Natural Defenses Reinforced with Vitamin C and Zinc

In the complex network of biological factors that regulate human health, vitamin C and zinc play an essential role in strengthening our natural defenses.

Vitamin C: an essential nutrient

Vitamin C, or L-ascorbic acid, is a micronutrient that plays a fundamental role in maintaining our health and well-being. For us, human beings, this vitamin is an essential nutrient, since our body is not able to produce it, lacking an enzyme called gulonolactone oxidase, capable of catalyzing the conversion of glucose to vitamin C. Moreover, since it is a water-soluble vitamin (water-soluble and fat-insoluble), it is unable to be stored in our body, so we must obtain it regularly through our diet.

Vitamin C is the main non-enzymatic water-soluble antioxidant present in blood plasma, where it is found predominantly in the form of ascorbate anion and to a lesser extent, as ascorbyl radical and dehydroascorbate anion. The latter two molecules are generated by two consecutive reversible oxidations of the ascorbate anion.

The main characteristic of vitamin C lies in its ability to donate electrons to other molecules, which gives vitamin C its function as an antioxidant agent and as an enzymatic cofactor, both associated with its benefit to our natural defenses.

Antioxidant function

Vitamin C is a highly effective antioxidant, thus protecting important biomolecules (proteins, lipids, carbohydrates and nucleic acids) against damage caused by free radicals, by oxidants generated during normal cellular metabolism or by exposure to toxins and pollutants ^{1, 2.} By counteracting the action of free radicals and oxidizing agents, vitamin C helps maintain the integrity of cells and tissues, protecting organs and skin against the aging process and diseases such as atherosclerosis (through oxidation of low-density lipoproteins), type 2 diabetes (through oxidative stress on the beta cell) and cancer (through the DNA repair mechanism and oxidative-related DNA damage^)2.

Enzyme cofactor and epithelial tissue integrity

Vitamin C acts as an enzymatic cofactor in numerous reactions such as lysine/proline hydroxylation, carnitine biosynthesis, neurotransmitter and hormone biosynthesis, and tyrosine metabolism. Of all these enzymatic reactions, the best studied is the hydroxylation of proline to form the hydroxyproline necessary for the synthesis of collagen, the most important protein in connective tissues (cartilage, bone matrix, ligaments, skin, tendons, veins, arteries, etc.).

The presence of collagen in the skin, joints and blood vessels allows the correct functioning of these structures, as well as their proper healing in case of injury, being essential to maintain and strengthen our natural defenses.

Vitamin C and natural defenses

According to several studies, vitamin C could have an effect on our natural defenses, as it seems to influence both cellular (functioning of defense cells) and humoral (production of antibodies by B lymphocytes) immune responses.

For example, in vitro studies have confirmed that vitamin C stimulates both the production ^3-7 and function ^{8, 9} of leukocytes, especially neutrophils, lymphocytes and phagocytes. These defense cells accumulate vitamin C in high concentrations, which may protect them from oxidative damage ^10-12. It has been observed that these cells are capable of storing 50 to 100 times more vitamin C than that present in the bloodstream ^13.

13 In fact, it is crucial that leukocytes contain high levels of vitamin C. When confronted with invading microorganisms, phagocytic leukocytes release non-specific toxins such as superoxide radicals, hypochlorous acid and peroxynitrite. Although these reactive oxygen species (ROS) play a key role in the elimination of pathogens, they can also cause damage to the leukocytes themselves during this process. Vitamin C, through its antioxidant properties, has been shown to play an essential role in protecting leukocytes against self-inflicted oxidative damage ^12.

By virtue of these benefits, EU Regulation No. 432/2012 authorizes several health claims associated with vitamin C. These include its contribution to the normal functioning of the immune system, proper collagen formation, normal energy metabolism, cellular protection against oxidative damage, reduction of fatigue and tiredness, regeneration of the reduced form of vitamin E and improved iron absorption ^14.

Zinc: an essential trace element

Zinc plays a fundamental role in various stages of cellular metabolism. Its essentiality is reflected in the activation of more than 300 enzymes, contributing significantly to key functions in the organism. Among its roles are its vital participation in immune function, protein synthesis and carbohydrate and lipid metabolism ^{15, 16.} In addition, it is involved in crucial processes related to the metabolism of specific vitamins, such as retinol (vitamin A) and pyridoxine (vitamin B6) ^{17, 18}, wound healing ¹⁹, hormone release (e.g. testosterone) ^20, DNA ^synthesis21, cell division and apoptosis (programmed or self-induced cell death) ²², synaptic activity (transmission of nerve impulses) ²³ and insulin action (hormone that regulates insulin levels in the blood) ^24.

Zinc also contributes to normal growth and development during pregnancy, childhood and adolescence ^25. In addition, it is an essential component for the senses of smell and taste ^26.

EU Regulation No. 432/2012 authorizes several health claims associated with vitamin C. These include its contribution to normal cognitive function, normal fertility and reproduction, and the maintenance of normal bones, hair, nails, skin and vision ^14.

Zinc and natural defenses

Zinc is possibly the most important mineral for our natural defenses. Adequate zinc intake is essential for the normal development and function of cells that mediate innate (neutrophils, macrophages, and NK cells) and adaptive immune responses, such as B-lymphocytes and T-lymphocytes ^16. In addition, the lack of this trace element can also reduce the production and activity of cytokines (cellular messengers that regulate the function of white blood cells) and macrophages ^16.

One sign of zinc deficiency is lymphopenia (or lymphocytopenia), which means a reduction in the total number of lymphocytes. When zinc deficiency occurs, the number of T and B lymphocytes in the thymus and bone marrow decreases, resulting in an increased risk of infections and weakening of the body’s natural defenses ^27.

For example, with regard to T lymphocytes, studies have shown that zinc deficiency causes a condition called thymic atrophy, which is a decrease in the size of this gland. Thymic atrophy reduces T-cell production and diversity, which can affect the immune response ^28.

Ultimately, zinc deficiency decreases the body’s ability to fight pathogens ^{16, 29}, leading to increased susceptibility to a variety of infectious agents ^30. This is especially relevant for the elderly, who often have lower zinc absorption ³¹, due to, for example, problems in intestinal absorption, inadequate chewing of food, psychosocial factors, drug interactions and disease ^32.

A dynamic approach to strengthening natural defenses

Undoubtedly, having a healthy diet that ensures adequate amounts of Vitamin C and Zinc is the essential starting point to protect us against the constant siege of pathogens in our body. However, in particular situations, supplementation may be necessary to ensure the supply of the minimum daily amounts of these nutrients or to obtain additional benefits by ingesting higher amounts than those usually obtained through the diet. Vitamin C clearly exemplifies this situation.

In this regard, Nutribiolite has developed a food supplement that provides a daily dose of 1000 mg of vitamin C, combined with 50 mg of highly bioavailable chelated zinc, providing 10 mg of elemental zinc (100% of the recommended daily intake for adults – NRV).

Vitamin C (1000 mg)

In addition to enjoying all the benefits of vitamin C mentioned throughout this blog , ingesting a daily dose of 1000 mg (1g) can bring additional benefits to your supplementation plan. Supplementation with 1000 mg of vitamin C has been shown to be associated with a rapid but transient increase in vitamin C concentrations in the fluids lining the airways ³³, which may provide immediate antioxidant protection to lung tissues and temporarily attenuate oxidative stress in the airways.

According to a clinical investigation carried out in the United Kingdom in 2002, involving 168 adults, it was observed that daily supplementation of 1000 mg of vitamin C for 60 days was associated with a reduction in the duration of colds (1.8 vs. 3.1 days) ^34.

The latest systematic review and meta-analysis of randomized controlled clinical studies, conducted by the Cochrane Foundation in 2013, reveals moderate beneficial effects of vitamin C supplementation in reducing the duration and severity of the common cold in the general population ^35. The authors highlight the consistency of these effects in regular supplementation studies, supporting the idea that, given the affordability and safety of vitamin C, it may be valuable for individuals with the common cold to personally consider the therapeutic utility of this nutrient, despite the recommendation to conduct further studies to support these findings ^35.

The review has even highlighted a significant benefit in individuals experiencing extreme physical stress, such as athletes and the military, where the need for the antioxidant action of vitamin C is crucial ^35.

It is essential to note that regular intake of doses higher than 2000 mg per day may cause symptoms such as diarrhea, heartburn, vomiting and even contribute to the formation of kidney stones, so this practice is discouraged. If you have any doubts about the right amount of vitamin C for your particular situation, we recommend that you consult your doctor. It is also important to note that vitamin C supplements should not be considered as a substitute for a healthy, balanced diet.

It is important to note that regular intake of doses higher than 2000 mg per day may cause symptoms such as diarrhea, heartburn, vomiting and even contribute to the formation of kidney stones, so this practice is discouraged. If you have any doubts about the right amount of vitamin C for your particular situation, we recommend that you consult your doctor. It is also important to note that vitamin C supplements should not be considered as a substitute for a healthy, balanced diet.

Zinc in the form of Zinc Picolinate

Given the wide geographic distribution and significant prevalence of zinc deficiency, along with the consequent implications for immune function, ensuring a continuous and moderate intake of this trace element could provide remarkable benefits, thus contributing to the preservation of respiratory health ^36.

In terms of supplementation, zinc chelates, such as zinc picolinate, have significant advantages over inorganic forms of zinc, such as zinc oxide or zinc sulfate, which are often found in lower quality supplements. These are chemical variants in which zinc is bound to an organic molecule, thus enhancing its absorption in the gastrointestinal tract. In addition, these zinc options are generally better tolerated and less likely to cause unpleasant side effects, such as the gastrointestinal problems associated with inorganic forms of zinc.

Various forms of zinc chelate are available in dietary supplements, the most common and approved for human consumption being zinc citrate, zinc gluconate and zinc picolinate. All of these forms of zinc are beneficial, but zinc picolinate stands out as having superior absorption ^38.

What is zinc picolinate?

Zinc picolinate is a form of zinc in which one atom of zinc is bound to two molecules of picolinic acid. Picolinic acid is a substance produced naturally in our body from tryptophan. It plays a very important role in the absorption and retention of zinc in the body, as well as other trace elements such as copper, chromium or manganese ^39. Its chelating capacity allows zinc and other minerals to be more easily absorbed in the intestine.

Superior bioavailability

In a clinical study, researchers determined zinc levels in different parts of the body (hair, red blood cells and urine) of participants who received zinc supplementation in the form of an organic chelate. The participants were divided into groups according to the form of chelate administered: zinc picolinate, zinc citrate or zinc gluconate, in addition to the placebo group (which received a tablet without zinc) ^38. The researchers observed that the group that received zinc supplementation in the form of zinc picolinate had better absorption of zinc, which resulted in a significant increase in zinc levels after 4 weeks of supplementation.

Why 50 mg of zinc picolinate?

Because zinc picolinate is well absorbed in the body ³⁸, it is possible to use lower amounts of elemental zinc per dose, reducing the risk of intestinal problems and nausea that can occur with higher doses of zinc ^40. In addition, with only 50 mg of zinc picolinate, we get 10 mg of elemental zinc, already meeting 100% of the recommended daily allowance for adults (NRV – nutrient reference values).

Another significant reason is that high concentrations of zinc can hinder the absorption of copper in the body. This is due to the affinity of metallothioneins, proteins crucial in the intracellular regulation of copper, to bind readily to zinc. This process can result in copper dysplasia, generating interferences in its absorption process.

Strengthened Natural Defenses: Immune Alliance of Vitamin C and Zinc

The effectiveness of the combination between vitamin C and zinc was demonstrated in a study published in 2012, which concluded that the joint supplementation of 1000 mg vitamin C and 10 mg elemental zinc was notably more effective than placebo in the recovery from infectious viral diseases, such as the common cold. For example, this combination was found to significantly reduce rhinorrhea and alleviate other cold symptoms in just 5 days of treatment ^41.

In summary, Nutribiolite offers a complete solution to strengthen natural defenses with its food supplement that combines 1000 mg of vitamin C and 50 mg of highly bioavailable zinc picolinate. This balanced combination seeks to enhance immune function and promote overall health.

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