Whether you're in the early stages of trying to conceive or already pregnant, you probably know the importance of adequate nutrition.
But between macronutrients, micronutrients, vitamins and minerals, it's not always easy to decipher the nitty-gritty of health advice for specific minerals like zinc.
We're sure you've heard of zinc (and maybe slapped some on your face over summer as a child) but why is it important during pregnancy? What are the signs of a severe zinc deficiency, and how does maternal zinc status affect a growing baby?
We've taken the time to read up on the clinical nutrition research and current recommendations to provide a rundown on how and why pregnant people can utilise zinc supplementation during pregnancy.
Zinc 101: what does it do?
Let's start with the basics — zinc is a trace mineral, which means that the body only needs small amounts of it, but it plays a role in many vital processes in the body.
Zinc is necessary for almost 100 enzymes to carry out essential chemical reactions including the creation of DNA, growth of cells, helping heal damaged tissue and building proteins.
You may have already heard zinc mentioned in relation to overall immunity and general health. This is because zinc supports the growth and normal functioning of immune cells, which can protect the body against viruses and bacteria.
Another key process of this mighty mineral is its role in wound healing. Adequate levels of zinc are needed to create new cells, particularly collagen and fibre-like tissues required for repairing damaged cells.
On top of this, zinc's function of supporting immune cell activity is also needed to combat inflammation from a wound.
Why is zinc important during pregnancy?
Zinc plays such an important role in helping cells to grow and multiply and adequate levels of zinc are needed during periods of rapid growth like pregnancy.
One study that examined the effect of zinc supplementation during pregnancy noted that many people of childbearing age may be experiencing mild to moderate zinc deficiency.
Low zinc status may cause preterm birth and there is evidence to suggest zinc deficiency may actually prolong labour. Researchers also measured child development outcomes and noted that zinc deficiency may affect infant growth as well.
The authors of this literature review found a small but significant reduction in preterm birth for the zinc supplemented group compared to the placebo group.
The World Health Organisation (WHO) recently published a report on zinc supplementation during pregnancy which highlighted that zinc is not stored in the body, so physiological needs must be met through dietary intake (including zinc supplements).
The WHO report noted the importance of the mineral in many biological processes relating to pregnancy as it contributes to human growth and development, supporting the healthy growth of the foetal nervous system as well as the aforementioned immune-boosting role.
Maternal zinc supplementation can help counteract any risks associated with maternal or gestational zinc deficiency, such as:
- Reduced fertility
- Foetal neurological malformations
- Slow or inhibited growth (small for gestational age)
- Congenital malformations
- Postpartum haemorrhage
- Pre-eclampsia
The WHO report makes note of the fact that overall nutrition is important for maternal and infant health, so while taking a specific zinc supplement may not cause harm, it's best to keep the bigger picture in mind.
When considering prenatal zinc supplementation, it is recommended pregnant women look for one that contains a range of nutrients to aim for an optimal pregnancy and infant outcome.
This evidence-backed oral zinc supplementation is a safe and handy way of ensuring you are receiving your daily zinc supplementation, as well as many other nutrients required for maternal and infant health.
How much zinc is safe in pregnancy?
Current recommendations in Australia about dietary zinc intake advise that pregnant people need about 10 to 11mg of zinc per day. To put that into context, the recommended daily intake of zinc for a typical adult woman is around 8mg per day.
So when aiming for an optimal pregnancy outcome, the additional amount required shouldn't be too difficult for the average person to consume.
Additionally, it's important for pregnant people to keep their nutrition in mind after childbirth as well, as breastfeeding can affect zinc status and deplete normal zinc levels.
Is too much zinc harmful?
As with a lot of nutrition advice, the recommended daily intakes are based on that 'sweet spot' between too little and too much. Too much zinc can be harmful to pregnant people (as well as the greater population) and can lead to zinc toxicity.
Symptoms of zinc toxicity may include:
- Nausea
- Vomiting
- Stomach pain/ache
- Diarrhoea
- Headaches
If high levels of zinc are consumed over a long period, this can result in chronic zinc toxicity, which can lead to low levels of high-density lipoprotein ('good' cholesterol), decreased immune function and copper deficiency.
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How much is 'too much' zinc?
One way to think about the recommended daily intake (RDI) of a vitamin or mineral is that the RDI sits in the middle of a spectrum. On one end you have deficiency, and on the other you have toxicity.
Toxicity occurs when a person exceeds what's known as the tolerable upper level (UL) — that is, the maximum amount consumed before it becomes harmful. For maternal zinc intakes, the tolerable upper level for zinc is 40mg across all adult populations.
Is vitamin C and zinc safe during pregnancy?
Both vitamin C and zinc are two of the many essential vitamins and minerals the body needs for optimum health but are especially important during pregnancy. These vitamins and minerals not only help foetal growth but support the immune system to support pregnancy outcomes for both the parent and the growing baby.
Zinc also assists with protein synthesis and plays a role in neonatal and infant health. Vitamin C, also known as ascorbic acid, supports the formation of connective tissue, while zinc is important for reproductive health, growth and development.
Getting enough of these nutrients during pregnancy is super important because they help support the immune system and the body's ability to repair wounds and support general healing.
The general recommended daily intake of vitamin C is around 75mg for women and 85mg for pregnant people.
Importantly, lactating parents need even more of a boost: it is advised that breastfeeding people aim for 120mg of vitamin C each day.
Vitamin C plays a number of key roles in the body, including:
- Acting as an antioxidant
- Helping the body to produce collagen and connective tissue
- Assisting the body in absorbing iron from plant-based foods
- Protecting the body's cells from free radicals (which, in turn, can hep prevent disease)
- Preventing diseases relating to deficiency
- Supporting a strong and healthy immune system
The best way to consume zinc while pregnant
Zinc is widely available from a range of food sources including meats, fish, poultry, cereals and dairy products. In general, zinc absorption from a diet high in animal proteins will be greater than from a diet rich in plant derived proteins.
Advice for vegetarians or vegans:
- Well-planned diets can provide adequate levels of zinc from plant sources
- There is some evidence that vegetarians can adapt to lower zinc levels by increased absorption and retention of zinc
- Great sources of zinc for vegetarians include whole grains, tempeh, tofu, legumes, nuts and seeds, and fortified breakfast cereals (these sometimes include folic acid as well).
As well as being mindful of eating a varied, well-balanced diet, you may consider a supplement to ensure you are more likely to hit all your nutrition needs.
Are there any other clinically relevant outcomes or contraindications with zinc?
At times, the body can seem a little bit fickle in terms of how it absorbs certain vitamins or minerals.
Importantly, it has been found that iron and folic acid supplementation can actually decrease zinc absorption, which is particularly relevant to pregnant people and breastfeeding mothers.
As with everything relating to prenatal, maternal and infant health, if you are concerned about your individual nutrition or wellbeing, we recommend you speak with a healthcare professional.
One recommendation to ensure you're getting the best bang for your buck nutritionally speaking is to be mindful of when you take a zinc supplement or vitamin that contains zinc.
If you are also taking any of the below drugs or supplements, try to take these at least two hours apart from a zinc supplement:
- Copper
- Iron
- Manganese
- Antacids such as calcium carbonate
- Penicillamine
Ultimately, zinc plays a major role in so many vital processes in the body, but is particularly important in pregnancy due to its properties relating to cell growth and human development.
As the World Health Organisation's report reminds us, pregnant and breastfeeding parents should be encouraged and supported to receive adequate nutrition in general — zinc is just one part of that.
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