Folate, Iron, and Iodine: The Three Nutrients You Need Most When Trying to Conceive

Folate is the natural form of vitamin B9 found in food. Folic acid is the synthetic form used in supplements and fortified foods. Both are important in the preconception period, and the terms are often used interchangeably — though they are not identical in how the body processes them.

What Folate Does

Folate is essential for DNA synthesis and cell division — two processes that are happening at extraordinary speed in the earliest days of a developing embryo. Its most well-documented role is in neural tube development: adequate folate in the weeks around conception is strongly associated with a reduced risk of neural tube defects (NTDs) such as spina bifida and anencephaly. The neural tube — which becomes the brain and spinal cord — closes between days 21 and 28 of pregnancy, typically before most women have taken a pregnancy test.

Beyond neural tube protection, folate supports egg quality, DNA repair, and the production of red blood cells — all of which are relevant to the preconception period specifically.

How Much Folate You Need

The Australian National Health and Medical Research Council (NHMRC) recommends 400 micrograms (mcg) of folic acid daily for women planning a pregnancy, beginning at least one month before conception and continuing through the first trimester. Women with a personal or family history of neural tube defects, diabetes, or who take certain medications (including some anticonvulsants) are typically advised to take a higher dose of 5mg daily — this should be discussed with a GP.

The folic acid pregnancy recommendation has been 400mcg as the minimum for decades, but emerging research suggests that higher intake — up to 800mcg in the preconception period — may offer additional benefit for women who carry variants in the MTHFR gene (which affects folate metabolism). MTHFR variants are common, and some practitioners now recommend methylfolate (the active form) rather than standard folic acid for this reason. This is worth discussing with a healthcare provider if you have concerns.

Best Folic Acid Pregnancy Foods

Food sources of folate include:

• Dark leafy greens — spinach, kale, silverbeet, and rocket are among the richest sources. One cup of cooked spinach provides approximately 260mcg of folate.
• Legumes — lentils, chickpeas, and black beans. One cup of cooked lentils provides approximately 360mcg of folate, making them one of the highest food sources available.
• Avocado — one whole avocado provides approximately 160mcg of folate, along with healthy fats that support hormonal function.
• Edamame — around 480mcg per cup cooked, making it one of the highest single food sources of folate.
• Citrus fruits — oranges, mandarins, and grapefruit. A medium orange provides around 50mcg.
• Fortified foods — since 2009, wheat flour used for bread-making in Australia has been mandatorily fortified with folic acid, contributing to population folate intake.
• Eggs — a useful contributor to folate intake alongside their many other preconception benefits (choline, protein, vitamin D).

Even with a diet rich in these foods, reaching 400mcg of folic acid per day consistently through diet alone is difficult for most women. This is why supplementation is recommended in addition to dietary sources — not instead of them. A preconception supplement with at least 400mcg folic acid, started one month before trying to conceive, is the Australian evidence-based standard.

Iron deficiency is the most common nutrient deficiency in Australian women of reproductive age. It is also one of the most directly relevant to fertility — yet it rarely receives the same attention as folic acid in preconception guidance.

What Iron Does for Fertility

Iron has a documented association with ovulatory function. Research published in the American Journal of Clinical Nutrition found that women with higher non-haem iron intake had a significantly lower risk of ovulatory infertility. The proposed mechanism involves iron’s role in supporting the development of the dominant follicle and the hormonal signals that trigger ovulation.

Beyond ovulation, adequate iron stores matter for implantation and early pregnancy. Iron deficiency anaemia in early pregnancy is associated with increased risk of preterm birth and low birth weight. Given that iron stores take months to rebuild, addressing low iron and fertility risk together in the preconception period — rather than waiting to address anaemia in the first trimester — is the more protective approach.

How Much Iron You Need

The NHMRC recommended dietary intake for iron for women aged 19–50 is 18mg per day. During pregnancy, this increases to 27mg. Iron requirements during the preconception period sit at the 18mg mark — but many Australian women are falling short of this, particularly those with heavy menstrual periods, those who avoid red meat, or those who have recently donated blood.

A blood test for ferritin (stored iron) before or early in the preconception period gives a much clearer picture of iron status than dietary estimates alone. A ferritin level below 30 mcg/L is generally considered below optimal for a woman planning pregnancy, even if the result sits within the broad “normal” reference range. This is worth discussing with a GP.

Best Iron Foods for Preconception

Iron exists in two dietary forms with significantly different absorption rates:

• Red meat (beef, lamb) — among the richest haem iron sources, with 100g of beef providing approximately 3–4mg of highly absorbable iron
• Chicken and turkey (particularly dark meat)
• Organ meats, particularly chicken or beef liver — very high in iron but consumed in moderation during preconception due to high vitamin A content
• Fish and shellfish — oysters are particularly high in iron
• Legumes (lentils, chickpeas, kidney beans, tofu)
• Dark leafy greens (spinach, silverbeet)
• Pumpkin seeds and sesame seeds
• Fortified breakfast cereals — check labels, as iron content varies significantly
• Dried apricots and other dried fruits

The absorption of non-haem iron is significantly enhanced by consuming it alongside vitamin C — pairing lentil soup with fresh lemon juice, or spinach salad with sliced capsicum and orange segments, meaningfully improves iron uptake. Conversely, tea and coffee consumed within an hour of iron-rich meals can reduce iron absorption — a practical consideration for women with lower iron stores.

Iodine is probably the least talked-about of the three essential preconception nutrients — and the one most likely to be genuinely deficient in Australian women, regardless of how well they eat.

What Iodine Does

Iodine is required for the production of thyroid hormones, which regulate metabolism, energy, and — critically for pregnancy — fetal brain development. In the first trimester, the fetus is entirely dependent on the mother’s thyroid hormones because its own thyroid does not become functional until around week 12. Iodine deficiency during this period is one of the most preventable causes of impaired fetal neurodevelopment worldwide.

Beyond early pregnancy, iodine deficiency before conception can affect thyroid function in ways that impair fertility directly. Subclinical hypothyroidism (mild thyroid underfunction, often linked to insufficient iodine) is associated with irregular cycles, impaired ovulation, and difficulty conceiving. Preconception iodine status has been specifically associated with IQ outcomes in children in longitudinal research.

How Much Iodine You Need

The NHMRC recommends 150mcg of iodine daily for women of reproductive age, increasing to 220mcg during pregnancy and 270mcg while breastfeeding. Most Australians are not meeting even the baseline 150mcg recommendation through diet — Australia’s soils are iodine-depleted, which means that iodine content in locally grown food is lower than in many other countries.

Australian guidelines from the NHMRC and the Royal Australian College of GPs (RACGP) specifically recommend that women who are pregnant, breastfeeding, or planning a pregnancy take an iodine supplement of 150mcg per day. This is one of the clearest and most consistent supplement recommendations in Australian preconception guidance, and one of the most commonly overlooked.

Best Iodine Food Sources

Iodine content in food varies significantly depending on where and how it was produced:

• Seafood — particularly white fish, prawns, and canned tuna. Seafood is among the most reliable dietary sources of iodine in Australia.
• Dairy products — milk, yoghurt, and cheese. Iodine in dairy comes largely from iodophor sanitisers used in dairy equipment rather than the milk itself, which means content can vary.
• Eggs — a moderate source of iodine, with content depending on the iodine content of hens’ feed.
• Seaweed and kelp — very high in iodine, but content is highly variable and certain seaweed types (kombu/kelp) can contain excessively high levels that may be harmful in pregnancy. Nori (used in sushi) is generally a moderate, safer option.
• Iodised salt — available in Australian supermarkets and a useful source if salt is used in cooking, though public health guidance generally discourages increasing salt intake for iodine alone.
• Prenatal vitamins with iodine — the most reliable and consistent way to meet the preconception iodine recommendation. Check that your prenatal supplement contains at least 150mcg of iodine, as not all formulations do.

It is worth noting that many standard multivitamins do not contain adequate iodine for preconception or pregnancy. Checking the label of any supplement you are taking and confirming it meets the 150mcg recommendation is important.

Folate, iron, and iodine are not simply three separate boxes to tick. They interact in ways that matter for preconception health:

• Iron supports the production of haemoglobin, which carries oxygen to every cell. Adequate iron supports energy, mood, and the physical demands of pregnancy — but it also supports thyroid function, creating a link to iodine status.
• Folate and iron both support red blood cell production. Iron deficiency anaemia and folate deficiency anaemia have overlapping symptoms (fatigue, breathlessness, pallor) but different causes and different solutions — a blood test is the only way to distinguish them.
• Thyroid hormones (dependent on iodine) regulate the metabolism of folate and B vitamins. Iodine deficiency that affects thyroid function can therefore indirectly affect how well the body uses folate — making iodine status relevant to neural tube protection in a secondary way.

The practical implication is that these three nutrients are best addressed together, ideally through a combination of a nutrient-rich whole-food diet and a quality preconception supplement that covers all three. Addressing one while remaining deficient in the others leaves gaps in a system where all three are required.