Best food groups: Vegetables, fruits
Also consider: Grapefruit juice, kohlrabi, papayas, Brussels sprouts
What is vitamin C why is it so important? Human beings need to consume a vitamin C source each and every day because it's neither made nor stored in the body. It is a powerful antioxidant that helps protect against free radical damage that can lead to aging, heart disease, cancer, and the list goes on and on. Vitamin C is also vital to the formation of collagen, a protein found in skin, tendons, cartilage, bones, and teeth. Signs of vitamin C deficiency include bleeding gums and loose teeth, nosebleeds and easy bruising, poor wound healing, and increased susceptibility to infections. A vitamin C deficiency disease called scurvy was commonly seen in sailors who embarked on long ocean voyages until in the mid-eighteenth century it was discovered that citrus fruits could prevent the disease. Today it is rarely seen except in elderly people who are malnourished. The word ascorbic, as in ascorbic acid (the chemical name for vitamin C), means "no scurvy."
Did you know? All mammals, with the exception of some monkeys, guinea pigs, Indian fruit-eating bats, and humans, can make their own vitamin C.
How much is enough?
The DV for vitamin C is 90 mg, based on a 2,000-calorie diet.
The UL is set at 2,000 mg, but even higher levels are known to be well tolerated in healthy individuals. Diarrhea is often the first indication that an excess level has been reached in the body and that its time to back off. Large doses of vitamin C have been associated with higher risk of developing kidney stones, too.
One of the unique benefits of vitamin C is that it can help increase iron absorption from food. That's a bad thing if you have blood disorders that produce too much iron in your system, such as hemochromatosis.
Supplements: Adequate vitamin C levels can be achieved easily through diet. However, if additional vitamin C is needed or you find it difficult to meet your needs through food sources, a supplement may be appropriate for you. Ascorbic acid comes in powder, tablets, capsules, chewables, and liquids. Buffered and time-released forms are also available.
1. Guavas
One cup of guava supplies four times what you need in a day of vitamin C! Guava comes in many shapes, sizes, and flavors. The flesh of the fruit is sweet and fragrant and ranges in color from white, yellow, and pink to red. The strawberry guava is quite popular but not as high in vitamin C as other varieties. Guava is also an excellent source of fiber, folate, lycopene, and vitamin A, and a good source of potassium and vitamin A. Guava also contains a vast amount of plant nutrients, such as essential oils, flavonoids, lectins, phenols, saponins, triterpenes, and tannins.
Studies showed that guava sends messages to cancer cells that their days are numbered by increasing apoptosis (programmed cell death) and preventing the spread of malignant cells.
2. Sweet Red Peppers
Besides providing vitamin C, red peppers are also an excellent source of vitamin A and a good source of folate, lycopene, and other carotenoids. Hot pepper varieties are cherished for their thermogenic (fat-burning) effect in the body. But a Japanese study showed that the sweet red bell pepper had similar thermogenic properties without creating all that heat in the mouth. Sweet red varieties were also shown to block pain receptors in a similar fashion to that of hot red peppers!
3. Kiwis
Kiwis are considered one of the most nutrient-dense fruits on the planet. Besides being an excellent source of vitamin C, they are also rich in fiber and a good source of folate and potassium. In a Chinese study, subjects Kiwi was originally known as the Chinese gooseberry, until Norman Sondag, an American importer, remarked how closely the fruit resembled the New Zealand kiwi bird.
who suffered from the constipation type of irritable bowel syndrome (IBS) ate two kiwis in addition to their regular diet for four weeks. The majority of the group experienced more frequent bowel movements and shorter bowel transit time (less time between eating and having a bowel movement).
4. Orange Juice
To pulp or not to pulp . . . that is the question. Research confirms that orange juice with pulp is healthier than the reduced-pulp or pulp-free versions. In addition to being a terrific source of vitamin C, OJ is also a good source of folate and potassium. Orange juice is rich in the plant nutrient hesperidin, which is mainly found in the pulp and white fleshy underbelly of the skin of the orange. Hesperidin was found to be helpful in lowering blood pressure and improving the health of arteries. Regular consumption of OJ also reduced inflammation and reduced risk factors for developing hardening of the arteries.
5. Hot Peppers
Hot peppers, if measured by the cup like the other vegetables in this book, would have ranked first runner-up! But, seriously, can you eat a cup? They are also a good source of vitamin A. Green chile peppers contain the plant nutrient capsaicin, which has strong antibacterial activity. This may explain why spicy foods have a long tradition in hot climates, where modern refrigeration was not always available to prevent food from spoiling. Capsaicin is also useful in controlling pain. A double-blind study looked at capsaicin's being applied to the surgical site in patients who received total knee replacements. Significantly less opioid medications were needed postsurgery, better ambulation was experienced, and much lower pain scores were reported in the capsaicin treatment group, compared to the placebo group that received standard postoperative care.
6. Broccoli
Broccoli belongs to the cruciferous family of vegetables that include cabbage, cauliflower, kale, collard greens, and Brussels sprouts. Broccoli is an excellent source of vitamin K and also a good source of folate and vitamins A and B6.
Broccoli reigns supreme in its cancer-fighting plant chemicals (glu-cosinolate) content, compared to other cruciferous cousins. However, regular consumption of any kind of cruciferous vegetables may reduce the risk of prostate, breast, lung, and colorectal cancers.
7. Strawberries
Besides being rich in vitamin C, strawberries are also a good source of folate and many plant nutrients, such as anthocyanins, catechins, ellagic acid, and flavonoids. Fisetin, a flavonoid found abundantly in strawberries, may help fight a variety of cancer types, including breast, prostate, cervical, and melanoma, as well as also fighting depression and improving cognitive function. A randomized double-blind study using freeze-dried strawberry powder found that those subjects who consumed the equivalent of four servings of frozen strawberries had the greatest reduction in risk factors associated with obesity, such as stroke, diabetes, and cardiovascular disease.
Source: USDA National Nutrient Database for Standard Reference, Release 24