In general, people take vitamin C supplements to boost their immune systems and keep diseases at bay, but did you know that vitamin C carries with it other health benefits? Otherwise known as L-ascorbic acid, vitamin C is an essential water soluble vitamin that the human body cannot produce on its own. Fortunately, there are a lot of food items that contain a lot of vitamin C. Aside from this, vitamin C supplements are cheap and widely available. 

Vitamin C is needed in a number of bodily processes such as protein metabolism, and biosynthesis of collagen, L-carnitine, and some neurotransmitters. One particular protein that vitamin C is heavily involved in is the protein Collagen. Our connective tissues are very reliant on this protein. On top of this, collagen has a critical role in the process of wound healing. We could say that vitamin C influences wound healing indirectly. This is the reason why some people take vitamin C, for they believe that it helps make the skin look good through its collagen promoting effect. One more reason that makes vitamin C a beauty enhancing product is that it is an essential physiological antioxidant. Some studies have shown that vitamin C can promote the regeneration of other used up antioxidants such as the alpha-tocopherol or vitamin E. This is the reason why most pharmaceutical companies would promote products that have both vitamin C and E, as the pair can prevent free radical damage which could promote beauty. Vitamin C also improves iron absorption, specifically, non-heme iron present in plant-based foods. There are still a lot of health benefits that come with sufficient vitamin C intake which we will discuss further in detail in this article.

There are some concerns regarding proper vitamin C intake. However, research has quelled this and revealed that vitamin C absorption is better when they are taken orally at moderate amounts, somewhere around 30 to 180 milligrams per day. At this amount, 70% to 90% of the vitamin is effectively absorbed through the intestines. Furthermore, intake of 1 gram per day results in less absorption; vitamin C absorption decreases to 50%. Studies on vitamin C supplements reveal that vitamin C concentrations in the plasma of the blood of a person taking a 1.25 gram ascorbic acid supplement each day can reach 135 micromol per liter. This vitamin C blood plasma concentration is about two times higher than what can be achieved through a 200 to 300mg/day ascorbic acid rich diet. It is important to note that there are certain conditions that can reduce the bioavailability of vitamin C. Stress, alcohol intake, painkillers, antibiotics, viral illnesses, fever, smoking, heavy metal toxicity, and exposure to petroleum products or carbon monoxide, are just some of the conditions that can lower vitamin C bioavailability.

Research on the Health Benefits of Vitamin C

Immunity

To boost immunity, this is the main reason why people take in vitamin C supplements. White Blood cells function better when there is sufficient vitamin C in our bodies. When white blood cells function better, our immune defense system is improved. Neutrophils, a kind of white blood cell that is effective against bacteria, are enhanced with regards to their chemotactic abilities, particulate ingestion, lysozyme-mediated non-oxidative attacks, resistance to superoxide anion radicals, halide-peroxide-myeloperoxidase inhibition, and hexose monophosphate shunt stimulation. 

Our skin is our primary protective barrier against microbial pathogens. Since, vitamin C also improves wound healing thereby closing any open wounds faster, it also lowers our exposure to pathogens. 

The findings mentioned previously suggest that vitamin C enhances our innate immunity, however, animal-studies have indicated that vitamin C also has the potential to improve our adaptive immunity as well. In a study involving guinea pigs, researchers observed that dietary supplementation of vitamin C increased the animals’ antibodies and C1q, an immune protein. Note that this animal, like humans, are not able to produce their own vitamin C and must obtain it from their diet. Vitamin C is also capable of regulating the immune system and is involved in the clean up process after immune processes have been carried out. Other research journals have shown that ascorbic acid can have a positive effect on the immune system by increasing the number of T-cells. Since these cells are involved in producing chemical signals that help B-cells produce antibodies and other immune-related products that regulate inflammatory reactions, we could then solidify the claim that vitamin C can improve our adaptive immunity.

Tissue Healing

This is another well known feature of vitamin C. Collagen production is improved by the presence of vitamin C. Since collagen is an important protein in wound healing, we can say that vitamin C supplements can indirectly improve tissue healing. What’s even more interesting is the fact that animal-studies have shown that scar tissue tensile strength was considerably stronger in animals who were given vitamin C compared to those who were not. 

Common colds

In the past, vitamin C was considered a wonder drug for preventing a common dreaded illness; scurvy. Recently, research is being focused on vitamin C’s effect on another disease, the common colds. There is a lot of anecdotal evidence regarding vitamin C’s efficacy against the common colds. However, in the scientific community, anecdotal evidence is poor. Thus, clinical trials aimed at investigating these personal accounts have been conducted. Through these clinical trials, researchers discovered that different doses of ascorbic acid did show a prophylactic effect against the common cold. On top of this, the clinical trials also revealed that it can reduce the duration of colds and reduce the severity of the symptoms. In other words, vitamin C is not a suitable therapeutic drug for the common colds. Furthermore, if vitamin C is taken at larger doses, it can have a moderate therapeutic effect against the common cold. However, researchers indicated that the evidence is not very strong. Still, taking in vitamin C when you have a cold is a good idea because it lessens the severity of the symptoms and makes you recover faster.  

Iron deficiency

Some forms of dietary iron, such as the non-heme iron, is not readily absorbed by the body. This form of dietary iron is present in plant-based diets which means those who restrict themselves to a plant-based diet are at risk of developing iron deficiency. Fortunately, vitamin C, which is present in a lot of vegetables and fruits, can improve the absorption of nonheme iron. Research suggests that the ascorbic acids’ ability to reduce iron may be the reason why this vitamin can improve absorption of nonheme iron. Other recent studies proposed that vitamin C increases iron absorption by inhibiting hepcidin and by influencing erythropoietin receptors.

Diabetes

Several studies have associated vitamin C intake to a reduction in the risk of developing diabetes mellitus. One study conducted over a 12-year period and involving 21,000 participants, showed a link between plasma levels of vitamin C, fruits and vegetables intake, and the risk of type 2 diabetes mellitus. The researchers in this study concluded that eating vitamin C rich fruits and vegetables increased the participants’ plasma levels of vitamin C which lead to a decrease in the risk of type 2 diabetes mellitus. Another similar study which was conducted over a longer period of time, 23 years, showed that antioxidants in general reduced the risk of type 2 diabetes. This study also revealed that those participants who have type 1 or type 2 diabetes have low vitamin C levels. These findings are consistent with what researchers have theorized; vitamin C has the ability to prevent oxidative-stress-induced hyperglycemia and its complications. There are other studies that delve deeper into this theory. One study involving diabetic aged rats showed that vitamin C and E supplementation prevented oxidative stress in the animal’s blood and tissues. Another study revealed that vitamin C can prevent acute hyperglycemic endothelial dysfunction by hindering reactive oxygen species from causing damage to the blood vessel’s endothelial cells. A different study also revealed that vitamin C and E can prevent retinopathy or diabetes-induced-eye damage by preventing oxidative stress. 

Cancer

In the 1970s, researchers and health professionals Pauling and Cameron tested the hypothesis that vitamin C has a positive effect against cancer. In their experimental research they recruited 100 cancer patients that cannot be cured and will eventually die. They then gave 10 grams of vitamin C to these patients everyday. They then compared the survival rate of these patients to those who received conventional treatment but did not take vitamin C everyday. Pauling and Cameron found out that 10.3% of the cancer patients that received 10 grams of vitamin C everyday survived while the other terminally ill patients died. Further experimental studies conducted on Gulo KO mice showed that ascorbic acid intake hampers inflammatory cytokine secretion, tumor growth and metastasis.

One thing to note regarding vitamin C’s effect on cancer is that pharmacological concentrations, around 0.3 to 20 mmol/L, is more effective at selectively targeting and killing cancer or tumour cells present in a living body compared to physiological concentrations which is about 0.1 mmol/L. The high concentration of hydrogen peroxide whose production is brought about by the increase in vitamin C is the well accepted explanation regarding this effect. 

Other studies have shown that vitamin C concentration can reach up to 70 times more than what can be achieved through oral intake when administered intravenously. Moreover, vitamin C of this concentration has significantly better anti-cancer effects. However, this presents some controversy as this mode of administration and dose might have unforeseen harmful effects. On top of this, it is difficult to determine what exactly vitamin C does against cancer. For now, intravenous administration of vitamin C to treat cancer is still not accepted scientifically but it does improve overall health and quality of life for those who have cancer even for those who are terminally ill.

High blood pressure and heart disease

Several studies have shown that peroxidation and oxidative modification of LDL can lead to the development of atherosclerosis and endothelial dysfunction. Fortunately, vitamin C is a reducing agent that can counteract the peroxidation and oxidative modification of LDL. Furthermore, several studies have also indicated that vitamin C can reduce a person’s cholesterol levels, triglyceride levels, and low density lipoprotein; while increasing their high density lipoprotein. These changes in blood lipid content can lead to a decreased risk for Cardiovascular diseases. 

Vitamin C’s cardioprotective effects are further supported by studies which sought to investigate the effects of low Vitamin C levels. In one study involving Guinea pigs which were deprived of vitamin C for 10 weeks, researchers observed a marked increase in cholesterol in the animal’s liver and in their blood serum. Another study revealed that vitamin C deficiency can lead to unhealthy changes in the blood vessels and accumulation of cholesterol in the thoracic aorta. Researchers mentioned that Vitamin C appears to play a role in cholesterol metabolism and that its deficiency would impair this process which could lead to unhealthy build-up of cholesterol and ultimately heart disease.

With these findings we could claim that vitamin C is not solely for boosting our immune system, its antioxidant effects also lowers the risk of heart disease by helping our body maintain a healthy blood lipid content, and prevent blood vessel endothelial dysfunction.

Mental functioning

High intake of vitamin C from dietary sources and supplements have been associated with the reduction of the likelihood of acquiring memory and cognitive disorders. The opposite, that vitamin C deficiency is associated with an increased likelihood of acquiring memory and thought impairment, is also well studied. One study involving 12 schizophrenic patients showed that the participants of the study excreted less vitamin C through their urine, which suggests low vitamin C levels, compared to those who are mentally healthy. The researchers then tried to test whether their patient’s low vitamin C level had something to do with their mental condition. So they gave them a large dose of vitamin C. After the administration of the vitamin C dose, researchers noted that 75% of their patients exhibited improvements in their mental condition. This finding prompted the researchers to conclude that schizophrenic patients may require higher than normal vitamin C intake compared to mentally healthy individuals. Other studies investigated the effects of increased free radical generation in the disease process of schizophrenia. Research shows that lipid peroxidation and altered antioxidant activities are present in the blood of schizophrenics in significant amounts which might relate oxidative damage to the disease. Furthermore, a different research paper mentioned that supplemental antioxidant therapy is effective for patients who have stress-related mental conditions. Although evidence is still not conclusive enough, vitamin C has been implicated to be beneficial for neurodegenerative disorders such as Alzheimer’s disease. In conclusion, there is evidence that supports the claim that vitamin C can help protect against age related decline in brain functioning but they are still not conclusive enough and requires further research.

How much do you need

The average adult male needs 90 milligrams of vitamin C each day. Females need less, they require 75 milligrams of ascorbic acid everyday. Pregnancy will increase a female’s vitamin C needs to 85 milligrams, and lactation will increase it further to 120 milligrams. Smokers may need to increase their vitamin C intake by 35 milligrams for smoking can lower the bioavailability of vitamin C.

Dietary sources

Vitamin C is abundant in fruits and vegetables, most notably in red pepper and orange. Half a cup of red pepper contains 95 milligrams of vitamin C with a percent Daily Value of 106%. Three-fourths of a cup of Orange juice contains 83 milligrams of vitamin C with a percent Daily Value of 103%. Have caution when eating red peppers, eating too much spicy foods can have detrimental effects to the gastrointestinal tract. Also limit yourself to three-fourths of a cup of orange juice. Unlike the fruit, the juice alone is high in sugar.

Precautions

Do not consume too much vitamin C supplements. If you take in too much you will experience digestive symptoms such as diarrhea and nausea. Be especially wary of your vitamin C intake if you have hemochromatosis. Vitamin C can increase iron absorption which could exacerbate the condition. If you are a known kidney stone former, be wary of your vitamin C intake as well. Excess vitamin C is excreted as oxalate and could form kidney stones. Other side effects that have been noted include sleeping problems, headaches, and cramps.

Sources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3783921/

https://www.healthline.com/nutrition/vitamin-c-benefits

https://www.healthline.com/health/food-nutrition/is-it-possible-to-have-a-vitamin-c-overdose#2

https://www.healthline.com/nutrition/side-effects-of-too-much-vitamin-c

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3169708/