You may not know it, but there’s a good chance you are deficient in at least one essential nutrient. Georgia Rickard explains how to avoid the most common dietary deficiencies in Australia.
The word ‘malnourished’ often evokes images of someone who is underweight, pale and unwell. But that’s not necessarily the case. You could be missing out on vital nutrients – and be at risk of serious health consequences – but show no symptoms. Dr Manny Noakes, Senior Research Dietitian at CSIRO Food and Nutritional Sciences, says it’s not uncommon for Australians to be simultaneously overweight and malnourished. We might be eating enough (or too much), she says, but “we’re not eating enough nutritious foods.” Here are six of the most common nutritional deficiencies in Australia – and the best ways to boost your intake of each of these essential nutrients.
If you answer ‘no’ to any of these questions you could be at risk of one of the deficiencies covered here.
Essential for healthy, strong bones and teeth. Also required to maintain correct pH levels in the blood.
Women 19–50 and men 19–70: 1000mg
Women 50+ and men 70+: 1300mg
Pregnant/lactating: 1000–1300mg
“Pretty common, and it’s a serious issue”, says Professor Peter Ebeling, Medical Director of Osteoporosis Australia. “The average calcium intake in Australia is around 700–800mg per day.” (The RDI is 1000–1300mg.)
“Everybody,” Ebeling says. Groups at particularly high risk include adolescents (especially girls) and post-menopausal women. The calcium requirements for both these groups are higher than other age and gender groups, at 1300mg per day (four to five serves of dairy or calcium-fortified equivalent), compared to 1000mg for most adults.
“You can’t tell, and that’s the problem”, Prof Ebeling says. “That’s why they call osteoporosis the silent killer – you can’t do blood tests to tell if you’re getting enough calcium.” However, eating less than three serves of dairy (or equivalent) each day; regularly consuming soft drink; or having more than three caffeinated drinks each day, may suggest an increased risk of deficiency.
Although not a direct measure of calcium status, bone mineral density scans are a good indicator as calcium is leached from the bones if not enough is eaten – meaning bone density is lower.
“Low calcium intake is mainly associated with low bone density or osteoporosis,” says Prof Ebeling, “but low vitamin D levels – which go hand in hand with low calcium levels – can be associated with other illnesses, such as cancer and diabetes, and an increased risk of falling because of reduced muscle strength.”
“It is really important to think about your calcium intake each day,” advises Prof Ebeling. “Focus on getting your recommended serves of dairy or calcium-enriched equivalents. You could also take a calcium supplement on the days where you don’t get your three to four serves of dairy.”
Needed to make thyroid hormones, which help control metabolism, growth and development (including growth and development of the brain).
Men and women 14+: 150ug
Pregnant: 220ug
Lactating: 270ug
Iodine deficiency is the number one cause of preventable intellectual disability in children, and recent studies have shown mild-to-moderate iodine deficiencies across all age groups in Australia.
Every Australian is potentially at risk, says Associate Professor Mu Li, international public health expert at the University of Sydney. “Up until the mid-80s, our dairy industry used a chemical loaded with iodine when processing dairy products, so we used to get quite a lot of iodine. But the dairy industry switched to chlorine-based sanitising, so our intake levels have fallen quite dramatically.”
The consequences of iodine deficiency are most serious for women who are pregnant, planning to fall pregnant or lactating. “They mightn’t be affected by their low iodine levels”, she explains, “but if pregnant women don’t get enough iodine while the foetus is developing, this can cause devastating and irreversible effects to the child.” These effects can include mental disabilities and problems with growth, hearing and speech.
You are most likely at risk if you follow a low-salt diet (salt is often fortified with iodine) and/or don’t eat iodine-rich seafood or bread. As of 2009, bread sold in Australia is legally required to be fortified with iodine (with the exception of organic bread).
However, you often can’t tell if you are iodine deficient unless it’s quite pronounced, says Assoc Prof Li. Moreover, she adds, the tests for checking iodine levels are not terribly reliable: “[The test] only reflects what you ate yesterday, so results are quite variable.”
You may also have heard of the iodine absorption test, but it’s considered by professionals to be “hocus pocus – absolute nonsense”, says Professor Cres Eastman, Chairman of the Australian Centre for Control of Iodine Deficiency Disorders at Sydney’s Westmead Hospital. The test involves rubbing iodine on the skin to see how long it takes to be absorbed. “You could rub Chanel No. 5 on your skin and get the same information!”.
Long-term iodine deficiency can be serious – apart from the ramifications for babies born to iodine-deficient mothers, it can result in enlarged thyroid glands (goitres) and hypothyroidism.
“Iodised salt is still the most simple andeffective way to get iodine into your diet. In fact, the World Health Organization (WHO) recommends that all salt for human consumption should be iodised”, says Prof Li. That doesn’t mean we should eat more salt, she’s quick to add – “far from it! It’s more that iodised salt should replace non-iodised salt wherever possible”. Prof Li also recommends including bread in your diet. In addition, the National Health and Medical Research Council (NHMRC ) recommends expecting and lactating mothers consult their doctor about taking iodine supplements.
To make sure your gluten-free bread contains iodised salt, check the pack – if it contains yeast, it’s legally classified as a bread, and therefore required to use iodised salt in its preparation.
Helps deliver oxygen throughout the body; important for transforming food into energy; assists in making neurotransmitters (chemical messengers in the brain); and plays a role in keeping the immune system healthy.
Women 19–50yrs: 18mg
Men 19+ and women 50+: 8mg
Pregnant: 27mg
Lactating: 9–10mg
Iron deficiency is the most common deficiency in the world, affecting up to 80 per cent of the global population, according to WHO. “Levels aren’t quite that high in Australia”, says dietitian Dr Amanda Patterson, “but they’re still unacceptable.” Figures suggest that 25–30 per cent of women of child-bearing age have a moderate form of iron deficiency (generally due to monthly blood loss).
Other high risk groups include children – especially pre-school children, (their iron requirements are quite high relative to the amount of food they eat), the elderly (due to reduced absorption capabilities), vegetarians and vegans (due to eating lower amounts of readily absorbed iron), disadvantaged communities and those with chronic inflammatory conditions, such as obesity.
“You may feel tired and lethargic, [like] you can’t pull yourself together… or you might not notice anything at all”, says Dr Patterson. A tell-tale sign is that the skin inside your bottom eyelid may be pale. If you are worried, see your GP for a blood test to check your iron and haemoglobin levels (red blood cells).
If the deficiency becomes serious, you may experience an inability to regulate your body temperature; developmental delay (such as stunted growth); impaired immune function; cognitive and intellectual impairment; and if pregnant, an increased chance of premature birth and/or an underweight baby.
“Red meat [which contains haem iron] is the best source of iron”, advises Dr Patterson. “Non-haem iron, found in vegetable sources such as leafy greens, is not easily absorbed – so you need to combine non-haem iron sources with foods containing vitamin C, as vitamin C helps our body absorb non-haem iron”.
You can also help your body absorb non-haem iron by avoiding tea, coffee and red wine at meals since the tannins they contain inhibit non-haem iron absorption.
Required to make insulin; maintain a healthy immune system; and for male reproductive health.
Men 14yrs +: 14mg
Women 19+: 8mg
Pregnant: 10–11mg
Lactating: 11–12mg
“We don’t know exactly how common zinc deficiency is, because it’s very difficult to measure peoples’ zinc status”, admits Samir Samman, Associate Professor of Human Nutrition at the University of Sydney. “But we know that zinc intakes are low.” This is partly because people are eating less zinc-rich foods, such as red meat and seafood, and partly because food-processing methods that make plant-based zinc more readily absorbed by the body – such as germination, soaking and fermentation – are not commonly used in Australian households.
Infants, toddlers and the elderly are particularly at risk of zinc deficiency, as are vegetarians and vegans.
“In Australia, we don’t see ‘overt’ symptoms of zinc deficiency very often”, says Assoc Prof Samman. “We see borderline symptoms, which are difficult to pin down as a zinc deficiency. A reduction in immune status, an increased incidence of the common cold… things that could be attributed to a number of different causes.”
There are many tests available to detect a zinc deficiency, including taste tests, blood tests, hair tests, urine tests and measuring certain enzymes. A blood test may be the most reliable, but most of these tests are only useful if you have a severe deficiency, says Assoc Prof Samman. Additionally, none of them are conclusive, which makes diagnosis quite difficult.
“Zinc is involved in many different functions in the body – we know it’s connected with hundreds of different enzymes involved in metabolism, it’s involved in interacting with DNA and it’s important for the cells to function – so a zinc deficiency can be quite serious”, says Assoc Prof Samman. Longterm deficiencies can lead to decreased immune function, increased susceptibility to respiratory and gastrointestinal infections (like pneumonia and infective diarrhoea) and stunted growth in children.
If you eat meat, increase your intake of lean red meat, dairy foods and seafood.
If you don’t eat animal products, it’s really important to break down the components in plant foods that prevent zinc from being absorbed by the body. Soaking and sprouting legumes and nuts or choosing plant-based foods that have been fermented (e.g. choosing sourdough bread, which has undergone a fermentation process) also helps your body absorb zinc.
You may also want to consider supplementation, but more than 40mg/day (from food and supplements) can result in adverse effects, so consult your doctor before taking them.
Vitamin D helps the body absorb calcium and is vital for healthy bones and muscles.
Women and men 19–50: 5ug
51–70yrs: 10ug
71yrs+: 15ug
Pregnant/lactating: 5ug
Research suggests that amongst the general population, around one in three of us will be vitamin D deficient by the end of winter, says Professor Rebecca Mason, President of the Australian and New Zealand Bone and Mineral Society. “And about 10 per cent [may be deficient] even at the end of summer.”
“Older people and anyone who’s chronically ill, because they don’t get out in the sun much; people with darker skin; and Asian women, due to a cultural appreciation for pale skin”, says Prof Mason.
New evidence also suggests teens are possibly at higher risk than previously estimated, because of increased computer screen time. Additionally, “those of us who work indoors all day, leaving home at 8am and coming home at 6pm, and work on the weekend, aren’t in the sun much”.
"Generally, you won’t know about it, unless you’ve got very severe symptoms – such as bone pain and muscle weakness [which can lead to an] increased risk of fracture”, explains Prof Mason. A blood test is readily available, so consult with your doctor if you suspect you’re vitamin D deficient.
“If you don’t get enough vitamin D, you don’t absorb calcium well, so you end up taking your calcium from your bones, resulting in osteoporotic fractures”, Prof Mason says.
“There’s also a link between low vitamin D and greater risk of some cancers – colon cancer, particularly – as well as increased risk of multiple sclerosis, rheumatoid arthritis and irritable bowl syndrome.” If a pregnant woman is deficient, then the baby’s bone calcium content can be low, which may lead to rickets if the deficiency is severe enough.
Even though there are some dietary sources of vitamin D available, “there’s not enough in an average Australian diet to account for more than 5–10 per cent of what you need”, says Prof Mason.
In other words, focus on getting enough sun exposure – which will vary depending on the time of year. “You need sun exposure on about 20 per cent of your body surface (i.e. face, arms and hands) on most days”, she advises. “In winter, go outside at lunchtime for about 20 minutes if you live in Sydney, seven minutes if you’re as far north as Cairns and as much as 40 minutes if you’re as far south as Hobart. Walk briskly and roll up your sleeves so you can get more skin exposure, and do it most days. If you’ve got darker skin, you will need 3–6 times longer in the sun.
In summer, if you’ve got pale skin, you need about 6–8 minutes of sun exposure, either midmorning or mid-afternoon.” Your doctor may also recommend vitamin D supplementation, especially as you get older.
Omega-3 fatty acids play a crucial role in brain function, and appear to have an anti-inflammatory effect, lowering our risk of many chronic diseases.
Men 19+: 160mg
Women 19+ 90mg
Pregnant: 110–115mg
Lactating: 140–145mg
The average Australian is not necessarily deficient in omega-3 – but they’re getting close, says Professor Peter Howe, Director of the Nutritional Physiology Research Centre at University of South Australia. “It’s been recommended that omega-3s should ideally be about 8 per cent of the total fatty acids in red blood cells… if they’re below 4 per cent, that’s associated with a high level of cardiovascular risk. And the assessment we’ve made is that the average Australian adult is at just over 5 per cent.”
Most of us aren’t hitting the omega-3 RDI. But those who are at particular risk of falling below the 4 per cent mark are vegetarians, vegans, children and the elderly.
Moreover, many of us are also at risk of being fooled by clever marketing, says Prof Howe. “When talking about omega-3, we need to be very clear that the type of omega-3 associated with the health benefits is long-chain omega-3 fatty acids [EPA and DHA], found mainly in marine sources. At the moment there’s a lot of promotion of products containing ALA [short-chain omega-3 fatty acids], which are poorly converted into long-chain omega-3s. This is not helping us meet our requirements.”
There are no symptoms and no conclusive tests to determine omega-3 levels. Your best bet is to examine your diet – if you don’t eat seafood, particularly oily fish, at least twice a week (or take the equivalent in supplements), then you may not be getting enough.
Inadequate intake of long-chain omega-3 fatty acids is associated with a higher risk of Alzheimer’s, cardiovascular disease, cancer, arthritis, depression and adult-onset macular degeneration.
The best way to boost your intake is to increase the amount of oily fish you eat. The National Heart Foundation recommends 2–3 serves per week. If you don’t eat fish, try fish oil capsules (or an algal alternative). The Heart Foundation recommends 500mg/day fish oil, or 1000mg fish oil if you have heart disease. You can also try getting omega-3 from other animal sources (chicken, beef or free-range eggs) and plant sources (soy, linseed, canola oil or spread and walnuts). CSIRO is also currently developing a plant similar to canola, which will contain pre-formed longchain omega-3s, and should be available in a few years’ time.
No one is entirely sure what Australia’s most common nutrient deficiencies currently are, as there has been no national nutrition survey conducted since 1995. We consulted 11 of the country’s top nutritional experts in preparing this article and while not conclusive, there is plenty of evidence to suggest that Australians are most at risk of the deficiencies listed here. For more advice on dietary deficiencies, consult a dietitian or your doctor.
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