Why You Might Be Low in Key Nutrients – Even With a Healthy Diet

Nutrient shortfalls during pregnancy are far more common than most people expect, with Australian research showing inadequate intakes of iron, calcium, folate, iodine, and vitamin D across a significant proportion of pregnant women. Reasons for nutrient gaps are not always obvious. Cooking methods, food processing, absorption variability, increased pregnancy demands, and dietary restrictions can all quietly affect nutritional status even when food choices are genuinely good.

You eat well, you try to cover your nutritional bases, and yet your blood results come back showing your nutrition levels need attention. Sound familiar? Understanding why this happens, and what you can do about it, is the focus of this article.

1. Ultra-Processed Foods Are Crowding Out the Nutrients in Your Diet

Australian diets are not short on food but they can be short on nutrients. Research shows that ultra-processed foods (UPFs) now account for 42% of daily energy intake in Australia.⁽¹⁾ These are the foods that go well beyond basic cooking; mass-produced breads, breakfast cereals, packaged snacks, soft drinks, fast food, and flavoured dairy products, and they share a few things in common: they are convenient, affordable, highly palatable, and nutritionally poor.

The problem is not just that UPFs replace more nutritious foods. The industrial processes used to make them, such as milling, heating and chemical preservation, actively deplete the vitamins and minerals that were present in the original ingredients. Refining grains removes fibre and B-vitamins. Heat processing degrades vitamin C. And across a high-UPF diet, research has identified reduced intake of vitamins A, C, D, E, B12 and B6, as well as folate, calcium, iron, magnesium, zinc, and more.⁽²⁾

What this means for you: If a significant proportion of your daily intake comes from packaged and processed foods, dietary strategies alone may not be enough to close nutritional gaps, and targeted supplementation becomes more relevant.

2. Your Medications May Be Affecting Your Nutrient Levels

This is one of the most under-recognised contributors to nutrient loss, and one that many people are never told about. Approximately 33% of Australians are currently taking a prescribed medication⁽³⁾, and many commonly used drugs can interfere with the absorption, metabolism, or retention of key micronutrients.

Up to 29% of drug-nutrient interactions can affect health outcomes⁽⁴⁾, meaning they are significant enough to affect how you feel and how your body functions.

What this means for you: If you are taking any regular medication, it is worth discussing with your GP or pharmacist whether your prescription may be affecting your micronutrient status, and whether nutritional testing or supplementation is appropriate.

3. Gut Health Conditions Can Affect How Well You Absorb Nutrients

Even if you are eating all the right things, your body still needs to absorb them, and conditions that affect the digestive system can impair this process. Different conditions affect different nutrients, depending on which part of the gut is affected.⁽⁵⁾

Some common affected nutrients include vitamin B12 andiron.⁽⁶⁾

Symptoms of nutritional shortfalls can be mild or entirely absent until picked up on a blood test.⁽⁶⁾

What this means for you: If you have been diagnosed with a gut condition, it may be worth speaking with your healthcare provider about whether it could be impacting your nutritional health.

4. Some Plant Foods Can Limit How Much Nutrition You Actually Absorb

This is particularly relevant for those following plant-based diets with the best of intentions. Plants naturally contain compounds called anti-nutrients, which can bind to minerals in the gut and reduce how much your body is able to absorb. These compounds exist as a natural plant defence mechanism.

The most relevant ones for everyday nutrition include:

Phytates: found in wholegrains, legumes, seeds, and soy – reduce the absorption of calcium, magnesium, zinc, iron, and copper.

Oxalates: found in spinach, soy, and amaranth – bind to calcium in the gut and reduce how much is absorbed. This is why spinach, despite being high in calcium, is a poor source of absorbable calcium compared to dairy.

Tannins: found in tea, coffee, cocoa, berries, and walnuts – reduce iron absorption. This is a relevant consideration for women who drink tea or coffee with meals.

Goitrogens: found in soy and some other legumes – can interfere with iodine uptake from the thyroid, particularly in people already consuming low amounts of iodine.

The reassuring news is that many of these anti-nutrients can be significantly reduced through everyday cooking and preparation techniques. Soaking legumes and grains before cooking, boiling rather than steaming or eating fermented foods can all reduce anti-nutrient content.⁽⁷⁾

What this means for you: If you follow a vegan or vegetarian diet, or eat a high proportion of plant foods, you may be absorbing less calcium, iron, and zinc than your dietary intake suggests. Cooking methods matter, and supplementation can be helpful to bridge nutritional gaps.

The Bottom Line

Nutritional gaps in Australia are not just a story about people who eat poorly. It is a more complex picture that includes the types of foods that dominate our food supply, the medications many of us take daily, the health of our digestive systems, and the ways we prepare the foods we eat.

If you have ever asked yourself the question – do I really need to take a supplement if I eat well – the answer is, possibly.

If you are eating well but still not feeling your best, or your nutritional results suggest otherwise, speak with your GP, dietitian, or nutritionist; there may be more to the picture than diet alone.

This article is intended for general health and nutritional education only and does not replace personalised medical advice. Always consult your GP or qualified healthcare practitioner for guidance specific to your individual health needs.

References

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