Vegan diets and fertility

In 2014, the number of vegans in the UK was estimated to be 150,000 which increased to 600,000 by 2018 and the figure is now suggested to stand at over 1 million vegans in the UK. A vegan lifestyle is chosen for many different reasons, including beneficial impacts on the environment and sustainability, animal welfare, or health benefits. It is a way of living that excludes all forms of animal derived products for food, clothing or any other purpose. A vegan diet is therefore based on fruits, vegetables, nuts, grains, seeds, beans and pulses avoiding all animal derived foods such as meat, fish, shellfish, insects, dairy, eggs and honey.

Benefits of a vegan diet

A well-planned vegan diet can be beneficial for heart health and the British Nutrition Foundation states that it can be suitable for people of all ages throughout the life cycle if carefully planned and includes a variety of different vegan food options.

A Mediterranean diet style may be protective of fertility, many aspects of which are incorporated in a vegan diet such as wholegrains and fibre. Consuming a wide variety of fruit and vegetables can improve fertility in both men and women due to their antioxidant properties. High levels of oxidative stress can impair implantation and fertilisation as well as cause damage to developing eggs (1,2). Oxidative stress can also influence male fertility by causing sperm damage.

Replacing animal sources of protein with plant sources, as is done on a vegan diet, has been found to reduce the risk of an ovulatory infertility (3). Individually, the majority of plant based foods are not complete protein sources and lack some of the essential amino acids required to support growth repair. Consuming a variety of plant based protein sources, for example combining beans or vegetables with wholegrain rice or legumes in a meal, will provide all the amino acids your body requires to support fertility.

Potential vitamin deficiencies

Due to its restrictive nature it is essential to be aware of and protect against vitamin deficiencies that can arise from not incorporating animal products from the diet. Micronutrient deficiencies impact our fertility and can be easy to rectify with the correct advice and knowledge.

• Vitamin B12 is generally not present in plant foods only animal products, leaving vegans at high risk of deficiency. Lower Vitamin B12 levels are associated with female infertility (4), higher intakes may even enhance fertility outcomes in women undergoing assisted reproduction treatments (5). Vitamin B12 can be found in fortified cereals, fortified soya drinks and fortified nutritional yeasts. Supplementation with at least 10mcg daily or at least 2000mcg weekly is recommended.
• Optimising stores of iodine pre pregnancy is essential for child brain development. Vegans are likely to be deficient as the main sources are milk, fish and eggs. Plant milks are now often fortified with iodine but not always so check the label. Seaweed and kelp are known sources of iodine however, regular consumption is not recommended as the iodine content is highly variable and can often be too high.
• Omega-3 intake has been linked to improved egg quality and delayed ovarian ageing in females. It has also been shown to positively affect sperm quality. EPA and DHA are the biologically active forms and are found in oily fish. Flaxseed, chia seeds, ground linseeds, hemp seeds and walnuts are all sources of alpha-linolenic acid, which can be converted to EPA and DHA however this conversion is not very efficient. Supplementation with omega-3 fats from microalgae can help to ensure optimal levels for fertility.   
• Iron deficiency can impact fertility (6). Non-haem plant based iron sources are not as easily absorbed as meat sources (7). Plant sources include lentils, chickpeas, beans, tofu, cashew nuts, chia seeds, ground linseed, hemp seeds, pumpkin seeds, kale, dried apricots and figs, raisins, quinoa and fortified breakfast cereal. Taking these with sources of vitamin C can help absorption, avoiding tea and coffee consumption at the same time can also help.
• Zinc is found in nuts, seeds, leafy green vegetables, whole grains, dairy and poultry. It can support and promote fertility by helping progesterone production, healthy cell division and ovulation (8). Meat sources are more bioavailable, incorporating more plant based sources or taking a prenatal supplement containing zinc can ensure requirements are met.  

How to optimise your vegan diet for health and fertility

A vegan diet can be a healthy one if planned appropriately, and similarly, if planned appropriately it can help to promote fertility. It is easy to lack certain nutrients when following a vegan diet such as iron, vitamin B12, zinc, selenium and omega-3 as mentioned above, but you can still consume adequate amounts, either by finding plant-based foods containing these nutrients, choosing fortified foods or taking supplements. 

For more information, visit the Vegan Society website where you will find several excellent resources to support your vegan journey. If you feel you need additional support to ensure your vegan diet is optimal for fertility, then book yourself an appointment with a fertility dietitian or registered nutritionist. 

References

1. Agarwal A, Gupta S, Sharma RK. Role of oxidative stress in female reproduction [Internet]. Vol. 3, Reproductive Biology and Endocrinology. BioMed Central; 2005 [cited 2020 Aug 24]. p. 28. Available from: /pmc/articles/PMC1215514/?report=abstract
2. Agarwal A, Aponte-Mellado A, Premkumar BJ, Shaman A, Gupta S. The effects of oxidative stress on female reproduction: A review [Internet]. Vol. 10, Reproductive Biology and Endocrinology. BioMed Central; 2012 [cited 2020 Aug 24]. p. 49. Available from: /pmc/articles/PMC3527168/?report=abstract
3. Mph JW, Chavarro JE. Diet and Lifestyle in the Prevention of Ovulatory Disorder Infertility. 2007 [cited 2020 Jun 17];110. Available from: http://journals.lww.com/greenjournal/Fulltext/2007/11000/Diet_and_Lifestyle_in_the_Prevention_of_Ovulatory.17.aspx
4. Chavarro JE, Rich-Edwards JW, Rosner BA, Willett WC. Use of multivitamins, intake of B vitamins, and risk of ovulatory infertility. Fertil Steril. 2008 Mar;89(3):668–76. Available from: https://www.fertstert.org/article/S0015-0282(07)00828-X/fulltext
5. Gaskins AJ, Chiu YH, Williams PL, Ford JB, Toth TL, Hauser R, et al. Association between serum folate and Vitamin B-12 and outcomes of assisted reproductive technologies. Am J Clin Nutr [Internet]. 2015 Oct 1 [cited 2020 Aug 24];102(4):943–50. Available from: /pmc/articles/PMC4588741/?report=abstract
6. Chavarro JE, Rich-Edwards JW, Rosner BA, Willett WC. Iron Intake and Risk of Ovulatory Infertility. Obstet Gynecol [Internet]. 2006 Nov [cited 2020 Aug 24];108(5):1145–52. Available from: http://journals.lww.com/00006250-200611000-00015
7. Pawlak R, Berger J, Hines I. Iron Status of Vegetarian Adults: A Review of Literature [Internet]. Vol. 12, American Journal of Lifestyle Medicine. SAGE Publications Inc.; 2018 [cited 2020 Aug 7]. p. 486–98. Available from: /pmc/articles/PMC6367879/?report=abstract
8. Tian X, Anthony K, Neuberger T, Diaz FJ. Preconception Zinc Deficiency Disrupts Postimplantation Fetal and Placental Development in Mice1. Biol Reprod [Internet]. 2014 Apr 1 [cited 2020 Jun 23];90(4). Available from: https://academic.oup.com/biolreprod/article-lookup/doi/10.1095/biolreprod.113.113910