fill the gaps when your body is already making a baby.

This paper is highlighting these issues and showing that many women are actually going into pregnancy already not hitting even the basic recommended guidelines — and the recommended guidelines aren’t necessarily optimized for women who are trying to get pregnant. That means the average woman is certainly not going into pregnancy with sufficient nutrient stores.

It’s not a big surprise to me that the key nutrients the researchers were looking at mirror the same key nutrients that Lily and I spoke about and focused on in Real Food for Fertility. I want to go through the short list of the nutrients that came up in their study.

Vitamin A was, hands down, the largest single nutrient gap between fertile and infertile women in the study. About 56% of infertile women fell below the ideal optimal amount compared to 44% of fertile women. When looking at the age distinction, that number hopped up to 58%.

There is just a lack of awareness on the importance of vitamin A retinol — retinol from animal sources. It’s not the same as beta carotene from plant sources. What we know about vitamin A from the research is that it’s essential for oocyte maturation, for ovulation, embryonic differentiation. When we get into pregnancy, vitamin A is essential for the formation of the heart, essential for the formation of baby’s lungs, essential for the development of your eyes and ears. It plays a significant role in fetal development, but it also plays a significant role in fertility. The best, most reliable way to get sufficient vitamin A is to incorporate liver or cod liver oil into your diet.

Vitamin E also came up and was quite significant in the research findings. About 87% of the infertile women fell below the estimated average requirement, but 83% of the fertile women also fell below that. With a rate of 87%, this was the highest inadequacy rate in the study.

Vitamin E was originally identified as the nutrient essential for reproduction. The name tocopherol literally means “to bear offspring.” Vitamin E plays a key role in protecting developing oocytes from oxidative damage and may even support endometrial receptivity.

A key piece for vitamin E that we should be aware of is that having a high intake of omega-6 vegetable oils can actually triple the body’s requirement for it. The more industrial seed oils we have in our diet, the higher our need for vitamin E. Low vitamin E has also been linked to first trimester miscarriage, and supplementation may reduce the risk by up to 50%. There are a lot of important benefits of vitamin E consumption that are directly related to fertility.

That could be one of the reasons why such a high percentage of infertile women fell below the requirement. But because even women in the fertile category — over 80% of them — typically fell below that requirement, it also speaks to the dietary mismatch. If high omega-6 consumption increases our requirement for it, and we’re not necessarily getting it through dietary sources, that can be a significant issue.

Food sources of vitamin E include sunflower seeds, almonds, avocados, and pasture-raised egg yolks. Grass-fed beef and pastured eggs have roughly twice as much vitamin E as conventionally raised. Staying away from omega-6 fats and cooking with more stable saturated fats are certainly strategies we can use to support vitamin E consumption and ensure that the vitamin E we are consuming can be used more efficiently.

A few other nutrients the study highlighted: vitamin B6 — a little over 20% of infertile women fell below the estimated average requirement compared to about 15% of fertile women. Vitamin C — over 50% of infertile women fell below the requirement compared to about 45% of fertile women. And choline, of course — 95% of infertile women fell below the estimated requirement compared to 93%. Huge shout out to liver for being an excellent source of choline, and of course, egg yolks.

Magnesium is an interesting one. About 54% of infertile women fell below the average requirement for magnesium. And lutein and zeaxanthin — almost 100% of infertile women fell below the requirement, and about 98% of fertile women. Such a high percentage of women overall were not getting a sufficient amount from diet. These nutrients are found in egg yolks, dark leafy greens, and orange and yellow vegetables. They are carotenoids with an antioxidant function protecting oocytes from oxidative damage.

For me, when looking at this paper, there are two key takeaways that really stand out.

One is that we really want to focus on supporting the optimal nutrient intake of women, especially women who have been trying to conceive. In the same breath, I always like to remind everybody that male factor infertility is responsible solely for 30% of infertility cases and a contributing factor to 50%. If we are looking at a couple who has been trying to conceive for a year or more, yes, we want to be focusing on the nutrient intake of the woman, but we also want to be looking at the nutrient intake of the man, because the sperm quality conversation is very, very important.

The research is clear that women who were struggling with infertility, who self-reported trying to conceive for a year or more unsuccessfully, certainly had a more pronounced nutrient inadequacy in a variety of areas. This was related to key nutrients that we know play an important role in fertility. But in the same breath, women in the fertile category who did not self-report infertility also had significant gaps in their nutrient intake.

Point number one: yes, we have to be focused on these key nutrients for fertility. But point number two: it’s kind of alarming that in some of these nutrients, 80%, 90% of women overall — or higher — were also experiencing insufficient intake. And they weren’t even hitting the estimated daily requirement. The estimated daily requirement hasn’t even been optimized for fertility.

This represents a significant opportunity to support your clients and yourself if you’re trying to conceive — to really increase your nutrient intake. If you have a read through Real Food for Fertility and look at some of the key foods that support fertility, and look at the nutrient profiles, learn a little bit more about choline, vitamin E, vitamin D, omega-3 fatty acids, vitamin A retinol, magnesium, zinc, selenium, B vitamins — you will see that following an ancestrally inspired diet that really focuses on foods that happen to be quite high in these key nutrients that we know support fertility — you will find yourself in a completely different category in terms of nutrient sufficiency.

The standard American diet certainly does not provide the sufficient level of nutrition that we’re looking at. If you are able to increase the overall nutrient intake from your diet and then add supplements on top of that to fill the gaps — as opposed to expecting supplements to do the whole job — you will find yourself in a much better nutrient-replete state going into pregnancy.

One of the main focuses in my work has always been for this preconception stage. We live in a world that’s so focused on avoiding pregnancy. For the typical woman, a lot of your late teens and early 20s is spent in this place of being terrified about an unplanned pregnancy. The whole focus is not wanting to get pregnant. But then things can shift so quickly — even within a few months, even a few days — and all of a sudden you’re ready. But that doesn’t mean your body’s ready.

Not only do we have the post birth control transition — where your body is kind of having to rebound, and your ovaries and your ovarian follicles have to resume the normal regularly scheduled program and rebound to normal hormone production — we also know that hormonal birth control suppresses ovulation, thus contributing to that rebound phase. And we know that it is associated with key nutrient deficiencies, the same nutrients that we need to support pregnancy.

Even if we take that factor out, even if we have a woman who hasn’t been on birth control and is just eating the regular diet, there are certainly going to be these gaps. This study highlights that the average woman is going into pregnancy significantly depleted — or, to use the specific wording from the study, not anywhere close to meeting her average daily requirement of any of these key nutrients that we know are required for optimal fertility.

If you think of your nutrient stores as a bank account — and I said this in Real Food for Fertility, and I think I also shared this in The Fifth Vital Sign — when you are pregnant and breastfeeding, the only thing that’s really happening during those times are massive withdrawals. There is nothing that’s ever going to require more nutrients than building a human with your body. It certainly warrants some attention.

We have a lot of research that shows us how important this is. And although we’re not looking at postpartum nutrient studies in today’s episode, consistently when you look at nutrient studies or analyses that include postpartum women who are breastfeeding or lactating, these women are typically the lowest in all of these nutrients. That is not a surprise, because they just made the most expensive withdrawal from their nutrient store bank account.

If you can think of someone who could benefit from hearing this episode, I would certainly encourage you to share. I’m sure you can think of someone in your life who could benefit — especially someone who may be trying to conceive, or one of your friends who works with women who are trying to conceive. Feel free to share today’s episode. I hope that you have a wonderful week, and as always, until next time, be well and happy charting.