Vitamin C is one of the most essential nutrients our body needs for survival and healthy functioning. No one can attest to that better than those who have ever experienced scurvy, a condition caused by vitamin C deficiency. Scurvy started attracting public attention in the 16th century when rumors of a mysterious and deadly disease afflicting sailors began to spread. In fact, the disease was so deadly that shipowners and governments assumed a 50% death rate for sailors undertaking longer voyages. It is estimated that over 2 million sailors succumbed to scurvy during the Age of Discovery.
Even though the cause of this condition was not yet known, it was found in the 18th century that consuming citrus fruits apparently protected ship crews from the disease. Physicians and scientists at the time assumed that there was some special substance within citrus that provided this protection. The answer to this puzzle was finally revealed in the 1930s when the “secret substance” was discovered and named ascorbic acid, also known as Vitamin C.
The Nuts and Bolts of Vitamin C
Today, scientific knowledge about vitamin C has grown dramatically. And so, let’s take a look and find out which health-promoting and disease-preventing properties make vitamin C so unique:
Tissue repair
Vitamin C plays a vital role in maintaining healthy tissues and their repair. It helps with the formation of collagen, blood vessels, skin, cartilage, muscles, bones, teeth as well as some hormones and chemical messengers in the brain and nerves (2, 3). That is why scurvy often presents with blisters, skin ulcers, easy bruising, bleeding gums, loose teeth and cognitive impairment (5).
Immunity and illness
Vitamin C is known to support the proper functioning of the immune system, prevent immune system deficiencies and lower inflammation which is often present during illness (4). Vitamin C is not a cure for colds, flu and other infections. However, there is evidence that it can decrease the duration and severity of symptoms from these illnesses (1). It can also help prevent complications such as pneumonia (1). Scientists believe that humans lost the ability to make their own vitamin C in response to stress during evolution, which makes us more vulnerable to illnesses (6).
Disease prevention
Ascorbic acid is a well-known antioxidant. As such, it prevents damage from harmful substances called free radicals that arise from multiple sources including exposure to x-rays, ozone, cigarette smoking, air pollutants, food preservatives as well as normal metabolic activity of the body. This can help prevent chronic health diseases such as cardiovascular disease, arthritis, cancer and the development of stroke (1).
Stress management
Studies suggest that oxidative stress (when free radicals outnumber antioxidants in the body) may trigger more frequent and/or exaggerated responses to stress leading to neuropsychological disorders (7). However, by neutralizing harmful free radicals, vitamin C can help alleviate psychological stress and anxiety. Some researchers and clinicians believe that vitamin C should be an integral part of stress management (8).
Skin health
With its antioxidant and tissue regeneration properties, vitamin C not only helps in wound healing but also with day-to-day maintenance of firm and healthy skin. By doing so, vitamin C not only improves skin appearance but also reduces skin wrinkling, dryness and premature aging (1).
Eye health
Vitamin C may also play an important role in eye health. In particular, vitamin C can help prevent the development of cataracts, slow the progression of age-related macular degeneration and delay age-related loss of visual acuity (9).
Iron absorption
Iron is an essential micronutrient that takes part in multiple vital functions of the body such as maintenance of normal energy level, oxygenation, cognition, gastrointestinal health and regulation of body temperature. Vitamin C boosts the absorption of dietary iron that comes from plant-based foods such as leafy greens (3). That is why adding fruit and vegetables rich in vitamin C or drinking a small glass of orange juice with a meal boosts iron absorption.
Seasonal allergies
Vitamin C acts as a natural antihistamine by reducing the amount of histamine produced by the body in response to an allergen (4). This property may help to alleviate symptoms of seasonal allergies such as sneezing, runny nose, itching and watery eyes. Several studies found that individuals who took vitamin C supplements up to the upper daily limit had a significant reduction in their allergy symptoms. It is important to note that vitamin C should never be used to prevent or treat severe allergic reactions such as anaphylaxis.
What is the recommended daily dose of vitamin C?
When it comes to ascorbic acid dosage, there are several factors to consider. In general, the recommended daily dose of vitamin C for most people is 90mg for adult men and 75mg for adult women. The recommended dose for pregnancy goes up to 85mg, and for lactation it is 120mg a day (3). A diet that includes a healthy amount of fruit and vegetables generally provides sufficient amounts of vitamin C for its essential properties.
Vitamin C rich diet
Foods that have highest levels of vitamin C include citrus fruits and citrus juice, bell peppers, strawberries, tomatoes, kiwi, broccoli, cantaloupe and potatoes. To get the most vitamin C it is best to eat some of these foods raw at their peak ripeness (3). In contrast, exposure to heat and light can destroy ascorbic acid. For example, vitamin C can escape into cooking liquid because it is a water-soluble vitamin so it can be lost if the liquid is not consumed. Therefore, it is best to use as little liquid as possible when cooking foods rich in vitamin C. Quick preparation methods such as stir-frying or blanching can help preserve vitamin C.
Who is at risk of Vitamin C deficiency?
Certain individuals are at higher risk for lower vitamin C levels and can benefit from a higher intake of this vital micronutrient. This usually includes smokers and those regularly exposed to secondhand smoke, drug users, individuals with obesity or excessive alcohol intake as well as persons who are malnourished, have gastrointestinal problems or certain other diseases such as cancer (2). For example, it is recommended that smokers add an extra 35mg of vitamin C daily to their recommended dose because smoking can deplete vitamin C (3).
Vitamin C supplementation
Nutrition experts tend to agree that in order to derive additional benefits of vitamin C, such as reduction in duration and symptom severity of colds, taking a higher daily dose of about 500mg might be optimal (1). This can be achieved by consuming an average of 9 servings of fruit and vegetables daily or taking a vitamin C supplement in addition to eating a healthy diet. For the majority of people, this is easily achieved by taking a multivitamin in addition to healthy eating. Symptoms of seasonal allergies, on the other hand, are more likely to respond better to higher vitamin C doses above 500mg a day (4). Clinicians may recommend a maximum daily vitamin C dose of 2,000mg for their patients with temporary seasonal allergies (4).
As with any supplements or medications, a healthcare provider should be consulted for recommendations on the right dose, and to make sure the addition of any supplement will not have any interactions with medications or supplements they may be taking.
Who should be careful about vitamin C supplements?
People with certain medical conditions may not be able to take vitamin C supplements as they may cause a worsening in their condition. People with hemochromatosis (an inherited condition that causes iron overload), kidney stones, chronic kidney disease, a metabolic condition called G6PD deficiency and certain types of cancer should avoid vitamin C supplements unless recommended by their healthcare provider (10).
References:
1) The Benefits of Vitamin C
2) Vitamin C
3) Vitamin C
4) Vitamin C for Allergies: Effectiveness, Uses, and Precautions
5) Guidance for Evaluating the Nutritional Status and Growth in Refugee Children During the Domestic Medical Screening Examination.
6) Guidance for Evaluating the Nutritional Status and Growth in Refugee Children During the Domestic Medical Screening Examination
7) Effects of Oral Vitamin C Supplementation on Anxiety in Students: A Double-Blind, Randomized, Placebo-Controlled Trial
8) Vitamin C: Stress Buster
9) Diet and Nutrition.
10) Vitamin C (Ascorbic Acid) – Uses, Side Effects, And More
