Evidence shows that healthy nutrition and fertility are linked in both men and women.
Zinc is an essential trace mineral critical for our immune and cellular health, keeping our gut lining healthy and wound healing.
It also plays a vital role in male and female fertility preconception and during really early stages of embryo development.
It contributes to ovulation and cell division and growth, so is essential for healthy eggs in women, and contributes to semen and testosterone production in men which increases sperm count. Zinc is found to be lower in the seminal fluid of infertile and sub-fertile men compared to fertile controls and is positively correlated with sperm concentration and motility.
Once pregnant, adequate zinc intake remains vital. It can decrease the risk of complications, including:
- Pre-eclampsia (high blood pressure and urinary protein concentrations during pregnancy);
- Premature rupture of membranes (when a woman’s amniotic sac/pregnancy water breaks before she experiences contractions); and
- Preterm delivery
- Low birth weigh
- Pregnancy complications, and
- foetal abnormalities including growth retardation and other congenital abnormalities including immune and behavioural dysfunction
So, are you getting enough zinc?
It turns out that up to 85% of women of child-bearing age are deficient despite needing much less than men aiming to conceive.
Pre-conception, 100-200mg per day of dietary zinc for men increases testosterone levels, sperm count and sperm motility.
During pregnancy the recommended daily intake of zinc jumps from 8 milligrams per day for adult women to 11 milligrams during pregnancy. Women trying to conceive can take the higher amount. The upper limit for zinc is 40mg/day for adult men and women and the same during pregnancy.
Dietary Sources of Zinc:
Zinc is found in a wide variety of foods. The most potent dietary sources of zinc include meat, seafood (oysters, crab and lobster) and poultry. Other food sources include nuts and seeds cooked dried beans, peas and lentils, whole grains, dairy products and fortified breakfast cereals.
Oysters: by far the richest source of zinc, containing more zinc per serving than any other food! They can be consumed during pregnancy, given they are cooked all the way through.
1 serving (75g) will provide ~75mg zinc.
Shellfish: such as crab, is a good source of zinc but also needs to be cooked all the way through if consuming while pregnant. 1 serving (75g) provides ~6.5mg zinc.
Pork chops: red meat is a great source of zinc as readily absorbed by the body. 1 serving (75g) provides ~2.9mg zinc.
Lentils: although not as good as meat or shellfish, 1 cup of cooked lentils covers around 20% of your daily zinc needs. If you are vegetarian, this intake may provide less than 20% of your requirements since zinc needs are higher amongst vegetarians. 1/2 cup of cooked chickpeas provides ~1.3mg zinc.
Cashews: the nut with the highest amount of zinc and an excellent addition to a vegetarian diet. ~25g dry roasted provides 1.6mg zinc.
Quinoa: Whole grains contain some zinc although, like other plant sources, it is not as well absorbed as animal sources of zinc. 3/4 cup quinoa contains ~2mg zinc.
The bioavailability of zinc varies markedly depending on the availability of protein in the diet, and zinc from protein rich animal foods is absorbed as much as 50% more readily than zinc from plant sources so vegetarians, particularly strict vegetarians, will need intakes about 50% higher than those set. There is some evidence that high levels of iron supplements (e.g. quantities similar to those found in supplements i.e. greater than 25mg) prescribed to pregnant and lactating women may decrease zinc absorption.
Taking iron supplements between meals helps decrease its effect on zinc absorption.
High zinc intakes can inhibit copper absorption, sometimes producing copper deficiency and associated anaemia.
Zinc supplements are not routinely provided to pregnant women in Australia. However, women who are vegetarian or vegan may be at risk of zinc deficiency during pregnancy because the zinc in their diet is absorbed less efficiently than in women who consume meat and dairy products.
To boost your fertility when planning for a baby, it is recommended to begin making healthy changes to your diet at least 3 months before you conceive.