The Not So Obvious Driving Factors Of Nutrient Deficiency

Nutritional deficiencies remain prevalent in Australia, despite widespread food availability and food fortification strategies. Common nutrient deficiencies, including calcium, iron, and vitamin D, are well recognised by healthcare professionals and therefore form part of routine testing.[1]^,[2] However, historical nutrient deficiency disorders, such as scurvy, appear to be making a come-back, indicating that the drivers of nutrient deficiencies in today’s patient are becomingly increasingly complex.[3] In addition to poor dietary intake, nutrient deficiency can be caused by a range of environmental, socio-economic, dietary, and pharmacological factors that contribute to inadequate nutrient intake and/or absorption.

This article examines the not-so-obvious drivers of nutrient deficiency, the implications for patient health and clinical tips to help convert this knowledge into improved nutritional health outcomes for your patients.

Inadequate dietary intake

Australians consume 42% of daily energy from ultra processed foods, which can result in nutritional short falls

Diet is the cornerstone of nutritional health and inadequate intake remains a significant contributor to nutritional deficiency in Australia.[4] Despite Government strategies, Australian diets remain largely deficient in nutrient-dense foods (e.g., fruits, vegetables, meat and dairy), and excessive in energy-dense, discretionary foods - such as ultra-processed foods (UPFs).[5]^,[6]

UPFs consist of multiple ingredients that undergo a sequence of industrial processes. Examples include mass produced breads, breakfast cereals, soft drinks, flavoured milks, fast foods, and confectionary.[7] They are often low cost, high in artificial additives and highly palatable; qualities that are conducive to overconsumption. UPFs currently account for 42% of energy consumption in Australian diets. ⁷

Increased consumption of UPFs can exacerbate nutritional shortfalls. Processing techniques, including milling, heating, and chemical preservation, contribute to significant losses of essential vitamins and minerals and disrupt the natural food matrix. For example, refining grains removes fibre and B vitamins, while heat processing degrades vitamin C.[8] Global studies on high UPF diets have shown reduced consumption of vitamins A, C, D, E, B12, B6, β-carotene, thiamine, riboflavin, niacin, folate, zinc, potassium, phosphorus, magnesium, calcium, and iron.[9]

Clinical considerations:

Dietary strategies that are personalised to address individual barriers to healthy eating patterns, including socio-economic status, food addictions and aversions, can help inform meaningful education and dietary change to help resolve nutritional inadequacies.[10] Vitamin and mineral supplementation may be required where diet is inadequate.

Drug-nutrient interactions

Up to 29% of drug-nutrient interactions can have clinically significant health outcomes

Many physicians may not be aware that the medications they prescribe are negatively affecting their patient’s micronutrient status. Recent statistics show that 33% of Australian’s are currently taking a prescribed medication, and 45% of those aged 75 years and over are prescribed polypharmacy (5 or more medications).[11] Up to 29% of drug-nutrient interactions can have clinically significant health outcomes, including the interference of nutrient metabolism and absorption (see Figure 1).[12] 

Fig 1: Drug-Nutrient Interactions

[13]^,[14]

Clinical Considerations:

Clinicians should assess medication-related nutrient depletion risks and implement appropriate nutritional testing and support strategies as required, with particular consideration for those exposed to polypharmacy who are at higher risk of deficiency.

Malabsorption Syndromes

Malabsorption syndromes such as small intestinal overgrowth, are notoriously underdiagnosed

Malabsorption syndromes occur in response to the disruption of the normal digestive, absorptive or nutrient transport process. Malabsorption syndromes vary in prevalence, from 0.3% for inflammatory bowel disease (IBD), to up to 22% for small bacterial overgrowth (SIBO); the latter being notoriously underdiagnosed.[15]^,[16]    Symptoms can present as overt, subclinical or asymptomatic, and depend on whether the malabsorption is partial, affecting selective nutrients, or global, affecting most nutrients.[17] Severe nutrient deficiencies occur in advanced malabsorption states, however iron deficiency anaemia may be the only symptom of mild malabsorption.[18]

Figure 2: Malabsorption syndromes and associated nutrient deficiencies

[19]^,[20],[21]

Clinical Considerations:

Clinicians should routinely assess the nutritional status of those at risk of malabsorption, including those with SIBO, inflammatory bowel disease and elderly patients. Additionally, those with that present with asymptomatic nutritional deficiency of non-dietary cause should be investigated for malabsorption disorders, including hydrogen breath testing for SIBO, which is a notoriously mis- and under-diagnosed malabsorption condition.

Anti-nutrient compounds

Plant food diets are high in anti-nutrient compounds

Anti-nutrients compounds (ANCs) are found naturally in foods and are responsible for reducing the absorption and bioavailability of nutrients in the body. ANC’s such as phytates, oxalates, saponins, lectins and tannins, are typically found in plant foods and are produced by plants as a protective mechanism to avoid being eaten. While ruminant animals possess the digestive capacity to process ANCs, humans do not.[22]^,[23]

For humans to better access the nutritional value of plant foods, these anti-nutrient compounds should be removed or inactivated. Often this is achieved by the cooking process, however some ANCs may require additional techniques, like soaking or fermenting.[24] Research has shown that those following vegan and/or vegetarian diets may be at risk of reduced mineral absorption from plant foods due to high phytate and oxalate consumption.[25]^,[26]

Figure 3: Anti-Nutrients Compounds and their health impacts

[27]^{,[28], [29]}

In Summary:

There are multiple contributing factors to nutritional deficiencies. Despite access to an abundant food supply, many Australians are still at risk of nutritional gaps. Clinicians can help minimise this risk by taking a holistic approach to their patients’ health by implementing the following practices:

ü  Routine nutritional assessments

ü  Thorough investigations into underlying causes (e.g., hydrogen breath testing)

ü   Personalised dietary advice

ü  Nutritional supplementation as required