Supplements and fertility is meant to be a good news story (and it mostly is) as they’re widely used (and advised) for pregnancy and preconception by lots of people (including salesmen!) to boost the health of parents-to-be and to reduce the likelihood of problems for their babies. Other people have quite rightly raised the question of whether they’re really needed, and in 2016 two reviews reached rather different conclusions:
- A review in the BMJi concluded that prenatal and pregnancy supplements are generally unnecessary (except for folic acid and vitamin D) as long as people have a healthy diet, and that they’re over sold to a vulnerable sector
- A review in Placentaii concluded it’s beneficial to supplement with a range of micronutrients (especially selenium) as they reduce the likelihood of complications in pregnancy and contribute to a healthy start in life
This is an important debate that raises a number of questions:
- Pretty much everyone agrees healthy diets and lifestyles are the cornerstone of good health, and that in an ideal world there’s little need to take additional supplements for a healthy pregnancy
- It’s also unfortunately true that not everyone has a healthy diet and lifestyle, plus the way that most food is grown (with modern fertilisers) has left the soil lacking essential nutrients that were traditionally present, so many foods don’t have an ideal range or level of minerals
- Not everyone gets pregnant easily, and studies assessing the effect of supplementing on pregnancy outcomes (such as neural tube defects and pre-eclampsia) aren’t directly transferable to couples trying (or struggling) to get pregnant
- The broader (more difficult to measure) issue of how supplements actually affect people’s health and fertility wasn’t part of this debate
- Another important question is how differences in the quality and ‘form’ of the multivitamins and minerals taken affects outcomes; for instance folic acid in methyfolate form is more beneficial for neural tube development and cognitive function than ‘straight’ folic acidiii
There’s an enormous range of pre- and post- conception products, with an equally wide range of quality and price, some of which are relatively inexpensive (but usually contain sugar or other “fillers” or minerals in poorly absorbed forms), while others are very expensive big brands with big marketing budgets who know how to approach what’s a fairly vulnerable audience.
Oxidative stress does reduce fertility, but unfortunately most oxidation is an unavoidable side effect of cells simply functioning, but the amount of damage it does to eggs and sperm increases when the body is low on antioxidants. There are many different antioxidants, including a wide range of minerals, vitamins and enzymes that are normally found in healthy diets, and it’s the range of antioxidants, rather than certain levels of just a few that provide the best protection for the body. A healthy diet also encourages the growth of a healthy gut microbiome that’s better at making antioxidants available from the diet or directly synthesises them for the body. Antioxidants reduce damage from oxidative stress in the body, and are so important for male fertility that antioxidant levels in a man’s semen sample more accurately predict fertilisation rates than the number of his viable sperm.iv v
When couples have a varied and healthy diet and lifestyle, and getting pregnant isn’t a problem, there’s little reason to recommend adding anything above folic acid and Vit D. But when this isn’t happening (and that’s a lot of us) it makes sense to add sensible amounts of quality vitamins and minerals to increase antioxidant levels to optimise the health and fertility of both the parents and the baby to be.
An easily made, but dangerous idea is that “the more of a good thing you have, the better it is for you” especially with supplements as they’re potentially harmful to health, and this is particularly true with high doses