Vitamins, minerals, spices, and other nutrients: the ingredients to live life to the fullest

Updated and contextualized version of an article originally published on December 21, 2020
The article retains its original focus by presenting it through a scholarly and accessible perspective, supported by verifiable references.

Authors

• Dr. M. Mondini – Biologist
• Roberto Panzironi –Independent researcher 

Note editoriali

• First publication: December 21, 2020
• Last update: April 18, 2026
• Version: 2026 narrative revision  

IN BRIEF

• Nutrients such as vitamin D, vitamin C, zinc, magnesium, and omega-3 are relevant for different dimensions of well-being (bones, immune system, metabolism, sleep), but they are not "miracles."
• Research shows moderate and contextual effects: the form of the nutrient, the dose, and the subject's status (e.g., deficiency) influence the results.
• Some supplementations (e.g., vitamin D in deficient individuals; fibers like psyllium for constipation) have solid support; other indications remain observational or await robust causal evidence.
• Informed choices, attention to doses and interactions, and consultation with a doctor are essential.

Abstract: what does science say?

Supplements and some plant extracts can complement a balanced diet when deficiencies or specific needs exist. Available evidence indicates that vitamin D supplementation reduces the risk of respiratory infections in some populations and that correcting a deficiency is important for bone health. Vitamin C and zinc influence parameters of duration and severity of viral infections in selected studies; the effect is greater in subjects with insufficient intake. Minerals such as magnesium participate in many cellular and metabolic functions, and fiber (psyllium) has a consolidated role in intestinal regularity. Omega-3s show effects on cardiovascular biomarkers and heterogeneous results on clinical events. For melatonin and plant compounds (e.g., curcumin), the literature indicates benefits in specific areas (sleep, inflammation), but the quality of evidence, formulation, and doses determine efficacy. In summary: biological plausibility and experimental results exist, but translating them into universal recommendations requires caution and personalization.

Vitamin D (cholecalciferol)

Vitamin D is often at the center of wellness discussions because it plays a multi-systemic role: it regulates calcium and phosphorus metabolism, contributes to bone health, and can modulate immune responses. The most studied form for supplementation is cholecalciferol (vitamin D3). Practically speaking, lack of sun exposure, advanced age, and certain clinical conditions increase the risk of deficiency. Intervention with cholecalciferol is proven to correct low levels of 25-OH-vitamin D and to improve parameters related to bone health; furthermore, several controlled studies suggest a benefit in reducing the risk of respiratory infections when supplementation is performed appropriately and especially in people with low baseline levels.

Key Evidence

A meta-analysis with individual data from randomized studies showed that vitamin D supplementation reduces the incidence of acute respiratory infections more significantly in people with low initial levels and when administration is regular rather than in sporadic intermittent doses [1]. The classic review on vitamin D physiology also documents its central role in bone health and muscle function, emphasizing the importance of correcting documented deficiencies [2]. This evidence supports a targeted approach: testing levels in at-risk individuals and supplementing when necessary, rather than administering to everyone without assessment.

Vitamin C and zinc: role in respiratory infections

Vitamin C and zinc are often associated with the prevention and treatment of colds and other upper respiratory tract infections. Biologically, vitamin C acts as an antioxidant and a cofactor in enzymatic reactions, and contributes to tissue maintenance (e.g., collagen). Zinc is an essential trace element involved in the function of numerous enzymes and in the regulation of the immune response: zinc deficiency impairs the maturation and function of immune cells.

Key evidence

Recent reviews and meta-analyses indicate that vitamin C can reduce the duration and, in some cases, the severity of common cold symptoms, especially when taken regularly in high doses by individuals exposed to physical stress or with insufficient intake [3]. For zinc, systematic reviews suggest that appropriate formulations and doses (particularly zinc in the form of lozenges, started within the first 24 hours of symptoms) can shorten the duration of the common cold; however, the quality of studies and the variability of formulations necessitate cautious judgments [4]. In both cases, the effect is more pronounced in the presence of suboptimal levels or if supplementation is started early.

Magnesium, potassium, and other minerals: metabolic drivers

Minerals like magnesium and potassium are cofactors for numerous enzymes and support functions ranging from electrolyte balance control to protein synthesis, nerve conduction, and muscle contraction. Magnesium, in particular, participates in hundreds of metabolic reactions: its deficiency can manifest as fatigue, muscle cramps, mood alterations, and metabolic problems. Potassium is essential for heart function and blood pressure, while trace elements like copper and iron are central to oxygen transport and energy metabolism.

Role and limitations of evidence

Review literature shows that the homeostatic regulation of magnesium is complex and that supplementation can correct deficiencies and improve symptoms associated with hypomagnesemia, but evidence in general populations is heterogeneous [5]. For potassium and other minerals, most recommendations are based on physiological data and specific studies in at-risk groups (elderly people, individuals with kidney disease, or those taking diuretics). In practice, replacement should be guided by clinical tests and clinical evaluation, as excesses and imbalances can create risks.

Omega‑3 and cardiovascular health

Omega‑3 fatty acids (EPA, DHA, and the shorter ALA) have been studied for their effects on cardiometabolic biomarkers, inflammation, and cardiovascular outcomes. Dietary sources such as fatty fish and some algae provide EPA/DHA; ALA is found in plant sources (e.g., flaxseeds) and can partially convert to DHA/EPA. Clinical studies have yielded mixed results: some trials show reductions in cardiovascular events with EPA-based preparations, while other meta-analyses show modest but present effects on biomarkers and certain endpoints.

What reviews show

Meta-analyses aggregating numerous randomized studies indicate favorable effects on cardiac indicators and, in some analyses, a modest reduction in the risk of major cardiac events; however, the effect varies depending on the composition (EPA vs EPA+DHA), the studied population, and the dose [6]. For this reason, modern guidelines recommend an approach based on individual risk, prioritizing increased fish consumption in the diet and considering targeted supplementation in selected patients following clinical indications.

Melatonin and sleep quality

Melatonin is a hormone involved in regulating the circadian rhythm and the onset of sleep. In clinical settings, it is studied as an aid to reduce sleep latency in people with circadian rhythm-related sleep disorders and as a support in specific cases (jet lag, shift work). Melatonin is available in immediate and prolonged-release formulations, and the response may depend on the timing of intake and the dose.

A meta-analysis of randomized controlled trials has shown that melatonin can significantly reduce the time it takes to fall asleep compared to placebo, with a generally mild adverse effect profile; however, variability remains between studies regarding population and dosage [7]. In general, the rule of personalization applies: melatonin can be useful in specific and temporary contexts, with attention to drug interactions.

Turmeric (curcumin) and plant compounds; fibers like psyllium

Plant compounds like curcumin, extracted from turmeric, exert antioxidant effects and modulate inflammatory pathways in experimental models. From a clinical perspective, reviews show potential benefits in terms of inflammatory markers and symptoms in some conditions, but the oral bioavailability of curcumin is limited, and formulations (e.g., with piperine or lipid carriers) greatly influence the effect.

Among soluble fibers, psyllium is one of the most studied: its ability to form a gel in the intestinal lumen increases stool volume and consistency, promoting regularity and improving some symptoms of chronic constipation. Controlled clinical trials and recent reviews indicate that psyllium is effective in increasing bowel movement frequency and improving stool consistency, with effects dependent on dose and treatment duration [8][9].

PRACTICAL SECTION

What it means in practice

For the reader: supplementation is not synonymous with replacement. Evidence suggests that supplementation is more likely to be beneficial if there is a documented deficiency, a specific clinical condition, or risk factors that warrant targeted intervention. Practical examples: measuring 25-OH-vitamin D in at-risk individuals and correcting low values; considering vitamin C or zinc in people with specific exposures or symptoms, knowing that the effects are moderate; using psyllium for persistent constipation when diet is insufficient; evaluating omega-3 as part of a dietary strategy for cardiometabolic health. Decisions should always consider doses, pharmaceutical form, potential drug interactions (e.g., zinc and copper absorption), and tolerability.

KEY POINTS TO REMEMBER

• Supplements can correct deficiencies and improve some outcomes, but they are not a substitute for a balanced diet.
• Efficacy depends on the initial state (presence/absence of deficiency), dose, form, and clinical context.
• Some supplements have a solid basis (vitamin D for deficiency; psyllium for constipation), while others require individual evaluation.
• Monitor doses and potential drug interactions; consult a healthcare professional before starting regular supplementation.

Limitations of Evidence

It is important to distinguish between association and causation. Many observational studies describe relationships between nutritional levels and health, but do not establish that supplementation produces the same effect. Randomized studies remain the strongest evidence, but often present heterogeneity in terms of population, doses, formulations, and endpoints. Methodological limitations (small size, short duration, surrogate measures) can reduce the certainty of conclusions. Furthermore, individual variability and context (baseline diet, comorbidities, medications) require cautious and personalized interpretation.

Editorial Conclusion

Nutritional science offers useful tools to support well-being: some supplements, if used in a targeted and controlled manner, can correct deficiencies and improve relevant health parameters. However, the picture is complex: evidence varies in quality and consistency, and the effect of a nutrient depends on the dose, form, and the individual's baseline status. A prudent approach, based on clinical evaluation, monitoring, and updated knowledge, remains the most solid path to translate research into useful and safe choices for the population.

SCIENTIFIC RESEARCH

1. Martineau AR et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta‑analysis of individual participant data. BMJ. 2017. https://doi.org/10.1136/bmj.i6583
2. Holick MF. Vitamin D deficiency. N Engl J Med. 2007. https://doi.org/10.1056/NEJMra070553
3. Hemilä H, Chalker E. Vitamin C reduces the severity of common colds: a meta‑analysis. BMC Public Health. 2023. https://doi.org/10.1186/s12889-023-17229-8
4. Prasad AS. Zinc in Human Health: Effect of Zinc on Immune Cells. Mol Med. 2008. https://doi.org/10.2119/2008-00033.Prasad
5. de Baaij JHF, Hoenderop JGJ, Bindels RJM. Magnesium in man: implications for health and disease. Physiol Rev. 2015. https://doi.org/10.1152/physrev.00012.2014
6. Aung T et al. Associations of Omega‑3 Fatty Acid Supplement Use With Cardiovascular Disease Risks: Meta‑analysis. JAMA Cardiol. 2018. https://doi.org/10.1001/jamacardio.2017.5205
7. Ferracioli‑Oda E, Qawasmi A, Bloch MH. Meta‑Analysis: Melatonin for the Treatment of Primary Sleep Disorders. PLOS ONE. 2013. https://doi.org/10.1371/journal.pone.0063773
8. Hewlings SJ, Kalman DS. Curcumin: A Review of Its’ Effects on Human Health. Foods. 2017. https://doi.org/10.3390/foods6100092
9. Erdogan A, Rao SS, Thiruvaiyaru D, et al. Randomised clinical trial: mixed soluble/insoluble fibre vs. psyllium for chronic constipation. Aliment Pharmacol Ther. 2016. https://doi.org/10.1111/apt.13647

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