Health Articles

Vitamin C – 10 minutes-read

Well, well, well. We all know a thing or two about vitamin C,
like it’s in oranges, it could boost your immune system and help with formation of collagen and all.

But there are some myths about this essential nutrient are still fairly common, while the truth is our knowledge about its benefits and functions continues to evolve.

Vitamin C, also known as ascorbic acid, it became known as an immune boosting super-nutrient after two-time Nobel Prize Winner Linus Pauling touted the substance’s supposed benefits in a series of books. Vitamin C is an essential vitamin, which means our body can’t produce them by ourselves. It has many roles and has been linked to impressive health benefits. Vitamin C is required for the biosynthesis of collagen, L-carnitine (for energy production), certain neurotransmitters as well as involved in protein metabolism. Other than that, vitamin C is an important physiological antioxidant and has been shown to regenerate other antioxidants within our body – including alpha-tocopherol (Vitamin E).

Since we can’t produce by ourselves, it is relatively easy to find and obtain from diet ranging from fruits such as kiwi, berries, citrus fruits to vegetables like broccoli, kale and so on as well as supplements. You should take note that vitamin C can be destroyed by high heat and prolonged cooking times. You should try quick heating methods when cooking such as stir-fry or blanching to preserve vitamin. Foods at peak ripeness eaten raw contain the most vitamin C. In case you wonder, the intestinal absorption of vitamin C is regulated by at least one specific does-dependant active transporter. Cells accumulate vitamin C via a second specific transport protein. The vitamin C is then oxidized and become dehydroascorbic acid and enters cells via facilitated glucose transporter and reduced internally to ascorbic acid. You know, just in case you wonder. Let’s dive down a little deeper, our body control oral vitamin C concentration produced in our tissue and plasma.

Approximately 70%-90% of vitamin C is absorbed at moderate intakes of 30-180mg/day. Then, at doses above 1g/day, absorption falls to less than 50%, the unmetabolized vitamin C is excreted through urine. So more is not always better, taking more doesn’t mean you absorb more.

Our body total content of vitamin C ranges from 300mg (near scurvy) to about 2g. High levels of vitamin C (in millimolar concentrations) are maintained in cells and tissues and are highest in leukocytes (white blood cells), eyes, adrenal glands, pituitary gland and brain. On the other side, it is relatively low level of vitamin C (micromolar concentrations) found in extracellular fluid, plasma, red blood cell and saliva.

The recommended daily intake (RDI) for vitamin C is 75mg for adult women and 90mg for adult men. While it is prioritized to get vitamin C from food, many people still turn to supplement to meet their needs. So, here are some scientifically proven benefits of Vitamin C:

1. Chronic Disease

As vitamin C is a powerful antioxidant, it can strengthen your body’s natural defences by protecting our cells from harmful free radical damage. So just as I mentioned before, when free radicals accumulate, they promote oxidative stress that linked to many chronic diseases. So in this case, vitamin C help us to reduce the risk of chronic disease by increasing our blood antioxidant level which boost our body natural defences to fight inflammation.

2. High Blood Pressure Management

High Blood Pressure increase the risk of heart disease and is one of the leading causes of death globally. Animal study shows that vitamin C helped relax the blood vessel that carry blood from the heart, which helped with blood pressure management. Human studies found that vitamin C reduced systolic blood pressure and diastolic blood pressure in healthy and high blood pressure. However, it is not clear vitamin C effect on blood pressure is long term and people with high blood pressure should not rely on vitamin C alone for treatment. Please note that effervescent type of vitamin C supplement might contain sodium that increase daily sodium intake that might contribute to high blood pressure.

3. Risk of Heart Disease

We all know that heart disease is the leading cause of death, worldwide. Many factors increase the risk of heart disease, which we have mentioned – High Blood Pressure, High LDL cholesterol level as well as high blood glucose level. Vitamin C comes in as antioxidant and help to reduce these risk factors, which may reduce heart disease risk. Researchers have found that consuming vitamin C rich foods and supplement were linked to lower risk for heart disease.

4. Iron Absorption

Iron is essential for making red blood cells and transport oxygen throughout the body. Vitamin C can improve the absorption of iron from diet. This is due to vitamin C is able to reduce ferric to ferrous iron and its potential to chelate iron. Other than that, vitamin C is able to overcome the negative effect on iron absorption of all inhibitors including phytate, polyphenols and calcium. In layman term, Vitamin C assists in converting the poorly absorbed form of iron such as plant-sourced iron into a form that is easier to absorb. This is important to people on a vegetarian/vegan diet as meat is a major source of high bioavailability iron (heme iron). So how much iron absorption is increase? So, simply consuming 100mg of vitamin C may improve iron absorption by 67%. Therefore, vitamin C may help reduce the risk of anemia for people prone to iron deficiency.

5. Immunity

I am sure you have heard of this one, and especially in times like this. So, does vitamin C able to boost your immunity? Yes, it does, but how? Vitamin C is able to boost immunity as it is involved in many parts of our immune system. For starters, vitamin C helps promoting the production of white blood cells specifically lymphocytes and phagocytes. They in turn help protect our body against infection. Then, after forming the white blood cells, vitamin C helps these white blood cells function more effectively while protecting them from damage from harmful molecules. Furthermore, vitamin C is an essential part of our skin defence system. It is actively transported to our skin to help strengthen our skin barriers by promoting formation of collagen. Studies have shown vitamin C enhanced wound healing and shorten the wound healing time. How about for cold? Well, despite being a popular fix, reviews of several studies show that supplemental megadoses >500mg vitamin C per day have no significant effect on prevention of common cold, but may provide a moderate benefit in decreasing the duration and severity of colds in some people. However, there are other findings that said otherwise and it is still inconclusive at the moment. Supplement or not, we would suggest to stick with diet to obtain your daily vitamin C needs and include vitamin C supplement occasionally.

Dietary supplements of Vitamin C

Supplement commonly contains vitamin C in the form of ascorbic acid. These form of vitamin C are mostly synthetic with its salt such as sodium, calcium and other mineral ascorbates unless stated otherwise. There is also ascorbic acid with bioflavonoid or combination with other polyphenol such as quercetin to mimic the other natural occurring compound in fruits to enhance the absorption of the vitamin C. Synthetic vitamin C usually contains higher dosage of vitamin C and is usually acidic which would cause digestive distress for people with gastrointestinal issue.

Therefore, there are buffered or ester vitamin C to reduce this side effect or you could take with your meal or after meal. On the other side, there are natural vitamin C usually sourced from natural fruit extract such as rosehip extract, acerola extract and etc. Natural vitamin C supplements also come with combination of fruit extract targeted for different standardized compound such as bioflavonoids and it is usually containing lower amount of vitamin C compared to synthetic vitamin C supplement. Generally, natural vitamin C is superior due to natural occurring beneficial compounds in real fruits such as bioflavonoids, phenolics group with higher bioavailability vitamin C and more benefits. In addition, due to natural extracts from fruits, it is unlikely to cause any digestion distress. However, this is still depending on the formulation and ingredients of the vitamin C supplement itself. Therefore, you might need to consult with your healthcare professional to check which form and dosage of vitamin C supplement is more suit for your needs.

Potential side effect of Excessive Vitamin C

We have heard of all the good thing about vitamin C, but when comes to the side effect of it, how much do you know? Well, for starters, vitamin c is a water-soluble vitamin, which means it dissolves in water and do not store in our body. It is transported to our tissues via body fluids and the extra ones would be excreted through our urine. Since we do not store vitamin C, it is crucial to obtain vitamin C in a daily basis. However, chances are you might over-supplementing with vitamin C from your high dose vitamin C supplement and cause accumulation that lead to overdose symptoms such as nausea, abdominal cramps, digestive distress and diarrhoea due to the osmotic effect of unabsorbed vitamin C in gastrointestinal tract. Other than that, high vitamin C intake would increase the potential of urinary oxalate and uric acid excretion that contribute to the formation of kidney stones, especially individuals with renal disorder. More is not always better like I mentioned with Antioxidant, high dose of vitamin C can act as pro-oxidant and contribute to oxidative damage. Therefore, it is important to supplement it with the right dosage.

A Brief one on Vitamin C for COVID-19

We know this is what you probably came for. We should mention this in the front, there is no studies to conclude any supplement will cure or prevent covid-19 up for now. While there are articles published the use of high dose vitamin C as treatment for hospitalized people, the doses are more than 10 times higher than RDA and must be given through intravenous (IV). Researchers pointed out that vitamin C level drop in patient with acute respiratory infections as inflammatory response when their body overreact to the infection, therefore it would be wise to increase their vitamin C level. IV vitamin C is a solution of vitamin C that is delivered directly into bloodstream through a vein that is done in medical setting. IV vitamin C goes straight into the bloodstream and vitamin C blood rises very high and quickly as it skips the stomach intestines.

High dose IV vitamin C is currently being tested if it can improve lung function in people with COVID-19, however there is no evidence suggests that high doses of oral vitamin C supplements can help with it. In addition, there are on-going clinical research to further study the effectiveness of IC vitamin C in hospitalized people with COVID-19. That being said vitamin C supplement does not made you invincible. Also, it is important to note that vitamin C is not yet a standard part of the treatment plan for COVID-19 because the evidence is still lacking up to now and all of the study are governed by healthcare professional in a hospital setting.

Takeaway from Nutritionist

Vitamin C is an important nutrient that keeps your immune system function properly. Studies show it has been linked to many impressive health benefits like we just mentioned. In case you were bored, it includes boosting your antioxidant levels, help manage blood pressure level, improve iron absorption as well as boosting immunity. In the case for COVID-19, it is still lack of any conclusion at the moment. We would always suggest to prioritize nutrients from dietary source; however, vitamin C supplements are a great and simple way to boost your vitamin C intake as well.