It was a favorite of Linus Pauling, the Nobel prize-winning scientist who studied it. Vitamin C is an antioxidant vitamin that plays a key role in your body’s immune response. In fact, vitamin C helps to recycle another important antioxidant vitamin, vitamin E. It does this by donating its own electrons to help vitamin E regenerate after it donates its electrons to stabilize cell-damaging free radicals. Getting enough vitamin C is on the radar as cold and flu season approaches. You need your immune system to be ready to fight off those pesky pathogens that become more common as the temperatures drop and people spend more time indoors.
You also need vitamin C for wound healing and tissue repair. Some studies show it helps wounds heal faster. In addition, vitamin C helps build new collagen, the support structure for healthy skin and joints. Since collagen lines the inner aspect of your blood vessels, vitamin C helps preserve blood vessel health. In addition, some studies show that vitamin C lowers blood pressure by relaxing the tension within the blood vessel wall. If you have hypertension or borderline high blood pressure, make sure you’re eating enough vitamin C-rich foods!
Why is it so important to get enough vitamin C through diet? Humans, guinea pigs, bats, and some primates can’t make vitamin C, as other animals can. So, for humans and these other species, diet is the only source. Before mankind knew that vitamin C was necessary for health, sailors often died of scurvy when they went on long voyages and didn’t eat fruits or vegetables. Fortunately, you don’t have to suffer that fate!
How Much Vitamin C Should You Get?
Recommendations are that adult men get 90 milligrams of vitamin C daily and women 75 milligrams. But, some experts believe we need more for optimal health. What’s clear is that certain factors and lifestyle habits increase the body’s requirement for vitamin C. For example, the National Institutes of Health states that smokers need an additional 35 milligrams of vitamin C daily relative to non-smokers. Even people exposed to secondhand smoke need more vitamin C. Certain malabsorption diseases and medical conditions also increase the requirement. Surprisingly, even stress depletes vitamin C, meaning you need to up the quantity in your diet if you’re under mental or physical stress.
Loss of Vitamin C: Why You Might Not Ge Enough Vitamin C
If you eat a whole food diet that includes fruits and vegetables, you should easily meet your body’s requirements for vitamin C. But, if you eat mostly processed food or restrict calories excessively to lose weight, you might experience a shortfall of this antioxidant vitamin. In addition, you may also need more vitamin C as you age to support immune health. We become more susceptible to infection after the age of 50 and vitamin C helps to optimize immune cell function.
How to Get Enough Vitamin C
Fruits and vegetables are the best natural sources of vitamin C. However, vitamin C is easily destroyed by heat. Also, if you cook vegetables in water, you’ll experience additional loss of vitamin C. This means boiling is the worst way to prepare produce to retain its vitamin C content.
In one study, researchers compared the degree of loss of vitamin C with three cooking methods: boiling, steaming and microwaving. Of the three, boiling led to the greatest loss of vitamin C, as high as 54% while steaming produced the least decline in vitamin C content, between 9 and 14%. Microwaving was in the middle with around 25% loss of vitamin C. Choose your cooking methods wisely! Lightly steaming vegetables is best for preserving vitamin C. Steaming is one way to reduce the loss of vitamin C loss when you cook, but why not enjoy your more raw fruits and vegetables? A mixture of both raw and cooked produce is ideal, as cooking enhances the bioavailability of some nutrients, particularly beta-carotene in carrots and lycopene in tomatoes.
Choose Your Sources of Vitamin C Wisely
Unfortunately, the vegetables you buy may already have lost some of their vitamin C by the time they reach your supermarket. A study published in the International Journal of Food Science and Nutrition found that broccoli loses as much as half of its vitamin C content when shipped out of the country as opposed to being sourced locally. Even when you bring produce home, it continues to lose vitamin C simply because its exposed to light. A University of California study found that vegetables lose between 15 and 55% of their vitamin C within a week after harvest.
Frozen vegetables are an acceptable alternative to fresh and maybe even higher in vitamin C content than fresh. That’s because vegetables are frozen right after harvest and freezing locks in nutrients. Don’t thaw frozen vegetables before preparing them. A 2000 study found that thawing led to an additional loss of vitamin C. The amount of vitamin C lost from thawing varies, but, in the study was almost 20% with frozen green beans.
The take-home message? Buying local helps maximize the loss of vitamin C you consume when you eat fresh produce. But, just as importantly, you’ll get more vitamin C from the produce you eat if you prepare and consume it quickly rather than letting it sit around for days as it gradually loses vitamin C. If you can’t use vegetables quickly, buy frozen ones, but don’t let them thaw before preparing them. Include raw fruits and vegetables in your diet as well. Some foods are an exceptionally good source of vitamin C. These include exotic-sounding fruits such as camu camu, acerola cherry, guava, and kiwifruit. Even common foods can be quite high in vitamin C. Red bell peppers have 190 milligrams per serving, almost triple the amount in an orange.
Why a Supplement Isn’t the Best Approach
Vitamin C supplements are readily available, but unless you have a documented deficiency, it’s best to get vitamin C through diet. It’s not uncommon for people who take vitamin C supplements to experience digestive upset such as nausea, vomiting, or diarrhea. In addition, high doses of vitamin C increase the risk of kidney stones in some people. So, get your vitamin C naturally and you’ll benefit from the components of vitamin-C rich foods, including fiber and other vitamins and minerals, and you’ll get the delicious taste as well!
National Institutes of Health. “Vitamin C”
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Am J Clin Nutr. 2012 May;95(5):1079-88. doi: 10.3945/ajcn.111.027995.
WebMD. “Supplement Speeds Wound Healing”
EmeraldInsight.com. ‘Effects of different cooking methods on the vitamin C content of selected vegetables”
Int J Food Sci Nutr. 2008 Feb;59(1):34-45.
Chicago Tribune. “Most produce loses 30 percent of nutrients three days after harvest”
Nahrung. 2000 Dec;44(6):451-3.
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