Vegan diets are all the rage. Not only is going vegan considered to be one of the healthiest options out there, but if you can stick with it, you can wear it as a badge of honour, as it is arguably the hardest diet to stick with long-term. A vegan diet involves zero animal products. No meat, no eggs, no dairy. It’s not easy to stop eating all animal products forever. After awhile, you may find yourself craving cheese and hamburgers again.
Some health professionals argue that a vegan diet is more of a fast, and can be beneficial as a way to cleanse the body over the short term, but may not be the best option long term. For many individuals, going vegan is not simply a dietary choice. There are numerous ethical implications that take veganism far outside the realm of nutrition. When you’re concerned about minimizing your environmental footprint, or championing animal rights, going vegan can feel like the only option.
I embraced a vegan diet for this reason. I couldn’t stomach the treatment of animals in factory farms, and I didn’t want to consume animal products that were laced with hormones and antibiotics. However, I quickly experienced a cascade of health problems that made it impossible for me to continue avoiding meat and dairy. Now I support local farmers, and source meat and dairy products from local farming operations that allow their livestock to graze on pasture. I have come to realize that modern agriculture will not “save the planet”.
There is no one diet for everyone. Many women do well when they transition to a vegan diet, but many do not. When you’re planning ahead for pregnancy, you’ll want to opt for a diet rich in the nutrients that support optimal fetal development. What the research tells us is that certain key nutrients are only found in animal foods. When choosing to consume a vegan diet during pregnancy and lactation, carefully consider where you’ll obtain these nutrients and how you’ll ensure your levels remain adequate.
Below are the top 6 reasons why a vegan diet may harm your fertility:
1. Vegan Diets Lack Vitamin B-12
B-12 deficiency is common in omnivores, but vegans and vegetarians are at a greater risk. Your risk of developing a B-12 deficiency is higher during pregnancy and lactation, because pregnant and lactating mothers have a greater requirement for vitamin B-12. Vitamin B-12 deficiency is dangerous during pregnancy, and is associated with impaired cognitive development (and other fetal abnormalities).
Vitamin B-12 is not found in plant foods. Vegetarians can obtain vitamin B-12 from dairy foods or eggs, but a vegan diet contains no natural food sources of this key nutrient. Vitamin B-12 must therefore be obtained through fortified foods and careful supplementation. Your liver stores enough vitamin B-12 to last several years, so you may get away with it for quite some time, but pregnancy and lactation are two seasons of life when your body requires significantly more nutrition (1).
Signs of vitamin B-12 deficiency include fatigue, poor cognition, poor digestion, and failure to thrive in small children. When it comes to vitamin B-12, not all food sources are made equal. Liver contains the highest concentration of vitamin B-12, followed by meat, fish, eggs, and dairy products.
2. Vegan Diets Lack Vitamin A (Retinol)
Vitamin A (retinol) plays an essential role in maintaining a healthy immune system, good eyesight, healthy skin, and fertility. Vitamin A is important in both male and female reproduction. In men, vitamin A helps the body to produce healthy sperm by aiding in spermatogenesis. In women, vitamin A is not only integral to the production of a healthy ovum, facilitating implantation and sustaining the pregnancy, but it is also integral in fetal development throughout pregnancy. Vitamin A plays a vital role in the development of fetal organs specifically the heart, the central nervous system, the circulatory system, and the skeletal system. Vitamin A deficiency in pregnancy can lead to either a malformation of any of these organs or systems or miscarriage if the fetus fails to develop normally. Vitamin A has also been implicated in the production of peak cervical mucus which is essential in ensuring the sperm survive long enough to reach the fallopian tubes for implantation.
You may have heard that you can get your vitamin A from carrots, but that’s only partially true. Plant foods contain beta carotene—a precursor to vitamin A that our bodies have to convert into retinol before we can fully utilize it. Beta carotene does not significantly increase your serum levels of vitamin A (2). Not to mention that 45% of adults aren’t capable of converting beta carotene to retinol at all (2).
When following a strict vegan diet, obtaining sufficient levels of vitamin A to support fertility and pregnancy is not possible without the consumption of fortified foods, and careful supplementation. Unfortunately, synthetic vitamin A is associated with an increased risk of birth defects, where as food based sources are not. The richest food sources of vitamin A include cod liver oil, liver, seafood, beef, poultry, eggs and dairy products.
3. Plant Foods Do Not Contain DHA and EPA (Omega 3 Fatty Acids)
Plant foods contain alpha-linolenic acid (ALA), whereas animal foods contain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The vast majority of the incredible health benefits associated with omega-3 fatty acids come from DHA and EPA — two fatty acids found in fish and seafood (and in smaller quantities in other animal foods) (3). When you get your omega-3s from plant foods (in the form of ALA), your body converts less than one percent of it into EPA and DHA (4). Microalgae oil is the only plant based source of DHA and EPA, however with numerous studies outlining the benefits associated with consuming fish during pregnancy, it’s unclear as to whether microalgae oil is equivalent.
One study found that women who consume 12 oz of seafood per week improved neurodevelopment in their children. Women who regularly ate seafood had children with better verbal and communication skills, better fine and gross motor skills, and less social and behavioural issues. In comparison, the children of women who ate very little (or no) seafood were more likely to suffer from developmental and behavioural issues (5). Given that plant foods do not contain DHA and EPA, careful consideration is required to ensure you are getting enough when planning for pregnancy.
4. Vegan Diets Do Not Contain Any Cholesterol
Vegan diets are cholesterol free. Cholesterol is only found food in animal foods, and even though decades of advertising has convinced many of us cholesterol is dangerous, cholesterol is essential for optimal hormone production (6). Your reproductive hormones, such as estrogen, progesterone, and testosterone are synthesized directly from cholesterol. Cholesterol forms a significant portion of your cell membranes, and you’ll find it in every cell in your body. 20 percent of your total cholesterol is found in your brain (the largest concentration in your body), and your brain is comprised of 60 percent fat (7). One study found that women who ate low-fat dairy were more than twice as likely to experience ovulatory disorders compared to women who ate full-fat dairy — speaking to the important role that animal fat plays in fertility (8).
Processed vegetable oils including canola, corn oil, soybean oil, etc are highly inflammatory, and are primarily comprised of omega 6 fatty acids. Optimal health is dependent on you having a balance of omega-3 and omega-6 fatty acids. Vegetable oils (for the most part) have already been damaged during the manufacturing process. The consumption of these damaged oils contribute to inflammatory conditions such as endometriosis and dysmenorrhea. Avoiding inflammatory vegetable oils in favour of coconut oil, or animal fats (particularly for cooking) will help you to avoid the problems associated with over-consumption of omega 6 fats. As will consuming adequate sources of omega 3s to establish a balance between these 2 essential fats.
5. Soy Products Are Often A Significant Protein Source
Soy is often a go-to protein source in vegan diets, however soy products are known to disrupt the normal balance of your reproductive hormones, The problem with processed soy products is that they contain high levels of phytoestrogens. Phytoestrogens are natural molecules in plants that have an estrogenic effect in the body (similar to xenoestrogens). In the past, Asian soy preparations included long periods of soaking and simmering that removed much of the soy isoflavones and phytoestrogens from traditional soy foods. Modern day soy processing does not utilize traditional methods of preparation, and this leaves much higher levels of phytoestrogens in processed soy products such as soy milk, tempeh, tofu, and soy based baby formula. Studies have found that soy consumption disrupts the menstrual cycle by delaying ovulation (9). When considering soy products as a protein source, caution should be used. Monitoring your menstrual cycle can help you to determine if regular consumption of soy is altering your normal cycle.
6. A Vegan Diet Increases Your Risk Of Developing Micronutrient Deficiencies
In addition to vitamin A (retinol) and vitamin B12, by eliminating all animal foods, you increase your risk of becoming deficient in certain nutrients including iron, zinc, and iodine. Increasing iodine intake is fairly strait forward. Regularly incorporating seaweed is helpful to ensure you obtain adequate dietary iodine. However, obtaining adequate iron and zinc may not be as simple.
Plant foods (such as spinach or other leafy green vegetables) are a source of non-heme iron. When you eat meat (particularly liver, and/or red meat), you’re getting heme iron. Heme iron is more readily absorbed than the non-heme iron found in plant foods (10). Maintaining sufficient iron stores is critical for maintaining menstrual cycle health and fertility. Iron deficiency can contribute to menorrhagia (heavy menstrual bleeding), iron deficiency anemia, and a variety of other health issues. Maintaining sufficient iron stores is especially crucial when you’re trying to conceive, as your requirements for iron significantly increase during pregnancy (11).
Zinc plays a critical role in normal ovulatory function and fertility (12). Similar to iron, animal sources of zinc (such as red meat and/or seafood) are more readily absorbed compared to plant sources (13). Zinc and iron are two nutrients known to be lower in individuals who adopt a vegan diet. This is of particular importance when planning for pregnancy, as your requirement for these and virtually all other nutrients increases dramatically.
When optimizing fertility and planning for pregnancy, you may wish to consider if a vegan diet is optimal. Without the addition of animal foods, you must be intentional in structuring your dietary choices to ensure you’re meeting your nutritional needs. Over the course of your adult life, pregnancy and lactation are the most intensive from a nutritional standpoint. Your requirements for all nutrients dramatically increase. When you opt for a diet known to be deficient in certain nutrients, you must be vigilant. Incorporating specific foods high in these key nutrients will help you maximize your intake (i.e. liver, organ meats, eggs, fish, full-fat dairy, etc.). If you find yourself facing fertility challenges, or menstrual cycle issues, you may have to consider if your diet is a contributing factor. Many women do well on a vegan diet, however many do not. The question is, where do you fall on that spectrum?
When you’re ready to optimize your diet for fertility and pregnancy, grab a copy of The Fifth Vital Sign: Master Your Cycles & Optimize Your Fertility! Chapter 17 lays out evidence-based practices for preparing your body for pregnancy including optimizing sperm and egg health during the preconception period.