Overview
· Getting the nutrition of the mother spot on during pregnancy presents a golden opportunity to shape the future health and wellbeing of the next generation.
· Understand how current dietary advice for pregnancy is mediocre, and missing some critical pieces of the nutritional ‘jigsaw’.
· Many pregnant women are at high risk of missing out on key nutrients essential to the optimal development and health of their offspring.
· Failure to get these nutrients can increase pregnancy complications, impair growth and compromise mental development.
· With the right know-how, you can avoid these pitfalls by including the right foods and supplements in pregnancy to give your child the best start in life.
As we’ve seen from the Foetal Origins Hypothesis, our time in the womb can hardwire our future health. And if you just stop for a second and think about it, there’s a big message for us here. What we have is a truly exciting opportunity to provide the next generation with the best possible start in life and to build a strong foundation for their health. Show us a parent on this planet who doesn’t want that for their children.
Unfortunately, when it comes to dispensing this vitally important advice in pregnancy, it’s a pretty pathetic effort. Sure, we get the usual sage advice to quit smoking, curb the booze, watch caffeine intake, eat a well-balanced diet (whatever that means for most people) and take a folic acid supplement – even though, as we’ll see, for many pregnant mums, that particular piece of advice is given too late for maximum benefits anyway. This is all well and good, and we don’t take issue with any of it. But all we’re really doing is ticking a few boxes, and in the process missing out on a whole lot of other important ones that are also vital for the optimal development of your child during his or her time in the womb.
The nutritional supplement companies haven’t missed this gap in the market, with their array of products ‘tailored’ for pregnancy. But in our opinion, these are often no more than a nutritional ‘lucky bag’ (many of the nutrients are unnecessary, and they even manage to miss out some of the important ones). Even the best of them, which do include the key nutrients that really do make a difference in pregnancy, are given in doses that lack scientific credibility.
Parents want to do the right thing by their children, so we’ll take up the mantle and give you a rundown of the real nutritional needs for an optimal pregnancy.
Iodine
When it comes to nutritional messages for pregnancy, iodine is clearly the one that got away, receiving very little limelight in the UK and USA alike. That’s all a bit worrying when we consider that iodine is absolutely vital for the developing foetus, as it has an indispensable role in thyroid function (it makes up 59–65% of the thyroid hormones in weight). Our thyroid hormones are essential for regulating our metabolism, and have a crucial role to play in the growth and development of organs, most importantly the brain. If you lack iodine, you run the risk of having low levels of thyroid hormones. And if that happens when you are pregnant, foetal development will be impaired.
So, it’s the sort of nutrient that everyone needs in sufficient quantities. But you only need to look at the iodine levels of populations across the globe to see how deluded we are when it comes to our health. Over 2.2 billion people in the world are iodine deficient, making it the greatest single cause of preventable brain damage worldwide1.
If you take a cursory look at women in the USA and UK, they seem to be doing okay with their iodine intake and are just about getting enough2,3. But once pregnancy kicks in it’s a whole different ball game. Requirements jump up to meet the additional need for sufficient thyroid hormones to satisfy mother and baby alike. While a normal adult needs 80mcg iodine per day for thyroid hormone synthesis, the greater metabolic demands of pregnancy increase this requirement to 120mcg per day4. And in pregnancy, the amount of iodine lost from the body via the kidneys actually increases by about 30–50%4. The upshot is that during pregnancy, the usual recommended intake of iodine of 150mcg per day is nowhere near enough – pregnant women need a hefty 250mcg per day5. The same amount is also needed throughout lactation, to ensure sufficient iodine is provided via the milk supply to the child.
When we apply these recommended levels for pregnancy to the US population, we see that a whopping 57% of pregnant women fall short of iodine2. The situation in the UK is similarly dire with about 50% of the pregnant population significantly iodine deficient6. Worryingly, a recent UK survey assessing iodine status in schoolgirls aged between 14 and 15 found iodine deficiency was present in over two-thirds of those sampled. In the not-too-distant future, it will be the children of these young women who will be most susceptible to the damaging effects of iodine deficiency, leading the authors to conclude that there was ‘an urgent need for a comprehensive investigation of UK iodine status, and evidence-based recommendations on the need to implement a policy of iodine prophylaxis’7.
The availability of iodized salt in the UK and Ireland is appallingly low – in fact, the UK and Ireland are firmly rooted at the bottom of the international league table when it comes to iodized salt availability6.
Why does all this matter? The most damaging effect of iodine deficiency is seen in the first trimester of pregnancy, spelling big trouble for a baby’s mental development. Iodine deficiency, or a lack of maternal thyroid hormones, is implicated in increased infant mortality, impaired growth, hearing defects, cretinism, impaired neurodevelopment, reduced IQ, impaired psychomotor development, reduced mental and motor skills and even ADHD1,5,8,9,10,11,12,13,14.
And while it takes severe deficiency to produce these more conspicuous disorders, mild to moderate deficiency – as seen in Europe and the USA – could have subtle adverse effects. The implications are clear – fall short of iodine in pregnancy and the mental development of your children could be hindered5,15.
The mother takes a hit, too. Lack of iodine in pregnancy places a great stress on the mother’s thyroid gland, causing functional and anatomical changes. In countries with moderately deficient iodine intakes (such as Ireland, Germany, Belgium, Italy and Denmark), increases in thyroid gland size of 14–30% are observed during pregnancy. This doesn’t occur in populations that are iodine sufficient (for example, Finland and the Netherlands)16.
It’s very important to raise iodine status and ensure good iodine stores in the thyroid before pregnancy; taking an iodine supplement after pregnancy has started could actually have an adverse effect.
It’s abundantly clear that building up iodine stores before pregnancy, and ensuring an appropriate iodine intake throughout pregnancy and lactation, is a massive priority. While this can be done through diet, for most women a supplement which contains about 150mcg of iodine is the most practical recommendation. In reality, though, that might be easier said than done. Many supplements marketed as suitable for pregnant women don’t actually contain iodine, and although 77% of pregnant women will take some form of dietary supplement, only 20% contain supplementary iodine17. Ironically, iodine is found in over double the number of supplements consumed by the non-pregnant population!17. In Europe, only between 13 and 50% of pregnant women (depending on the country) consume prenatal iodine supplements16.
Ensure the iodine in your supplement is in the form of potassium iodide. Steer clear of all kelp products. The iodine content of a kelp product might be stated on the label, but what the manufacturer says generally can’t be trusted. One study showed that actual iodine amounts ranged from 45–914% of the manufacturer’s stated amount16.
The richest sources of iodine in our diet are found in fish, seafood, milk, dairy and eggs. The lowest levels are found in plants. The main source of iodine in the UK diet is milk (which makes up 40%) and dairy products, so women who do not consume milk are at special risk of deficiency unless they are big fish or seafood eaters.
In the UK, organic milk is 42% lower in iodine than conventional milk18. As milk is the main source of iodine in the UK, British women who opt for organic milk could be compromising their iodine status.
Vegetarians and vegans need to be especially conscious of the importance of iodine supplementation. Lack of fish and milk can greatly diminish iodine intake19,20,21. In a study of British vegans, it was found that 63% of women had iodine intakes of less than 70mcg per day22, which is appallingly low. A lot of plant foods that might be especially abundant in vegetarian diets can be ‘goitrogenic’, impeding iodine utilization and thyroid hormone production. Common examples include cassava, sweet potatoes, the brassicas (cabbage, kale, cauliflower, broccoli and turnip), soy and millet. Some vegans rely on seaweed for their iodine, and while it is an abundant source, it has a massive variation in iodine content and can unwittingly lead to excessive iodine intakes23, which can also be harmful to the thyroid. For that reason, we don’t recommend it. With all this in mind, and to err on the side of caution, vegetarian women should aim for an iodine supplement of up to 200mcg per day before and during pregnancy and lactation, while vegans may need as much as the full 250mcg per day.
Cigarette smoking produces thiocyanate, which is a goitrogen and reduces iodine uptake by the thyroid. Yet another reason to give up smoking.
Selenium
As we discussed in Chapter 4, while Americans fare well in the selenium stakes, Europe is languishing far behind. The growing foetus needs selenium, and sufficient levels are also needed to reduce the risks of birth complications. Women with lower selenium levels have greater miscarriage rates24,25 (miscarriage occurs in 10–20% of pregnancies26). Lower selenium levels have been associated with a 440% increased risk of pre-eclampsia27 (pre-eclampsia occurs in about 3% of pregnancies and causes 60,000 maternal deaths a year26). There are also indications that low selenium levels increase the risk of preterm labour26. In a study of 1,129 Dutch women who were followed through pregnancy, those with the lowest levels of selenium had twice the risk of preterm birth28. In women pregnant for the first time, supplementation with 100mcg of selenium per day reduced premature (pre-labour) rupture of membranes by over 60%29. Higher selenium levels may also reduce gestational diabetes risk26.
We’ve something important to add to this catalogue of benefits. Selenium is also needed for healthy thyroid function. Low selenium increases oxidative stress and damage to the thyroid30. So what do we have in the UK – a double whammy of selenium and iodine deficiency – which means the thyroid takes a real battering during pregnancy, exacerbating the risk of the developing baby being exposed to low thyroid hormone levels, with all the problems that entails, and increasing the risk of the mother developing thyroid problems after birth.
So, as we trumpeted in Chapter 4, it’s time for the UK (and Europe) to raise its game and ensure that pregnant women get their fill of selenium by supplementing with 50–60mcg per day.
Vitamin D
We covered vitamin D and its multitude of health benefits earlier in the book. Now we hone in on its role in the precious nine months of pregnancy, and in early life. As you might guess, a low vitamin D level in pregnancy sparks problems. Having a vitamin D level less than 15ng/ml is associated with an almost fivefold increase in the occurrence of pre-eclampsia31, although not all studies have confirmed this link. In contrast, a higher vitamin D intake during pregnancy is associated with increased birth weight32, which is highly desirable as a positive predictor of future health. Supplementing with vitamin D as laid out in Chapter 7 for all winter/spring pregnancies will ensure that the mother is vitamin D replete and able to reap these benefits.
Post-birth is when things start to get more complicated. When it comes to the health of the baby and mother alike, breastfeeding is the way to go. Despite the almost infinite list of benefits we could cite, breast milk has one tiny flaw – its vitamin D content is extremely poor. And that’s the case even if the mother is vitamin D replete. In mothers with high vitamin D levels (32–33ng/ml), the breast milk still contained far too little vitamin D to keep their children sufficient in it33,34. Even mothers supplementing as high as 2,000IU per day was inadequate to supply sufficient vitamin D to the infant35. It appears that giving breastfeeding mothers vitamin D supplements of 4,000IU per day is necessary to get enough vitamin D into the infant36.
Considering that doses of this magnitude are not generally advised for adult use, the solution is to supplement the infant instead. Recommendations from the US Institute of Medicine and American Academy of Pediatrics are for a daily vitamin D intake of 400IU for all infants, beginning in the first few days of life37. These recommendations come on the back of research showing that while rickets is typically associated with very low vitamin D levels (<10–11ng/ml), having vitamin D levels as high as 20ng/ml can still cause rickets in some cases38. This is a level that the majority of breastfed infants will have without supplementation.
Giving 400IU vitamin D to infants consistently raises levels above 20ng/ml and can even exceed the upper range we recommend for adults (32ng/ml)34,37,38,39,40,41. In Germany, breastfed infants born with sufficient vitamin D levels (27ng/ml) given just 250IU per day saw their levels rise to a massive 55ng/ml after six weeks (the infants also received small amounts of sun exposure)41. In a pilot study of children born to mothers at the top end of vitamin D sufficiency (32ng/ml), breastfeeding alone was an inadequate source of vitamin D, but adding a 300IU per day supplement ensured levels were at the top end of sufficiency at month four34.
Maybe then, the recommendation to give an infant 400IU per day is a bit too generous? We should point out that this recommended intake has a few caveats. First, that infants younger than six months are kept out of the sun altogether, and those aged six months or older wear protective clothing and sunscreen to minimize sun exposure42. Second, it is common for infants not to receive the supplement every day (the rate of non-compliance with vitamin D supplements is as high as 45%41). Finally, many infants are born to vitamin D deficient mothers and need larger amounts initially.
So for many, to whom these caveats are not applicable, the UK recommendation for supplements of just 280–300IU per day43 will be more suitable. Alas, the UK only recommends supplementation from six months. For reasons unbeknown to us, they deem breast milk to provide a sufficient supply before this point. As we’ve seen, though, supplementation is actually necessary from the first few days after birth.
We back the ‘breast is best’ brigade 100%, but don’t be fooled into thinking that breast milk is perfect. Unfortunately, parents don’t believe there’s a need to supplement their newborns – a survey found that only 16% of breastfed infants received vitamin D supplements44. But as we’ve seen, it was never intended for vitamin D to come from the diet, and since we vigorously protect our children from the sun, supplementation is a necessity.
Infant formulas are fortified with vitamin D. Once formula-fed infants are ingesting sufficient formula to achieve a vitamin D intake of 300–400IU per day, they will be receiving an adequate intake and will not require supplementation.
Iron
If there’s one thing that gets drummed into pregnant women, it’s that they need iron. It’s no wonder, when we consider that iron deficiency is rife, occurring in up to 40% of pregnant women in the West45. And that’s certainly not a good thing, with iron deficiency in pregnancy associated with a greater than twofold increase in the risk of preterm delivery46. What’s more, it increases the risk of a low birth weight and can impair intelligence and motor and behavioural development in the child45. In studies of iron-replete women, iron supplements (30mg per day) gave rise to children with a higher birth weight47 and reduced preterm deliveries48.
So getting your fill of iron in pregnancy is clearly a good thing. The hitch, once again, is that our typical intakes are pretty poor. Figures from the 2001 National Diet and Nutrition Survey in the UK showed an average intake of 10mg for women aged 19–64 (well below the recommended daily intake of 15mg)3. In the USA, only about a quarter of females aged 12–49 hit the 15mg mark49. The upshot is that a lot of women enter pregnancy with low iron reserves, or worse still, already iron deficient50. Pregnancy adds further to the demand for iron, meaning that as pregnancy progresses, the prevalence of iron deficiency increases. Data from the NHANES study in the USA showed that, while 7% of pregnant women were iron deficient in the first trimester, this increased to 30% by the third trimester51. In the first trimester, the increased requirements are easily met by the savings made by not menstruating. However, needs rise in the second trimester to between 4–5mg per day52 (normal requirements are 1–2mg per day), and in the third trimester to 6mg or more per day, as iron accumulation in the foetus really picks up pace. For the last six to eight weeks the need for iron can be as much as 10mg per day52.
That doesn’t sound too bad though, right? Even with poor intakes surely we’re easily hitting the 6mg per day mark? The big snag with iron is that it’s poorly absorbed, and the typical 10mg intake seen in the UK diet won’t even come close. Even with the body increasing its ability to absorb iron as pregnancy progresses, the best-case scenario is for 30% of the iron from the diet to be absorbed53. So, even with a diet rich in highly bioavailable iron, women still fall short of meeting their iron needs, hitting only about 1.9mg in the second trimester and 5mg in the third52.
And that only really leaves one solution: to supplement iron in order to prevent deficiency. Guidelines vary considerably. The World Health Organization (WHO) recommends 60mg per day for six months during pregnancy, and even to increase the amount to 120mg if it is to be taken for less than six months45. The US Center for Disease Control recommends a ‘low-dose’ 30mg iron supplement during pregnancy, as well as a diet high in iron and vitamin C to aid its absorption49. And the UK? True to form, the UK doesn’t recommend universal supplementation. It maintains that the recommended daily intake of 15mg is enough, advising that pregnant women should have sufficient stores coming into pregnancy and that increased absorption from the diet will cover it53.
Although the UK appears to lag behind the USA in nutrition, first with selenium, and then with vitamin D, in the case of iron it comes up trumps. We’ve focused on the benefits of iron in pregnancy so far, but that all-too-familiar ‘more is better’ mentality rears its ugly head again. Correcting iron deficiency is one thing, but universal supplementation is quite another, and takes us into questionable territory46. The wisdom of this approach has been questioned by a Cochrane Review, which found insufficient evidence that blanket treatment in pregnancy improves functional and health outcomes for women and babies54.
It’s one thing to find no benefit, but quite another to discover that it may even cause harm. And that’s exactly what is happening. When it comes to iron, a delicate balance is needed. Get too gung ho with it and you run into problems. High iron levels are now linked to the development of gestational diabetes and pre-eclampsia, as well as increased oxidative stress46,55. It has also been suggested that building up the mother’s iron stores will increase the thickness of the blood, hindering placental blood flow to the uterus46. Besides, we shouldn’t forget that high iron intakes can interfere with the intestinal absorption of other essential nutrients (e.g. zinc, copper, chromium, molybdenum, manganese, magnesium and calcium), many of which have important roles53. Iron supplements also have side effects, especially at high doses, such as stomach upset, nausea, diarrhoea and constipation – pregnancy is good enough at causing these problems without getting outside help.
Despite all of these concerns, a study in the USA found that about 70% of pregnant and lactating women were taking iron supplements, the mid-range dose being 60mg per day. Yet less than 15% of women of reproductive age taking iron supplements had reason to believe they were at risk of anaemia46. It is naïve to think that blanket supplementation carries no risks for those who have no need for extra iron. That’s why the National Institute of Clinical Excellence (NICE) in the UK only advocates supplements after low haemoglobin levels have been measured. This seems to make more sense as it identifies exactly which pregnant women require iron supplementation. While NICE recommends the measurement of haemoglobin levels, we must warn that such an approach has been found to be insensitive and that a measure of iron stores (ferritin) should be taken as well. Iron sufficiency is indicated by a haemoglobin level greater than 110g/L and a serum ferritin of 12mcg/L or greater in early pregnancy56.
The amount of iron we absorb from a supplement reduces as the dose increases. The absorption rate of a 5mg dose of iron is about 36% towards the end of pregnancy but only 14% from a 100mg dose52.
Consuming tea or coffee with, or shortly after, a meal dramatically inhibits the absorption of dietary iron. In contrast, vitamin C-rich foods greatly enhance absorption.
Foods rich in iron include meats (especially red meat), beans, tofu, nuts, most dark green leafy vegetables (e.g. kale and watercress) and dried fruits such as dried apricots.
DHA
Docosahexaenoic acid, or DHA for short, is the predominant omega-3 fat found in the retina of the eye and the central nervous system, making it of great importance for foetal growth, and especially brain development57. It accumulates rapidly in the brain, particularly in the last trimester, when development really takes off, with the brain amassing a staggering 67mg per day58. You’d be right in thinking this is a pretty important type of fat in any pregnancy, and evidence has grown to suggest that insufficient intakes of DHA can have a range of unwanted consequences, including increased postnatal depression, preterm and low weight births and pre-eclampsia58.
An insufficient supply of DHA to the infant during pregnancy may result in permanent impairment of learning ability59. Visual acuity may be hampered and immune system development blunted increasing the occurrence of allergies58. But where exactly does the DHA come from for all this important stuff to happen? The maternal diet – which means that DHA availability throughout pregnancy, and breastfeeding, is dependent on the mother’s dietary intake57.
And herein lies the problem. Several expert groups recommend average DHA intakes of 200–300mg per day to meet the needs of pregnancy60. That’s all well and good, but the Western diet falls way, way short of this, providing a paltry 60–80mg daily60. Hitting the recommended two servings of fish a week (one of them oily fish) would give a sufficient DHA intake, but just 19% of Americans meet this recommendation61. With the recent scares about contaminants in fish (such as mercury and polychlorinated biphenyls), many people have reduced their fish intake, a drop seen most noticeably in pregnant women60.
And what a shame! Compared with mothers who consume more than 340g of seafood per week, mothers who consume no seafood have a 48% increased risk of their children being in the lowest quartile for verbal IQ62. A low maternal intake of seafood was also linked with a greater risk of poorer developmental outcomes on a range of behaviour, fine motor, communication and social development scores62. While it’s not possible to say exactly which component of seafood was having this positive effect – for example, it could have been due to the iodine rather than omega-3 – it does provide proof of principle that, when it comes to fish, the benefits of eating it far outweigh the risks of avoiding it. This is supported by the FDA and the Institute of Medicine, both of which concur that the benefits of consuming fish during pregnancy outweigh the risks60. Avoiding tilefish, swordfish, shark, and king mackerel, and limiting albacore tuna to no more than 170g per week, is recommended. For those who still wish to shy away from fish, the alternative is a DHA supplement. With the purity of these also questionable, it’s essential to ensure you go for a brand that guarantees quality and is produced to ‘good manufacturing practices’.
Just 170g of Atlantic salmon provides over 2,400mg of DHA. Choosing wild over farmed varieties and trimming away the fatty areas before cooking will reduce PCB intake60.
Being vegetarian or vegan doesn’t mean you have to scrimp on your DHA intake, as supplements derived from algae offer an excellent vegetarian source of DHA.
Folic acid
Last, but by no means least, the one we’ve all heard of: folic acid. Neural tube defects are among the most common types of birth defect63, with spina bifida and anencephaly, caused by the incomplete closing of the spine and skull, occurring in about three in every 10,000 live births64. This equates to about 3,000 cases in the USA each year65. It is now well established that a diet high in folate reduces this risk dramatically. Folate is found in high amounts in the likes of green leafy vegetables, broccoli, Brussels sprouts, asparagus, peas, chickpeas, citrus fruits and brown rice. However, only about half of the folate in the diet is absorbed, and cooking practices – such as stewing, processing and storage – can also reduce folate content. This means that, without care, diet alone can be insufficient to supply the necessary amounts of folate needed by prospective mothers. For this reason, massive campaigns have been undertaken to promote supplementation of folic acid before conception and in the first trimester of pregnancy. Folic acid is a synthetic derivative of folate with a greater stability and superior absorption. Taking just 400mcg per day before and during pregnancy could prevent up to 70% of neural tube defects65.
It has also been proposed that folic acid may reduce preterm birth, pre-eclampsia, placental abruption, intrauterine growth restriction and foetal death63. However, the evidence is just suggestive and nowhere near the strength of evidence that exists for neural tube defect prevention.
Alas, despite all the education and publicity, folate levels in pregnancy remained low, with 25% of US women still folate deficient during pregnancy63. In the UK, it’s estimated that over 13 million people currently consume too little folic acid in their diet66. In response, compulsory fortification of products like flour, rice, pasta, bread and cereals with folic acid was introduced in the USA in 1998. By 2008, 52 countries had instituted fortification programmes and their success is believed to have reduced the prevalence of neural tube defects by an impressive 46%63.
However, mandatory folic acid fortification was not introduced in the UK. After careful consideration, the UK opted out, based on concerns that giving high amounts to the non-pregnant population could cause unforeseen problems. For instance, high levels could mask a vitamin B12 deficiency, facilitate the progression of early cancer formations and hinder the activity of anti-folate medications used in rheumatoid arthritis and cancer63,67
Irrespective of fortification programmes, it is recommended that all women trying to conceive supplement 400mcg per day of folic acid, or consume a product with a known 400mcg content, such as many cereals in the USA66. And here’s the important bit. Folic acid works its magic in the first 28 days after conception, before the closure of the neural tube. This makes it crucial for women to start supplementing one month before conception and throughout the first trimester. Considering that half of all pregnancies are unplanned65, all women of childbearing age should routinely supplement with folic acid. Yet, despite all the education campaigns, only 12% of women are aware of this fact65.
If you are obese, you run a particularly high risk of being deficient in folate. In 2010, the UK Guidelines for Management of Women with Obesity in Pregnancy recommended the folic acid dose be upped to 5mg in women with a BMI over 30, one month before conception and for the first trimester66. Women with diabetes and epilepsy are also at considerable risk and should follow this advice for increased intakes66.
THE PARTING SHOT
The health and wellbeing of our children is without question a most precious thing. Given the choice, it’s not something that any parent is going to compromise. Following standard advice for healthy eating in pregnancy is undoubtedly a good start. But why settle for second best?
It is patently obvious that simply eating a ‘well-balanced diet’ is just not enough. Stick with that idea and there’s every chance that critical vitamins, minerals and omega-3 fats will fall short of the mark. But supplying the mother with all the pieces of the nutritional jigsaw before, during and after pregnancy (ensuring neither too much, nor too little), not only minimizes the risk of complications but sets the stage for a bright and prosperous future that will allow future generations to flourish.
SUMMARY AND RECOMMENDATIONS
· Iodine is critically important for a baby’s mental development and supplements of about 150mcg per day should be started preconceptionally and continued throughout pregnancy and lactation. Vegetarians, and especially vegans, may need 200– 250mcg per day.
· For selenium-depleted populations such as the UK (see Chapter 4) a supplement of 50–60mcg per day should be taken.
· Mothers should ensure their vitamin D levels are adequately topped up (see Chapter 7). From the first days after birth, breastfed infants and those not consuming 300–400IU a day from formula, should be supplemented with vitamin D daily.
· Iron deficiency in pregnancy is prevalent, but this does not justify universal high-dose supplementation. Insist your doctor measures your haemoglobin and ferritin levels before any iron supplementation regime is commenced.
· Women who eat little or no fish should take a supplement providing 200–300mg of DHA during pregnancy and breastfeeding. Vegetarians and vegans can take DHA supplements derived from algae. When buying formula for infants, ensure DHA is a listed ingredient.
· Folic acid supplements of 400mcg per day should be taken by all women of childbearing age, and continued for the first trimester of pregnancy. For the obese, diabetics and epileptics, a dose of 5mg is advised for one month prior to conception and throughout the first trimester, under medical supervision.