Nutrition experts agree that a perfectly balanced diet should provide all essential nutrients.^[1] In practice, however, achieving this ideal proves challenging for many people. Over two billion people worldwide experience micronutrient deficiencies, even in developed countries with abundant food supplies.^[2]

 

Although required in much smaller amounts than macronutrients, micronutrients are essential for everything from immune function to brain health. Common deficiencies – particularly iron, iodine, folate, vitamin A, and zinc – may affect physical and mental health, cognitive function, and perinatal health, as well as potentially increasing the risk of certain illnesses and speeding up the ageing process.^[3]

 

NOTE: Supplement regulations and recommended daily nutrient intakes vary significantly between countries, so what’s considered safe and effective in one nation may not meet another’s standards.

 

Where diets may fall short

Research suggests that even in cases of adequate nutrient and energy intake, nutritional status can be challenged by a compromised nutrient metabolism and absorption, drug–nutrient interactions, or altered nutrient needs.

 

Understanding these modern nutritional challenges helps explain why even health-conscious individuals may benefit from targeted supplementation.

 

Modern diet challenges

Increased intake of processed, refined foods over whole foods has reduced the micronutrient quality of the modern Western diet.^[4] Ultra-processed foods – packaged meals and snacks, soft drinks, breakfast cereals, cookies, and processed meats – account for 56.8% of total energy intake in the UK, but are high in added sugars, saturated and trans fatty acids, and low in protein, fibre, and micronutrients.^[5].^[6] This suggests that more than half of what people eat provides calories but lacks essential nutrients, creating a paradox of being ‘overfed and undernourished’.

In addition, modern farming methods have also disrupted the nutrient content of soil, contributing to reduced nutrient content in food.^[7]

 

Lifestyle barriers

Lifestyle factors such as stress, alcohol intake, lack of exercise, and poor sleep patterns each impact the gut microbiome and digestive processes, potentially contributing to dysbiosis (an imbalance of healthy gut bacteria) and reducing the body’s ability to obtain sufficient nutrients from food .^[8]

 

Medical factors

Malabsorption syndromes such as Celiac disease and inflammatory bowel disease (IBD) can cause damage to the intestinal lining, potentially compromising nutritional status.^[9]  Medications such as diuretics, antimicrobials, metformin, contraceptives, and proton pump inhibitors may also interfere with nutrient uptake. However, individual cases must be discussed with healthcare professionals.

 

Who may benefit most from supplements?

In addition to those affected by reduced nutrient intake or absorption, people in certain life stages or with specific health conditions may have increased demand for particular nutrients.

 

Pregnant women and infants

Pregnancy and lactation increase the body’s requirement for specific nutrients to support both mother and baby. Iron is the most common nutrient deficiency in pregnant and breastfeeding mothers, and the World Health Organisation recommends that women supplement with elemental iron daily to support healthy iron levels and reduce the risk of developing anemia.^[10] Other nutrients often recommended to support healthy development of the fetus include folate, calcium and iodine.^[11].^[12]

 

Aged individuals

People aged 65+ are at higher risk of nutritional deficiencies due to reduced digestive function, medication interactions, poor oral health, cognitive decline, and poor diet.^[13]
However, studies suggest that elderly people who take dietary supplements have lower rates of subclinical deficiencies of most micronutrients, particularly iron and B12.^[14]

 

Vegetarians/vegans

While plant-based diets offer significant health benefits, vegans and some vegetarians may need to pay special attention to B12 (found only in animal products), iron (less easily absorbed from plants), and omega-3 fatty acids. With planning, these nutrients can be obtained through fortified foods or supplements.^[15]

 

Individuals with digestive impairments

People with digestive disorders such as celiac disease, Crohn’s disease, or those who have undergone gastrointestinal surgeries may not absorb nutrients properly from food alone, regardless of diet quality.^[16]

 

Individuals with low sun exposure

Vitamin D deficiency affects up to 1 billion people worldwide, including 35% of US adults.^[17] While sunlight exposure is the primary method of producing vitamin D in the body, factors such as indoor lifestyles, sunscreen use, and living in northern climates can all limit vitamin D production.^[18]

 

Do you need to supplement?

While whole foods should be the main source of your nutritional intake (i.e., fresh foods with minimal processing and/or additives), supplements can help to fill in the gaps.

Before starting a supplement regime, ask yourself:

Do I have any symptoms or lifestyle factors that might indicate deficiency?

Consider starting with a comprehensive blood test to identify any existing deficiencies. This objective data can help you and your health professional to understand which supplements may be helpful for you, and how best to take them.

 

This information is provided for educational purposes only and is not a substitute for professional medical advice. Always seek the guidance of your physician or qualified healthcare provider with any questions you may have regarding your health or a medical condition.

 

References

^[1] InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. In brief: What are dietary supplements? [Updated 2024 Jan 23]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279425/

^[2] Bhardwaj, R. L., Parashar, A., Parewa, H. P., & Vyas, L. (2024). An Alarming Decline in the Nutritional Quality of Foods: The Biggest Challenge for Future Generations’ Health. Foods (Basel, Switzerland), 13(6), 877. https://doi.org/10.3390/foods13060877

^[3] Kiani, A. K., Dhuli, K., Donato, K., Aquilanti, B., Velluti, V., Matera, G., Iaconelli, A., Connelly, S. T., Bellinato, F., Gisondi, P., & Bertelli, M. (2022). Main nutritional deficiencies. Journal of preventive medicine and hygiene, 63(2 Suppl 3), E93–E101. https://doi.org/10.15167/2421-4248/jpmh2022.63.2S3.2752

^[4] Ames B. N. (2006). Low micronutrient intake may accelerate the degenerative diseases of aging through allocation of scarce micronutrients by triage. Proceedings of the National Academy of Sciences of the United States of America, 103(47), 17589–17594. https://doi.org/10.1073/pnas.0608757103

^[5] Vitale, M., Costabile, G., Testa, R., D’Abbronzo, G., Nettore, I. C., Macchia, P. E., & Giacco, R. (2024). Ultra-Processed Foods and Human Health: A Systematic Review and Meta-Analysis of Prospective Cohort Studies. Advances in nutrition (Bethesda, Md.), 15(1), 100121. https://doi.org/10.1016/j.advnut.2023.09.009

^[6] Rauber, F., Louzada, M. L. D. C., Martinez Steele, E., Rezende, L. F. M., Millett, C., Monteiro, C. A., & Levy, R. B. (2019). Ultra-processed foods and excessive free sugar intake in the UK: a nationally representative cross-sectional study. BMJ open, 9(10), e027546. https://doi.org/10.1136/bmjopen-2018-027546

^[7] Bhardwaj, R. L., Parashar, A., Parewa, H. P., & Vyas, L. (2024). An Alarming Decline in the Nutritional Quality of Foods: The Biggest Challenge for Future Generations’ Health. Foods (Basel, Switzerland), 13(6), 877. https://doi.org/10.3390/foods13060877

^[8] Conlon, M. A., & Bird, A. R. (2014). The impact of diet and lifestyle on gut microbiota and human health. Nutrients, 7(1), 17–44. https://doi.org/10.3390/nu7010017

^[9] Zuvarox T, Belletieri C. Malabsorption Syndromes. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK553106/

^[10] Di Renzo GC, Spano F, Giardina I, Brillo E, Clerici G, Roura LC. Iron Deficiency Anemia in Pregnancy. Women’s Health. 2015;11(6):891-900. doi:10.2217/whe.15.35

^[11] Irvine, N., England-Mason, G., Field, C. J., Dewey, D., & Aghajafari, F. (2022). Prenatal Folate and Choline Levels and Brain and Cognitive Development in Children: A Critical Narrative Review. Nutrients, 14(2), 364. https://doi.org/10.3390/nu14020364

^[12] Guidelines Review Committee. (2016, November 28). WHO recommendations on antenatal care for a positive pregnancy experience. https://www.who.int/publications/i/item/9789241549912

^[13] Kaur, D., Rasane, P., Singh, J., Kaur, S., Kumar, V., Mahato, D. K., Dey, A., Dhawan, K., & Kumar, S. (2019). Nutritional Interventions for Elderly and Considerations for the Development of Geriatric Foods. Current aging science, 12(1), 15–27. https://doi.org/10.2174/1874609812666190521110548

^[14] Wallace, T. C., Frankenfeld, C. L., Frei, B., Shah, A. V., Yu, C. R., van Klinken, B. J., & Adeleke, M. (2019). Multivitamin/Multimineral Supplement Use is Associated with Increased Micronutrient Intakes and Biomarkers and Decreased Prevalence of Inadequacies and Deficiencies in Middle-Aged and Older Adults in the United States. Journal of nutrition in gerontology and geriatrics, 38(4), 307–328. https://doi.org/10.1080/21551197.2019.1656135

^[15] Wang, T., Masedunskas, A., Willett, W. C., & Fontana, L. (2023). Vegetarian and vegan diets: benefits and drawbacks. European heart journal, 44(36), 3423–3439. https://doi.org/10.1093/eurheartj/ehad436

^[16] Johanna T. Dwyer, Leila G. Saldanha, Richard Bailen, Dietary supplement databases: Public health tools, Journal of Food Composition and Analysis, Volume 105, 2022, 104244, ISSN 0889-1575,

https://doi.org/10.1016/j.jfca.2021.104244.

^[17] Palacios, C., & Gonzalez, L. (2014). Is vitamin D deficiency a major global public health problem?. The Journal of steroid biochemistry and molecular biology, 144 Pt A, 138–145. https://doi.org/10.1016/j.jsbmb.2013.11.003

^[18] Cui, A., Zhang, T., Xiao, P., Fan, Z., Wang, H., & Zhuang, Y. (2023). Global and regional prevalence of vitamin D deficiency in population-based studies from 2000 to 2022: A pooled analysis of 7.9 million participants. Frontiers in nutrition, 10, 1070808. https://doi.org/10.3389/fnut.2023.1070808