Vitamin C (ascorbic acid) :Health Benefits, Side effects and Sources

Vitamin C, also called L-ascorbic acid, is a water-soluble vitamin that are naturally found in fresh fruits and vegetables, Good sources include citrus, red and green peppers, tomatoes, broccoli, and greens. Some juices and cereals have added vitamin C and Some animals can make their own vitamin C.
Vitamin C is required for the biosynthesis of collagen, L-carnitine, and certain neurotransmitters; vitamin C is also involved in protein metabolism Vitamin C is also an important physiological antioxidant and has been shown to regenerate other antioxidants within the body, including alpha-tocopherol (vitamin E). Ongoing research is examining whether vitamin C, by limiting the damaging effects of free radicals through its antioxidant activity, might help prevent or delay the development of certain cancers, cardiovascular disease, and other diseases in which oxidative stress plays a causal role. In addition to its biosynthetic and antioxidant functions, vitamin C plays an important role in immune function  and improves the absorption of nonheme iron, the form of iron present in plant-based foods. Insufficient vitamin C intake causes scurvy, which is characterized by fatigue or lassitude, widespread connective tissue weakness, and capillary fragility.

Oral vitamin C produces tissue and plasma concentrations that the body tightly controls. Approximately 70%–90% of vitamin C is absorbed at moderate intakes of 30–180 mg/day. However, at doses above 1 g/day, absorption falls to less than 50% and absorbed, unmetabolized ascorbic acid is excreted in the urine.

Health Benefits of Vitamin C

Vitamin C’s immuno-protective, anti-inflammatory, antiviral, and antibacterial roles are well-known. It works as the co-factor for a number of enzymes (including collagen synthesis) and as a water-soluble antioxidant. Researchers prize vitamin C because it benefits numerous conditions including cancer and neurodegenerative diseases.

These are several of the reasons you want an optimal dose of vitamin C. Vitamin C plays multiple roles to support and maintain health. Vitamin C is important for:

• keeping your skin, bones and connective tissue healthy
• helping wounds heal
• helping prevent infections
• helping you absorb iron from your food.

Side effects of over dose of vitamin c 

 The daily recommended dietary allowances (RDAs) are: 90 mg for men and 75 mg for women; Pregnancy and Lactation: age 18 or younger, 115 mg; ages 19 to 50 years 120 mg. People who use tobacco should take an additional 35 mg per day. Do not take more than the following amounts of vitamin C: 1800 mg per day for adolescents and pregnant and breast-feeding women 14 to 18 years, and 2000 mg per day for adults and pregnant and lactating women.
When taken at appropriate doses, oral vitamin C supplements are generally considered safe. Side effects tend to be dose-related. Oral vitamin C supplements can cause:

• Nausea
• Vomiting
• Heartburn
• Inflammation that might damage the esophagus (esophagitis)
• A blockage that keeps food or liquid from passing through your small intestine or large intestine (intestinal obstruction)
• Stomach cramps
• Fatigue
• Headache
• Sleepiness
• Diarrhea
• Insomnia
• Skin flushing

In some people, oral use of vitamin C can cause kidney stones. Long-term use of oral vitamin C supplements over 2,000 milligrams a day increases the risk of significant side effects.

Tell your doctor that you're taking vitamin C supplements before having any medical tests. High levels of vitamin C might interfere with the results of certain tests, such as stool tests for occult blood or glucose screening tests.

Vitamin C from Supplements

Should you need to consume higher doses of Vitamin C, one way to determine your optimal dose is through titration, where you gradually increase vitamin C intake to bowel tolerance. Specific amounts will vary among individuals, but you might start with one to two grams of vitamin C and gradually increase to tolerance. Again, discuss this and other options with your healthcare professional.

Vitamin C supplements typically come in capsules and powders of varying quality. The vitamin C you get in your food is very similar to what you get in a supplement, although better supplements combine vitamin C with other nutrients to mimic the nutrient profile you consume in food.

Among them include bioflavonoids (alternately called flavonoids), the over 6,000 plant chemicals that give fruits and vegetables their unique color. Bioflavonoids work synergistically to support the absorption of vitamin C while providing additional nutrient support.

One specific bioflavonoid quercetin, found in apples and other foods, can provide additional anti-inflammatory and antioxidant benefits combined with vitamin C. Better supplements will combine vitamin C with bioflavonoids including quercetin to provide a comprehensive synergistic formula.

Your body tightly regulates vitamin C. Researchers find you absorb about 70 to 90 percent of vitamin C when you take 30–180 mg a day. At higher doses (above one gram a day), absorption falls to less than 50 percent. The rest gets excreted in your urine. That doesn’t mean you shouldn’t use higher doses, especially because vitamin C is inexpensive and performs so many roles.

As a water-soluble nutrient, you can take vitamin C supplements with or without food, although some people may feel stomach upset taking it on an empty stomach.

If you’re not eating a healthy diet and maintaining good lifestyle habits like optimal sleep, stress management, and consistent exercise, vitamin C supplements probably won’t do much. Vitamin C also isn’t a cure-all nutrient; it works as a team with other vitamins and minerals to support immunity and everything else. Research shows, for instance, that vitamin C works better with vitamin D and zinc for the common cold.

Sources of Vitamin C

The best way to meet your vitamin C needs is by incorporating a few foods rich in vitamin C into your diet. So what foods have vitamin C? Here are a few of the top vitamin C superfoods to start stocking up on, according to the USDA national nutrient database, many of which are low in calories but full of nutrients beyond just vitamin C:

Black Currant — 1 cup: 203 milligrams (338 percent DV)

Red Pepper — 1 cup: 190 milligrams (317 percent DV)

Kiwifruit — 1 cup: 164 milligrams (273 percent DV)

Guava — 1 fruit: 126 milligrams (209 percent DV)

Green Bell Pepper — 1 cup: 120 milligrams (200 percent DV)

Orange — 1 large: 98 milligrams (163 percent DV)

Strawberries — 1 cup: 89 milligrams (149 percent DV)

Papaya — 1 cup: 87 milligrams (144 percent DV)

Broccoli — 1 cup, raw: 81 milligrams (135 percent DV)

Kale — 1 cup, raw: 80 milligrams (134 percent DV)

Parsley — 1 cup: 80 milligrams (133 percent DV)

Pineapple — 1 cup: 79 milligrams (131 percent DV)

Brussels Sprouts — 1/2 cup, cooked: 48 milligrams (81 percent DV)

Cauliflower — 1 cup, raw: 46 milligrams (77 percent DV)

Mango — 1 cup: 46 milligrams (76 percent DV)